Climate Change Affecting Marine Ecosystem
Even though climate change hurts forests, crops, freshwater sources, and the economy, ocean ecosystems continue to be at the heart of global warming. With an increase in greenhouse gas concentrations, the oceans are capturing increasing energy from the sun, causing an increase in sea surface temperatures and rising sea levels. Particular creatures, such as corals and shellfish, find it more challenging to construct their skeletons and shells when the acidity of the water rises in the atmosphere. Oceans contain dissolved oxygen as a gas, and aquatic creatures, like terrestrial animals, require that oxygen to breathe. However, when the seas are warm due to climate change, their water may store less oxygen. As a result, marine animal life suffers from suffocation and declines.
Recent research claims that by 2080, nearly 70% of the world's seas may be oxygen-deficient, threatening marine ecosystems everywhere. Many fisheries globally depend on mid-ocean depths that are already losing oxygen at unnatural rates and will reach a crisis point in 2021. Aquatic creatures, like terrestrial species, require dissolved oxygen to breathe. Because of climate change, the oceans' water may store less oxygen. Scientists have been watching the oceans' oxygen decrease for years, but the new report gives them fresh urgency. The new study is the first to utilize climate models to anticipate deoxygenation, or the loss of dissolved oxygen in water, throughout the globe's seas. Global fisheries are projected to be impacted by considerable, perhaps irreversible deoxygenation of the ocean's middle depths that sustain many of the world's fished species. The new models estimate that deoxygenation will affect all ocean zones by 2080. The findings were published in Geophysical Research Letters, an AGU publication that publishes high-impact, short-format research encompassing all Earth and space disciplines.
The new research shows that the mesopelagic zones (between 200 and 1,000 meters deep) would be the first to lose large amounts of oxygen owing to climate change. Because many commercially fished species live in the mesopelagic zone, the discovery might mean economic hardship, seafood shortages, and environmental disturbance.
Warmer seas store less dissolved oxygen, reducing circulation between ocean layers. Aside from not being supplemented with oxygen by the environment or photosynthesis like the top layer, the intermediate layer is also the most susceptible to deoxygenation due to algal breakdown, which consumes oxygen. "This zone is significant to us because it has a lot of commercial fish," says Yuntao Zhou, lead author and oceanographer at Shanghai Jiao Tong University. In addition to fisheries, deoxygenation impacts other marine resources. The new findings are highly alarming and underscore the urgency of significant climate change mitigation, says NCAR oceanographer Matthew Long.
Around 30% of the carbon dioxide (CO2) emitted into the atmosphere is absorbed by the ocean as atmospheric CO2 levels rise as a result of human activity such as fossil fuel combustion (e.g., automobile emissions) and land-use change (e.g., deforestation), the quantity of carbon dioxide absorbed by the ocean increases. When saltwater absorbs CO2, a sequence of chemical processes occurs, increasing hydrogen ions' concentration. This process has far-reaching consequences for the ocean and its inhabitants. Ocean acidification lowers the quantity of carbonate in saltwater, a critical building ingredient. This complicates the formation of marine species' shells and skeletons, such as coral and certain plankton, and existing shells may begin to disintegrate.
Changes in the chemistry of the water can also affect the behavior of non-calcifying creatures. Certain fish, such as clownfish, lose their capacity to detect predators in more acidic conditions. Reduced pH levels have also been demonstrated to impair the capacity of larval clownfish offsite links to seek adequate habitat. When these species are threatened, the entire food web may be threatened as well.
While certain species will be hurt by ocean acidification, algae and seagrasses may benefit from increased CO2 levels in the water, as they, like terrestrial plants, require CO2 for photosynthesis. Research is underway to determine whether cultivating seaweed might help prevent ocean acidification.
It is undeniable that many coral reefs, notably the Great Barrier Reef in Australia, are in danger of extinction. Mass coral bleaching causes the hunger, shrinking, and death of corals, which causes the extinction of the hundreds of species that live on coral reefs as a result. Coral reefs are particularly vulnerable to temperature rises since they are made of living coral. Furthermore, according to a new study, the oceans are also experiencing more extended and more severe "marine heatwaves," which may be pushing even more ocean organisms and ecosystems to their breaking points.
But perhaps most concerning is that the introductory chemistry of the oceans is changing quicker than it has in the previous 65 million years. If the present rates of temperature increase continue, scientists predict that the oceans will be too warm for coral reefs by 2050. Despite the enormity of tackling climate change, solutions to ensure a living ocean for a healthy global climate are available. We're off to a good start: more than 100 nations, accounting for 90% of global emissions, have already signed national climate commitments to reduce carbon pollution. In 2015, world leaders convened Paris to responsibly formulate subsequent actions to address climate change.