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Detailed Reference Information |
Santschi, P.H., Hung, C., Schultz, G., Alvarado-Quiroz, N., Guo, L., Pinckney, J. and Walsh, I. (2003). Control of acid polysaccharide production and 234Th and POC export fluxes by marine organisms. Geophysical Research Letters 30: doi: 10.1029/2002GL016046. issn: 0094-8276. |
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Ratios of particulate organic carbon (POC) to particulate 234Th activities (POC/234Th) in the ocean are used to determine the POC export flux, and thus, the power of the biological pump. In order to understand the main reasons why this ratio frequently varies as a function of depth, size, and kind (suspended vs. sinking particles), we measured vertical profiles in a cold core ring and warm core ring in the Gulf of Mexico in May 2001. Here we show that particulate 234Th/POC ratios in the Gulf of Mexico are positively correlated to the content of different Th(IV)-binding polysaccharide fractions (uronic acids, total acid polysaccharides, total polysaccharides) in both suspended and sinking particles as well as to prymnesiophyte abundance, but negatively correlated to bacterial production. Variations in acid polysaccharide compounds, produced by both algae and bacteria, but degraded only by bacteria, can account for observed variations in POC/234Th ratios seen in the ocean. |
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Abstract |
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Keywords
Oceanography, Biological and Chemical, Biogeochemical cycles, Oceanography, Biological and Chemical, Radioactivity and radioisotopes, Oceanography, Biological and Chemical, Chemical speciation and complexation |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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