Why whale poo is awesome

You might not think about whale poo very often, but it’s actually pretty awesome stuff, as it’s vital for keeping ecosystems healthy.

(Image by Amanda Kae’s Photoz on Flickr)

To understand why whale poo is so important, we first need to talk about some tiny creatures called phytoplankton. These little guys are a type of algae that are right at the bottom of the food chain. They use photosynthesis underwater to convert carbon dioxide and sunlight into oxygen and food for other sea creatures. When I hear about photosynthesis, I tend to think about it happening mainly in trees on land. Yet these microscopic-sized algae do 50% of all the photosynthesis on the planet. This means they also generate half of all the world’s oxygen. (Pause for a moment to take a big breath in and be grateful to the phytoplankton for that lovely fresh air).

These phytoplankton need iron as part of the photosynthesis process. So the iron levels of the seawater around them limit the number of algae that can grow. Unfortunately, in places like the Southern Ocean, the iron concentration is below what’s ideal for a healthy phytoplankton population. This can be a real problem, as less iron means fewer algae and less oxygen for everyone.

This is where our hero, the whale poo, comes in. Whale poo has 10,000,000 times more iron than regular seawater. So the poo acts as an excellent fertiliser to boost the growth of algae.

The whales accumulate all this iron by eating krill, which contain lots of the mineral. The krill eat the phytoplankton and the phytoplankton can flourish thanks to whale poo. So this creates a wonderful positive feedback loop, where the whales, krill and phytoplankton can all thrive.

Also, whale poo can help the oceans be a valuable carbon sink. Remember that phytoplankton draw in a lot of carbon dioxide when they photosynthesise. So if there was more whale poo in the oceans, there would be more phytoplankton to suck in even more CO2. This process is super beneficial, since carbon dioxide is harmful to our planet, animals and people.

There used to be millions of beautiful whales in the waters around Antarctica in the time before industrial whaling. Yet when people killed large numbers of these creatures, it was not only awful for the whales themselves, but it also had harmful flow on effect for the entire ecosystem. Killing whales has meant there’s now less poo to help the phytoplankton produce vital oxygen for animals and us to breathe. Killing whales has meant our oceans aren’t living up to their potential for drawing down dangerous carbon dioxide.

There is currently an international ban on whaling, but they are still not entirely safe from hazards such as illegal hunting. So let’s save these wonderful creatures so that their poo can help bring us oxygen, draw down harmful carbon dioxide and allow ecosystems to thrive.

One Response to “Why whale poo is awesome”

  1. Alasdair Browning says:

    That’s amazing about the feedback loop between whales, phytoplankton and krill. It’s often easy to forget the roles that large animals have in an ecosystem rather than just be at the top of the food chain, consuming everything.