Sorry not sorry about the back-to-back #whalelife content lately, but covering this is one part follow-up story one part redemption so buckle up for some totally uncharacteristic toilet talk.
I’ve already written at length about the wonders of whale poos and the science behind them. However, reading that back now even I was a bit confused. So I’m going to try again because this actually a pretty well-researched area of study despite sounding like mad (rad) science.
So. The basic idea is the Southern Ocean (the ocean around Antarctica) is starved of iron, a vital nutrient necessary for phytoplankton growth. Phytoplankton are huge absorbers of atmospheric CO2, and so man-made iron fertilization has been proposed as a potential climate intervention. Before industrial whaling decimated baleen whale populations, iron was provided by whales pooping it into the ecosystem.
One of the proposed ways to get more iron into the ecosystem, other than through direct human means, is to restore whale populations to their pre-whaling levels. It’s actually all over the whale-nerd zeitgeist as seen here, here, and here. But what if iron fertilization and whale restoration were two facets of the same solution?
Enter today’s creature feature. According to our man on the inside, Ed Yong, when whale numbers reached all time lows in the ’70s, experts predicted their food – the tiny copepod crustacean krill – would boom. But the opposite happened, and krill populations diminished as their phytoplankton food source suffered from lack of available iron. Turns out, the whales eating the krill and then droppin’ dookies is what freed up that iron to be available to phytoplankton. Without that iron recycling, this Southern Ocean ecosystem is a fraction as productive as it once was.
Using a lot of cool science to make measurements of how much an individual whale can eat much more accurately than ever before, scientists were able to better estimate how much krill all those pre-whaling whales would have eaten. From there, they extrapolated to how much iron would be recycled and available to fuel phytoplankton populations and therefore the krill.
Now as I mentioned, we’ve been toying with the idea of man-made iron fertilization as a climate intervention for a while – since the ’90s, actually. A number of studies have demonstrated that iron fertilization does indeed stimulate phytoplankton blooms. But larger-scale intervention has been opposed in the past as just too risky and unpredictable.
However, with this new calculation of exactly how much iron is missing, we can be much more precise in our fertilization efforts, the researchers argue. The lead scientist also says he wants to act as a “surrogate defecator,” so just take that into consideration. Folks are right to be skeptical of these kinds of ‘geoengineering’ schemes. But as he says, in this case, we’re aiming to correct a recent imbalance – as recent as our grandparents’ early lives.
Of course, just as the krill bust defied expectations, iron fertilization could similarly have wildly unpredicted and unintended consequences. But as I said from the top, this is actually a well-established area of research, and as the climate crisis accelerates, more and more outlandish interventions will start to seem reasonable. You should definitely expect to see news about whale poo float to the surface again in the near future.
Johnny Venger apologizes for that last poo joke, but once it occurred to him he was contractually obligated to leave it in.