Sea-Air Flux Estimates In the Northern Labrador Sea and Baffin Bay

Every year since 2003, the CCGS Amundsen welcome on board teams from Canada and abroad for Arctic multidisciplinary scientific expeditions. As the Arctic is a rapidly warming region, it is necessary to study this area in order to learn more about future climate trends and impacts. In summer 2021, between July 20th and August 10th, Judith Vogt was on board the CCGS Amundsen to measure the atmospheric methane (CH4) levels continuously in a corridor between St. John’s (Newfoundland) and Iqaluit (Nunavut) in order to detect early signs of CH4 release. In fact, vast amounts of CH4 stored in submarine sediments are prone to being released as the Arctic warms. This release has the potential to intensify climate changes in a positive feedback.

From high-resolution atmospheric CH4 measurements and discrete surface water samples, Judith Vogt’s team estimated instantaneous sea–air CH4 fluxes at various locations. In addition, they measured CH4 concentrations across the water column at various stations using the CTD rosette. In the northern Labrador Sea and Baffin Bay, the continuous measurements of atmospheric CH4 levels in the northern Labrador Sea and Baffin Bay were consistently higher than the global marine average with small instantaneous input from the ocean. These findings indicate that variations in dissolved CH4 concentrations were mainly affected by ocean currents and seafloor sources. However, atmospheric CH4 levels showed interrelations with environmental factors, location, and time, with minor temporal fluctuations. Deeper investigation is required to validate potential sources of CH4 and to elucidate the reasons behind the increased methane levels in the shallow-water region of Southwind Fjord, where recent landslides triggered by an iceberg were observed.

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