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| Minas, Hj; Minas, M. |
| An analysis of tropical upwelling systems shows a great range in the rate of increase of the standing stock expressed in terms of the water column chlorophyll content. Grazing appears to be the main factor responsible for lowering the rate of increase, especially in moderate and strong High Nutrient-Low Chlorophyll (HNLC) waters. A simple model comparing Net Community Production (NCP) rates with observed chlorophyll increase rates, leads us to conclude that phytoplankton population must present high specific growth rates on a daily rhythm in order to overcome grazing. Maximum specific growth rates (V(max)) calculated for daily total production (TP) are, in the two main upwelling areas, 137 d-1 off NW Africa and 1.04 d-1 off Peru. For extreme HNLC... |
| Tipo: Text |
Palavras-chave: NUTRIENTS; NEW PRODUCTION; GRAZING; TROPICAL OCEAN; ANTARCTIC. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/00100/21149/18768.pdf |
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| Sautour, B; Castel, Jerome. |
| Zooplankton distribution in Marennes-Oleron Bay (France) varies during the year and is essentially determined by seasonal rhythms. The whole set of zooplanktonic taxa can be divided into three groups: the first bearing oceanic affinities; the second with estuarine tendencies; and the third more intermediate. Important water flows inhibit the establishment in a specific zone of an autochthonous community (this community is reduced to such species as Acartia discaudata, Acartia grani and Euterpina acutifrons). Zooplanktonic populations reach their maximum abundances at the end of spring and during summer, particularly during spring tide in the inner neritic zone. The estimation of die grazing pressure of copepods (which are the dominant taxa) is variable... |
| Tipo: Text |
Palavras-chave: MARENNES-OLERON; ZOOPLANKTON; COPEPODS; BIOMASS; GRAZING. |
| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00099/21055/18681.pdf |
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