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Marine Sciences Program Student Interdisciplinary Seminar – Jianxing Wang
February 27 @ 12:20 pm - 1:20 pm
Monday, February 27th at 12:20 PM
IMS Seminar Room 222
Zoom Webinar ID: 979 0142 6135
|Oxygen is fundamental to life. However, it has been decreasing in coastal oceans since at least the middle of the 20th century. Estuaries and coastal waters are often shallow and have limited exchange with the open ocean, making them more sensitive to climate change and nutrient loading from the land. Over 500 sites in coastal waters have reported hypoxia since 1950, causing extensive damage to the marine ecosystem and human society. The Baltic Sea, as an example, has warmed about 1.5 °C and has experienced a large increase in nutrients since 1850. Warmer and eutrophic water has stimulated the growth of phytoplankton dramatically. Sinking and sedimentation of this biomass induces a large consumption of oxygen in the bottom layer, which combined with stratification, causes bottom water hypoxia. The bottom oxygen depletion area has expanded significantly in this time. The severity of the hypoxia is modulated by physical drivers such as river discharge, tide and wind. In the Chesapeake Bay, hypoxia happens mostly during summertime. Based on the model, bottom water hypoxia decreases with increasing wind speed under all wind directions by strengthening lateral advection and vertical mixing. In all, coastal water hypoxia has increased significantly due to warming and rising nutrient loading and is affected by the wind speed and direction.