Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf
In September 2009, a series of sediment cores were collected across the Alaskan Beaufort Sea shelf-slope. Sediment and porewater organic carbon (OC) concentrations and stable carbon isotope ratios (δ13C) were measured to investigate spatial variations in sediment organic matter (OM) sources and dist...
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| Format: | Article |
| Language: | English |
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MDPI AG
2017-08-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/10/9/1265 |
| _version_ | 1828112651476008960 |
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| author | Richard B. Coffin Joseph P. Smith Brandon Yoza Thomas J. Boyd Michael T. Montgomery |
| author_facet | Richard B. Coffin Joseph P. Smith Brandon Yoza Thomas J. Boyd Michael T. Montgomery |
| author_sort | Richard B. Coffin |
| collection | DOAJ |
| description | In September 2009, a series of sediment cores were collected across the Alaskan Beaufort Sea shelf-slope. Sediment and porewater organic carbon (OC) concentrations and stable carbon isotope ratios (δ13C) were measured to investigate spatial variations in sediment organic matter (OM) sources and distribution of these materials across the shelf. Cores were collected along three main nearshore (shelf) to offshore (slope) sampling lines (transects) from east-to-west along the North Slope of Alaska: Hammerhead (near Camden Bay), Thetis Island (near Prudhoe Bay), and Cape Halkett (towards Point Barrow). Measured sediment organic carbon (TOC) and porewater dissolved organic carbon (DOC) concentrations and their respective δ13C values were used to investigate the relative contribution of different OM sources to sediment OC pool cycled at each location. Sources of OM considered included: water column-sourced phytodetritus, deep sediment methane (CH4), and terrestrial, tundra/river-sourced OM. Results of these measurements, when coupled with results from previous research and additional analyses of sediment and porewater composition, show a pattern of spatial variation in sediment OC concentrations, OM source contributions, and OM cycled along the Alaskan Beaufort Sea shelf. In general, measured sediment total organic carbon (TOC) concentrations, δ13CTOC values, porewater DOC concentrations, and δ13CDOC values are consistent with an east-to-west transport of modern Holocene sediments with higher OC concentrations primarily sourced from relatively labile terrestrial, tundra OM sources and phytodetritus along the Alaskan Beaufort shelf. Sediment transport along the shelf results in the medium-to-long term accumulation and burial of sediment OM focused to the west which in turn results in higher biogenic CH4 production rates and higher upward CH4 diffusion through the sediments resulting in CH4−AMO-sourced contribution to sediment OC westward along the shelf. Understanding current OM sources and distributions along the Alaskan Beaufort shelf is important for enhancing models of carbon cycling in Arctic coastal shelf systems. This will help support the prediction of the climate response of the Arctic created in the face of future warming scenarios. |
| first_indexed | 2024-04-11T11:53:46Z |
| format | Article |
| id | doaj.art-13941f21cb564f968177154a1d565a3d |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T11:53:46Z |
| publishDate | 2017-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-13941f21cb564f968177154a1d565a3d2022-12-22T04:25:14ZengMDPI AGEnergies1996-10732017-08-01109126510.3390/en10091265en10091265Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea ShelfRichard B. Coffin0Joseph P. Smith1Brandon Yoza2Thomas J. Boyd3Michael T. Montgomery4Department of Physical and Environmental Sciences, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USADepartment of Oceanography, US Naval Academy, Annapolis, MD 21402, USAHawaii Natural Energy Institute, University of Hawaii, Honolulu, HI 96822, USAMarine Biogeochemistry, Naval Research Laboratory, Washington, DC 20375, USAMarine Biogeochemistry, Naval Research Laboratory, Washington, DC 20375, USAIn September 2009, a series of sediment cores were collected across the Alaskan Beaufort Sea shelf-slope. Sediment and porewater organic carbon (OC) concentrations and stable carbon isotope ratios (δ13C) were measured to investigate spatial variations in sediment organic matter (OM) sources and distribution of these materials across the shelf. Cores were collected along three main nearshore (shelf) to offshore (slope) sampling lines (transects) from east-to-west along the North Slope of Alaska: Hammerhead (near Camden Bay), Thetis Island (near Prudhoe Bay), and Cape Halkett (towards Point Barrow). Measured sediment organic carbon (TOC) and porewater dissolved organic carbon (DOC) concentrations and their respective δ13C values were used to investigate the relative contribution of different OM sources to sediment OC pool cycled at each location. Sources of OM considered included: water column-sourced phytodetritus, deep sediment methane (CH4), and terrestrial, tundra/river-sourced OM. Results of these measurements, when coupled with results from previous research and additional analyses of sediment and porewater composition, show a pattern of spatial variation in sediment OC concentrations, OM source contributions, and OM cycled along the Alaskan Beaufort Sea shelf. In general, measured sediment total organic carbon (TOC) concentrations, δ13CTOC values, porewater DOC concentrations, and δ13CDOC values are consistent with an east-to-west transport of modern Holocene sediments with higher OC concentrations primarily sourced from relatively labile terrestrial, tundra OM sources and phytodetritus along the Alaskan Beaufort shelf. Sediment transport along the shelf results in the medium-to-long term accumulation and burial of sediment OM focused to the west which in turn results in higher biogenic CH4 production rates and higher upward CH4 diffusion through the sediments resulting in CH4−AMO-sourced contribution to sediment OC westward along the shelf. Understanding current OM sources and distributions along the Alaskan Beaufort shelf is important for enhancing models of carbon cycling in Arctic coastal shelf systems. This will help support the prediction of the climate response of the Arctic created in the face of future warming scenarios.https://www.mdpi.com/1996-1073/10/9/1265Beaufort Seamethanetundraorganic carbonstable isotopessedimentporewater |
| spellingShingle | Richard B. Coffin Joseph P. Smith Brandon Yoza Thomas J. Boyd Michael T. Montgomery Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf Energies Beaufort Sea methane tundra organic carbon stable isotopes sediment porewater |
| title | Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf |
| title_full | Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf |
| title_fullStr | Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf |
| title_full_unstemmed | Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf |
| title_short | Spatial Variation in Sediment Organic Carbon Distribution across the Alaskan Beaufort Sea Shelf |
| title_sort | spatial variation in sediment organic carbon distribution across the alaskan beaufort sea shelf |
| topic | Beaufort Sea methane tundra organic carbon stable isotopes sediment porewater |
| url | https://www.mdpi.com/1996-1073/10/9/1265 |
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