scholarly journals Lateral organic carbon supply to the deep Canada Basin

2008 ◽  
Vol 35 (11) ◽  
Author(s):  
Jeomshik Hwang ◽  
Timothy I. Eglinton ◽  
Richard A. Krishfield ◽  
Steven J. Manganini ◽  
Susumu Honjo
Keyword(s):  
Organic Carbon ◽  
Canada Basin ◽  
Carbon Supply

The vulnerability of Arctic shelf sediments to climate change

2015 ◽  
Vol 23 (4) ◽  
pp. 461-479 ◽  
Author(s):  
Robie W. Macdonald ◽  
Zou Zou A. Kuzyk ◽  
Sophia C. Johannessen
Keyword(s):  
Organic Carbon ◽  
Carbon Sources ◽  
The Arctic ◽  
Sedimentary Environments ◽  
Carbon Supply ◽  
Shelf Sediment ◽  
Wide Range ◽  
Metabolic Conditions ◽  
Shelf Sediments ◽  
Ocean Ecosystem

The sediments of the pan-Arctic shelves contribute an important component to the Arctic Ocean ecosystem by providing a habitat for biota (benthos), a repository for organic and inorganic non-conservative substances entering or produced within the ocean, a reactor and source of transformed substances back to the water column, and a mechanism of burial. Sediments interact with ice, ocean, and the surrounding land over a wide range of space and time scales. We discuss the vulnerability of shelf sediment to changes in (i) organic carbon sources, (ii) pathways of sediment and organic carbon supply, and (iii) physical and biogeochemical alteration (diagenesis). Sedimentary environments of the shelves and basins are likely to exhibit a wide variance in their response to global change because of their wide variation in sediment sources, processes, and metabolic conditions. In particular, the Chukchi and Barents shelves are dominated by inflowing waters from oceans to the south, whereas the interior shelves are more closely tied to terrigenous sources due to river inflow and coastal erosion.

scholarly journals Prominent bacterial heterotrophy and sources of <sup>13</sup>C-depleted fatty acids to the interior Canada Basin

2013 ◽  
Vol 10 (11) ◽  
pp. 7065-7080 ◽  
Author(s):  
S. R. Shah ◽  
D. R. Griffith ◽  
V. Galy ◽  
A. P. McNichol ◽  
T. I. Eglinton
Keyword(s):  
Fatty Acids ◽  
Particulate Matter ◽  
Organic Carbon ◽  
Suspended Particulate Matter ◽  
Surface Waters ◽  
Canada Basin ◽  
The Arctic ◽  
Deep Basin ◽  
Suspended Particulate ◽  
Chemoautotrophic Bacteria

Abstract. In recent decades, the Canada Basin of the Arctic Ocean has experienced rapidly decreasing summer sea ice coverage and freshening of surface waters. It is unclear how these changes translate to deeper waters, particularly as our baseline understanding of organic carbon cycling in the deep basin is quite limited. In this study, we describe full-depth profiles of the abundance, distribution and carbon isotopic composition of fatty acids from suspended particulate matter at a seasonally ice-free station and a semi-permanently ice-covered station. Fatty acids, along with suspended particulate organic carbon (POC), are more concentrated and 13C-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150 m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have δ13C values that are similar to suspended POC at all depths and are more 13C-enriched than even-numbered saturated fatty acids at depths above 3000 m. These are likely to be produced in situ by heterotrophic bacteria incorporating organic carbon that is isotopically similar to total suspended POC. Below surface waters, there is also the suggestion of a source of saturated even-numbered fatty acids which could represent contributions from laterally advected organic carbon and/or from chemoautotrophic bacteria. At 3000 m depth and below, a greater relative abundance of long-chain (C20–24), branched and unsaturated fatty acids is consistent with a stronger influence of re-suspended sedimentary organic carbon. At these deep depths, two individual fatty acids (C12 and iso-C17) are significantly depleted in 13C, allowing for the possibility that methane oxidizing bacteria contribute fatty acids, either directly to suspended particulate matter or to shallow sediments that are subsequently mobilized and incorporated into suspended particulate matter within the deep basin.

