ABSTRACT: In this study, we confirm the relationship between temperature and Synechococcus sp. experimental growth rates (r = 0.87, p < 0.005) and provide evidence of the existence of a general relationship. This link leads to a strong seasonality of abundance and biomass of Synechococcus sp. in the Bay of Blanes (NW Mediterranean), which was followed for 2 yr (1995, 1996), with high values in summer months (6 x 10⁷ cells l^-1) and low values in winter (5 x 10⁵ cells l^-1). The growth rate achieved in summer months (1.5 d^-1) is close to or at the maximum possible at the in situ water temperature. As a result, Synechococcus growth may exceed the grazing capacity of its predators in summer, and this explains its significant contribution of >30% of the total gross autotrophic production and >20% of the total autotrophic biomass in summer. Thus, Synechococcus is an important source of organic C and nutrients for the coastal Mediterranean food web in the summer.

KEY WORDS: Synechococcus sp. · NW Mediterranean Sea · Growth and abundance · Temperature

Published in MEPS Vol. 170 (1998) on September 3
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1998