Two expeditions to Dorado Outcrop on the eastern flank of the East Pacific Rise and west of the Middle America Trench collected images, video, rocks and sediment samples and measured temperature and fluid discharge rates to document the physical and biogeochemical characteristics of a regional, low‐temperature (~15°C) hydrothermal system. Analysis of video and images identified lava morphologies: pillow, lobate, and sheet flows. Glasses from collected lavas were consistent with an off‐axis formation. Hydrothermal discharge generally occurs through pillow lavas, but is patchy, sporadic, and sometimes ceases at particular sites of discharge. Year‐long temperature measurements at five of these discharge sites show daily ranges that oscillate with tidal frequencies by 6°C or more. Instantaneous fluid discharge rates (0.16 to 0.19 L s‐1) were determined resulting in a calculated discharge of ~200 L s‐1 when integrated over the area defined by the most robust fluid discharge. Such discharge has a power output of 10‐12 MW. Hydrothermal seepage through thin sediment adjacent to the outcrop accounts for <3% of this discharge, but seepage may support an oxic sediment column. High extractable Mn concentrations and depleted δ13C in the low but variable organic solid phase suggest hydrothermal fluids provide a source for manganese accumulation and likely enhance the oxidation of organic carbon. Comparisons of the physical and geochemical characteristics at Dorado and Baby Bare Outcrops, the latter being the only other site of ridge‐flank hydrothermal discharge that has been sampled directly, suggest commonalities and differences that have implications for future discoveries.
The CarbonSAFE Cascadia project team is conducting a pre-feasibility study to evaluate technical and nontechnical aspects of collecting and storing 50 MMT of CO2 in a safe, ocean basalt reservoir offshore from Washington State and British Columbia. Sub-seafloor basalts are very common on Earth and enable CO2 mineralization as a long-term storage mechanism, permanently sequestering the carbon in solid rock form. Our project goals include the evaluation of this reservoir as an industrial-scale CO2 storage complex, developing potential source/transport scenarios, conducting laboratory and modeling studies to determine the potential capacity of the reservoir, and completing an assessment of economic, regulatory and project management risks. Potential scenarios include sources and transport options in the USA and in Canada. The overall project network consists of a coordination team of researchers from collaborating academic institutions, subcontractors, and external participants. Lessons learned from this study at the Cascadia Basin location may be transferrable elsewhere around the globe.
We present results from three-dimensional, transient, fully coupled simulations of fluid and heat transport on a ridge flank in fast-spread ocean crust. The simulations quantify relationships between rates of fluid flow, the extent of advective heat extraction, the geometry of crustal aquifers and outcrops, and crustal hydrologic parameters, with the goal of simulating conditions similar to those seen on 18–24 M.y. old seafloor of the Cocos plate, offshore Costa Rica. Extensive surveys of this region documented a ∼14,500 km2 area of the seafloor with heat flux values that are 10–35% of those predicted from conductive cooling models, and identified basement outcrops that serve as pathways for hydrothermal circulation via recharge of bottom water and discharge of cool hydrothermal fluid. Simulations suggest that in order for rapid hydrothermal circulation to achieve observed seafloor heat flux values, upper crustal permeability is likely to be ~10-10 to 10-9m2, with more simulations matching observations at the upper end of this range. These permeabilities are at the upper end of values measured in boreholes elsewhere in the volcanic ocean crust, and higher than inferred from three-dimensional modeling of another ridge-flank field site where there is less fluid flow and lower advective power output. The simulations also show that, in a region with high crustal permeability and variable sized outcrops, hydrothermal outcrop-to-outcrop circulation is likely to constitute a small fraction of total fluid circulation, with most of fluid flow occurring locally through individual outcrops that both recharge and discharge hydrothermal fluid.
Marine dissolved organic carbon (DOC) is one of the largest active reservoirs of reduced carbon on Earth. In the deep ocean, DOC has been described as biologically recalcitrant and has a radiocarbon age of 4,000 to 6,000 years, which far exceeds the timescale of ocean overturning. However, abiotic removal mechanisms cannot account for the full magnitude of deep-ocean DOC loss. Deep-ocean water circulates at low temperatures through volcanic crust on ridge flanks, but little is known about the associated biogeochemical processes and carbon cycling. Here we present analyses of DOC in fluids from two borehole observatories installed in crustal rocks west of the Mid-Atlantic Ridge, and show that deep-ocean DOC is removed from these cool circulating fluids. The removal mechanism is isotopically selective and causes a shift in specific features of molecular composition, consistent with microbe-mediated oxidation. We suggest organic molecules with an average radiocarbon age of 3,200 years are bioavailable to crustal microbes, and that this removal mechanism may account for at least 5% of the global loss of DOC in the deep ocean. Cool crustal circulation probably contributes to maintaining the deep ocean as a reservoir of ‘aged’ and refractory DOC by discharging the surviving organic carbon constituents that are molecularly degraded and depleted in 14C and 13C into the deep ocean.
Geothermal heat flux (GHF) is an important part of the basal heat budget of continental ice sheets. The difficulty of measuring GHF below ice sheets has directly hindered progress in understanding of ice sheet dynamics. We present a new GHF measurement from below the West Antarctic Ice Sheet, made in subglacial sediment near the grounding zone of the Whillans Ice Stream. The measured GHF is 88 ± 7 mW m-2, a relatively high value compared to other continental settings and to other GHF measurements along the eastern Ross Sea of 55 mW m-2 and 69 ± 21 mW m-2, but within the range of regional values indicated by geophysical estimates. The new GHF measurement was made ~100 km from the only other direct GHF measurement below the ice sheet, which was considerably higher at 285 ± 80 mW m-2, suggesting spatial variability that could be explained by shallow magmatic intrusions or the advection of heat by crustal fluids. Analytical calculations suggest that spatial variability in GHF exceeds spatial variability in the conductive heat flux through ice along the Siple Coast. Accurate GHF measurements and high-resolution GHF models may be necessary to reliably predict ice sheet evolution, including responses to ongoing and future climate change.
