Phytoplankton community adaptation to changing light levels in the southern Beaufort Sea, Canadian Arctic

Atsushi Matsuoka (1) , Pierre Larouche , Michel Poulin (2) , Warwick Vincent (3) , Hiroshi Hattori

1 LOV - Laboratoire d'océanographie de Villefranche
2 GEOSCIENCES - Centre de Géosciences
3 Département de Biologie [Université Laval]

The chlorophyll a specific absorption coefficient of phytoplankton, a(phi)*(lambda) is an important parameter to determine for primary production models and for the estimation of phytoplankton physiological condition. Knowledge of this parameter at high latitudes where nutrient rich cold water submitted to low incident light is a common environment is almost nonexistent. To address this issue, we investigated the light absorption properties of phytoplankton as a function of irradiance, temperature, and nutrients using a large data set in the southern Beaufort Sea during the open water to ice cover transition period. The a(phi)*(lambda) tended to increase from autumn when open water still existed to early winter when sea ice cover was formed, resulting from a biological selection of smaller-size phytoplankton more efficient to absorb light. There was no significant correlation between a(phi)*(lambda) and irradiance or temperature for both seasons. However, a(phi)*(lambda) showed a significant positive correlation with NO3 + NO2. Implications of the results for phytoplankton community adaptation to changing light levels are discussed. (C) 2009 Elsevier Ltd. All rights reserved.

Domaines: Océanographie

Atsushi Matsuoka, Pierre Larouche, Michel Poulin, Warwick Vincent, Hiroshi Hattori. Phytoplankton community adaptation to changing light levels in the southern Beaufort Sea, Canadian Arctic. ESTUARINE COASTAL AND SHELF SCIENCE, 2009, 82 (3), pp.537-546. ⟨10.1016/j.ecss.2009.02.024⟩. ⟨hal-03505026⟩