If penguins disappear in Antarctica, the ecosystem is at risk, also for iron

The Antarctic pigeon pigeon (Pygoscelis antarcticus) is a penguin and not doing well, not at all. Compared to forty years ago its populations have decreased by 50%. And if this is already bad news, it is not the only one: if this penguin disappears, the entire iron cycle of the Southern Ocean is also at risk, because penguins, like whales, eat the krillrich in iron, and re-pass it in the feces. Thus, if the penguins disappear, the iron in the ocean also disappears, where it serves to make the world thrive. phytoplankton (in turn food for krill), also jeopardizing the absorption of carbon dioxide by the waters. To tell all this, emphasizing the – negative – role played by climate changesis a team of Spanish researchers, on the pages of Nature Communications.

The basic idea of ​​the studio, they say, was to look beyond whales as actors important in the iron cycle in the Southern Ocean, above all considering that compared to cetaceans these penguins spend their entire lives in the area. To study them, the researchers studied some populations of Antarctic penguins, estimating their size, calculating the volume of their guano using drones and also analyzing some samples to measure iron levels. In this way they observed that these penguins produce a guano particularly rich in iron, especially when compared to that released by those giant whales. To the point that, the researchers write, it is estimated that thanks to the guano of the penguins, about half of the iron emitted by the whales is released into the ocean.

What does all this say? First of all it confirms that penguins weigh on the iron cycle in Antarctica. But considering today’s populations of these birds compared to the past, the study says something else: penguins, probably due to climate change, are disappearing, putting the entire ecosystem at risk. Today they help recycle around 500 tonnes of iron a year, half the amount in the 1980s when the population was twice as many. “These estimates – reads the paper – serve as evidence to underline the role that these penguins have as one of the main vertebrate mediators of the pelagic iron recycling system, capable of causing a possible imbalance in the ecosystem due to the significant decrease in their population”. Studying them, as well as studying other penguins, would help improve conservation policies for Antarctica’s marine ecosystem, experts conclude.