Hydrothermal circulation within oceanic basement can have a profound influence on temperatures in the upper crust, including those close to the subduction thrust and in the overlying plate. Heat flow evidence for hydrothermal circulation in the volcanic basement of incoming plates includes: (1) values that are well below conductive predictions due to the advection of heat into the ocean, and (2) variability about conductive predictions that cannot be explained by variations in seafloor relief or thermal conductivity. In this review we summarize evidence for hydrothermal circulation in subducting oceanic basement from the Nankai, Costa Rica, south-central Chile, Haida Gwaii, and Cascadia margins and explore its influence on plate boundary temperatures. Models of these systems using a high Nusselt number proxy for hydrothermal circulation are used to illustrate the influence of this process on seafloor observations and thermal conditions at depth. We show that at these subduction zones, patterns of seafloor heat flow are best explained by thermal models that include the influence of hydrothermal circulation.
We present geochemical data from the first samples of spring fluids from Dorado Outcrop, a basaltic edifice on 23 M.y. old seafloor of the Cocos Plate, eastern Pacific Ocean. These samples were collected from the discharge of a cool hydrothermal system (CHS) on a ridge flank, where typical reaction temperatures in the volcanic crust are low (2–20 °C) and fluid residence times are short. Ridge-flank hydrothermal systems extract 25% of Earth’s lithospheric heat, with a global discharge rate equivalent to that of Earth’s river discharge to the ocean; CHSs comprise a significant fraction of this global flow. Upper crustal temperatures around Dorado Outcrop are ∼15 °C, the calculated residence time is <3 y, and the composition of discharging fluids is only slightly altered from bottom seawater. Many of the major ions concentrations in spring fluids are indistinguishable from those of bottom seawater; however, concentrations of Rb, Mo, V, U, Mg, phosphate, Si and Li are different. Applying these observed differences to calculated global CHS fluxes results in chemical fluxes for these ions that are ≥15% of riverine fluxes. Fluxes of K and B also may be significant, but better analytical resolution is required to confirm this result. Spring fluids also have ∼50% less dissolved oxygen (DO) than bottom seawater. Calculations of an analytical model suggest that the loss of DO occurs primarily (>80%) within the upper basaltic crust by biotic and/or abiotic consumption. This calculation demonstrates that permeable pathways within the upper crust can support oxic water–rock interactions for millions of years.
| URL | https://www.bco-dmo.org/dataset/671260 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/671260/data/download |
| Media Type | text/tab-separated-values |
| Created | December 27, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Pore fluid chemistry from gravity cores |
Gravity core sampling took place at Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise page which contains a link to the cruise report (AT26-24).
Phosphate, N+N, silicate, and NH4, were all run at Oregon State University using standard colorimetric techniques. Dissolved inorganic carbon (DIC) was run at Oregon State University using coulometry. Remaining elements were analyzed using Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES). Comparison of Si measured via the two techniques shows an offset with the colorimetric results being ~7 uM higher than the ICP-OES results.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* BD indicates Below Detection
* blank values replaced with no data value 'nd'
* added ,dive_date, dive_lat, dive_lon from information in the cruise report (Table 4)
Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.
Depth below sea floor of sample
depth below seafloor. Includes mbsf (meters below seafloor) and cmbsf (centimeters below seafloor).
Gravity core identifier
core number/identification, to be used with ice, rock and sediment cores
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Alvin submersible dive latitude; north is positive
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Alvin submersible dive longitude; east is positive
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Orthophosphate (phosphate, reactive phosphorus), Various units.
Nitrate and Nitrite, µM (micromolar) or µg-at NO3-N and NO2-N/l
Silicate (Orthosilicic Acid), Si(OH)4, uM (micromolar) or ug-at Si(OH)4-Si/l (colloquially known as 'silicate') [Note: this parameter name was redefined to remove the parentheses.)
Ammonium and ammonia concentration parameters in any body of fresh or salt water.
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Delta 13C (d13C) is the ratio of stable isotopes 13C:12C, reported in parts per thousand (per mil, 0/00).
Ba (Barium). May be reported in parts per million, nanomoles per Liter, or other units. Refer to dataset metadata for units.
B (Boron) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mn (Manganese) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Si (Silicon) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Sr (Strontium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Na (Sodium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Ca (Calcium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
K (potassium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/671242 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/671242/data/download |
| Media Type | text/tab-separated-values |
| Created | December 27, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Pore fluid chemistry from push cores |
Push core sampling took place at Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise page which contains a link to the cruise report (AT26-24).
Phosphate, N+N, silicate, and NH4, were all run at Oregon State University using standard colorimetric techniques. Dissolved inorganic carbon (DIC) was run at Oregon State University using coulometry. Remaining elements were analyzed using Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES). Comparison of Si measured via the two techniques shows an offset with the colorimetric results being ~7 uM higher than the ICP-OES results.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* BD indicates Below Detection
* blank values replaced with no data value 'nd'
* added ,dive_date, dive_lat, dive_lon from information in the cruise report (Table 4)
Capable of being performed in numerous environments, push coring is just as it sounds. Push coring is simply pushing the core barrel (often an aluminum or polycarbonate tube) into the sediment by hand. A push core is useful in that it causes very little disturbance to the more delicate upper layers of a sub-aqueous sediment.
Description obtained from: http://web.whoi.edu/coastal-group/about/how-we-work/field-methods/coring/
Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.
depth below seafloor. Includes mbsf (meters below seafloor) and cmbsf (centimeters below seafloor).
Gravity core identifier
core number/identification, to be used with ice, rock and sediment cores
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Alvin submersible dive latitude; north is positive
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Alvin submersible dive longitude; east is positive
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Orthophosphate (phosphate, reactive phosphorus), Various units.
Nitrate and Nitrite, µM (micromolar) or µg-at NO3-N and NO2-N/l
Silicate (Orthosilicic Acid), Si(OH)4, uM (micromolar) or ug-at Si(OH)4-Si/l (colloquially known as 'silicate') [Note: this parameter name was redefined to remove the parentheses.)
Ammonium and ammonia concentration parameters in any body of fresh or salt water.
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Ba (Barium). May be reported in parts per million, nanomoles per Liter, or other units. Refer to dataset metadata for units.
B (Boron) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mn (Manganese) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Si (Silicon) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Sr (Strontium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Na (Sodium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Ca (Calcium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
K (potassium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/671225 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/671225/data/download |
| Media Type | text/tab-separated-values |
| Created | December 27, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Solid phase chemistry from push cores |
Push core sampling took place at Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise page which contains a link to the cruise report (AT26-24).
