engleski

Physiological adaptation within the Chaetocerotaceae to the ecological challenges in the northern Adriatic

The northern Adriatic is a suitable ecosystem for observing phytoplankton under a variety of different ecological conditions. This shallow basin is characterized by a multitude of steep and quickly changing gradients (e.g. nutrients), both temporal and spatial. The current systems and the major freshwater input (River Po) generate strong gradients in utrient concentrations with an expressed N/P imbalance and sustained phosphate limitation. The genus Chatoceros is among the most diverse and pecies rich diatoms often dominating the phytoplankton community in the Adriatic Sea. There is a big number of species belonging to this genus with different physiology, seasonality and ecology. We analyzed species from the genus Chaetoceros, with a special focus on their metabolic eaction towards phosphate limitation. Here we report data on species-specific growth rates under different nutrient regimes, phosphate uptake rates, alkaline phosphatase activity, localization and activation patterns and characteristics of alkaline phosphatase activity. Our results demonstrate a high interspecific variation in metabolic responses to phosphate limitation in sympatric congeneric species. Ecological characteristics and hence significance and function appears hence to be defined on the species level and appears far from homogeneous within genera. This results in a highly structured planktonic ecosystem that allows for a high level of sympatric congeneric species diversity.

phytoplankton ; Adriatic sea ; diatoms ; Chaetoceros ; APA ; phosphorus limitation

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