Research has shown that the nutrients can worsen the effects of climate change on corals, leading to coral bleaching.
Typically, coral reef environments are low in nutrients such as nitrogen and phosphorous compounds. However, such conditions are not set in stone as sometimes, passing ocean currents can bring in nutrients from elsewhere. In addition, man-made fertilisers and stormwater runoff from adjacent coastlines can also contribute to the nutrient levels.
And, high levels of nutrients are bad news for corals.
"In our study, we found that already heat-stressed corals exposed to excess nutrient levels were even more susceptible to bleaching," said lead author Dr Thomas DeCarlo, from the King Abdullah University of Science and Technology (KAUST).
The study was published in the Science Advances journal (Vol. 6, No. 34).
Co-author Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland said this and previous studies related coral bleaching to combinations of heat and nutrient stresses.