Total inorganic carbon (TIC) was measured using coulometry and CaCO3 is calculated from this value. Organic carbon (OC) and nitrogen (N) were measured on a Perkin Elmer Series II 2400 CHNS/O analyzer. The Fe, Cr, Cu, Mn, and Zn represent results from dithionite extractions (see Roy et al., 2012, Continental Shelf Research, 54, 67-79). Metals were analyzed by Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES) at the University of Akron. d13C was measured on a Carlo Erba NA-1500 elemental analyzer connected to a DeltaPlus XL mass spectrometer at Oregon State University.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* BD indicates Below Detection
* blank values replaced with no data value 'nd'
* added dive_date,dive_id,dive_lat,dive_lon from information in the cruise report (Table 4)
Capable of being performed in numerous environments, push coring is just as it sounds. Push coring is simply pushing the core barrel (often an aluminum or polycarbonate tube) into the sediment by hand. A push core is useful in that it causes very little disturbance to the more delicate upper layers of a sub-aqueous sediment.
Description obtained from: http://web.whoi.edu/coastal-group/about/how-we-work/field-methods/coring/
Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.
Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.
Carlo Erba NA-1500 elemental analyzer connected to a DeltaPlus XL mass spectrometer.
Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.
core number/identification, to be used with ice, rock and sediment cores
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Approximate latitude of Alvin Dive.
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Approximate longitude of Alvin dive.
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Calcium Carbonate, in sediments as percent; or CaCO3 from water samples reported in various units; CAUTION measured in sediment and water column samples
Calcium Carbonate, in sediments as percent; or CaCO3 from water samples reported in various units; CAUTION measured in sediment and water column samples
Dissolved Inorganic Carbon
Dissolved Inorganic Carbon
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Delta 13C (d13C) is the ratio of stable isotopes 13C:12C, reported in parts per thousand (per mil, 0/00).
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/671199 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/671199/data/download |
| Media Type | text/tab-separated-values |
| Created | December 27, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Solid phase chemistry from gravity cores |
Gravity core sampling took place at Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise page which contains a link to the cruise report (AT26-24).
Total inorganic carbon (TIC) was measured using coulometry and CaCO3 is calculated from this value. Organic carbon (OC) and nitrogen (N) were measured on a Perkin Elmer Series II 2400 CHNS/O analyzer. The Fe, Cr, Cu, Mn, and Zn represent results from dithionite extractions (see Roy et al., 2012, Continental Shelf Research, 54, 67-79). Metals were analyzed by Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES) at the University of Akron. d13C was measured on a Carlo Erba NA-1500 elemental analyzer connected to a DeltaPlus XL mass spectrometer at Oregon State University.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* BD indicates Below Detection
* blank values replaced with no data value 'nd'
* added dive_id,dive_date,dive_lat, and dive_lon from information in the cruise report (Table 4)
Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.
Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.
Carlo Erba NA-1500 elemental analyzer connected to a DeltaPlus XL mass spectrometer.
Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.
Gravity core identifier
core number/identification, to be used with ice, rock and sediment cores
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Alvin submersible dive latitude; north is positive
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Alvin submersible dive longitude; east is positive
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Calcium Carbonate, in sediments as percent; or CaCO3 from water samples reported in various units; CAUTION measured in sediment and water column samples
Calcium Carbonate, in sediments as percent; or CaCO3 from water samples reported in various units; CAUTION measured in sediment and water column samples
Dissolved Inorganic Carbon
Dissolved Inorganic Carbon
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Delta 13C (d13C) is the ratio of stable isotopes 13C:12C, reported in parts per thousand (per mil, 0/00).
Delta 13C (d13C) is the ratio of stable isotopes 13C:12C, reported in parts per thousand (per mil, 0/00).
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/664454 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/664454/data/download |
| Media Type | text/tab-separated-values |
| Created | November 10, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Chemistry from discrete samples of hydrothermal springs |
Syringe samples of hydrothermal water were collected during Alvin dives.
The Alvin dives were conducted off the west coast of Costa Rica in the Pacific Ocean at Dorado Outcrop during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise pages which contain links to cruise reports (AT26-24)
Chemical Measurements:
All fluids were measured using established standard protocols. At sea, alkalinity was determined potentiometrically via titration with 0.1N hydrochloric acid; a pH measurement is conducted as part of this procedure. An Inductively Coupled Plasma Optical Emission Spectrophotometer (ICPOES) was used to measure Na, K, Sr, Li, Mg, Ca, and S with a 1:200 dilution and Sr, Li, Fe, Mn, and B with a 1:25 dilution in 1% nitric acid. An inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze Rb, Cs, Ba, Mo, V and U with a 1:75 dilution in 3% nitric acid. Nutrients (silicate, phosphate, total nitrogen and nitrate) were measured at Oregon State University using standard colorimetric, automated, segmented flow procedures. Chlorinity was determined potentiometrically via titration with silver nitrate. Carbon analyses were conducted at Oregon State University
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* added lat, lon, and date of Alvin dives as listed in the Alvin Dive Log
A device that collects an in-situ discrete water sample from any depth and returns it to the surface without contamination by the waters through which it passes, such as a water bottle.
Also referred to as an Inductively coupled plasma atomic emission spectroscope (ICP-AES). These instruments pass nebulised samples into an inductively-coupled gas plasma (8-10000 K) where they are atomised and excited. The de-excitation optical emissions at characteristic wavelengths are spectroscopically analysed. It is often used in the detection of trace metals.
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Alvin submersible dive latitude; north is positive
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Alvin submersible dive longitude; east is positive
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Sample identifier
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Dissolved Inorganic Carbon
Dissolved Inorganic Carbon
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Mo (Molybdenum) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
V (Vanadium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
A measure of chloride content (Cl).
Rb (rubidium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Cs (Cesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
U (Uranium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Nitrate and Nitrite, µM (micromolar) or µg-at NO3-N and NO2-N/l
Silicate (Orthosilicic Acid), Si(OH)4, uM (micromolar) or ug-at Si(OH)4-Si/l (colloquially known as 'silicate') [Note: this parameter name was redefined to remove the parentheses.)
Sr (Strontium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Li (Lithium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Na (Sodium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Ca (Calcium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
K (potassium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
B (Boron) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mn (Manganese) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/664422 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/664422/data/download |
| Media Type | text/tab-separated-values |
| Created | November 10, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | DO of pore water from sediment gravity and push cores |
Sampling took place at Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean during the R/V Atlantis cruises AT26-09 and AT26-24. For more information about operations of this cruise see the cruise pages which contain links to cruise reports ( AT26-09, AT26-24).
