Mooring Measurements of Anadyr Current Nitrate, Phosphate, and Silicate Enable Updated Bering Strait Nutrient Flux Estimates
Tyler D. Hennon, Seth L. Danielson, Rebecca A. Woodgate, Brita Irving, Dean A. Stockwell, Calvin W. Mordy
Abstract
Abstract In situ nutrient concentration data and salinity‐nutrient parameterizations established at Anadyr Strait from June 2017 to June 2018 are used to estimate monthly Pacific‐to‐Arctic fluxes of nitrate, phosphate, and silicate through Bering Strait over 1997–2019. In most months our estimates rely on measurements made from mooring‐based sensors and whole water samples, while over May–August the basis is shipboard hydrography. We find annually averaged Bering Strait fluxes of 16 ± 6, 1.5 ± 0.5, and 30 ± 11 kmol/s for nitrate, phosphate, and silicate, respectively, with inter‐annual variability ±30% of the mean. Maximum fluxes occur in April, exceeding the annual average by ∼50%, while minimum fluxes occur in December. Annually averaged fluxes estimated here are ∼50% higher than previous estimates. Significant ( p < 0.05) increasing trends in phosphate and silicate fluxes are found over 1998–2018, but not nitrate. However, it is unclear if these trend results are due to differences in draw‐down or limitations of the salinity‐nutrient parameterizations.