Single-Celled Heroes: Foraminifera’s Power to Combat Ocean Phosphate Pollution

So-called foraminifera are found in all the world’s oceans. Now an international study led by the University of Hamburg has shown that the microorganisms, most of which bear shells, absorb phosphate from the water that pollutes the oceans to an unprecedented extent. The work has been published in the scientific journal “Nature”.

Phosphate Use in Agriculture and Its Environmental Impact

Phosphate is one of the main components of many fertilizers. It stimulates the growth of many crops – but is not only effective in the field, but also in the sea. It gets there via the rivers and can contribute to large areas tipping over. The fertilizer input into the sea becomes visible, for example, through excessive, sometimes even toxic algae growth, which destroys entire ecosystems.

The fact that foraminifera absorb large amounts of phosphate was discovered by Dr. Nicolaas Glock in 2020 almost incidentally and as the first to do so. Now the research assistant in the Department of Earth System Sciences at the University of Hamburg has investigated how widespread this property is among single-celled organisms. Together with colleagues from Japan, Canada and the Helmholtz Centre GEOMAR in Kiel, he studied foraminifera living on the seafloor. They come from the German Wadden Sea, Peruvian and Japanese coastal waters, the Canadian Bedford Basin and from a depth of 2000 meters from the Mid-Atlantic Ridge.

In the laboratory, the research team shock-froze them, broke through them and scanned them with X-rays. The result: Almost all the species studied had phosphate stored. “And since these single-celled organisms are so widespread and occur in huge quantities, the amount of phosphate they absorb is very, very large overall,” says study leader Glock, summarizing the result.

Quantifying Foraminifera’s Role as a Phosphate Sink

Glock’s team has calculated this precisely for the German Wadden Sea and a single foraminifera species: Ammonia confertistesta alone stores about five percent of the total phosphate that is used as fertilizer on the fields in Germany every year. This makes foraminifera an important sink for this substance: without the single-celled organisms, the oceans would be even more phosphate-polluted. They delay the human phosphate input into the sea by one month – this is what Glock’s team has calculated for the examples of the southern North Sea and Peru. It also suspects that the fact that the Baltic Sea is more overfertilized than other seas could be due to the fact that significantly fewer foraminifera live there – Baltic Sea water is simply too sweet for them.

“Unfortunately, the single-celled organisms cannot break down phosphate,” explains the biogeochemist. “They store it as an energy reserve and release it again when needed.” Only when the foraminifera die and form new sediments do they permanently remove the absorbed phosphate from the seawater, at least in part.

Original Source: https://www.uni-hamburg.de/newsroom/presse/2025/pm-2.html

Original Publication
Nicolaas Glock, Julien Richirt, Christian Woehle, Christopher Algar, Maria Armstrong, Daniela Eichner, Hanna Firrincieli, Akiko Makabe, Anjaly Govindankutty Menon, Yoshiyuki Ishitani, Thomas Hackl, Raphaël Hubert-Huard, Markus Kienast, Yvonne Milker, André Mutzberg, Sha Ni, Satoshi Okada, Subhadeep Rakshit, Gerhard Schmiedl, Zvi Steiner, Akihiro Tame, Zhouling Zhang & Hidetaka Nomaki
Journal: Nature
Article Title: Widespread occurrence and relevance of phosphate storage in foraminifera
Article Publication Date: 15 January 2025
DOI: 10.1038/s41586-024-08431-8
Website address: www.uni-hamburg.de

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