Whales play an important role in combating climate change, and why?

In order to deal with climate change, in addition to reducing anthropogenic greenhouse gas emissions, it is also necessary

to remove carbon dioxide from the atmosphere . is also of interest. Forests tend to be the focus of attention when it comes to biological carbon storage, but a newly published paper reports that the carbon storage capacity of whales, the largest organisms on Earth, plays an important role in combating climate change. It has been.

Whales in the carbon cycle: can recovery remove carbon dioxide?: Trends in Ecology & Evolution

Whales Can Actually Help Us Fight Climate Change. Here's How : ScienceAlert

A research team at the University of Alaska Southeast , USA, said, `` Blue whales and fin whales are the two largest animals that have ever existed on Earth.'' By ingesting large amounts of prey and excreting large amounts of waste, they store carbon more effectively than small animals, and have a strong impact on the carbon cycle.'

In addition to blue and fin whales, large whales, including baleen whales and sperm whales , are said to live for several decades or more. Considering whales as a giant mass of carbon, their importance to the ocean-atmosphere carbon cycle and carbon sequestration is enormous.

Blue whales eat 8000 pounds (about 3.6 tons) of krill and plankton, which is about 4% of their body weight a day, and the resulting excrement is rich in nutrients such as iron and nitrogen, so plankton It will be the bait of. Plankton that live near the surface of the sea store carbon in their bodies, and krill that feed on this plankton store more carbon, and other animals such as penguins, seabirds, seals, fish, and whales circulate nutrients and carbon. I'm going to do it.

The diagram below shows the ocean carbon cycle of whales and their excrement, plankton, krill, and other animals.

by Alex Boersma/Pearson et al., Trends Ecol. Evol. 2022

Previous studies have shown

that krill densities are higher in waters where whales are more abundant, even though whales eat large amounts of krill every day. This phenomenon, also called the `` krill paradox '', is said to occur because whale hun functions as an important food source in the lower layers of the ecosystem, resulting in an increase in the number of krill. Krill also play a role in delivering carbon to the deep layers of the ocean.

Since the beginning of industrial whaling, large whale populations have declined sharply and are no longer able to play a role in carbon cycling and removal in the ocean. It seems that sperm whales that once lived in the Antarctic Ocean helped remove 2 million tons of carbon, but now that amount has fallen to about 200,000 tons .

The carcasses of large whales sink to the bottom of the sea and become food for many animals that live on the seabed, causing a large-scale carbon cycle here as well. In addition, many large whales travel back and forth between nutrient-rich feeding grounds and nutrient-poor breeding grounds, and also play a role in transporting nutrients to nutrient-poor sea areas.

The figure below shows large whales moving between nutrient-rich feeding grounds (light orange areas) and nutrient-poor breeding grounds (dark orange areas). ``Given that baleen whales have the longest migration distances on Earth, whale migration potentially affects nutrient dynamics and carbon cycling at the ocean basin scale,'' the research team argued. The decline of large whales is also a blow in this respect. For example, before industrial whaling began, blue whales transported as much as 140 kilotons of carbon in the Southern Hemisphere, but at the time of writing the article, it was about 0.51 kilotons.

by Alex Boersma/Pearson et al., Trends Ecol. Evol. 2022

In recent years, efforts to protect whales have begun to bear fruit, with reports of an astonishing recovery in humpback whale populations in the western South Atlantic.

Report that ``The population of humpback whales, which were in danger of extinction, has recovered surprisingly''-GIGAZINE

The researchers believe that assessing whales as a carbon sink to protect their populations is a better option than geoengineering solutions such as fertilizing the oceans to increase carbon uptake or injecting carbon deep into the ocean. It claims that the risk is low and that it can be expected in terms of durability and effects. 'Whale population recovery has the potential to enhance long-term, autonomous carbon sources in the ocean.' This can only be achieved through robust conservation and management interventions that promote

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