Temporal and spatial distribution of transparent exopolymer particles off the northern coast of Baja California, Mexico
Transparent exopolymer particles (TEP) have been reported as a significant fraction of organic microgels in different oceans. No TEP data have been published for the California Current region off Baja California that indicate the potential contribution of this reservoir to the carbon budget. We meas...
| Autores: | , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | México |
| Recursos: | Universidad Autónoma de Baja California |
| Repositorio: | Redalyc-UABC |
| OAI Identifier: | oai:redalyc.org:48054149004 |
| Acesso em linha: | https://www.redalyc.org/articulo.oa?id=48054149004 |
| Access Level: | acceso abierto |
| Palavra-chave: | Ciencias de la Tierra Hydrography California Current Community respiration Bacterioplankton abundance Transparent exopolymer particles |
| Resumo: | Transparent exopolymer particles (TEP) have been reported as a significant fraction of organic microgels in different oceans. No TEP data have been published for the California Current region off Baja California that indicate the potential contribution of this reservoir to the carbon budget. We measured TEP in seawater samples, using t he spectrophotometric method with alcian blue stain, and additi onal envi- ronmental and biological variables during 3 seasons at coastal stations between ~1.4 and 12.0 mi offshore, near 31ºN. Concentr ations of TEP obtained with 0.45 μm pore size filters showed spatial and temp oral distributions with a tendency to increase from offshore to nearshore and from winter to summer, respectively, ranging from undetectable values to 7.18 μg XG eq·mL −1 (median: 0.70). A significant positive correlation was observed between the concentration of TEP and bacterioplank ton abundance ( P < 0.05), and between total organic carbon and bacterio- plankton abundance ( P < 0.05). Transparent exopolymer particles also presented a neg ative correlation with community respiration ( P < 0.05), suggesting that TEP provided a physical substrate for settlemen t of prokaryotic microorganisms but probably did not supply lab ile carbon. We compared the concentration of alcian blue stainable particles r etained by the standard 0.45 μm pore size with the concentratio n obtained with 0.22 μm filters; the latter showed 1.7 to 64.0 fold (median: 4. 1) higher TEP concentrations. This strong dependence of TEP con centration on pore size makes it difficult to define the quantitative contrib ution of TEP and their precursors to particulate organic matter and their role in the carbon cycle. Further studies on TEP in the Mexican portion of the California Current must corroborate the observed spatia l and seasonal trends, and estimate a TEP-to-carbon conversion factor that pro vides a better approximation to its contribution to the regiona l carbon budget. |
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