|Created||November 22, 2019|
|Modified||November 22, 2019|
|State||Data not available yet|
Sediment samples were stored at 4°C prior to analysis. Proteinaceous material was extracted and quantified with Qubit fluorescent reagent (Life Technologies), following Estes et al. (2016) as modified from Ehrenreich and Widdel (1994).
Assay was quantified using bovine serum albumin standard (Bio-Rad).
See Estes el al. 2019, for complete methods.
BCO-DMO Data Manager Processing Notes:
* exported data in xlsx file to csv file
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values in this dataset are displayed as "nd" for "no data." nd is the default missing data identifier in the BCO-DMO system.
* latitude and longitude in degrees decimal minutes converted to decimal degrees
latitude, in decimal degrees, North is positive, negative denotes South; Reported in some datasets as degrees, minutes
longitude, in decimal degrees, East is positive, negative denotes West; Reported in some datsets as degrees, minutes
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.
Meters below seafloor (mbsf); convention used for depths below the seabed in geology, oceanography, petrology and ocean drilling; often used in reporting measurements made from sediment cores.
|Emily R. Estes||Texas A&M University (TAMU)||✓|
|Colleen M. Hansel||Woods Hole Oceanographic Institution (WHOI)|
|Amber York||Woods Hole Oceanographic Institution (WHOI BCO-DMO)|
BCO-DMO Project Info
|Project Title||Geochemical controls on organic carbon quantity and quality in the deep subsurface|
|Acronym||Org C Sed II|
|Created||October 15, 2019|
|Modified||October 16, 2019|
Abstract from the C-DEBI project page:
Sediment underlying ocean gyres receives minimal input of fresh organic matter yet sustains a small but active heterotrophic microbial community. The concentration and composition of the organic carbon (OC) available to this deep biosphere however is unknown. We analyzed the content and composition of OC in pelagic sediment in order to identify mechanism(s) that dictate the balance between OC preservation and utilization by microorganisms. Sediment cores from the North Atlantic gyre (KN223), South Pacific Gyre (Knox02-RR), and Peru Basin (IODP site 1231) allowed for a global comparison and a test of how sediment lithology and redox state affect OC preservation. OC was present in low concentrations in all samples (0.01—0.61%), at depths up to 112 meters below seafloor and estimated sediment ages of up to 50 million years. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy was conducted on over 100 samples, one of the first applications of NEXAFS to sedimentary environments. NEXAFS revealed an OC reservoir dominated by amide and carboxylic functionalities in a scaffolding of O-alkyl and aliphatic carbons. Detection of extractable, extracellular proteins supports this composition and suggests that sedimentary OC is protein-derived. This composition was common across all sites and depths, implicating physical rather than chemical mechanisms in OC preservation on long timescales. This study thereby points to physical access rather than energy or metabolic potential as a key constraint on subsurface heterotrophic life.
|Emily R. Estes||Woods Hole Oceanographic Institution (WHOI)||Principal Investigator|