Earth's Oceans Suffocating And Creating More 'Dead Zones': Study , II Scientists say 'dead zones' like those in Chesapeake have grown four-fold across oceans, threaten marine life , II Scientists shocked by huge discovery deep under the sea

Dead zones around the globe have quadrupled, indicating that climate change is rapidly affect life under the sea.

 

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An alarming new study suggests that climate change is having some big effects on life deep below the ocean waves. The new research suggests that global warming has quaedrupled the number of dead zones in the ocean, which scientists warn could cause collapse of ecosystems.
Dead zones are areas of the ocean that are starved of oxygen, which can kill plants and animals are at least cause them to flee. The huge increase in the number of dead zones is yet another indication that climate change is having a dramatic effect on areas of the world we can’t see, thanks to a dramatic increase in greenhouse gases and agricultural runoff.
The study, published in the journal Science, claims that climate change caused by human activities is changing the biogeochemistry of the ocean and increasing the consumption of oxygen. This will cause tremendous economic and societal harm, they argue, when it eventually results in the collapse of ecosystems around the globe.
“Oxygen is fundamental to life in the oceans,” said Denise Breitburg, lead author and marine ecologist with the Smithsonian Environmental Research Center. “The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth’s environment.”
Since 1950, the number of coastal ecosystems that scientists say are “suffocating” has grown tenfold. The problem has grown four times over in the open ocean, which is generally a more stable and resilient environment.
Scientists say ocean oxygen content has declined 2 percent over the past 50 years.
Scientists say the trend is another consequence of global warming that threatens to disrupt food chains, destroy habitats and make it harder for some creatures and microorganisms to survive.

 

The extent of the problem was reported in the journal Science last week by an international team of researchers led by and including Chesapeake-focused scientists in Maryland.
“This is really a global issue — it’s not just a local issue,” said lead author Denise Breitburg, a marine ecologist with the Smithsonian Environmental Research Center in Edgewater. “The severity of the changes that we’re seeing are really worrisome.”

 

In the Chesapeake and other estuaries, excessive amounts of nutrients such as nitrogen and phosphorus begin the chain reaction that can lead to fish kills. The pollution, which flows into waterways from farms and wastewater treatment plants and urban stormwater runoff, fertilizes growth of algae blooms. When the algae dies and decomposes, microbes use up the oxygen in the water.
Climate change is exacerbating and spreading the problem, the researchers say. Warmer water doesn’t hold as much oxygen as cooler water, so as global temperatures rise, ocean oxygen levels are steadily declining. Rising water temperatures also speed up metabolism in many ocean creatures, forcing them to breathe in more oxygen to survive.

 

It’s a “double whammy” for ecosystems, said co-author Michael Roman, director of the University of Maryland Center for Environmental Science’s Horn Point Laboratory in Cambridge.
“T hat has some severe effects for things we care about, like fisheries,” Roman said.
While many fish and other organisms can swim away from suffocating waters, an increase in low-oxygen waters means less suitable habitat is available, potentially making some creatures more prone to predation, the scientists said. Organisms that can’t get away will die.
Fish such as sturgeon and striped bass swim to cooler waters on the bottom of the Chesapeake during the summer. But if those areas have no oxygen, “that habitat is lost,” Roman said.
The research was the product of a United Nations Intergovernmental Oceanographic Commission work group created in 2016. Breitburg is leading the group known as the Global Ocean Oxygen Network, or GO₂NE. Its members include Roman and UMCES professor Kenny Rose, along with researchers from Louisiana, Canada, Peru, Kuwait, Sweden, France and the Philippines.

 

While concerns about low oxygen levels and their consequences are well known among scientists and advocates in many parts of the world, the researchers said their goal was to show the broad and growing scope of the problem and to raise public awareness.
“It highlights the magnitude of the problem,” Breitburg said. “It’s not just upwelling on the Oregon coast; it’s not just low oxygen in Chesapeake Bay because of nutrients. This is truly a global problem, and it’s going to require global solutions.”
Dead zones have steadily decreased in the Chesapeake amid federally coordinated efforts by several states to reduce the nutrients applied to farm fields or released in wastewater. About 13.6 percent of water samples collected by the Maryland Department of Natural Resources last summer contained dissolved oxygen concentrations below two milligrams per liter, second-fewest since 1985, officials said.
Roman and colleagues alreadyhave applied lessons from the bay to reversing oxygen loss in the Gulf of Mexico and the Arabian Sea. Now, as more waterways around the world grapple with low oxygen levels, he said, people from China to India to Peru are looking to the Chesapeake for lessons on how to protect ecosystems.
Parts of the world's oceans with zero oxygen have increased up to four times according to a new study by an international team of scientists. This is problematic because it threatens the destruction of marine ecosystems and because a majority of the Earth's oxygen comes from the oceans.

Oxygen Depletion

Plastic pollution in the oceans and coral bleaching are the most talked about issues of late when it comes to the health of the planet's waters, but a lesser known issue that is equally problematic appears to be the depleting oxygen in the world's waters.
In fact, according to a new study, the bodies of water in the open ocean with zero oxygen have increased over fourfold in the last 50 years. What's more, the low-oxygen zones in coastal waters have evidently increased tenfold since 1950 and are expected to increase as the Earth continues to warm.

Marine Ecosystem Threatened In 'Dead Zones'

This is a serious problem for marine life because without oxygen, the marine life in a particular site could eventually die. The so-called dead zones become unable to support life, so both the animals and the corals end up suffocating. This is evident in the dead zones in the Gulf of Mexico and Chesapeake Bay.
In other areas where the oxygen is already low, marine animals' growth could be affected, as well as their reproduction and vulnerability to disease. Because the animals avoid these areas, many of them, including bigger fish such as marlins, remain in habitats where they become more vulnerable to predators and fishing.

The World's Oxygen And Nitrous Oxide

Low oxygen levels can evidently trigger the release of nitrous oxide, which is a greenhouse gas that is 300 times more powerful than carbon dioxide and hydrogen sulfide. According to researchers, climate change is the likely cause of the oxygen decrease in the open ocean, as warmer oceans hold less oxygen and even makes it hard for the oxygen to even reach the water in the first place.
Apart from the threat to marine biodiversity, it's also worth noting that about half of the oxygen on the planet comes from the ocean, which is an added problem to the damages to economy as a result of fish kills and tourism decline.

Solvable Problem

Despite the grim-sounding fate of our oceans, researchers note that there are things that people can do to tackle the problem head-on. For instance, reducing fossil fuel use could slash the air pollution and cut the greenhouse gases that contribute to climate change while addressing the water pollution problem could help as well.
What's more, the waters where the fish escape from low-oxygen areas could be protected further by turning them into marine protected areas or no-catch zones. Lastly, further and enhanced monitoring of the oxygen levels of the Earth's waters could help determine at-risk areas and possible effective solutions.
"Halting climate change requires a global effort, but even local actions can help with nutrient-driven oxygen decline," said Denise Breitburg of the Smithsonian Environmental Research Center, lead author of the study.
The paper is published in the journal Science.

 World Ocean, Ocean, Climate change

Earth's Oceans Suffocating And Creating More 'Dead Zones': Study , II Scientists say 'dead zones' like those in Chesapeake have grown four-fold across oceans, threaten marine life , II Scientists shocked by huge discovery deep under the sea