ISSN:
1573-5117
Schlagwort(e):
tropical zooplankton
;
upwelling
;
Brazil
;
statistic analysis
;
spatial structure
;
copepod diversity
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Cabo Frio area (Central-southern Brazilian littoral) is characterized by a coastal upwelling due to prevailing E-NE winds, mainly during the spring-summer season. The geographic distribution of the zooplankton was described in order to separate ecological areas in terms of specific communities. Cluster analysis by weighted pair-group method (WPGA) and principal component (PC) analysis was performed on the most important hydrological parameters and zooplankton taxa. The first PC, explaining 38% of the total zooplankton variability, represented the influence of the nearshore-offshore gradient. Zooplankton communities and ecological areas were defined as follows: i) nearshore neritic: the richest region with more than 5 000 org. m-3. In this very narrow nearshore region we observed 3 groups of taxa deliminated by upwelling effects and trophic conditions: a) Ctenocalanus vanus, Penilia avirostris, Calanoides carinatus and Copepod larva, all herbivorous species associated with the phytoplankton blooms in the upwelling zone; b) Creseis acicula and Temora stylifera; c) Siphonophora, Chaetognaths and a high diversity of Copepoda dominated by Coryceus amazonicus, C. giesbrechti, Eucalanus pileatus, Clausocalanus acuicornis, all carnivorous or omnivorous feeders representing a high degree of complexity of the ecosystem. ii) offshore neritic: characterized by appendicularians, this region constitutes an intermediate zone between coastal and oceanic waters. iii) oceanic: occupied by the Brazil Current where zooplankton is poor, but diversified, with typical copepods from tropical warm water: Clausocalanus furcatus, Mecynocera clausi, Corycella gracilis, Oithona setigera, Coryceus typicus, Oncea conifera, Undinula vulgaris, Calocalanus pavo, Haloptilus longicornis, Lucicutia flavicornis.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00026607
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