According to a recent study led by the University of Washington (UW), deoxygenation in Canada’s Gulf of St. Lawrence may lead to loss of marine animal life.
The study, published in Nature Climate Change, tracked temperature and oxygen level due to large-scale ocean circulation in Canada’s eastern coast.
Using a high-resolution computer model called Geophysical Fluid Dynamics from the National Oceanic and Atmospheric Administration, a simulation of the world’s ocean was observed for nine months.
The study examined two powerful oceanic currents that may be warming the waters and reducing it’s ability to hold oxygen: the Gulf Stream (which has less oxygen exchange between the top and bottom layers of the ocean) and the Labrador Current (which is rich in oxygen and remains colder from storms in the Labrador Sea).
The models showed the Gulf Stream was shifting further north. This, coupled with a weaker Labrador current, resulted in oxygen-poor warm water entering the Gulf of St. Lawrence.
“Observations in the very inner Gulf of St. Lawrence show a dramatic oxygen decline, which is reaching hypoxic conditions, meaning it can’t fully support marine life,” said Moriana Claret, lead researcher for the study at UW’s Institute for the Study of the Atmosphere and the Ocean.
Oxygen declines have already begun to threaten species such as Atlantic wolffish, Atlantic cod, snow crabs, and Greenland halibut.
“This is very concerning,” Claret told CTV News. “The effects right now are kind of mild, but in the near future, it can get worse.”
The full effects of this current change are not known, but researchers predict human interference will be the deciding factor on whether the conditions worsen or improve.
The Gulf of St. Lawrence is considered one of the most rapidly deoxygenating areas, with the lower depths having lost 55 percent of oxygen since 1930, reported CBC News. Warm waters due to climate change take the majority of the blame, but agricultural and industrial waste residue contaminating waterways also plays a big part.
Excess runoff nutrients in the oceans can create algae blooms, leading to a high growth of plants and algae. When they die due to a high concentration and lack of nutrition, the decaying process begins. This takes up a large amount of oxygen in the water and forms hypoxic conditions.
Deoxygenation throughout the oceans is well documented.
Due to imbalances in the ocean, waters with little to no oxygen form Oxygen Minimum Zones (OMZ), or dead zones, and severely impact wildlife in the area. One such area in the Middle East stretches nearly as large as the state of Florida between Oman and India, according to Gizmodo.
“The region is now anoxic — essentially extending the Arabian Sea OMZ into the marginal regions, much closer to where people live, fish, and depend on the marine environment.” Bastian Queste, surveyor of Oman’s OMZ told Gizmodo. “It’s an incredibly intricate system with many moving parts.”
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