URLhttps://www.bco-dmo.org/dataset/756152
Download URLhttps://www.bco-dmo.org/dataset/756152/data/download
Media Typetext/tab-separated-values
CreatedFebruary 19, 2019
ModifiedFebruary 22, 2019
StateFinal no updates expected
Brief DescriptionScanning Electron Microscopy (SEM) photographs of biofilms and mineral alteration products

Acquisition Description

Polished mineral chips were prepared and deployed as described in Edwards et al. 2012 (DOI: 110.2204/iodp.proc.336.109.2012). Mineral colonization experiments were recovered during cruise AT39-01 in October 2017 and processed as described in Orcutt et al. 2011 (DOI: 10.1038/ismej.2010.157). Mineral chips were preserved in cold 4% paraformaldehyde in 1XPBS buffer, rinsed with 1XPBS, and then stored at -20ºC in a 1:1 mixture of 1XPBS:ethanol. Chips were serially dehydrated in the ethanol baths of increasing concentration for 10 minutes each, immersed in 100% hexodimethylsilane for 10 minutes, and air dried for 48 hours. Dehydrated chips were then mounted on SEM stubs, sputter coated with gold, and imaged on a Zeiss Supra25 field emission scanning microscope (SEM).   

Processing Description

BCO-DMO Processing Notes:
- zipped all image subfolders into individual packages based on the Sample Identification text string
- modified parameter names to conform with BCO-DMO naming conventions
- added conventional header with dataset name, PI name, version date

Instruments

Zeiss Supra25 field emission scanning microscope [Scanning Electron Microscope]
Details
Instance Description (Zeiss Supra25 field emission scanning microscope)

Zeiss Supra25 field emission scanning microscope

Scanning electron microscope

Parameters

SampleIdentification [sample]
Details
SampleIdentification
Identification label of mineral colonization experiment

unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent

RockType [sample_descrip]
Details
RockType
Type of rock substrate in mineral colonization experiment
text description of sample collected
DeploymentLocation [site]
Details
DeploymentLocation
CORK borehole observatory Hole number (U1382A; U1383B; or U1383C) and horizon within the borehole observatory (wellhead; shallow; shallowEnriched)
Sampling site identification.
File_count [count]
Details
File_count
number of Scanning Electron Microscopy (SEM) files for each experiment
Number of individuals counted in sample or sample fraction
WaterDepth [depth]
Details
WaterDepth

meters of water depth to the seafloor where the CORK borehole observatory sits

Observation/sample depth below the sea surface. Units often reported as: meters, feet.


When used in a JGOFS/GLOBEC dataset the depth is a best estimate; usually but not always calculated from pressure; calculated either from CTD pressure using Fofonoff and Millard (1982; UNESCO Tech Paper #44) algorithm adjusted for 1980 equation of state for seawater (EOS80) or simply equivalent to nominal depth as recorded during sampling if CTD pressure was unavailable.

DeploymentType [sample_descrip]
Details
DeploymentType
location (wellhead or downhole) within the CORK borehole observatory where the experiment took place
text description of sample collected
FluidDepth [depth]
Details
FluidDepth
average depth (in meters below seafloor) where crustal fluids are sourced for the experiment

Observation/sample depth below the sea surface. Units often reported as: meters, feet.


When used in a JGOFS/GLOBEC dataset the depth is a best estimate; usually but not always calculated from pressure; calculated either from CTD pressure using Fofonoff and Millard (1982; UNESCO Tech Paper #44) algorithm adjusted for 1980 equation of state for seawater (EOS80) or simply equivalent to nominal depth as recorded during sampling if CTD pressure was unavailable.

DeploymentDate [date]
Details
DeploymentDate
date of the experiment deployment

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)

RecoveryDate [date]
Details
RecoveryDate

date of the experiment recovery

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)

package_url [file_link]
Details
package_url

web url to the zip file of images for the specified sample identification value.

