Marine Environmental Safety Protection

Florida newspapers have published articles describing how polluted waters have accelerated the growth of alga that is threatening coral reefs off the coast of Florida.

Plant life? Like alga? Plant life like alga: you read is right. Usually, alga is not a problem. Water on the reefs is nutrient poor and alga growth is minimal. So, what's all the fuss?

Well, the fuss is about the type and quantity of the many kinds of alga in the water. The fuss is also about where these alga grow; especially the kinds that grow on and over corals. The fuss is really about what alga does to the coral and what effect that has on the fish and plant life that depend on coral reefs for their survival, Survival is what the fuss is really about.

A few facts about corals will make the problem of polluted water clearer. There are corals that grow in many places including the North and South poles. However, the greatest variety of coral grow in tropical waters. Florida has the only tropical reefs in the continental US.

Corals need sunlight to grow and survive. So the water must be shallow and clear. Corals grow very slowly. Almost everything on the reef grows faster than corals. Many of the fish and animals that depend on coral reefs eat or damage corals as they forage for food.

Finally, corals need sunlight to support an alga that lives within the coral. You read it right; alga lives in the coral. The coral (animal) and the alga (plant) are mutually beneficial to each other. The alga uses sunlight to produce sugars. The alga consumes carbon dioxide given off by the corals and release oxygen that is consumed by the corals. The corals leftovers nourish the alga. The corals consume excess sugars from the alga.

With those facts in mind, the problem with polluted water is easier to understand. First, polluted waters come from treatment sources that contain fresh, acidic water. Corals need salt water. Acidic waters damage the corals skeletal structure. Excess nutrients in polluted water accelerate the growth of grass-like alga that eventually covers the corals.

When the growth covers the corals, currents carrying food to corals may be deflected, reducing the source of the corals' food. When the alga becomes thick enough to block the sunlight, the alga in the corals cannot photosynthesize, further reducing the amount of food available to the corals. Eventually, the alga in the corals abandons the corals. The corals turn white and if the alga surrounding the corals does not die, the corals do.

Corals cannot survive in polluted water. here are a few more facts to emphasize that the survival of corals matter.

Written by Otto Spielbichler FSO-MS