Effects and projections of corrosive acidified Pacific water on a large scale of aragonite undersaturation in the Arctic Ocean

Chair: Kumiko Azetsu-Scott

Liqi Chen

Key Laboratory of Global Change and Marine-Atmospheric Chemistry of State Oceanic Administration (SOA), Third Institute of Oceanography, SOA, Xiamen, China. E-mail: Chenliqi@tio.org.cn

An expansion of acidifying water in the Arctic Ocean has been found from CHINARE’s investigation since last decade. Here, we present seawater CO2-carbonate chemistry and aragonite saturation data from the 2010 Chinese Antarctic Research Expedition cruise along a transect in the western Arctic Ocean from the Chukchi Sea towards 88°N in the Makarov Basin, and compare these data to measurements from the Arctic Ocean Section 94 (AOS94) cruise in 1994 to illustrate changes over the last two decades. We observed considerable aragonite undersaturation in the upper layer (<300 m) waters of Canada Basin in recent years with the greatest difference between 2010 and 1994. In 1994, the zone of aragonite undersaturation is limited to slope of Chukchi Seas. Model simulations suggest that recent significant increases in Pacific winter waters inflows via Bering Strait have contributed to widespread “corrosive acidified” waters into the Arctic Ocean Basins. In addition, although the intrusion of winter Pacific undersaturated waters into the western Arctic Ocean is a natural phenomenon in this region, increased biological processes induced by sea-ice retreat and the ocean uptake of anthropogenic CO2 have both significantly increased the areal extent of the affected area.