Toxic soup for coral reefs: Who knew?

"It is our task in our time and in our generation to hand down undiminished to those who come after us, as it was handed down to us by those who went before, that natural wealth and beauty which is ours."

President John F. Kennedy

While the world worries and debates about increased levels of carbon dioxide in our atmosphere, a more insidious and perhaps irreversible change threatens the oceans.

Like the air we breathe, oceans also represent a dumping ground for the gases released when human beings burn fossil fuels. Marine waters have absorbed approximately half of the carbon dioxide released from industrialization, and the resulting phenomenon is ocean acidification.

Oceanographers estimate that the ocean absorbs more than 22 million tons of carbon dioxide per day and that by the end of the century, the upper 300 feet of sea water will be more acidic than any time in the last 20 million years.

The increasing acidity is creating toxic soup that significantly degrades the environment for sea life. It may prevent the calcification process, which is key to growth of the exterior structures of many marine organisms.

The loss of coral reefs and their fish populations has enormous consequences to tourism, global food supplies, food chains that link to land, biodiversity, potential medicines from marine organisms, cultures, and the aesthetics of our environment.

Another human activity is also toxic to coral reefs.

A team at the University of the Marche in Italy discovered that an estimated 25 percent of applied sunscreen washes off the typical swimmer or snorkeler visiting a coral reef, contributing to the death of the algae (called zooxanthellae) associated with corals.

How? Sunscreen chemicals trigger dormant viruses within the algae.

An estimated 4,000 to 6,000 metric tons of sunscreen bombard coral reefs every year, according to conservative estimates.

At Heron Island research station in the Great Barrier Reef off the coast of Australia, scientists are working around the clock to formulate a sunscreen based on natural, non-toxic ingredients.

So how does a tropical tourist balance reef conservation with the advice of a skin doctor?

Use sunscreens that have physical filters such as zinc oxide: They do not contain chemicals that kill coralline algae.

Or wear protective clothing instead of applying sunscreen. Reason: Fabric does not contribute toxins to coral reefs.

With more than 7 billion people inhabiting Earth, the multiplier effects of our daily behavior increasingly has unintended consequences.