Nitrate assimilation and regeneration in the Barents Sea: insights from nitrate isotopes
نویسندگان
چکیده
Abstract. While the entire Arctic Ocean is warming rapidly, Barents Sea in particular experiencing significant and sea ice retreat. An increase ocean heat transport from Atlantic causing to be transformed a cold, salinity-stratified system into warmer, less-stratified Atlantic-dominated climate regime. Productivity shelf fuelled by waters of origin (AW) which are ultimately exported Basin. The consequences this current regime shift on nutrient characteristics poorly defined. Here we use stable isotopic ratios nitrate (?15N-NO3, ?18O-NO3) determine uptake modification AW nutrients Sea. In summer months, phytoplankton consume nitrate, surface become depleted, particulate nitrogen (?15N-PN) reflects source. ammonification organic matter shallow sediments resupplies N water column replenishes inventory for following season. Low ?18O-NO3 northern reveals that lower-temperature > 80 % regenerated through seasonal nitrification. During on-shelf regeneration, there no change ?15N-NO3 or N*, suggesting benthic denitrification does not impart an imprint pelagic nitrate. Our results demonstrate distinct other shelves where enriches decreases N*. As efficiently recycled loss denitrification, changes productivity unlikely alter availability magnitude advected central However, suggest source determines delivery have potential primary production subsequent supply Ocean.
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ژورنال
عنوان ژورنال: Biogeosciences
سال: 2021
ISSN: ['1726-4189', '1726-4170']
DOI: https://doi.org/10.5194/bg-18-637-2021