Dissolved oxygen (DO) was measured at-sea in pore waters from sediment gravity cores and cores collected by the submersible ALVIN with a needle-type oxygen optode inserted radially into sediment cores, following published protocols (e.g., Orcutt et al., 2013).
Reference:
Orcutt, B. N., Wheat, C. G., Rouxel, O., Hulme, S., Edwards, K. J., Bach, W., 2013. Oxygen Consumption rates in subseafloor basaltic crust derived from a reaction transport model, Nature Comm., published 27 Sep 2013, pg. 1-8, doi:10.1038/ncomms3539.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values replaced with no data value 'nd'
* added approximate lat/lon values for Dorado Outcrop sample site
Capable of being performed in numerous environments, push coring is just as it sounds. Push coring is simply pushing the core barrel (often an aluminum or polycarbonate tube) into the sediment by hand. A push core is useful in that it causes very little disturbance to the more delicate upper layers of a sub-aqueous sediment.
Description obtained from: http://web.whoi.edu/coastal-group/about/how-we-work/field-methods/coring/
Approximate latitude of Dorado Outcrop
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Approximate longitude of Dorado Outcrop
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Core identifier
core number/identification, to be used with ice, rock and sediment cores
Depth in core sample
Dissolved oxygen
Oxygen; dissolved; reported in units of micromoles/liter
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/664335 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/664335/data/download |
| Media Type | text/tab-separated-values |
| Created | November 10, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Discrete temperature and DO measured with Alvin |
Temperature measurements were made with the thermal couple on board the HOV Alvin. The dissolved oxygen concentrations were measured with an Aanderra optode.
The Alvin dives were conducted off the west coast of Costa Rica in the Pacific Ocean at Dorado Outcrop during the R/V Atlantis cruise AT26-24. For more information about operations of this cruise see the cruise pages which contain links to cruise reports (AT26-24)
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* added lat/lon of Alvin dives as listed in the Alvin Dive Log
Discrete measurements of temperature were made with the thermal couple on board the HOV Alvin.
Records temperature data over a period of time.
Dive identifier for Alvin dive
Date (UTC) in format yyyy-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Latitude of Alvin dive where measurement was taken
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Longitude of Alvin dive where measurement was taken; west is negative.
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Temperature
Dissolved oxygen
Oxygen; dissolved; reported in units of micromoles/liter
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/662060 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/662060/data/download |
| Media Type | text/tab-separated-values |
| Created | October 20, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | DO and temperature from soloDO logger measured with Alvin |
In situ sensor data was collected by Alvin with the soloDO logger (RBR Ltd., Canada). The prototype recorded temperature using an internal RBR probe (0.0018 C resolution), and dissolved oxygen using an Aandera DO probe.
The R/V Atlantis cruise AT26-24 went to Dorado Outcrop off the west coast of Costa Rica in the Pacific Ocean at location 9 degrees 5.5 minutes north, 87 degrees 6.0 minutes west. For more information about operations of this cruise see the AT26-24 deployment page and cruise report.
The data have not been processed further.
BCO-DMO Processing Notes:
Prototype of the soloDO logger (RBR Ltd., Canada) also measured temperature.
Records temperature data over a period of time.
Prototype of the soloDO logger (RBR Ltd., Canada).
Instrument deployment name includes the order (first or second) of deployment and location; R indicates Marker R and KW indicates the deployment was between markers K and W.
deployment number; often associated with sediment trap deployments
Date/Time (UTC) ISO formatted
This standard is based on ISO 8601:2004(E) and takes on any of the following forms:
2009-08-30T09:05:00[.xx] (local time)
2009-08-30T14:05:00[.xx]Z (UTC time)
2009-08-30T14:05:00[.xx]-05:00
The dashes and the colons can be dropped.
The T can also be dropped "by mutual agreement", but one needs the trailing Z if the time is UTC.
Sample ISO_datetime_utc:
2009-08-30T14:05:00[.xx]Z (UTC time)
Temperature
Oxygen; dissolved; reported in units of micromoles/liter
Approximate latitude of sampling area (Dorado Outcrop)
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Approximate longitude of sampling area (Dorado Outcrop); west is negative
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Date (UTC) in format yyyy-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Time (UTC) in format HHMM
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/661921 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/661921/data/download |
| Media Type | text/tab-separated-values |
| Created | October 19, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Continuous temperature at marker K |
This temperature record was collected by a HOBO temperature logger deployed in conjunction with the green OsmoSampler that was deployed at Marker K. To access data from the OsmoSamplers see the OsmoSampler fluid chemistry dataset page. The temperature logger deployments were made off the west coast of Costa Rica in the Pacific Ocean at Dorado Outcrop during the R/V Atlantis cruise AT26-09 and recovered during the cruise AT26-24. For more information about operations of this cruise see the cruise pages which contain links to cruise reports (AT26-24, AT26-09)
The temperature logger was started before the deployment and was turned off upon recovery on the ship. Increased temperatures relating to deployment and retrieval can be seen in the data.
The data have not been processed further.
BCO-DMO Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values replaced with no data value 'nd'
* added approximate lat/lon values for Dorado Outcrop sample site
* ISO Date format generated from Date and Time values
Onset Computer Corporation HOBO model U12-015 modified with a titanium pressure case and long-life battery for use in the deep sea. The Onset tools have a working range of –40–100C but a lower resolution (0.02–0.1C across their working range)
Records temperature data over a period of time.
Date/time (UTC) in ISO format YYYY-mm-ddTHH:MM:SS[.xx]
Date/Time (UTC) ISO formatted
This standard is based on ISO 8601:2004(E) and takes on any of the following forms:
2009-08-30T09:05:00[.xx] (local time)
2009-08-30T14:05:00[.xx]Z (UTC time)
2009-08-30T14:05:00[.xx]-05:00
The dashes and the colons can be dropped.
The T can also be dropped "by mutual agreement", but one needs the trailing Z if the time is UTC.
