Phosphonates and Particulate Organic Phosphorus Cycling in an Anoxic Marine Basin

Total particulate phosphorus (TPP), particulate inorganic P (PIP), and particulate organic P (POP) concentrations were measured in a year-long series of sediment trap samples collected throughout the oxic-anoxic water column (275 m, 455 m, 930 m, and 1,255 m) of the Cariaco Basin. TPP, PIP, and POP...

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Bibliographic Details
Published in:Limnology and oceanography 2004-09, Vol.49 (5), p.1593-1604
Main Authors: Benitez-Nelson, C. R., O'Neill, Lauren, Kolowith, Lauren C., Pellechia, Perry, Thunell, Robert
Format: Article
Language:English
Subjects:
Earth sciences
Earth, ocean, space
Esters
Exact sciences and technology
External geophysics
Geochemistry
Marine
Mineralogy
Oceans
Particulate matter
Phosphates
Phosphonic acids
Phosphorus
Phosphorus cycle
Physical and chemical properties of sea water
Physics of the oceans
Plankton
Sea water
Sediments
Silicates
Water geochemistry
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Summary:Total particulate phosphorus (TPP), particulate inorganic P (PIP), and particulate organic P (POP) concentrations were measured in a year-long series of sediment trap samples collected throughout the oxic-anoxic water column (275 m, 455 m, 930 m, and 1,255 m) of the Cariaco Basin. TPP, PIP, and POP fluxes varied seasonally and decreased significantly with depth, from 65 to 19 μmol TPP m-2 d-1, 43 to 8 μmol PIP m-2 d-1, and 22 to 11 μmol POP m-2 d-1. Significant flux relationships (p < 0.001) were found between POP and particulate organic carbon (POC) and particulate organic nitrogen (PON). The lack of a relationship between POC and PIP fluxes and the large fraction of TPP associated with the PIP pool in both oxic and anoxic traps suggests that future analyses must separate PIP and POP when evaluating biological relationships between C, N, and P. The strong relationships between POC, PON, and POP also suggest that POP is not preferentially remineralized relative to PON and POC with increasing depth in this anoxic environment. P composition was also determined using solid state 31P nuclear magnetic resonance (NMR), and it was found that phosphonates, chemically and thermally inert compounds, are a significant fraction of the TPP pool. Furthermore, these compounds were preferentially removed relative to more bioavailable P esters during a low flux event. Their selective removal suggests that these compounds may be an unrecognized source of bioavailable P under anoxic conditions.
ISSN:0024-3590
1939-5590
DOI:10.4319/lo.2004.49.5.1593