Phytoplankton responses to increasing Arctic river discharge under the present and future climate simulations

• Published in: Environmental Research Letters
• Main Authors: Jung Hyun Park, Seong-Joong Kim, Hyung-Gyu Lim, Jong-Seong Kug, Eun Jin Yang, Baek-Min Kim
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2023
• Subjects: river discharge; Arctic Ocean; phytoplankton; sea ice concentration; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Arctic; Canada; Chukchi Sea; East Siberian Sea; Kara Sea; canada basin; Chukchi; Phytoplankton; Sea ice
• Online Access: https://doi.org/10.1088/1748-9326/acd568; https://doaj.org/article/ba07287795514e65805c71a5c4096ce5

In recent decades, the unprecedented rate of Arctic warming has accelerated the high-latitude landmass hydrological cycle, leading to increased river discharge into the Arctic Ocean. This study elucidates the role of Arctic river discharge, which was the large model uncertainty in the Coupled Model Intercomparison Project 6, for the phytoplankton responses in present-day and future climate simulations by adding fresh water into the model. In the present-day climate simulation, additional river discharge decreases the spring phytoplankton biomass. Freshening of Arctic seawater facilitates freezing, increasing sea ice concentration in spring and eventually decreasing phytoplankton due to less availability of light. On the other hand, in the summer, phytoplankton increases due to the surplus of surface nitrate and the increase in the vertical mixing induced by the reduced summer sea ice melting water. In the future climate, the plankton response to the additional freshwater input is similar to the present-day climate. Nevertheless, the major phytoplankton responses are shifted from the Eurasian Basin to the Canada Basin and the East-Siberian Sea, mainly due to the marginal sea ice zone shift from the Barents-Kara Sea to the East Siberian-Chukchi Sea in the future.