Abstract
In summer season, huge amount of fresh water is supplied from Mackenzie River in the south-eastern area in Beaufort Sea, Canada. This seasonal event drastically fluctuates the oceanic condition for the growth of microalgae such as irradiance, salinity, temperature and nutrient. In this study, we investigated the photosynthetic properties of phytoplankton collected from surface water (less than 5 m) during summer season (from 13 May to 04 Aug, 2004) in Beaufort Sea by using a pulse amplitude modulation fluorometer (Phyto-PAM).
The properties of photosynthesis in phytoplankton assessed in this work were influenced by irradiance rather than salinity, nutrients, or temperature. The values of the maximum yield of photosystem II (Fv/Fm), the maximal electron transport rate (rETRmax) and the maximum of NPQ (NPQmax) decreased according to the increase of irradiance. In summer season, the photosynthetic activity in phytoplankton was suppressed by irradiance in this area.
