In an Arctic glacial fjord, the phytoplankton bloom is controlled by light transparency together with nutrient supply and Atlantic inflow. To explore the issues of climate change and glacial melting in an Arctic fjord, the biological and physiochemical environments of Kongsfjorden, a glacial fjord in Svalbard, have been investigated. The hydrography of Kongsfjorden is controlled by the water mass balance of Atlantic inflow, Arctic waters, and glacial melt through the cross-shelf exchange, and its dominant water masses are determined according to the temperature-salinity diagram.