@article { ISI:000319838200023,
	title = {Carbon isotopic evidence for microbial control of carbon supply to Orca Basin at the seawater-brine interface},
	journal = {BIOGEOSCIENCES},
	volume = {10},
	number = {{5}},
	year = {2013},
	pages = {3175-3183},
	type = {Article},
	abstract = {Orca Basin, an intraslope basin on the Texas-Louisiana continental slope, hosts a hypersaline, anoxic brine in its lowermost 200m in which limited microbial activity has been reported. This brine contains a large reservoir of reduced and aged carbon, and appears to be stable at decadal time scales: concentrations and isotopic composition of dissolved inorganic (DIC) and organic carbon (DOC) are similar to measurements made in the 1970s. Both DIC and DOC are more {\textquoteleft}{\textquoteleft}aged{{\textquoteright}{\textquoteright}} within the brine pool than in overlying water, and the isotopic contrast between brine carbon and seawater carbon is much greater for DIC than DOC. While the stable carbon isotopic composition of brine DIC points towards a combination of methane and organic carbon remineralization as its source, radiocarbon and box model results point to the brine interface as the major source region for DIC, allowing for only limited oxidation of methane diffusing upwards from sediments. This conclusion is consistent with previous studies that identify the seawater-brine interface as the focus of microbial activity associated with Orca Basin brine. Isotopic similarities between DIC and DOC suggest a different relationship between these two carbon reservoirs than is typically observed in deep ocean basins. Radiocarbon values implicate the seawater-brine interface region as the likely source region for DOC to the brine as well as DIC.},
	issn = {1726-4170},
	doi = {10.5194/bg-10-3175-2013},
	author = {Shah, S. R. and Joye, S. B. and Brandes, J. A. and McNichol, A. P.}
}
@article {2508,
	title = {Export of submicron particulate organic matter to mesopelagic depth in an oligotrophic gyre},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {110},
	year = {2013},
	month = {Jun-07-2015},
	pages = {12565 - 12570},
	abstract = {Sixty percent of the world ocean by area is contained in oligotrophic gyres [Longhurst A (1995) Prog Oceanog 36:77-16], the biomass of which is dominated by picophytoplankton, including cyanobacteria and picoeukaryotic algae, as well as picoheterotrophs. Despite their recognized importance in carbon cycling in the surface ocean, the role of small cells and their detrital remains in the transfer of particulate organic matter (POM) to the deep ocean remains disputed. Because oligotrophic marine conditions are projected to expand under current climate trends, a better understanding of the role of small particles in the global carbon cycle is a timely goal. Here we use the lipid profiles, radiocarbon, and stable carbon isotopic signatures of lipids from the North Pacific Subtropical Gyre to show that in the surface ocean, lipids from submicron POM (here called extra-small POM) are distinct from larger classes of suspended POM. Remarkably, this distinct extra-small POM signature dominates the total lipids collected at mesopelagic depth, suggesting that the lipid component of mesopelagic POM primarily contains the exported remains of small particles. Transfer of submicron material to mesopelagic depths in this location is consistent with model results that claim the biological origin of exported carbon should be proportional to the distribution of cell types in the surface community, irrespective of cell size [Richardson TL, Jackson GA (2007) Science 315:838-840]. Our data suggest that the submicron component of exported POM is an important contributor to the global biological pump, especially in oligotrophic waters. 
},
	keywords = {Biogeochemistry, biomarkers, carbon isotopes, Oceanography},
	issn = {0027-8424},
	doi = {10.1073/pnas.1217514110},
	url = {http://www.pnas.org/cgi/doi/10.1073/pnas.1217514110https://syndication.highwire.org/content/doi/10.1073/pnas.1217514110},
	author = {Close, H. G. and Shah, S. R. and Ingalls, A. E. and Diefendorf, A. F. and Brodie, E. L. and Hansman, R. L. and Freeman, K. H. and Aluwihare, L. I. and Pearson, A.}
}
@article { ISI:000327814700020,
	title = {Prominent bacterial heterotrophy and sources of C-13-depleted fatty acids to the interior Canada Basin},
	journal = {BIOGEOSCIENCES},
	volume = {10},
	number = {{11}},
	year = {2013},
	pages = {7065-7080},
	type = {Article},
	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 C-13-enriched under ice cover than in ice-free waters. But this influence, apparent at 50 m depth, does not propagate downward below 150m depth, likely due to the weak biological pump in the central Canada Basin. Branched fatty acids have delta C-13 values that are similar to suspended POC at all depths and are more C-13-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 (C-12 and iso-C-17) are significantly depleted in C-13, 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.},
	issn = {1726-4170},
	doi = {10.5194/bg-10-7065-2013},
	author = {Shah, S. R. and Griffith, D. R. and Galy, V. and McNichol, A. P. and Eglinton, T. I.}
}
@article {1890,
	title = {Ultra-microscale analysis of lipids by 14C-AMS: Assessment and correction for sample processing blanks},
	journal = {Radiocarbon},
	volume = {49},
	year = {2007},
	note = {id: 501},
	month = {2007},
	pages = {69-82},
	author = {Shah, S. R. and Pearson, A.}
}
@article {1942,
	title = {Quantifying archaeal community autotrophy in the mesopelogic ocean using natural radiocarbon},
	journal = {Proc. Natl. Acad. Sci. USA},
	volume = {103},
	year = {2006},
	note = {id: 502},
	month = {2006},
	pages = {6442-6447},
	author = {Ingalls, A. E. and Shah, S. R. and Hansman, R. L. and Aluwihare, L. I. and Santos, G. M. and Druffel, E. R. M. and Pearson, A.}
}
