@article {2676,
	title = {Removal of Refractory Dissolved Organic Carbon in the Amundsen Sea, Antarctica},
	journal = {Scientific Reports},
	volume = {10},
	year = {2020},
	month = {Jan-12-2020},
	abstract = {The removal mechanism of refractory deep-ocean dissolved organic carbon (deep-DOC) is poorly understood. The Amundsen Sea Polynya (ASP) serves as a natural test basin for assessing the fate of deep-DOC when it is supplied with a large amount of fresh-DOC and exposed to strong solar radiation during the polynya opening in austral summer. We measured the radiocarbon content of DOC in the water column on the western Amundsen shelf. The radiocarbon content of DOC in the surface water of the ASP reflected higher primary production than in the region covered by sea ice. The radiocarbon measurements of DOC, taken two years apart in the ASP, were different, suggesting rapid cycling of DOC. The increase in DOC concentration was less than expected from the observed increase in radiocarbon content from those at the greatest depths. Based on a radiocarbon mass balance, we show that deep-DOC is consumed along with fresh-DOC in the ASP. Our observations imply that water circulation through the surface layer, where fresh-DOC is produced, may play an important role in global DOC cycling.},
	keywords = {CIRCUMPOLAR DEEP-WATER, cycle, DOC, glaciers, INFLOW, MATTER, pacific, phytoplankton, poc, radiocarbon},
	doi = {10.1038/s41598-020-57870-6},
	url = {http://www.nature.com/articles/s41598-020-57870-6http://www.nature.com/articles/s41598-020-57870-6.pdfhttp://www.nature.com/articles/s41598-020-57870-6.pdfhttp://www.nature.com/articles/s41598-020-57870-6},
	author = {Fang, Ling and Lee, SangHoon and Lee, Shin-Ah and Hahm, Doshik and Kim, Guebuem and Druffel, Ellen R. M. and Hwang, Jeomshik}
}
@article {2644,
	title = {Upwelling in the Ocean Basins North of the ACC: 1. On the Upwelling Exposed by the Surface Distribution of C-14},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {124},
	year = {2019},
	month = {Apr-04-2020},
	pages = {2591 - 2608},
	abstract = {he upwelling associated with the ocean{\textquoteright}s overturning circulation is hard to observe directly. Here, a large data set of surface C-14 measurements is compiled in order to show where deep water is brought back up to the surface in the ocean basins north of the Antarctic Circumpolar Current (ACC). Maps constructed from the data set show that low-C-14 deep water from the ACC is drawn up to the surface in or near the upwelling zones off Northwest Africa and Namibia in the Atlantic, off Costa Rica and Peru in the Pacific, and in the northern Arabian Sea in the Indian Ocean. Deep water also seems to be reaching the surface in the subarctic Pacific gyre near the Kamchatka Peninsula. The low-C-14 water drawn up to the surface in the upwelling zones is also shown to spread across the ocean basins. It is easily seen, for example, in the western Atlantic off Florida and in the western Pacific off New Guinea and Palau. The spreading allows one to estimate the volumes of upwelling, which, it turns out, are similar to the volumes of large-scale upwelling derived from inverse box models. This means that very large volumes of cool subsurface water are reaching the surface in and near the upwelling zonesmuch larger volumes than would be expected from the local winds.