Sample ISO_datetime_utc:
2009-08-30T14:05:00[.xx]Z (UTC time)
Approximate latitude of sampling area (Dorado Outcrop)
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
Approximate longitude of sampling area (Dorado Outcrop); west is negative
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
Date (UTC) in format yyyy-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| URL | https://www.bco-dmo.org/dataset/661481 |
|---|---|
| Download URL | https://www.bco-dmo.org/dataset/661481/data/download |
| Media Type | text/tab-separated-values |
| Created | October 12, 2016 |
| Modified | July 3, 2017 |
| State | Final no updates expected |
| Brief Description | Spring and pore fluid chemistry from samples taken by OsmoSamplers |
Continuous fluid samplers (OsmoSamplers) included a 12-membrane pump and one coil of Teflon tubing that was 300-m-long and small bore (1.1 mm ID). The tubing was initially filled with 18 MΩ distilled water. Upon retrieval, the Teflon coil was cut in 1.1 m lengths and the fluid was expelled into hot acid cleaned plastic microcentrifuge tubes. For more information about OsmoSamplers see the instruments page.
The R/V Atlantis cruise AT26-09 (2013 Jason/Sentry Expedition) deployed the OsmoSamplers. They were deployed for almost a full year. The R/V Atlantis cruise AT26-24 recovered the OsmoSamplers. Dorado Outcrop is off the west coast of Costa Rica in the Pacific Ocean at location 9 degrees 5.5 minutes north, 87 degrees 6.0 minutes west. For more information about operations of this cruise see the expedition reports and cruise information (AT26-24, AT26-09).
Other than converting signal counts, voltages, etc. to concentrations, the data have not been processed further.
BCO-DMO Processing Notes:
* added conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* added fields for OsmoSampler_name, date_deployed, date_recovered, location (e.g. Marker_K) from information in comments of original files submitted.
* Date format converted to ISO Date format
OsmoSamplers are long-term osmotically pumped fluid samplers. For more information see the following reference:
Jannasch Hans W. , Wheat C. Geoff , Plant Josh N. , Kastner Miriam , Stakes Debra S. , (2004),Continuous chemical monitoring with osmotically pumped water samplers: OsmoSampler design and applications, Limnol. Oceanogr. Methods, 2, doi:10.4319/lom.2004.2.102.
A pump that uses osmotic pressure to collect water samples.
An example of an osmotic pump is an OsmoSampler (Jannasch et al., 2004) which has no electrical or mechanical parts.
References:
Jannasch Hans W. , Wheat C. Geoff , Plant Josh N. , Kastner Miriam , Stakes Debra S. , (2004),Continuous chemical monitoring with osmotically pumped water samplers: OsmoSampler design and applications, Limnol. Oceanogr. Methods, 2, doi:10.4319/lom.2004.2.102.
Name of the OsmoSampler Instrument
Date of OsmoSampler deployment in ISO format YYYY-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Date of OsmoSampler recovery in ISO format YYYY-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Sample number
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Date of chemical analysis in ISO format YYYY-mm-dd
date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)
Standard deviation of dissolved inorganic carbon
Stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC).
Standard deviation of the stable carbon isotope ratio of dissolved inorganic carbon (13C/12C ratio in DIC)
V (Vanadium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Rb (rubidium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mo (Molybdenum) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Cs (Cesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Ba (Barium). May be reported in parts per million, nanomoles per Liter, or other units. Refer to dataset metadata for units.
U (Uranium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Silicon concentration
Si (Silicon) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Sr (Strontium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Li (Lithium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Concentration of a trace element in seawater. Does not include trace metals and metaloids. Refer to dataset for element name and units.
Na (Sodium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Ca (Calcium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Mg (magnesium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
K (potassium) concentration. May be reported in parts per million, nanomoles/Liter, or other units. Refer to dataset metadata for units.
Approximate latitude of sampling area Dorado Outcrop
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
| Name | Affiliation | Contact |
|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| James McManus | University of Akron (UAkron) | |
| Beth N. Orcutt | Bigelow Laboratory for Ocean Sciences | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | |
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF) | ✓ |
| Amber York | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
| Project Title | Collaborative Research: Completing single- and cross-hole hydrgeologic and microbial experiments: Juan de Fuca Flank |
|---|---|
| Acronym | JdF Flank |
| URL | https://www.bco-dmo.org/project/625989 |
| Created | October 29, 2015 |
| Modified | December 21, 2018 |
NSF Award Abstract:
In 2010, IODP exp. 327 launched series of experiments based on instrumentation placed in 6 boreholes (Holes 1026B, 1027C, 1301A, 1301B, 1362A, and 1362B) on and near the Juan de Fuca Ridge (JDFR). The experiments were designed to examine hydrological and biological processes in basaltic ocean crust. Major issues to be addressed include overall permeability, the magnitudes, velocity and directions of fluid, solute,and heat transport,constraints on the fluid storage properties of crust, determining how fluid reservoirs respond to seismic perturbations, and investigating the variability, diversity, and metabolism of resident microbial populations. This project will recover sensors and samplers in the instrumented boreholes(CORKs),access data and samples, collect biological incubators placed at depth within the boreholes, and seal the CORKs. All of these activities are needed for the completion of the JDFR experiments
Once the data and samples are retrieved, the PI's will develop new numerical models for the hydrology (permeability, thickness and extent of permeable zones, connectivity, direction of flow, and anisotropy) of ocean crust based on the results of flow tests. T sensors will enable thermal structure to be determined in conjunction with flow parameters. DNA will be analyzed via 16S ribosomal RNA (rRNA) genes as well as select full-length Sanger-style sequencing and gene fingerprinting techniques. The PI's will look at diversity, shared species, emergence and disappearance of groups. Metagenomic work will be done on some samples.
