Accelerated Climate Change in the Deep Ocean

• by iDiveblue
• October 18, 2020

Climate Change in the Ocean: Warming Depths

The deepest parts of the ocean and its inhabitants were thought to be more protected from climate change than the surface. This perception came from the fact that the deep ocean is warming at slower rates than other parts of the water column. However, a recent study by researchers from Hokkaido University and The University of Queensland suggests that, even if this is true, creatures from this parts of the ocean are more susceptible to climate change due to their specialized adaptation and, therefore, climate velocity is much faster in deeper seas (at 1,000 meters or more) than at the surface.

The Issue

Climate velocity refers to the rates at which the range of species shifts. In the ocean, the range of different species is crucial to maintaining healthy food chains and delimiting marine conservation areas, which are crucial to conservation. A good example of climate velocity and range shifts in more superficial waters is that of some orca populations to find food. Also, because deep-sea species have adapted to more specific thermal environments, a shift in their range could put them in danger.

According to the study, the mesopelagic layer, which lies between 200 and 1,000 meters, shows a climate velocity between 4 and 11 times higher than that at the surface. This is the place in the water column where many animals at the bottom of the food chain live. If these species are forced to find a different range, either in terms of depth or geography, they could potentially displace many other species that depend on them. Shifts like this could have an impact on the entire ecosystem and even on fisheries, if fish stocks shift to a deeper range.

Another problem is that species living in even deeper ranges are not only adapted to temperature but also to extreme pressures and lack of light and oxygen. Even if we know little about these creatures, the authors believe a precautionary approach should be taken, since they are a crucial part of the ecosystem and a change in their range could be highly dangerous for such specialized organisms.

Moreover, researchers tested many different greenhouse emission scenarios and found that, even in the most optimistic of situations, the deep-sea climate velocity would continue to accelerate, putting more than 20,000 species at risk. Because biodiversity on the deep ocean is still seldom studied, the impact this problem could have on the ecosystem as a whole is hard to predict.

The Solution

Climate change in the ocean in a complex issue because it encounters underwater inhabitants and their complex ecosystems. Species vary in depth and range, so while we can be certain marine life is impacted by climate change considerably in the deep ocean, the scope of that impact is hard to measure or predict. As such, the study suggests following a precautionary approach.

Species living within marine protected areas could be at risk if their ranges shift and they now find themselves in unprotected waters. Therefore, expanding the current areas and creating a smart network of protected areas and corridors is one of the steps we can take to counteract the effects of climate velocity in the deep seas.

Likewise, tightening legislation on deep-sea mining and fishing and reducing human impact, including ocean plastics, in the deep sea is crucial to maintain the health of the ocean. Considering that even if greenhouse gas emissions are greatly reduced climate velocity will continue to accelerate in the deep ocean, combined with our lack of knowledge and research of the deep sea and its biodiversity, it is imperative to put measures in place to protect it. Shifts in this remote part of the ocean could have exponential consequences in the health of marine ecosystems.

Climate Change in the Ocean: Warming Depths The deepest parts of the ocean and its inhabitants were thought to be more protected from climate change than the surface. This perception came from the fact that the deep ocean is warming at slower rates than other parts of the water column. However, a recent study by…