Plain Language Summary The deep layers of the ocean are filled with cold dense water that sinks from the surface near Antarctica and in the northern North Atlantic. This process is understood reasonably well. The countervailing processthe way that the dense water is brought back up to the surfaceis not as well understood. Oceanographers now agree that the ocean{\textquoteright}s deep water is drawn back up to the surface (upwelled) mainly around Antarctica as part of the wind-driven overturning in the Antarctic Circumpolar Current (ACC). But cool water is also known to reach the surface in upwelling zones around the ocean{\textquoteright}s margins. Here we map the upwelling north of the ACC with the radioactive isotope carbon-14 and show that the deep water upwelled to the surface around Antarctica seems to be drawn up to the surface a second time in the upwelling zones. The water drawn up to the surface in the upwelling zones then flows back to the North Atlantic and sinks again to complete the cycle.},
	keywords = {Ocean circulation, overturning circulation, radiocarbon, Upwelling},
	issn = {2169-9275},
	doi = {10.1029/2018JC014794},
	url = {https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JC014794},
	author = {Toggweiler, J. R. and Druffel, Ellen R. M. and Key, Robert M. and Galbraith, Eric D.}
}
@article {2645,
	title = {Upwelling in the Ocean Basins North of the ACC: 2. How Cool Subantarctic Water Reaches the Surface in the Tropics},
	journal = {Journal of Geophysical Research: Oceans},
	volume = {124},
	year = {2019},
	month = {Apr-04-2020},
	pages = {2609 - 2625},
	abstract = {Large volumes of cool water are drawn up to the surface in the tropical oceans. A companion paper shows that the cool water reaches the surface in or near the upwelling zones off northern and southern Africa and Peru. The cool water has a subantarctic origin and spreads extensively across the Atlantic and Pacific basins after it reaches the surface. Here, we look at the spreading in two low-resolution ocean general circulation models and find that the spreading in the models is much less extensive than observed. The problem seems to be the way the upwelling and the spreading are connected (or not connected) to the ocean{\textquoteright}s large-scale overturning. As proposed here, the cool upwelling develops when warm buoyant water in the western tropics is drawn away to become deep water in the North Atlantic. The drawing away shoals the tropical thermocline in a way that allows cool subantarctic water to be drawn up to the surface along the eastern margins. The amounts of upwelling produced this way exceed the amounts generated by the winds in the upwelling zones by as much as 4 times. Flow restrictions make it difficult for the warm buoyant water in our models to be drawn away.

Plain Language Summary A companion paper uses the radioactive isotope carbon-14 to map the upwelling in the ocean basins north of the Antarctic Circumpolar Current (ACC). It shows that deep water drawn up to the surface to the south of the ACC is drawn up to the surface a second time in a number of upwelling areas in the tropics. In this paper, we attempt to simulate the tropical upwelling in an ocean circulation model and find that it is largely missing. Other circulation features are missing as well. The other features operate on the opposite sides of the ocean basins from the upwelling areas and help carry warm water out of the tropics (outflows). The combination of missing elements leads to a hypothesis about the upwelling mechanism. Our hypothesis is that the tropical upwelling is driven by the outflows and the fact that the warm water being carried away ultimately becomes deep water again in the North Atlantic.},
	keywords = {numerical modeling, Ocean circulation, overturning circulation, Upwelling},
	issn = {2169-9275},
	doi = {10.1029/2018JC014795},
	url = {https://www.researchgate.net/publication/331524382_Upwelling_in_the_Ocean_Basins_north_of_the_ACC_Part_1_On_the_Upwelling_Exposed_by_the_Surface_Distribution_of_D_14_C},
	author = {Toggweiler, J. R. and Druffel, Ellen R. M. and Key, Robert M. and Galbraith, Eric D.}
}
@article {162,
	title = {Photochemical reactivity of ancient marine dissolved organic carbon},
	journal = {Geophysical Research Letters},
	volume = {39},
	year = {2012},
	note = {id: 2249; PT: J; TC: 0; UT: WOS:000309136800001},
	pages = {L18602-L18602},
