Quirks and Quarks

Turns out coral reefs like when fish pee on them

Another example of an incredible symbiotic relationship.
An international team of 39 scientists looked at the amount of fish or "biomass" at 2,514 coral reefs worldwide and tried to identify which reefs had unexpectedly more or less fish than others. (Tane Sinclair-Taylor)

The recycling of nutrients that are in animal feces and urine has been studied extensively on land, in places like the Serengeti in Africa. 

But a new study by Dr. Jacob Allgeier, at the School of Aquatic and Fishery Science at the University of Washington, has found that nitrogen and phosphorous released in fish urine is beneficial to coral reef systems. In a mutualistic relationship, the reef provides shelter and foraging opportunities for fish.

The green moray eel was one of the biggest specimens that Dr. Jacob Allgeier was able to catch and analyse. (Laszlo Ilyes)

In return, the algae that grow on corals absorb the nutrients from the fish urine in the water, promoting the health of the reef system. 

The researchers found that the healthiest reefs had more large fish living around them. Reefs depleted of big fish had absorbed about 50% less healthy nutrients that those with larger species of fish.     

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