A recent study found that too much nutrients can be harmful for coral health, which at first is sort of a no brainer as we are always told that too much nutrients (or nutrient pollution as it might be called) is always a bad thing. However, what is novel about this study is that the researchers show that it is not as simple as “all nutrients are bad”, but more specifically, too much of just one nutrient is bad.
Specifically, the researchers show that under conditions of too much nitrogen, and not enough phosphorus (the two main nutrients needed for algal and coral growth, but also two major nutrients produced by human activities), coral become more susceptible to coral bleaching. The reason for this is that the coral become stressed when phosphorus levels are too low to sustain the level of growth that is initially stimulated by the nitrogen. These findings suggests that there is actually a critical balance of nutrients that is needed by coral to ensure proper growth and survivorship, and that when this balance is altered too much it can have important repercussions for coral health.
This study has great implications for coastal management as it may help managers set standards that more appropriately regulate the input of nutrient(s) to these ecosystems. It also has interesting implications when thinking about the how fish, through the delivery of nutrients via excretion, may help facilitate the growth of coral possibly by supplying a favorable amount of both nitrogen and phosphorus. This idea has been demonstrated by a few researchers in the past and is something that Dr. Layman and I are continuing to work on today.