	abstract = {Marine dissolved organic carbon (DOC) is the largest reservoir of reduced carbon in seawater and persists up to 4,000-6,000 conventional radiocarbon (C-14) years on average. Photochemical degradation has been suggested as a geochemical sink for these long-lived molecules, yet there have been no studies relating photochemical lability to the C-14-ages of surface DOC. We observed apparent second order (2 degrees) kinetics with respect to DOC and a strong trend from Delta C-14-enriched to depleted values during exhaustive photomineralization of surface marine DOC with high energy UV light. Geochemically, these results suggest that surface DOC is an isotopically-heterogeneous mixture of molecules for which photochemical lability and C-14 ages are correlated. Photochemical mineralization may therefore be an important control on the persistence of C-14-depleted DOC in the ocean. Citation: Beaupre, S. R., and E. R. M. Druffel (2012), Photochemical reactivity of ancient marine dissolved organic carbon, Geophys. Res. Lett., 39, L18602, doi:10.1029/2012GL052974.},
	issn = {0094-8276},
	doi = {10.1029/2012GL052974},
	author = {Beaupr{\'e}, Steven R. and Druffel, Ellen R. M.}
}
@article {317,
	title = {A new look at old carbon in active margin sediments RID F-1809-2010},
	journal = {Geology},
	volume = {37},
	year = {2009},
	note = {id: 1987; PT: J; UT: WOS:000263842200012},
	pages = {239-242},
	abstract = {Recent studies suggest that as much as half of the organic carbon (OC) undergoing burial in the sediments of tectonically active continental margins may be the product of fossil shale weathering. These estimates rely on the assumption that vascular plant detritus spends little time sequestered in intermediate reservoirs such as soils, freshwater sediments, and river deltas, and thus only minimally contributes to the extraneously old (14)C ages of total organic matter often observed on adjacent shelves. Here we test this paradigm by measuring the (14)C and delta(13)C values of individual higher plant wax fatty acids as well as the d13C values of extractable alkanes isolated from the Eel River margin (California). The isotopic signatures of the long chain fatty acids indicate that vascular plant material has been sequestered for several thousand years before deposition. A coupled molecular isotope mass balance used to reassess the sedimentary carbon budget indicates that the fossil component is less abundant than previously estimated, with pre-aged terrestrial material instead composing a considerable proportion of all organic matter. If these findings are characteristic of other continental margins proximal to small mountainous rivers, then the importance of petrogenic OC burial in marine sediments may need to be reevaluated.},
	issn = {0091-7613},
	doi = {10.1130/G25351A.1},
	author = {Drenzek, Nicholas J. and Hughen, Konrad A. and Montlu{\c c}on, Daniel B. and Southon, John R. and dos Santos, Guaciara M. and Druffel, Ellen R. M. and Giosan, Liviu and Eglinton, Timothy I.}
}
@article {1991,
	title = {Blank correction for Delta 14C measurements in organic compound classes of oceanic particulate matter},
	journal = {Radiocarbon},
	volume = {47},
	year = {2005},
	note = {id: 1054},
	month = {2005},
	pages = {75-87},
	author = {Hwang, Jeomshik and Druffel, Ellen R. M.}
}
@article {2047,
	title = {Temporal variability of Delta 14C, delta13C, and C/N in sinking particulate organic matter at a deep time series station in the northeast Pacific Ocean},
	journal = {Global Biogeochemical Cycles},
	volume = {18},
	year = {2004},
	note = {id: 531},
	month = {2004},
	pages = {1-9},
	author = {Hwang, Jeomshik and Druffel, Ellen R. M. and Griffin, Sheila and L, Smith Kenneth, Jr. and Baldwin, Roberta J. and Bauer, James E.}
}
@article {2077,
	title = {Lipid-Like material as the source of the uncharacterized organic carbon in the ocean?},
	journal = {Science},
	volume = {299},
	year = {2003},
	note = {id: 530},
	month = {2003},
	pages = {881-884},
	author = {Hwang, Jeomshik and Druffel, Ellen R. M.}
}
@article {2339,
	title = {Seasonal variability of particulate organic radiocarbon in the northeastern Pacific},
	journal = {Journal of Geophysical Research},
	volume = {101},
	year = {1996},
	note = {id: 1239},
	month = {1996},
	pages = {20543-20552},
	author = {Druffel, Ellen R. M. and Bauer, J. E. and Williams, P. M. and Griffin, S. and Wolgast, D.}
}