Broader Impacts include training of 4 shipboard educators, with an emphasis on recruiting underrepresented groups for these positions, teacher workshops, and special training for undergraduate and graduate students and post-docs. Research team includes grads, undergrads, and post-docs
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Lead Principal Investigator | ✓ |
| Katrina J. Edwards | University of Southern California (USC) | Principal Investigator | |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Jordan F. Clark | University of California-Santa Barbara (UCSB) | Principal Investigator | |
| Keir Becker | University of Miami Rosenstiel School of Marine and Atmospheric Science (UM-RSMAS) | Principal Investigator | |
| Michael S. Rappé | University of Hawaii at Manoa (HIMB) | Co-Principal Investigator |
| Project Title | Discovery, sampling, and quantification of flows from cool yet massive ridge-flank hydrothermal springs on Dorado Outcrop, eastern Pacific Ocean |
|---|---|
| Acronym | Dorado Outcrop |
| URL | https://www.bco-dmo.org/project/627844 |
| Created | November 30, 2015 |
| Modified | December 1, 2015 |
Description from NSF award abstract:
Pristine fluids from a typical ridge-flank hydrothermal system have never been sampled, mainly because it has not been possible to locate a site of focused discharge where representative samples could be collected. The PIs have located a small basement feature, Dorado outcrop, on 23 m.y.-old seafloor on the eastern flank of the East Pacific Rise that they plan to sample to determine the fluid composition, and to assess the rate of discharge from the outcrop, so that they can quantify the chemical impact of this hydrothermal system. They plan an 18-day expedition that combines the surveying capabilities of the AUV Sentry (bathymetric, sub-bottom sonar, photo mosaics, water column anomalies) and an ocean-class vessel capable of collecting high-quality multi-beam data and CTD samples, and supporting the survey and sampling capabilities of the ROV Jason II for collection of spring and plume fluids, heat flow data, sediment push cores, and still and video photography. These data and samples will be combined hopefully to generate the first well-constrained estimates of hydrothermal flows from Dorado outcrop. This expedition will result in the collection of samples and data from a "fire hose" of ridge-flank, hydrothermal system, challenging the commonly held view that discharge from ridge flank hydrothermal systems occurs primarily from diffuse seeps.
| Name | Affiliation | Role | Contact |
|---|---|---|---|
| Charles Geoffrey Wheat | University of Alaska Fairbanks (UAF-IMS) | Principal Investigator | ✓ |
| Andrew T. Fisher | University of California-Santa Cruz (UC Santa Cruz) | Principal Investigator | |
| Samuel M. Hulme | Moss Landing Marine Laboratories (MLML) | Principal Investigator |
Numerous field, laboratory, and modeling studies have explored the flows of fluid, heat, and solutes during seafloor hydrothermal circulation, but it has been challenging to determine transport rates and flow directions within natural systems. Here we present results from the first cross-hole tracer experiment in the upper oceanic crust, using four subseafloor borehole observatories equipped with autonomous samplers to track the transport of a dissolved tracer (sulfur hexafluoride, SF6) injected into a ridge-flank hydrothermal system. During the first three years after tracer injection, SF6 was transported both north and south through the basaltic aquifer. The observed tracer transport rate of ∼2–3 m/day is orders of magnitude greater than bulk rates of flow inferred from thermal and chemical observations and calculated with coupled fluid-heat flow simulations. Taken together, these results suggest that the effective porosity of the upper volcanic crust through which much tracer was transported is <1%, with fluid flowing rapidly along a few well-connected channels. This is consistent with the heterogeneous (layered, faulted, and/or fractured) nature of the volcanic upper oceanic crust.
We present three‐dimensional simulations of coupled fluid and heat transport in the ocean crust, to explore patterns and controls on ridge‐flank hydrothermal circulation on the eastern flank of the Juan de Fuca Ridge. Field studies have shown that there is large‐scale fluid flow in the volcanic ocean crust in this region, including local convection and circulation between two basement outcrops separated by ~50 km. New simulations include an assessment of crustal permeability and aquifer thickness, outcrop permeability, the potential influence of multiple discharging outcrops, and a comparison between two‐dimensional (profile) and three‐dimensional representations of the natural system. Field observations that help to constrain new simulations include a modest range of flow rates between recharging and discharging outcrops, secondary convection adjacent to the recharging outcrop, crustal permeability determinations made in boreholes, and the lack of a regional seafloor heat flux anomaly as a consequence of advective heat loss from the crust. Three‐dimensional simulations are most consistent with field observations when models use a crustal permeability of 3 × 10−13 to 2 × 10−12 m2, and the crustal aquifer is ≤300 m thick, values consistent with borehole observations. We find fluid flow rates and crustal cooling efficiencies that are an order of magnitude greater in three‐dimensional simulations than in two‐dimensional simulations using equivalent properties. Simulations including discharge from an additional outcrop can also replicate field observations but tend to increase the overall rate of recharge and reduce the flow rate at the primary discharge site.
Liquid water occurs below glaciers and ice sheets globally, enabling the existence of an array of aquatic microbial ecosystems. In Antarctica, large subglacial lakes are present beneath hundreds to thousands of metres of ice, and scientific interest in exploring these environments has escalated over the past decade. After years of planning, the first team of scientists and engineers cleanly accessed and retrieved pristine samples from a West Antarctic subglacial lake ecosystem in January 2013. This paper reviews the findings to date on Subglacial Lake Whillans and presents new supporting data on the carbon and energy metabolism of resident microbes. The analysis of water and sediments from the lake revealed a diverse microbial community composed of bacteria and archaea that are close relatives of species known to use reduced N, S or Fe and CH4 as energy sources. The water chemistry of Subglacial Lake Whillans was dominated by weathering products from silicate minerals with a minor influence from seawater. Contributions to water chemistry from microbial sulfide oxidation and carbonation reactions were supported by genomic data. Collectively, these results provide unequivocal evidence that subglacial environments in this region of West Antarctica host active microbial ecosystems that participate in subglacial biogeochemical cycling.
The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m2, significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m2. The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.
Most seafloor hydrothermal circulation occurs far from the magmatic influence of mid-ocean ridges, driving large flows of water, heat and solutes through volcanic rock outcrops on ridge flanks. Here we create three-dimensional simulations of ridge–flank hydrothermal circulation, flowing between and through seamounts, to determine what controls hydrogeological sustainability, flow rate and preferred flow direction in these systems. We find that sustaining flow between outcrops that penetrate less-permeable sediment depends on a contrast in transmittance (the product of outcrop permeability and the area of outcrop exposure) between recharging and discharging sites, with discharge favoured through less-transmissive outcrops. Many simulations include local discharge through outcrops at the recharge end of an outcrop-to-outcrop system. Both of these characteristics are observed in the field. In addition, smaller discharging outcrops sustain higher flow rates than larger outcrops, which may help to explain how so much lithospheric heat is extracted globally by this process.
