weird science

Whale Poo Is Good For You September 12, 2010

In fact, it’s good for all living things.  Australian researchers recently found that whale poo is battling one of the planet’s toughest battles ever – climate change.  The poor whales previously had a horrid reputation.  Since they breathe out a common greenhouse gas known as carbon dioxide (CO2), they were disliked for contributing to global warming.  Estimates are that they breathe out 200,000 tonnes of CO2 a year.  Eep!  It isn’t surprising people had a bad opinion of them!

But there’s way more to the story than this one fact.  Let’s start with the basics and see how something so gross can actually be good for us all.  Major science geeks can read the full study results in the Fish and Fisheries journal.

Benefits Of Whale Poo

A young sperm whale gracefully swims in the Southern Ocean. A trip up to the surface might mean a poopy feeding for the hungry phytoplankton, helping to fight global warming. Image credit: National Oceanic and Atmospheric Administration (NOAA).

In the Southern Ocean, we’ve got an estimated 12,000 sperm whales.  They hunt down fish and squid for food.  Once digested, out comes all that poo.  Why should we care about whale feces?  Well, it contains loads of iron.  All of those whales poop out approximately 50 tonnes of iron each year.

What’s so special about the iron?  It’s a fabulously delicious food for phytoplankton, which are marine plants that exist up near the surface of the ocean.  These helpful plants like to take in CO2 from the atmosphere through a process called photosynthesis.

Better still is that the whales pop out their poop (even I chuckled as I wrote that) in a liquid form that’s close to the surface of the ocean, making it easier for the phytoplankton to access.  After, the whale dives down into the ocean, presumably feeling a little – or a lot – lighter!

Let’s Do The Math

First, we have to see how much CO2 gets sucked up by the plants, which is all thanks to the whale poo.  It’s 400,000 tonnes.  Now that’s twice as much as the 200,000 tonnes they breathe out through respiration each year.  The 200,000 tonnes is equivalent to emissions from 40,000 cars!

I got in touch with Steve Nicol of the Australian Antarctic Division to find out how the study all started.  He explained:

Our research was actually looking at baleen (krill eating) whales and the iron that they release.  The research was stimulated by some ideas raised by Victor Smetacek and we had the samples and the expertise here in Hobart to do the measurements necessary to test these ideas.

When I asked Steve what we can do to help, his answer was a simple one.  Simple but not necessarily easy to attain, especially given the attraction of whale hunting in many places around the world.  According to Steve:

Many populations of great whales are recovering fairly fast – some at about the maximum rate possible.  The best assistance we can give them is to avoid killing them – either accidentally or deliberately.

Don’t Judge Too Soon

I think an important lesson here is that we can’t judge too quickly and instead, should always look at the big picture.  When we first hear about all the CO2 the whales are putting out there, it’s easy to think badly of these massive sea creatures.  But with the Southern Ocean normally being a poor source of iron, the whales are making sure those phytoplankton are happily fed.  This way, the phytoplankton can do their job of taking out the nasty CO2.

Now, if only human poo had such fantastic capabilities.