Seasonal and inter-annual variability of the phytoplankton communities in an upwelling area of the Alborán Sea (SW Mediterranean Sea)

摘要: Temporal variability (seasonal and inter-annual) in the assembly of phytoplankton communities from northern Alboran Sea was investigated. For this purpose, taxonomic composition micro- nano-phytoplankton at three fixed stations determined every months 1994 to 2002. A total 357 different taxa were identified. Most them (about 54%) diatom species belonging 57 genera. Dinoflagellates coccolitophorids accounted for 118 30 respectively. Two time periods could be differentiated with respect cell abundance. Thus, mean abundance 1999 338 ml-1 it dropped about 60 during period 2000-2002. Diatoms un-identified small flagellates dominated first period, although a significant increase occurred after 1997. Pseudo-nitzschia, Leptocylindrus Chaetoceros dominant In contrast, Emiliania huxleyi Gephyrocapsa spp. quantitatively 2000 These shifts community assessed by performing sample-oriented stepwise discriminant analysis (SDA). The separated samples into year-groups, great inter-annual variability. SDA did not find any seasonal sucessional pattern. spite result, chlorophyll tended higher spring which has been described whole basin. nutrient concentrations 75 m upper seawater layer had fluctuations. NO3-+NO2-, PO4-3 Si(OH)4 decreased significantly 1997-1998. Additionally, lower Si:P molar ratios obtained 2000. results suggest that due alterations regime. paper we discuss possible rationale these changes.