Influence of local environmental conditions on the seasonal acclimation process and the daily integrated production rates of Laminaria digitata (Phaeophyta) in the English Channel
Abstract
Two populations of Laminaria digitata (Hudson) Lamouroux (Ann Mus Hist Nat Paris 20:21-47, 1813) were examined for their seasonal photosynthetic acclimation to clear and turbid-light environments along the French coast of the English Channel. Photosynthesis-irradiance curves, pigment concentrations and the daily in situ integrated oxygen production rates were measured in both populations. Despite the great differences in light attenuation between the sites, the two populations achieved similar oxygen production rates in the field, in relation to high maximal photosynthetic rates, total pigment concentrations and antenna (fucoxanthin + chlorophyll c)/chl a pigment ratios in sporophytes from the turbid environment. Environmental conditions (i.e. light, temperature and nitrogen availability) changed throughout the year in both sites. While the seasonal acclimation trends were evident in the clear-light environment, the strategy in the turbid-light environment differed, tending to maximize light capture throughout the year. This study highlights the diversity of the response of a single species to contrasted light environments.