A clean hot-water drill was used to gain access to Subglacial Lake Whillans (SLW) in late January 2013 as part of the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project. Over 3 days, we deployed an array of scientific tools through the SLW borehole: a downhole camera, a conductivity–temperature–depth (CTD) probe, a Niskin water sampler, an in situ filtration unit, three different sediment corers, a geothermal probe and a geophysical sensor string. Our observations confirm the existence of a subglacial water reservoir whose presence was previously inferred from satellite altimetry and surface geophysics. Subglacial water is about two orders of magnitude less saline than sea water (0.37–0.41 psu vs 35 psu) and two orders of magnitude more saline than pure drill meltwater (<0.002 psu). It reaches a minimum temperature of –0.55°C, consistent with depression of the freezing point by 7.019 MPa of water pressure. Subglacial water was turbid and remained turbid following filtration through 0.45 μm filters. The recovered sediment cores, which sampled down to 0.8 m below the lake bottom, contained a macroscopically structureless diamicton with shear strength between 2 and 6 kPa. Our main operational recommendation for future subglacial access through water-filled boreholes is to supply enough heat to the top of the borehole to keep it from freezing.
The hydrogeologic properties of igneous ocean crust have been tested directly in only a few locations during IODP, but more common studies of crustal structure and rock alteration (using core samples and wireline logs) provide insight as to how water–rock interactions modify the crust over time. Collectively these studies reveal strong lithologic and hydrogeologic control on the nature of water–rock interactions, with hydrogeology following crustal architectures and histories. Permeability is generally greatest in the upper crust, but is heterogeneously distributed with depth and (at least in one location) may be azimuthally anisotropic. There appears to be a spreading rate dependence of basic patterns of rock alteration in the upper oceanic crust, with more variable and extensive alteration observed in crust created at slow- and medium-rate spreading centers. There may also be a spreading rate dependence of hydrogeologic properties, but we currently lack direct observations to test this hypothesis. The evolution of crustal properties with age is consistent with sustained ridge-flank water–rock interactions, and a continued dependence on fluid flow rates and reaction temperatures.
Since 1981, Robert Ballard has envisioned a concept of ocean exploration with multiple ships collecting video and data from the depths of the world ocean and broadcasting discoveries in real time through ship-to-shore satellite technology. In 1989, the telepresence vision was realized when the first Jason Project broadcasts employed ROV technology developed by the Deep Submergence Laboratory at Woods Hole Oceanographic Institution (WHOI). Those early telepresence-enabled broadcasts delivered live educational programming to vast audiences who could participate in the exploration as it was happening.
Thermal records from boreholes in young oceanic crust, in which water is flowing up or down, are used to assess formation and borehole flow properties using three analytic equations that describe the transient thermal and barometric influence of downhole or uphole flow. We link these calculations with an iterative model and apply Markov chain Monte Carlo (MCMC) analysis to quantify ranges of possible values. The model is applied to two data sets interpreted in previous studies, from Deep Sea Drilling Project Hole 504B on the southern flank of the Costa Rica Rift and Ocean Drilling Program Hole 1026B on the eastern flank of the Juan de Fuca Ridge, and to two new records collected in Integrated Ocean Drilling Program Holes U1301A and U1301B, also on the eastern flank of the Juan de Fuca Ridge. Our calculations indicate that fluid flow rates when thermal logs were collected were ∼2 L/s in Holes 504B, 1026B, and U1301A, and >20 L/s in Hole U1301B. The median bulk permeabilities determined with MCMC analyses are 4 to 7 × 10−12 m2 around the uppermost parts of Holes 504B, 1026B, and U1301A, and 1.5 × 10−11 m2 around a deeper section of Hole U1301B, with a standard deviation of 0.2 to 0.3 log cycles at each borehole. The consistency of permeability values inferred from these four holes is surprising, given the range of values determined globally and the tendency for permeability to be highly variable in fractured crystalline rock formations such as the upper oceanic crust.
[1] We report new drillstring packer permeability tests conducted during Integrated Ocean Drilling Program (IODP) Expedition 327 in upper oceanic basement in Hole U1362A on the eastern flank of the Juan de Fuca Ridge. Hole U1362A lies within a closely spaced array (40–2460 m separation) of six holes in well‐sedimented 3.5–3.6 m.y. old crust that were drilled, tested, and instrumented with borehole observatories during Ocean Drilling Program Leg 168 and IODP Expeditions 301 and 327. The permeability tests in Hole U1362A complement similar experiments previously conducted in nearby Holes 1026B, 1027C, and U1301B. The new results suggest consistency of upper crustal permeability between Holes U1362A and U1301B, which penetrate 290 and 320 m of basement and are separated by ∼825 m. We obtain similar bulk permeability values of 1–3 × 10−12 m2 for the sections deeper than ∼150 m into basement in both holes. These values are significantly higher than results of packer experiments in the shallowest few tens of meters of basement in nearby Holes 1026B and 1027C, suggesting that the highest basement permeabilities in this area are not found in the shallowest basement layers. Downhole logs of density and penetration rate during drilling and coring in Holes U1362A and U1301B show similar trends within the upper crust, reinforcing the inference that there may be considerable lateral continuity in hydrogeologic properties. This continuity may be associated with the fundamental lithostratigraphy of the crust and/or influenced by ridge‐parallel faulting and fracturing associated with the formation of abyssal hill topography.
Systematic differences in sediment thermal and pore water chemical profiles from Integrated Ocean Drilling Program Site U1363 document mixing and reaction within the basaltic crust adjacent to Grizzly Bare outcrop, a site of hydrothermal recharge into 3.6 My‐old basaltic crust. A transect of seven holes was drilled ~50 m to ~750 m away from the base of the outcrop. Temperatures at the sediment‐basement interface increase from ~6°C to >30°C with increasing distance from the outcrop, and heat flow is suppressed within several hundred meters from the outcrop. Calculated fluid compositions at the sediment‐basement interface are generally explained by mixing between bottom seawater and altered crustal basement fluids, with a composition similar but not identical to fluids from seeps at Baby Bare outcrop, located ~45 km to the northeast. Reactions within upper basement and overlying sediment affect a variety of ions (Mn, Fe, Mo, Si, PO43‐, V, and U) and δ13DIC, indicating a diagenetic influence and diffusive exchange with overlying sediment pore waters. The apparent 14C age of basal pore fluids is much older than bottom seawater. Collectively, these results are consistent with seawater recharge at Grizzly Bare outcrop; however, there are strong gradients in fluid composition within 50 m of the outcrop, providing evidence for complex flow paths and vigorous mixing of young, recently recharged seawater with much older, more reacted basement fluid. The proximity of these altered fluids to the edge of the outcrop raises the possibility for fluid seepage from the outcrop in addition to seawater recharge.
