Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal) during the summer of 2001

• Autores: Sofia Loureiro, John D. Icely, Alice Newton
• Localización: Scientia Marina, ISSN 0214-8358, Vol. 69, Nº. 3, 2005, págs. 323-341
• Idioma: inglés
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• Resumen

  • Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal) during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling centre off Cabo S. Vicente, and 2 km west of an offshore installation for bivalve aquaculture. Three major periods were distinguished according to sea surface temperature (SST): period 1 (P1; May and June), characterised by high temperature values (17.0±1.8°C); period 2 (P2; July), characterised by lower temperatures (14.6±0.3°C), identified as an upwelling-blooming stage; and period 3 (P3; August), characterised by a high temperature pattern (16.25±1.14°C). Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. and Pseudo-nitzschia spp. were the major taxa contributing to the dissimilarities between P2 (July) and the other periods. In July (P2), the average gross production (GP; 52.5±12.3 µM O2 d-1) and net community production (NCP; 46.9±15.3 µM O2 d-1) peaked with the maximal concentrations of diatom-chl a. Dark community respiration (DCR) remained low and more constant throughout (4.6±3.6 µM O2 d-1). The plankton assemblage was dominated by diatoms throughout the survey. Physical events were the primary factors determining the microplankton structure and distribution at this location