Muso

There are many effects of climate change on oceans. One of the main ones is an increase inocean temperatures. More frequent marine heatwaves are linked to this. The rising temperature contributes to a rise in sea levels. Other effects include ocean acidification, sea ice decline, increased ocean stratification and reductions in oxygen levels. Changes to ocean currents including a weakening of the Atlantic meridional overturning circulation are another important effect. All these changes have knock-on effects which disturb marine ecosystems. The main cause of these changes is climate change due to human emissions of greenhouse gases. Carbon dioxide and methane are examples of greenhouse gases. This leads to ocean warming, because the ocean takes up most of the additional heat in the climate system. The ocean absorbs some of the extra carbon dioxide in the atmosphere. This causes the pH value of the ocean to drop. Scientists estimate that the ocean absorbs about 25% of all human-caused CO2 emissions.Ocean temperature stratification is the difference in temperature between the various layers of the ocean. It increases as the ocean surface warms due to rising air temperatures.: 471  The decline in mixing of the ocean layers stabilizes warm water near the surface. It also reduces cold, deep water circulation. The reduced vertical mixing makes it harder for the ocean to absorb heat. So a larger share of future warming goes into the atmosphere and land. One result is an increase in the amount of energy available for tropical cyclones and other storms. Another result is a decrease in nutrients for fish in the upper ocean layers. These changes also reduce the ocean's capacity to store carbon. At the same time, contrasts in salinity are increasing. Salty areas are becoming saltier and fresher areas less salty.Warmer water cannot contain the same amount of oxygen as cold water. As a result, oxygen from the oceans moves to the atmosphere. Increased thermal stratification may reduce the supply of oxygen from surface waters to deeper waters. This lowers the water's oxygen content even more. The ocean has already lost oxygen throughout its water column. Oxygen minimum zones are expanding worldwide.: 471 These changes harm marine ecosystems, which can accelerate species extinctions or cause population explosions, altering species distribution. This also affects coastal fishing and tourism. Rising water temperatures will also harm various oceanic ecosystems, such as coral reefs. The direct effect is coral bleaching on these reefs, which are sensitive to even minor temperature changes, so a small increase in temperature could have a significant impact in these environments. Ocean acidification and temperature rise will also affect the productivity and distribution of species within the ocean, threatening fisheries and upsetting marine ecosystems. Loss of sea ice habitats due to warming will severely impact the many polar species that rely on it. The interactions between many of these climate change factors increase pressures on the climate system and ocean ecosystems.