scholarly journals Mineralization pathways in lake sediments with different oxygen and organic carbon supply

2009 ◽  
Vol 54 (2) ◽  
pp. 428-438 ◽  
Author(s):  
Martin Maerki ◽  
Beat Müller ◽  
Christian Dinkel ◽  
Bernhard Wehrli
Keyword(s):  
Organic Carbon ◽  
Lake Sediments ◽  
Carbon Supply

ORGANIC CARBON SUPPLY AND METABOLISM IN A SHALLOW GROUNDWATER ECOSYSTEM

Ecology ◽  
2000 ◽  
Vol 81 (11) ◽  
pp. 3133-3148 ◽  
Author(s):  
Michelle A. Baker ◽  
H. Maurice Valett ◽  
Clifford N. Dahm
Keyword(s):  
Organic Carbon ◽  
Shallow Groundwater ◽  
Carbon Supply

scholarly journals Reviews and syntheses: to the bottom of carbon processing at the seafloor

2018 ◽  
Vol 15 (2) ◽  
pp. 413-427 ◽  
Author(s):  
Jack J. Middelburg
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Secondary Production ◽  
Ecological Approach ◽  
Labile Organic Matter ◽  
Carbon Supply ◽  
Sediment Organic Carbon ◽  
Compositional Changes ◽  
Carbon Processing ◽  
Organic Resources

Abstract. Organic carbon processing at the seafloor is studied by biogeochemists to quantify burial and respiration, by organic geochemists to elucidate compositional changes and by ecologists to follow carbon transfers within food webs. Here I review these disciplinary approaches and discuss where they agree and disagree. It will be shown that the biogeochemical approach (ignoring the identity of organisms) and the ecological approach (focussing on growth and biomass of organisms) are consistent on longer timescales. Secondary production by microbes and animals is identified to potentially impact the composition of sedimentary organic matter. Animals impact sediment organic carbon processing by microbes in multiple ways: by governing organic carbon supply to sediments, by aeration via bio-irrigation and by mixing labile organic matter to deeper layers. I will present an inverted microbial loop in which microbes profit from bioturbation rather than animals profiting from microbial processing of otherwise lost dissolved organic resources. Sediments devoid of fauna therefore function differently and are less efficient in processing organic matter with the consequence that more organic matter is buried and transferred from Vernadsky's biosphere to the geosphere.

Determination of particulate organic carbon sources to the surface mixed layer of the Canada Basin, Arctic Ocean

2014 ◽  
Vol 119 (2) ◽  
pp. 1084-1102 ◽  
Author(s):  
Kristina A. Brown ◽  
Fiona McLaughlin ◽  
Philippe D. Tortell ◽  
Diana E. Varela ◽  
Michiyo Yamamoto-Kawai ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Particulate Organic Carbon ◽  
Mixed Layer ◽  
Carbon Sources ◽  
Canada Basin ◽  
Surface Mixed Layer ◽  
Organic Carbon Sources

Response of sediment biofilm to increased dissolved organic carbon supply in groundwater artificially recharged with stormwater

2010 ◽  
Vol 11 (2) ◽  
pp. 382-393 ◽  
Author(s):  
Arnaud Foulquier ◽  
Florian Mermillod-Blondin ◽  
Florian Malard ◽  
Janine Gibert
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Supply ◽  
Sediment Biofilm

scholarly journals Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC

2012 ◽  
Vol 9 (3) ◽  
pp. 1217-1224 ◽  
Author(s):  
D. R. Griffith ◽  
A. P. McNichol ◽  
L. Xu ◽  
F. A. McLaughlin ◽  
R. W. Macdonald ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Carbon Isotope ◽  
Dissolved Inorganic Carbon ◽  
Isotope Composition ◽  
Canada Basin ◽  
The Arctic ◽  
Arctic Ecosystems ◽  
The Arctic Ocean

Abstract. Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance calculations suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.

Sign in / Sign up

Export Citation Format

Share Document