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| Etheridge, S.M.; Roesler, C.S.; Pitcher, G.C.. |
| A forward reflectance model is used to demonstrate the sensitivity of hyperspectral ocean color observations to phytoplankton biomass, species composition and cell size. An inverse ocean color model is developed which has explicit terms for 5 taxonomic groups of phytoplankton. The model expresses the contributions of each group in terms of the magnitude of the absorption coefficient, which is proportional to biomass. The model is applied to a time series of reflectance data from an expansive red tide off the west coast of South Africa. The results compare favorably with those derived from microscopic cell counts. This demonstrates the utility of in situ ocean color detection of the composition and concentration of potentially harmful algae. |
| Tipo: Report |
Palavras-chave: Algae; Plankton studies; Phytoplankton; Colorimetric techniques. |
| Ano: 2000 |
URL: http://hdl.handle.net/1834/826 |
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| Pitcher, G.C.; Roesler, C.S.; Etheridge, S.M.. |
| Abalone were grown: on diets of 1) artificial feed, 2) kelp, their in situ food source, which contained saxitoxin (STX) derivatives, and 3) in filtered seawater without a food source, to investigate the depuration and transformation of toxins under feeding and starving conditions. The abalone were toxic at the start of each treatment (~160 µg STX eq 100 g-1 tissue). They depurated at a rate of 6.27 µg STX eq 100 g-1 tissue d-1 over the 2 week incubation period when fed artificial feed; however, no depuration was observed in starved or kelp-fed animals. Toxin transformations occurred in abalone for each treatment. Toxin derivatives decreased in organisms fed artificial feed, and no B1 was detected during this treatment. Toxin composition was not... |
| Tipo: Working Paper |
Palavras-chave: Toxins. |
| Ano: 2003 |
URL: http://hdl.handle.net/1834/376 |
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