Stratification in the northern Bering Sea in early summer of 2017 and 2018

Autor: Keiri Imai, Ryo Dobashi, Toru Hirawake, Zhaoqianyi Ji, Mizuki Komatsu, Miaki Muramatsu, Atushi Ooki, Hiroto Abe, Hiromichi Ueno
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Deep Sea Research Part II Topical Studies in Oceanography. :104820
ISSN: 0967-0645
Popis: We investigated spatial and interannual variation in the physical environment in the northern Bering Sea focusing on stratification, which is one factor affecting biological production in Arctic/subarctic regions. In particular, we analyzed in situ data obtained onboard the training ship Oshoro Maru in early summer in 2017 and 2018. We found that stratification in the areas just north of St. Lawrence Island (around 64.5 degrees N and west of 168.5 degrees W) and south/southwest of St. Lawrence Island was significantly weaker in 2018 than in 2017. These results are consistent with the extremely low sea-ice extent present in the winter of 2017/2018, which would have resulted in less freshwater being supplied to the surface layers and a warmer and less saline bottom water. Conversely, stratification was as strong in 2018 as in 2017 in the area close to the Alaska mainland, including the Bering Strait area, suggesting that the Alaskan Coastal Water dominates stratification in this area in early summer. Moreover, we found that the weakly stratified water column in the Bering Strait area stratified quickly shortly after the occurrence of strong northerly winds, likely because of the Ekman transport of warm and low-salinity Alaskan Coastal Water from the east.
Databáze: OpenAIRE
Popis
Abstrakt:We investigated spatial and interannual variation in the physical environment in the northern Bering Sea focusing on stratification, which is one factor affecting biological production in Arctic/subarctic regions. In particular, we analyzed in situ data obtained onboard the training ship Oshoro Maru in early summer in 2017 and 2018. We found that stratification in the areas just north of St. Lawrence Island (around 64.5 degrees N and west of 168.5 degrees W) and south/southwest of St. Lawrence Island was significantly weaker in 2018 than in 2017. These results are consistent with the extremely low sea-ice extent present in the winter of 2017/2018, which would have resulted in less freshwater being supplied to the surface layers and a warmer and less saline bottom water. Conversely, stratification was as strong in 2018 as in 2017 in the area close to the Alaska mainland, including the Bering Strait area, suggesting that the Alaskan Coastal Water dominates stratification in this area in early summer. Moreover, we found that the weakly stratified water column in the Bering Strait area stratified quickly shortly after the occurrence of strong northerly winds, likely because of the Ekman transport of warm and low-salinity Alaskan Coastal Water from the east.
ISSN:09670645