Spatial and temporal variation of photosynthetic parameters in natural phytoplankton assemblages in the Beaufort Sea, Canadian Arctic

摘要: During summer 2008, as part of the Circumpolar Flaw Lead system study, we measured phytoplankton photosynthetic parameters to understand regional patterns in primary productivity, including degree and timescale photoacclimation how variability environmental conditions influences this response. Photosynthesis–irradiance measurements were taken at 15 sites primarily from depth subsurface chlorophyll a (Chl a) maximum (SCM) within Beaufort Sea flaw lead polynya. The physiological response range light levels was used assess rates carbon (C) fixation (P m * ), efficiency (α *), (E k), photoinhibition (β *). SCM samples along transect under ice into open water exhibited >3-fold increase α * P , showing these can vary substantially over relatively small spatial scales, changes ambient field. Algae able maintain high C despite low SCM, particularly large (>5 μm) size fraction sites. This may impact biogenic drawdown if species composition shifts future climate change. Our results suggest that region are well acclimated existing conditions, sea cover, light, nutrient pulses. Furthermore, photoacclimatory be rapid keep pace with developing efficiencies narrow “shade-acclimated” range.