Penguins play a fundamental role in metal supply recycled to the surface waters of the Antarctic Ocean. That is the conclusion reached by an investigation led by a team from the Institute of Marine Sciences of Andalusia (ICMAN) of the CSIC.
The study, published in Nature Communicationsestimates that the species of chinstrap penguin (Pygoscelis antarctica) contributes 521 tons per year of recycled iron to Antarctic surface waters, through guano (substrate resulting from the accumulation of faeces). This amounts to about three milligrams of iron per gram of guano.
Traces of iron are of great relevance in the ecology of the Antarctic, as they promote the growth of phytoplankton and the absorption of carbon dioxide.
Traces of metals such as iron are highly relevant to the ecological functioning of the Antarctic Ocean, since they promote the growth of phytoplankton and the absorption of carbon dioxide from the atmosphere. That is why, in recent years, scientists have worked hard to understand the processes that regulate the amount and distribution of this metal.
Until now, studies have shown that other organisms, such as krill or whalesplay a crucial role in the biogeochemical cycles of ironbut this research is pioneering in addressing and accrediting the influence that penguins also have on the regeneration of this metal.
“The results of the study not only contribute to a better understanding of the biogeochemical cycle of iron in the Southern Ocean, but also highlight the key role of penguin populations in it, influencing the their environmental concentrations and in their ecological functioning“, Explain Antonio Tovar-Sanchezco-author of the work.
Iron recycling may have halved in the last four decades
The researchers also point out that 40 years ago the iron intake figures could be twice the current ones, since, according to recent studies, penguin populations have decreased by around 50% since then.
This drop would have a direct impact on primary production rates and carbon sequestration”, points out the ICMAN researcher and lead author Oleg Belyaev.
A drone flies over the colony of chinstrap penguins in Collado Vapor. / Oleg Belyaev Korolev
An innovative methodology
The study has focused on Collado Vapor chinstrap penguin colony located west of Deception Island. The methodology involved three phases: firstly, guano samples were collected using a collection system that allowed fresh guano to be obtained without interference with the soil to its subsequent chemical characterization.
In addition, a census of the penguin colony was carried out through drone images and the use of deep learning software, with the aim of estimate the number of specimens of this species. Finally, coastal water samples were collected using Awa technologyan automatic water collection system operated by drones that made it possible to reach areas that were inaccessible from a boat.
This work, carried out by four researchers from ICMAN and a researcher from the University of Cádiz, is the result of the participation of the PiMetAn project in the XXXIV Antártica Campaña. The team was at the Gabriel de Castilla Spanish Antarctic Base on Deception Island from January 23 to February 26, 2021.
Reference:
Belyaev, O. et al. “The contribution of penguin guano to the Southern Ocean iron pool”. Nature Communications (2023)
Rights: Creative Commons.