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Title: Dissolved Organic Matter in the Global Ocean: A Primer
Marine dissolved organic matter (DOM) holds ~660 billion metric tons of carbon, making it one of Earth’s major carbon reservoirs that is exchangeable with the atmosphere on annual to millennial time scales. The global ocean scale dynamics of the pool have become better illuminated over the past few decades, and those are very briefly described here. What is still far from understood is the dynamical control on this pool at the molecular level; in the case of this Special Issue, the role of microgels is poorly known. This manuscript provides the global context of a large pool of marine DOM upon which those missing insights can be built.  more » « less
Award ID(s):
2023500
PAR ID:
10293016
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Gels
Volume:
7
Issue:
3
ISSN:
2310-2861
Page Range / eLocation ID:
128
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  2. ; ; (, Global Biogeochemical Cycles)
    Abstract Surface ocean marine dissolved organic matter (DOM) serves as an important reservoir of carbon (C), nitrogen (N), and phosphorus (P) in the global ocean, and is produced and consumed by both autotrophic and heterotrophic communities. While prior work has described distributions of dissolved organic carbon (DOC) and nitrogen (DON) concentrations, our understanding of DOC:DON:DOP stoichiometry in the global surface ocean has been limited by the availability of DOP concentration measurements. Here, we estimate mean surface ocean bulk and semi‐labile DOC:DON:DOP stoichiometry in biogeochemically and geographically defined regions using newly available marine DOM concentration databases. Global mean surface ocean bulk (C:N:P = 387:26:1) and semi‐labile (C:N:P = 179:20:1) DOM stoichiometries are higher than Redfield stoichiometry, with semi‐labile DOM stoichiometry similar to that of global mean surface ocean particulate organic matter (C:N:P = 160:21:1) reported in a recent compilation. DOM stoichiometry varies across ocean basins, ranging from 251:17:1 to 638:43:1 for bulk and 83:15:1 to 414:49:1 for semi‐labile DOM C:N:P, respectively. Surface ocean DOP concentration exhibits larger relative changes than DOC and DON, driving surface ocean gradients in DOC:DON:DOP stoichiometry. Inferred autotrophic consumption of DOP helps explain intra‐ and inter‐basin patterns of marine DOM C:N:P stoichiometry, with regional patterns of water column denitrification and iron supply influencing the biogeochemical conditions favoring DOP use as an organic nutrient. Specifically, surface ocean marine DOM exhibits increasingly P‐depleted stoichiometries from east to west in the Pacific and from south to north in the Atlantic, consistent with patterns of increasing P stress and alleviated iron stress. 
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    Francois Morel (Ed.)
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