User:Lazypossum/Dead zone (ecology)

Dead zones
Jinhae Bay

Jinhae Bay is the first of Korea's two major dead zones, hypoxia was first reported in Jinhae Bay in September of 1974. In 2011, a joint study was done to observe and record causes, effects, and what can be done about Korea's hypoxic zones. It was discovered that Jinhae Bay exhibits a seasonal dead zone from early June to late September. This dead zone is caused by "domestic and land use waste and thermal stratification". Jinhae Bay experiences hypoxia largely at the bottom of it's bay. The ratios of Phosphorous:Nitrogen is imbalanced at the bottom, where it's otherwise balanced at the top, except for the months that the Bay is largely experiencing eutrophication. The effects of Jinhae Bay's hypoxia is seen in the marine system surrounding Korea, with a loss of biological diversity, particularly of the calcareous shelled organisms.

Shihwa Bay

Shihwa Bay is a costal resevior created in 1994 to supply surrounding agricultural lands with water, and act as a run off lake for nearby industrial plants. The Bay was made without much enviornmental consideration, and by 1999, water quality had a significant drop. This drop in water quality is attributed to the bay not having enough circulation or new water flow to accomadate for the domestic and industrial waste being dumped. In response, the Korean government set up a pollution management system within the bay, and has a gate system that allows the Bay to mix with water in the sea. Shihwa Bay is also experiencing an imbalance of phosphorus:nitrogen, but also large sources of Ammonium.

Chesapeake Bay
According to the National Geographic, the Chesapeake Bay was one of the first hypoxic zones to be identified in the 1970s. The Chesapeake Bay experiences seasonal hypoxia due to high nitrogen levels. These nitrogen levels are caused by urbanization, there are multiple factories that pollute the atmosphere with nitrogen, and agriculture, the opposite side of the bay is used for poultry farming, which produces a lot of manure that ends up running off into the Chesapeake Bay.

From 1985 - 2019, there were efforts from the caretakers of Chesapeake Bay to reduce the annual hypoxic volumes. There was significant improvement in 2016-2017 that gave assurance to the caretakers that the efforts were successful, however recent data has shown that further efforts are needed to continuously curb the effects of global warming.

Elizabeth River, Virginia
The Elizabeth River estuary is used for commercial and military use and is one of the most commonly used ports on the East Coast of the USA. From 2015-2019, 11 different conditions were measured in various areas of the Elizabeth River. Throughout the river, there were consistently high levels of nitrogen and phosphorus, along with high levels of other contaminants contributing to the poor quality of life for bottom feeders along the river. The main cause of the pollution to the Elizabeth river has been the military and industrial activities through the 1990s. In 1993, the Elizabeth River Project was started in attempt to do a restoration project on the river. Adopting one of the fish whose species had been largely impacted by the pollution, the Fundulus heteroclitus (Mummichog), the group was able to gain traction and carry out multiple projects and has removed thousands of tons of contaminated sediment. In 2006, Maersk-APM, a major shipping company, wanted to build a new port on the Elizabeth River. As part of the environmental mitigation they worked with the Elizabeth River Project to create the Money Point Project, which was an effort to restore Money Point, which had been deemed biologically depleted due to a black tar like substance called creosote laying at the bottom. Maersk-APM gave $5 million to help get the project up and running. By 2012, they were able to restore over 7 acres of tidal marsh, 3 acres of oyster reef and created a new shoreline. In 2019, the Money Point Project received the "Best Restored Shore" award from the American Shore and Beach Preservation Association.