Penguin decline could worsen climate change

2023-04-11T16:24:55.803Z

Highlights: Chinstrap penguins are a major source of iron in the Southern Ocean. Their feces contain a high amount of iron, which can be used to recycle CO2. The loss of the penguin population could have a major impact on the environment, scientists say. The study was published in the journal Nature Communications. It is the first study to show the impact of the loss of penguin populations on the ocean's iron content. The research was carried out by scientists at the University of California, San Diego.

The decline in penguin populations could impact the Southern Ocean's iron cycle, and therefore the ocean's ability to capture CO2 from the atmosphere, according to a study published Tuesday.

Iron is a crucial component of Southern Ocean ecosystems, as a nutrient source for phytoplankton (plant plankton).

The study, published in the journal Nature Communications, highlights the essential role of penguins in consuming krill (iron-rich animal plankton) and fertilizing southern waters with their droppings.

The researchers calculated the volume of feces, or guano, of a chinstrap penguin colony on Deception Island, off the Antarctic Peninsula, by processing drone images using artificial intelligence. Thanks to chemical analyses of this guano, they found a very high concentration of iron, on the order of 3 milligrams per gram.

Extrapolating these data to the entire species, the authors estimate that chinstrap penguins, one of the most abundant penguin species, recycle about 521 tons of iron each year.

Penguin colonies in Antarctica © Jonathan WALTER / AFP

If this makes them, according to the authors, one of the "major" contributors of the iron cycle, it is half as much as 40 years ago, since their population has been halved since the 80s.

The oceans capture a third of the carbon dioxide (CO2) emitted into the atmosphere each year, thanks in particular to the photosynthesis activity of phytoplankton. In regions such as the Antarctic Circumpolar Current, their growth is limited by the low availability of micronutrients such as iron.

Baleen whales are known for the role they play in consuming krill and making iron available, but the similar impact of seabirds like penguins had not yet been studied.

Unlike whales that cross different ocean regions, penguins spend their lives confined to the ecosystems of the Southern Ocean: specifically, for chinstrap penguins, the Antarctic Peninsula and the surrounding islands.

"They would therefore contribute to a more concentrated iron recycling in these regions," said Oleg Belyaev, the study's lead author, a researcher at the Institute of Marine Sciences of Andalusia (ICMAN).

Because of the collapse of the population of these birds, linked to climate change, the authors are concerned about a possible imbalance in the ecosystem of the Southern Ocean, and its ability to sequester CO2 from the atmosphere. "The aim of this research is to raise awareness of the ecological importance of these seabirds," Belyaev said.

Penguin decline could worsen climate change

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