Why are whales important to the ecosystem?

Whales play an important role in the ecosystem of the oceans and whales are an important topic of conversation between marine biologists as their major role in the oceanic ecosystem is being fully understood for the first time and importantly, this includes their role in helping to prevent climate change, the greatest threat to life on earth…

Whales are important in the marine ecosystem as they regulate the amount of food by maintaining a stable food chain. If whales became extinct, the species that they feed on  could quickly over populate and destroy other marine species. Whales maintain the balance in the marine food chain. It has been proved that the krill and other foods eaten by whales increase in number when there is a healthy whale population. When the number of whales fall in an area, scientists have found that their food stocks fall too. The different whale species feed on different marine creatures, yet support many other species and this helps maintain the balance. https://www.whalefacts.org/why-are-whales-important/ 

A very important role played by whales in the ecosystem is that they absorb carbon dioxide and their excrement combats the negative effects of CO². The whales usually excrete a faecal plume close to the surface of the water. These faeces are rich in iron, phosphorous and nitrogen and act as the perfect fertiliser for plankton (marine algae) and other marine plants- encouraging a growth in their numbers. If there is a healthy whale population in an area, there is usually plenty of phytoplankton. The phytoplankton is the base food of many marine food chains and also the principal food of zooplankton which itself is a critical food source for many marine species. The faeces of a whale are light and foamy so float and can be easily fed on by marine plants and numerous small fish.

The process of cycling of nutrients in the oceans by whales is described by Jessica Perelman in National Geographic –

‘A major contributor to this cycling is actually the production of whale faeces. By consuming matter in deep, nutrient-rich waters and fertilizing nutrient-poor waters, whales help mix the water column and spread essential nutrients like iron and nitrogen through various marine layers. The “flocculent faecal plumes” emitted as excrement from whales stimulate growth of plankton and other microorganisms that are the foundation of all oceanic food chains’.

The microscopic phytoplankton floating on the surface of the water uses the process of photosynthesis to feed and this means that the phytoplankton absorbs huge amounts of carbon dioxide from the atmosphere and releases oxygen into the atmosphere. The phytoplankton, full of carbon dioxide, eventually sinks down to the ocean floor where it remains for thousands of years – thus removing huge quantities of CO² from the atmosphere. Scientists believe that whales are responsible for the absorption of over 400,000 tonnes of CO² every year and this is vital in the fight to combat global warming and climate change. https://phys.org/news/2014-07-whales-ecosystem.html 

During each day, whales love to swim – both close to the surface and then diving to the greatest depths. This action is also very beneficial for the marine ecosystem as when the whales dive down deep into the ocean, they push nutrients up to the surface which help feed the phytoplankton and other marine plants and small fish. This action by whales is described by Animal Welfare Institute (AWI) Online-

The deep diving and surfacing behaviour of sperm whales and some baleen whales transports nutrients in their faecal plumes from deeper water to the surface and, for grey and humpback whales, by carrying sediment from the sea floor and redistributing it in the water column, to the benefit of sea birds and other marine species. As noted by Drs. Joe Roman and James McCarthy, “Cetaceans feeding deep in the water column effectively create an upward pump, enhancing nutrient availability for primary production in locations where whales gather to feed.” This vertical transport of nutrients is referred to as the “whale pump” and was first postulated in 1983. Scientists have determined that bio-mixing by marine vertebrates, including whales, contributes one-third of total ocean mixing, comparable to the effect of tides or winds.

Even when a whale dies, its carcass is important in the ocean food chain.  The carcass will sink to the ocean floor where it will provide nutritional food for up to 400 different deep sea life, for many months. Importantly, the carcass will also contain a large amount of carbon dioxide which is locked in it for many years. Many experts believe that the huge slaughter of whales in the last 50 years has been responsible for the high level of carbon dioxide in the atmosphere which has led to global warming. As the article on AWI Online continues –

‘When whales die, their massive bodies contain a large amount of carbon. As their carcasses sink to the ocean floor—often referred to as “whale fall,” this carbon is effectively stored in the ocean for centuries. Scientists have estimated that the combined global populations of nine great whale species (blue, fin, grey, humpback, bowhead, sei, Bryde’s, minke, and right whales) sequester nearly 29,000 tonnes of carbon per year via whale falls. Due to the significant loss of whales to commercial whaling, current populations of large baleen whales store 9.1 million tonnes less carbon than if their numbers were at pre-exploitation levels. If these whale stocks were rebuilt, they would remove 160,000 tonnes of carbon each year through whale falls, which is roughly equivalent to 110,000 hectares of forest (or an area the size of Rocky Mountain National Park’.

Without a doubt, scientists have gathered enough evidence to prove that whales play an intrinsic part in the world’s ecosystem and that it is essential that they are protected rather than hunted….