Saldanha Bay, South Africa II: estimating bay productivity
| Autor: | Grant C. Pitcher, T. A. Probyn, Marié E. Smith |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | African Journal of Marine Science. 37:513-520 |
| ISSN: | 1814-2338 1814-232X |
| Popis: | Saldanha Bay is a narrow-mouth bay on the west coast of South Africa linked to the southern Benguela upwelling system. Bay productivity was investigated by use of the conventional light-and-dark bottle oxygen method, and, for comparison, through assimilation of the stable isotope tracer 13C. Gross community production GCP and net community production NCP, as determined from the oxygen method, were respectively 2.6 and 2.4 times higher than estimates determined from the stable isotope method. Chlorophyll a (Chl a) concentrations increased with the onset of spring and well-defined subsurface maxima developed in association with increasingly stratified conditions (mean water column Chl a concentrations ranged from 5.4 to 31.5 mg m−3 [mean 15.5 mg m−3; SD 7.6]). A sharp decline in photosynthetic rates P* (GCP normalised to Chl a concentration) with depth was attributed to light limitation, as demonstrated by the high vertical attenuation coefficients for downward irradiance Kd, which varied from 0.29 to 0.70 ... |
| Databáze: | OpenAIRE |
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