|Created||March 22, 2017|
|Modified||August 30, 2018|
|State||Preliminary and in progress|
Organic acid concentrations from the Strytan Hydrothermal Field
Samples were collected from 3 sites: Big Strytan, Arnarnasstrytan, and Hrisey (see lat/lon below). SCUBA diving was utilized to collect vent fluids and hydrothermal precipitates. Vent fluids for geochemistry were sampled in sterile 60 ml syringes. The first 20 ml was discarded to decrease the amount of seawater contamination during sampling. Vent fluid sampling for dissolved gases consisted of 2 methods: 1) the “syringe-to- syringe” method (STS), and 2) the “syringe-to-bottle” method (STB). The STS method consisted of pulling 40 ml of vent fluid at the end of a dive, transporting it back to the lab, and equilibrating the fluid with 20 ml of purified N2. The gas was then injected into Cali-5-Bond gas sampling bags for transport prior to analysis by GC. The STB method consisted of pulling a known volume of vent fluid (typically 40 ml) into a syringe, and immediately injecting into a 60 ml N2-flushed, evacuated, serum bottle.
Temperatures were measured in situ using a temperature probe. The pH/ORP/Conductivity/TDS were measured on shore using a Myron-L field pH meter. Aliquots for H2S measurements were preserved in the field by precipitation of ZnS following the addition of 1 ml of a 50 mM zinc acetate solution to a 3 ml sample, placed on dry ice, and analyzed in the laboratory with a spectrophotometer at a wavelength of 670 nm. Samples for anion analysis (Br, Cl, and SO4) were filtered in the field (0.2 um), placed on dry ice, and kept frozen until measurement in the laboratory using ion chromatography. Samples for analysis of major cations and trace elements (Na, B, Mg, Si, K, Ca, Al, As, V, Cr, Cu, Zn, Sr, Mo, and W) were preserved in the field by filtering (0.2 um) and acidification with 0.1% ultrapure HNO3, and measured by inductively coupled plasma-mass spectrometry (ICP-MS). Dissolved gases (H2, CH4, and CO), as well as organic acids and DIC, were analyzed at NASA Ames in the lab of Tori Hoehler. D13C-CH4 was measured at Montana State University by Eric Boyd.
BCO-DMO Data Manager 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’
* location names, latitude, and longitude added
pH/ORP/Conductivity/TDS were measured on shore using a Myron-L field pH meter.
spectrophotometer at a wavelength of 670 nm
An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.
|Roy E. Price||Stony Brook University (SUNY Stony Brook)||✓|
|Jan P. Amend||University of Southern California (USC)|
|Amber York||Woods Hole Oceanographic Institution (WHOI BCO-DMO)|
BCO-DMO Project Info
|Project Title||A Lost City-type hydrothermal system in readily accessible, shallow water|
|Acronym||Lost City-type hydrothermal system|
|Created||January 22, 2016|
|Modified||January 22, 2016|
The Strytan Hydrothermal Field (SHF; Eyjafjord, northern Iceland) exhibits alkaline (pH ~ 10), hot (up to 78 degrees C), submarine hydrothermal venting, resulting in the formation of numerous saponite towers. We performed a detailed geochemical and microbiological characterization of hydrothermal fluids and precipitates from the site. End-member calculations revealed elevated concentrations of many major and trace elements (e.g., 2.4 mM Na, 3 to 27 uM K, 40 to 120 uM Ca, 10 to 25 uM B, and overall high concentrations of trace elements). We hypothesize that recharge of meteoric water occurs in the mountains south of Eyjafjord, and low temperature alteration of plagioclase, pyroxene and olivine in basalt, and precipitation of calcite, occurs in a closed system. This explains the observed high pH, variable Ca concentrations, and low DIC. CH4, H2, and CO concentrations were all elevated relative to normal seawater (up to 1.41, 5.19, and 0.13 uM, respectively), and a range of δ13C-CH4 was measured. Weathering of pyroxene may produce H2, which combines with CO2 to form abiotic CH4. The abiotic production of H2 and CH4 in a site such as the SHF broadens the range of potential origin of life environments significantly. Intact polar lipids indicate Bacteria dominated all samples except one. Up to 50% of the lipids at this site were archaeal. Bacterial clone sequences were dominated by betaproteobacteria (Dechloromonas sp.), followed by deltaproteobacteria (Desulfovibrio sp.) Archaeal results indicate a dominance of Crenarchaeota, particularly Thermoproteales, followed by Desulfurococcales. More detailed analysis of microbial communities is currently underway.