Balance of nature: corals farm algae (Introduction)

by David Turell , Thursday, August 24, 2023, 17:45 (248 days ago) @ David Turell

Keeps them in food supply in barren areas:

https://www.science.org/content/article/hard-working-farmers-corals-cultivate-and-eat-t...

"A new study published today in Nature offers a solution. According to its authors, corals make up for nutrient scarcity by harvesting and feeding on their resident algae, like hungry farmers. It’s “a really, really beautiful study,” says coral biologist Mónica Medina of Pennsylvania State University, who was not involved in the work.

"Researchers have long known that corals maintain a mutually beneficial relationship with the single-celled algae that call the animals’ tissue home. There, sheltered from the harsh conditions of the open ocean, the algae feed on the corals’ waste products. In return, the algae convert sunlight into energy-rich food molecules that nourish themselves and their hosts. Corals also feed on drifting zooplankton to capture other essential nutrients.

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:...sea creatures living in the vicinity excrete plenty of inorganic nitrogen and phosphorus, which the coral’s algal residents can readily consume. Jörg Wiedenmann, head of the coral reef laboratory at the University of Southampton, wondered whether there was a connection. Could the algae somehow be passing these nutrients along to their coral hosts?

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"Over a period of 3 years, the researchers found that reefs near islands with lots of birds—and, therefore, plenty of algae food—grew twice as fast as those near islands where birds were scarce. A unique form of nitrogen that is plentiful in bird droppings, but not zooplankton, also reappeared in corals around bird-dense islands. To the researchers, this was further evidence that the algae were indeed shuttling nutrients from the birds to their coral hosts.

"The study nicely combines laboratory and fieldwork to crack a long-standing mystery, Medina says. It could also help scientists better understand the devastating effects of coral bleaching, she adds, in which the relationship between corals and their algal residents breaks down."

Comment: a vivid example of an ecosystem, all interlocking from birds to algae to corals. Not to mention the fish that hide in the corals.