Eastern Mediterranean sediments were collected by gravity corer. In the Marmara Sea, deeper sediments (from 570-585 cm and 520-530 cm) were collected by gravity corer.
URL | https://www.bco-dmo.org/dataset/668648 |
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Download URL | https://www.bco-dmo.org/dataset/668648/data/download |
Media Type | text/tab-separated-values |
Created | December 6, 2016 |
Modified | January 21, 2020 |
State | Final no updates expected |
Brief Description | Polysaccharide hydrolysis rates for Marmara Sea, Guaymas Basin, and Eastern Mediterranean Sea sediments |
Acquisition Description
In the Marmara Sea, surficial sediments were collected by multicorer, and deeper sediments from 570-585 cm and 520-530 cm were collected by gravity corer. Eastern Mediterranean sediments were collected by gravity corer. Guaymas Basin sediments were collected by push core.
Sediment incubations with fluorescently labeled organic substrates were set up with three live incubations, a kill control, and one live blank. Incubations were subsampled over time, and each subsample was centrifuged and syringe filtered through a 0.2 um GF filter. Porewater containing partially hydrolyzed fluorescent substrate products were processed using gel permeation chromatography with fluorescence detection. Standards of fluorescent substrates of known molecular weight were also run for the purpose of rate calculations.
GPC chromatographic analysis was conducted on a Shimadzu liquid chromatography system and a Hitachi fluorescence detector.
Instruments
In the Marmara Sea, surficial sediments were collected by multicorer.
Guaymas Basin sediments were collected by push core.
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/
GPC chromatographic analysis was conducted on a Shimadzu liquid chromatography system and a Hitachi fluorescence detector.
Instruments that separate components in aqueous or organic solution based on molecular size generally for molecular weight determination. Gel permeation chromatography (GPC) is a type of size exclusion chromatography (SEC), that separates analytes on the basis of size.
Parameters
unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent
Experimental conditions applied to experimental units. In comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.
Dataset Maintainers
Name | Affiliation | Contact |
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Adrienne Hoarfrost | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | ✓ |
Carol Arnosti | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | ✓ |
Shannon Rauch | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | |
Shannon Rauch | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | |
Shannon Rauch | Woods Hole Oceanographic Institution (WHOI BCO-DMO) |
BCO-DMO Project Info
Project Title | Investigating microbial activities driving organic matter transformations in the deep subsurface |
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Acronym | SedS |
URL | https://www.bco-dmo.org/project/662055 |
Created | October 20, 2016 |
Modified | October 20, 2016 |
Project Description
Project description from C-DEBI:
Heterotrophic organisms are central to subsurface microbial communities and play an important role in carbon cycling. Most approaches to measuring enzymatic activities rely on the addition of a fluorescently labeled substrate to a sediment incubation. However, quantifying rates of extracellular enzymatic hydrolysis of organic matter is often problematic due to the tendency for a fluorescently labeled organic substrate to sorb to the sediment matrix. This results in lower fluorescence intensities and distorted, inaccurate hydrolysis rate calculations. In this project, a desorption treatment was developed to counteract the adverse effects of sorption on enzymatic activity measurements. Upon subsampling a sediment incubation amended with a fluorescently labeled substrate, the subsample is treated with a concentrated solution of unlabeled substrate, along with 0.2% sodium dodecyl sulfate (SDS), in order to competitively desorb the adsorbed, fluorescent substrate target. This treatment improves measured fluorescence intensities by a median of 62.5%, and is particularly effective at desorbing high molecular weight substrate products, resulting in debiased hydrolysis rates that are 14.75 nM/hr lower on average. Competitive desorption treatment was demonstrated to be effective for multiple substrates and in a broad range of sediments from diverse geological and geochemical contexts. Future applications of this method will result in more quantitative and comparable hydrolysis rates in subsurface sediments, will enable enzymatic activity measurements in problematic sediments that were previously infeasible, and will facilitate physiological characterization of microbial communities and model organisms in order to better understand heterotrophic carbon cycling in the subsurface environment.
This project was funded by a C-DEBI Graduate Fellowship.
Data Project Maintainers
Name | Affiliation | Role |
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Adrienne Hoarfrost | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Principal Investigator |
Carol Arnosti | University of North Carolina at Chapel Hill (UNC-Chapel Hill) | Co-Principal Investigator |