Link to file (such as a data file or document).

Dataset Maintainers

NameAffiliationContact
Beth N. OrcuttBigelow Laboratory for Ocean Sciences
Timothy D'AngeloBigelow Laboratory for Ocean Sciences
Mathew BiddleWoods Hole Oceanographic Institution (WHOI BCO-DMO)

BCO-DMO Project Info

Project TitleCollaborative Research: Completing North Pond Borehole Experiments to Elucidate the Hydrology of Young, Slow-Spread Crust
AcronymNorth Pond 2017
URLhttps://www.bco-dmo.org/project/707762
CreatedJuly 5, 2017
ModifiedJuly 5, 2017
Project Description

NSF Award Abstract:
Seawater circulates through the upper part of the oceanic crust much like groundwater flows through continental aquifers. However, in the ocean this seawater circulation, many times heated by buried magmatic bodies, transports and releases 25% of the Earth's heat. The rate of fluid flow through ocean crust is estimated to be equal to the amount of water delivered by rivers to the ocean. Much of what we know of this subseafloor fluid flow comes from studies in the eastern Pacific Ocean on ocean crust created by medium and fast spreading mid-ocean ridges. These studies indicate that seawater and its circulation through the seafloor significantly impact crustal evolution and biogeochemical cycles in the ocean and affect the biosphere in ways that are just now beginning to be quantified and understood. To expand this understanding, this research focuses on fluid flow of seafloor generated by slow spreading ridges, like those in the Atlantic, Indian and Arctic Oceans because it is significantly different in structure, mineralogy, and morphology than that formed at fast and intermediate spreading ridges. This research returns to North Pond, a long-term; seafloor; fluid flow monitoring site, drilled and instumented by the Ocean Drilling Program in the Atlantic Ocean. This research site was punctured by boreholes in which fluid flow and geochemical and biological samplers have been deployed for a number of years to collect data and samples. It also provides resources for shipboard and on-shore geochemical and biological analysis. Broader impacts of the work include sensor and technology development, which increases infrastructure for science and has commercial applications. It also provides training for students and the integration of education and research at three US academic institutions, one of which is an EPSCoR state (Mississippi), and supports a PI whose gender is under-represented in sciences and engineering. Public outreach will be carried out in conjunction with the Center for Dark Energy Biosphere Investigations.

This project completes a long-term biogeochemical and hydrologic study of ridge flank hydrothermal processes on slow-spreading, 8 million year old crust on the western flank of the Mid-Atlantic Ridge. The site, North Pond, is an isolated northeast-trending sediment pond, bounded by undersea mountains that have been studied since the 1970s. During Integrated Ocean Drilling Program Expedition 336 in 2011 and an expedition five months later (2012), sensors, samplers, and experiments were deployed in four borehole observatories drilled into the seafloor that penetrated into volcanic crust, with the purpose of monitoring changes in hydrologic properties, crustal fluid composition and mineral alteration, among other objectives. Wellhead sampling in 2012 and 2014 already revealed changes in crustal fluid compositions; and associated pressure data confirm that the boreholes are sealed and overpressured, reflecting a change in the formation as the boreholes recover from drilling disturbances. This research includes a 13-day oceanographic expedition and use of on-site robotically operated vehicles to recover downhole instrument packages at North Pond. It will allow the sampling of crustal fluids, recovering pressure data, and measuring fluid flow rates. Ship- and shore-based analyses will be used to address fundamental questions related to the hydrogeology of hydrothermal processes on slow-spread crust.

Project Maintainers
NameAffiliationRoleContact
Beth N. OrcuttBigelow Laboratory for Ocean SciencesLead Principal Investigator
Charles Geoffrey WheatUniversity of Alaska Fairbanks (UAF-IMS)Principal Investigator
Keir BeckerUniversity of Miami Rosenstiel School of Marine and Atmospheric Science (UM-RSMAS)Principal Investigator
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