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  • Writer's pictureSarah-Jo Lobwein

What is the value of a great whale?

Two million dollars?

This does not include their intrinsic or tourism value, but ‘only’ their estimated worth as carbon capture heroes. Some great whales are worth tonnes of stored carbon - from the carbon they store as 'whale falls' to the carbon sequestration by the producers feeding on benefits of whale ‘poonamis’ (that’s right …whale poo explosions). Whales are carbon capturers, carbon sequesters, life-creators, powering forests and part of the global food web affecting oxygen production.

Whales as Carbon sinks:

‘Whale falls’ are when the carcass of a whale falls to the ocean floor, and the carbon “trapped” in their fat not only provides sustenance for deep water creatures, but also contributing to the downward travel of carbon: ‘A carcass of forty tonnes carries, on average, two tonnes of carbon to rest beneath the sea. That much carbon would otherwise take 2000 years to accrue on the sea floor. Each whale has been calculated to be worth more than a thousand trees in terms of carbon absorption’ (Giggs, R. 2020 ‘Fathoms’)’.

Whales as agents for carbon sequestration and how they affect oxygen production:

The great whales are deep and long divers so need to conserve oxygen including in their digestion, and feed on nutritious organisms such as krill, when they come to the surface to release faecal matter, it is so nutrient rich (for example the iron content is millions more than the concentration of the surrounding water). This is basically a fertiliser for phytoplankton, which are one of our marine producers, and this bloom of plankton absorbs carbon dioxide through photosynthesis to use for energy to develop their cells …and produce oxygen! Hands up who needs oxygen?! Oxygen and producers are important bases of food chains.

More than two thirds of the oxygen we breathe no matter where we live, work or play is generated by marine photosynthesis, not only by these phytoplankton but also seagrass, algae and seaweed. And these plankton are also mini carbon sinks too, some sink to the depths of the ocean as part of marine snow, the carbon locked in marine sediments. Their captured carbon on the sea floor alongside the previously mentioned whale carcasses, the carbon locked in marine sediments.

Whale poop influences the forests on the land:

Animals such as whales and fish excrete nutrients into the water. These nutrients help to fuel the plankton, which make their way into smaller fish. The fish are then either eaten by seabirds* which in turn deposit their own faecal matter on land, or feed larger migratory fish. These fish then travel up the river systems and deep inland through the vast network of waterways. They will then be eaten by predators such as birds of prey and big cats, or simply die in the rivers, and as a result spread these nutrients that originated in the oceans over the land and deep within the forests.

*Side note: seabird guano has a direct link to establishing, enriching and stabilising land and isolated island vegetation (that are carbon stores and oxygen factories) by adding nitrogen, phosphate and potassium to poor soils and marine ecosystems like coral reefs, and other birds are important for seed dispersal, pollination, weed and pest control. Without birds many ecosystems wouldn't exist ......gosh talk about #interconnectedness !!

What could affect these important ecological assets?

The irony is, as more carbon dioxide is released into the atmosphere (by fossil fuel use emissions) and dissolves into our oceans, the water becomes more acidic. This a complex topic for another day, but to note is our plankton friends and other marine organisms build their shells out of calcium carbonate and this shell building is affected by this pH change. Put simply the chemistry change means the organisms attain less of their shell building material, and can also release more carbon dioxide! Some grow faster and bigger, but the shells are weaker. Altering the ocean chemistry can also affect how nutritious they are, affecting metabolism, and affects what nutrients get passed up the food chain to the animal that eats them. Some organisms may grow better, and that could alter biodiversity - altering the natural mix and processes of the marine food chains, that will in turn affect humans. That is why healthy oceans and maintaining marine food web are very important … worth more than the estimated millions in saving the lives of big whales to the small phytoplankton.

Sarah-Jo Lobwein

(that's me above with a great whale !)

World Whale Day

#worldwhaleday is the third Sunday in February and celebrates the ecological value of our ocean giants.

To celebrate, I wrote this article in February 2021, to kick off SeaWeek 2021 which had the theme "Our interconnectedness with the sea" based on the Ocean Literacy Principle 6: The ocean and humans are inextricably interconnected. I will be posting more about #OceanLiteracy and #SeaWeek soon !

Follow up activity:

1. Research all the great whale species (all are balleen whales except for the toothed Sperm whale) and their classification from Phylum to Species. You may like to construct classification and dichotomous keys

2. Draw a food chain that includes a great whale (hint: information on a great one related to this post is below ...flow of iron movement through the diatom-krill-whale food chain. Then include related food chains to create a food web.

3. Research the First Nations word for whale in your local area. for example, I live in Dharawal Nation, and the word for whale is burri burri or barribarri

More reading:

Some further articles on the great whales you might to read are listed below (and keep an eye out for my further blog posts on whales including on Bowhead whales and minke whales ) !

Some great images here including flow chart on iron movement through the diatom-krill-whale food chain

The above study used high-resolution #biologging tags, aerial #drones, and echosounders to estimate daily and annual prey consumption on daily and annual scales for the largest species in earth’s history. In brief, they found that whales eat more than previous work predicted. Using these findings to better understand ecosystem change over the last century- the Southern Ocean is of particular interest, where industrial whaling removed 80% of the large whales in only 60y (1910-1970). Blue whale populations were reduced by >99%. Whales supported more productive marine ecosystems. Rebuilding whale populations will have benefits on ecosystem health and function. We need a world with whales. Whales acted as mobile krill processing plants, digesting krill and dispersing the nutrients locked inside (e.g., iron) to the base of the food web (phytoplankton). These iron-starved phytoplankton are food for the krill. Whales manured their pastures, just as a farmer would.

How could an ecosystem with >1 million more huge krill predators (baleen whales) have supported hundreds of millions of tonnes of more krill (twice the biomass of krill today)? Behold, the power of poop... Using the new estimates from the study of prey consumption in past systems with over 1 million more whales, the scientists concluded that the Southern Ocean must have been far more productive than at present. This is in general agreement with previously published findings.

Image credit:

Brett Lobwein


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