Late spring nitrate distributions beneath the ice-covered northeastern Chukchi Shelf


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Reiner.Schlitzer [ at ] awi.de

Abstract

Measurements of late springtime nutrient concentrations in Arctic waters are relatively rare due to the extensive sea ice cover that makes sampling difficult. During the SUBICE cruise in May-June 2014, an extensive survey of hydrography and pre-bloom nutrient concentrations was conducted in the Chukchi Sea. Cold (< -1.5°C) winter water was prevalent throughout the Chukchi Sea shelf, and the water column was weakly stratified. Nitrate (NO3-) concentration averaged 12.6±1.92 µM in surface waters and 14.0±1.91 µM near the bottom and was significantly correlated with salinity. The highest NO3- concentrations were associated with winter water within the Central Channel flow path. NO3- concentrations were much reduced near the northern shelfbreak within the upper halocline waters of the Canada Basin and along the eastern side of the shelf near the Alaskan coast. Net community production (NCP), estimated as the difference in depth-integrated NO3- content between spring (this study) and summer (historical), varied from 28-38 g C m-2 a-1. This is much lower than previous NCP estimates using NO3- concentrations from the southeastern Bering Sea as a baseline. These results demonstrate the importance of using local profiles of NO3- measured as close to the beginning of the spring bloom as possible when estimating NCP.



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Article
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Peer-reviewed
Publication Status
Published
Eprint ID
45438
DOI 10.1002/2017JG003881

Cite as
Arrigo, K. R. , Mills, M. M. , van Dijken, G. L. , Lowry, K. E. , Pickart, R. and Schlitzer, R. (2017): Late spring nitrate distributions beneath the ice-covered northeastern Chukchi Shelf , Journal of Geophysical Research-Biogeosciences . doi: 10.1002/2017JG003881


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