Siliceous plankton dominate primary and new productivity during the onset of El Niño conditions in the Santa Barbara Basin, California
Shipe, R.F.; Brzezinski, M. (2003). Siliceous plankton dominate primary and new productivity during the onset of El Niño conditions in the Santa Barbara Basin, California. J. Mar. Syst. 42(3-4): 127-143. https://dx.doi.org/10.1016/S0924-7963(03)00071-X
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, meer
Ook verschenen in:Runcie, J.W.; Smith, J.E. (Ed.) (2003). Nutrient dynamics in coastal ecosystems - linking physical and biological processes. Journal of Marine Systems, 42(3-4). [S.n.]: [s.l.]. 81-157 pp., meer
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| Trefwoorden |
Algae > Diatoms
Biological production > Primary production
Chemical compounds > Nitrogen compounds > Nitrates
Chemical compounds > Silicon compounds > Silica
El Nino phenomena
Uptake
Marien/Kust |
| Author keywords |
diatoms; El Nino; new production; nitrate uptake; primary production;silica production |
| Auteurs | | Top |
- Shipe, R.F.
- Brzezinski, M.
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| Abstract |
The potential for carbon export and the role of siliceous plankton in the cycling of C and N was assessed in natural plankton assemblages in the Santa Barbara Basin, California, by examining uptake rates of inorganic carbon, nitrate and silicic acid. In April–August 1997, the concentrations of chlorophyll a, particulate organic carbon, particulate organic nitrogen and biogenic silica were measured twice monthly, and results revealed the occurrence of at least three blooms, the largest in June. Particulate elemental ratios of C, N and Si were similar to ratios of nutrient-replete diatoms, suggesting that they dominated this bloom. Mean integrated rates of carbon, nitrate and silicon uptake during the 4-month study period are similar to other productive coastal and upwelling regions (103, 8.3 and 13 mmol m−2 day−1, respectively). New production rates were twice as high as previously reported in this region and indicate that high rates of new production along eastern boundary currents are not confined to the major coastal upwelling regions. C/NO3−, Si/NO3− and Si/C uptake ratios varied widely, and mean integrated ratios were 14±5.4, 1.6±1.0 and 0.12±0.07 (S.D.), respectively. That mean C/NO3− uptake ratio corresponds to an f-ratio of about 0.5 indicating a large potential for particulate export. Based on the average Si/NO3− and Si/C uptake ratios, diatoms could perform all of the primary production and nitrate uptake that occurred during the study; these rates also suggest that export is controlled by diatoms in this system. The mean Si/C biomass ratio was lower than the mean Si/C uptake ratio, consistent with the preferential export of Si relative to C observed in sediment traps in the basin. The study took place during a period of surface-water warming, with nitrate and silicic acid concentrations decreasing throughout the onset of the 1997–1998 El Niño conditions. Although diatoms contributed less to particulate biomass during the low nutrient conditions, high f-ratios (0.33–0.66) were maintained. |
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