Too much sugar not good for coral reefs

The race is on to buy up inexpensive land along coastlines for vacation homes and tourist hotels. But increased development can mean more nutrient rich runoff that threatens the very coral reefs attracting tourists in the first place. David Kline at the Smithsonian Tropical Research Institute and colleagues find that bacteria on coral reefs grow out of control as the level of simple sugars in seawater increases.

“I set up a seawater system at the Smithsonian station in Bocas del Toro, Panama so that I could test individual components of runoff on live corals. I was very surprised to find that, rather than the usual suspects measured to determine water quality: nitrogen and phosphates, it was simple carbon compounds–too much sugar–that often kills corals indirectly by stimulating bacterial growth.”

“Sugars in runoff cause bacteria normally associated with corals to grow out of control. People don’t usually even measure carbon when they do water quality studies. They only look at the nutrients found in fertilizers. Nitrogen and phosphates cause algal overgrowth on corals, which also contributes sugars to the system. It is vital to consider the carbon component as we develop conservation strategies for coral reefs.”