Short‐term variability of aragonite saturation state in the central <scp>M</scp>id‐<scp>A</scp>tlantic <scp>B</scp>ight

Abstract

Abstract The uptake of anthropogenic carbon dioxide (CO 2 ) from the atmosphere has resulted in a decrease in seawater aragonite saturation state (Ω arag ), which affects the health of carbonate‐bearing organisms and the marine ecosystem. A substantial short‐term variability of surface water Ω arag , with an increase of up to 0.32, was observed in the central Mid‐Atlantic Bight off the Delaware and the Chesapeake Bays over a short period of 10 days in summer 2015. High‐frequency underway measurements for temperature, salinity, percentage saturation of dissolved oxygen, oxygen to argon ratio, pH, f CO 2 , and measurements based on discrete samples for pH, dissolved inorganic carbon, and total alkalinity are used to investigate how physical and biogeochemical processes contribute to the changes of Ω arag . Quantitative analyses show that physical advection and mixing processes are the dominant forces for higher Ω arag in slope waters while biological carbon removal and CO 2 degassing contribute to increased Ω arag in shelf waters.