We discuss ridge flank environments in the ocean crust as habitats for subseafloor microbial life. Oceanic ridge flanks, areas far from the magmatic and tectonic influence of seafloor spreading, comprise one of the largest and least explored microbial habitats on the planet. We describe the nature of selected ridge flank crustal environments, and present a framework for delineating a continuum of conditions and processes that are likely to be important for defining subseafloor microbial “provinces.” The basis for this framework is three governing conditions that help to determine the nature of subseafloor biomes: crustal age, extent of fluid flow, and thermal state. We present a brief overview of subseafloor conditions, within the context of these three characteristics, for five field sites where microbial studies have been done, are underway, or have been proposed. Technical challenges remain and likely will limit progress in studies of microbial ridge flank ecosystems, which is why it is vital to select and design future studies so as to leverage as much general understanding as possible from work focused at a small number of sites. A characterization framework such that as presented in this paper, perhaps including alternative or additional physical or chemical characteristics, is essential for achieving the greatest benefit from multidisciplinary microbial investigations of oceanic ridge flanks.
The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long‐term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbial colonization preferences for 12 minerals and glasses present in igneous rocks. Following recovery of the colonization systems, we measured cell density on the minerals and glasses by fluorescent staining and direct counting and found some significant differences between mineral samples. We also determined the abundance of mesophilic and thermophilic culturable organotrophs grown on marine R2A medium and identified isolates by partial 16S or 18S rDNA sequencing. We found that nine distinct phylotypes of culturable mesophilic oligotrophs were present on the minerals and glasses and that eight of the nine can reduce nitrate and oxidize iron. Fe(II)‐rich olivine minerals had the highest density of total countable cells and culturable organotrophic mesophiles, as well as the only culturable organotrophic thermophiles. These results suggest that olivine (a common igneous mineral) in seawater‐recharged ocean crust is capable of supporting microbial communities, that iron oxidation and nitrate reduction may be important physiological characteristics of ocean crust microbes, and that heterogeneously distributed minerals in marine igneous rocks likely influence the distribution of microbial communities in the ocean crust.
Integrated Ocean Drilling Program (IODP) Expedition 327 (summer 2010) was designed to resolve the nature of fluid-rock interactions in young, upper volcanic crust on the eastern flank of the Juan de Fuca Ridge. Expedition 327 drilled, cased and cored two new basement holes, conducted hydrogeologic experiments, and installed subseafloor borehole observatories (Circulation Obviation Retrofit Kits, CORKs). These CORKs were intended to allow borehole conditions to recover to a more natural state after the dissipation of disturbances caused by drilling, casing, and other operations; provide a long-term monitoring and sampling presence for determining fluid pressure, temperature, composition, and microbiology; and facilitate the completion of active experiments to resolve crustal hydrogeologic conditions and processes. Expedition 327 was followed (summer 2011) by R/V Atlantis Expedition AT18-07, with the remotely-operated vehicle (ROV) Jason, to service these CORKs, collect subseafloor pressure data, recover and deploy autonomous fluid and microbial samplers, collect large volumes of borehole fluids, and initiate a cross-hole hydrogeologic experiment using an electromagnetic flow meter. In addition, Atlantis Expedition AT18-07 refurbished an old CORK that could not be replaced during IODP Expedition 327, completing a critical part of the three-dimensional observation network that is currently being used to monitor a large-scale, directional formation response to long-term fluid flow from the crust.
[1] Mark Twain once said, “I was seldom able to see an opportunity until it had ceased to be one.” The scientific community could soon miss an opportunity in ocean drilling. A recent article in Eos by D. K. Smith et al. (Ocean drilling: Forty years of international collaboration, Eos, 91(43), 393–394, 2010) summarized the history of scientific ocean drilling and presented an overview of the Integrated Ocean Drilling Program (IODP) as it currently operates. IODP will end in 2013, and an ambitious science plan is being developed to launch a new drilling program. Some people have asked, Given the program’s past successes, why do we need more scientific ocean drilling?
Multiple tracers were pumped into upper basement around Hole U1362B during Integrated Ocean Drilling Program (IODP) Expedition 327 as part of a single- and cross-hole tracer experiment on the eastern flank of Juan de Fuca Ridge. Tracers injected were sulfur hexafluoride (dissolved gas), cesium chloride hexahydrate, erbium chloride, and holmium chloride hexahydrate (solutes), and several sizes of fluorescent microspheres and fluorescent-stained microbes filtered from surface seawater (particles). Tracers were injected as part of a 24 h pumping experiment intended to test a large volume of basement rock around Hole U1362B. We report on the design of the tracer experiment, methods used to prepare and inject tracers using shipboard mud and cement pump systems, and tools developed to permit shipboard and downhole sampling of injectate. Shore-based analysis of injectate samples will be essential for interpretation of long-term samples collected from subseafloor borehole observatories (“CORKs”). Borehole samples are being collected continuously within a long-term CORK installed in Hole U1362B after tracer injection was complete and within similar CORK systems installed in nearby boreholes before and during Expedition 327. CORK servicing expeditions are currently planned for summer 2011 and 2012. These expeditions and additional work in subsequent years will provide data and samples that will permit a quantitative assessment of tracer transport behavior in the upper ocean crust.
Integrated Ocean Drilling Program (IODP) Expedition 327 installed two new subseafloor borehole observatory systems (“CORKs”) in 3.5 m.y. old upper ocean crust on the eastern flank of Juan de Fuca Ridge in Holes U1362A and U1362B. Expedition 327 participants also recovered part of an instrument string previously deployed in a CORK in Hole U1301B and deployed a short replacement string. These observatories are part of a network of six CORKs that was designed to monitor, sample, and complete multidisciplinary cross-hole experiments. We present an overview of project goals and describe the design, construction, and deployment of new CORK systems. We also provide an update on the status of preexisting CORK systems as of the start of Expedition 327. Additional CORK servicing and sampling are scheduled for summer 2011 and 2012, including a long-term free-flow perturbation experiment that will test the large-scale directional properties of the upper ocean crust around the observatories.
