Improvement in the dissolved oxygen concentration and water exchange in Ofunato Bay, Japan, after the collapse of the bay‐mouth breakwater by the 2011 Tohoku Earthquake and tsunami
Improvement in the dissolved oxygen concentration and water exchange in Ofunato Bay, Japan, after the collapse of the bay‐mouth breakwater by the 2011 Tohoku Earthquake and tsunami
复制标题
2011 年东北地震和海啸导致湾口防波堤倒塌后，日本大船渡湾的溶解氧浓度和水交换有所改善
DOI：
10.1111/fog.12184
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发表时间：
2017
影响因子：
2.6
通讯作者：
Shinnosuke Kaga
中科院分区：
文献类型：
--
作者：
S. Kakehi;T. Kamiyama;Yoshimasa Kaga;K. Naiki;Shinnosuke Kaga
牡蛎和扇贝养殖在日本三陆海岸的大船渡湾蓬勃发展。在1967年至2011年期间，这个海湾是一个由湾口防波堤高度封闭的区域，虽然防波堤提供了适合水产养殖的平静条件，但人们担心水质恶化。2011年3月11日，东北太平洋沿岸发生地震，随后发生大海啸，三陆海岸遭到广泛破坏，导致大船渡湾防波堤倒塌。我们分析了1996年至2015年收集的月度水文观测数据，并补充了地震后进行的水文观测和直流测量。历史水文观测资料表明，溶解氧（DO）浓度最低的观察在海湾底部附近。地震前后各月最低溶解氧浓度的平均值和标准差分别为5.81 ± 3.72和7.22 ± 1.49 mg L−1，差异显著。根据稳态河口环流下的盐收支，用箱型模型估算的海洋水流入量和水交换率在地震前后也有显著差异。地震后海水流入量的增加和海湾内水交换的加快导致了底质溶解氧浓度的显著改善。这些变化被认为是由于湾口防波堤倒塌导致海湾海水循环改善。
Oyster and scallop aquaculture has flourished in Ofunato Bay, on the Sanriku Coast of Japan. Between 1967 and 2011, this bay was a highly enclosed area by a bay-mouth breakwater, and while the breakwater provided calm conditions suitable for aquaculture, there was concern about water quality deterioration. The Tohoku Earthquake off the Pacific coast and the subsequent major tsunami on 11 March 2011 caused extensive damage to the Sanriku Coast, resulting in the collapse of the breakwater of Ofunato Bay. We analyzed the monthly hydrographic observational data that were collected between 1996 and 2015, supplemented with hydrographic observations and direct current measurements that were carried out after the earthquake. The historical hydrographic observational data showed the lowest dissolved oxygen (DO) concentrations were observed near the bottom in the bay. The average and standard deviation of the lowest DO concentrations of each monthly observation during the period before and after the earthquake were 5.81 ± 3.72 and 7.22 ± 1.49 mg L−1, respectively, and are significantly different. The oceanic water inflow and water exchange rate estimated by a box model based on the salt budget under the steady-state estuarine circulation were also significantly different before and after the earthquake. An increase in the inflow of oceanic water and the more rapid water exchange in the bay after the earthquake induced marked improvements in the bottom DO concentration. These changes are considered to be attributable to the improved circulation of oceanic water in the bay that resulted from the collapse of the bay-mouth breakwater.
DOI：
10.1007/s11027-011-9297-7
发表时间：
2011-10-01
影响因子：
4
作者：
Mimura, Nobuo;Yasuhara, Kazuya;Kazama, So
通讯作者：
Kazama, So