Monday, July 21, 2014

Two Years Wasted

I spent nearly two years on Saipan from 2006-2007 advocating for the protection of coral reefs.  The slogan I came up with was, "What we do on land affects our marine environment."  My focuses were land use practices, particularly reducing pollution and runoff.  I took students on field trips, planted thousands of trees to reduce erosion, and tried to start a stream sampling project that never really took off after the DEQ staffer quit and moved back to the mainland.

I look back on that work and realize I had it all wrong.

In my new work with sharks, I try to find ways to make sharks relatable to island leaders.  Shark Stanley helps reach out to the masses, but political leaders are a different sort.  I've found that most island leaders understand the threats of climate change and the importance of coral reefs to ecotourism, especially dive tourism.

About a year ago, a colleague at the University of Hawaii recommended I read Forest Rohwer's book Coral Reefs in the Microbial SeasForest is molecular biologist who pioneered the use metagenomics and investigates the role of viruses and microbes in coral reef health and disease.  His book is my new bible.

This book, through Forest's pioneering work on viruses, postulates that the biggest threat to coral reefs is not nonpoint sources of pollution from agriculture and sewage, but overfishing, particularly the removal of large predators such as sharks.

Corals are not fragile creatures. They are tough, extremely well-adapted, and adaptable organisms, yet we are killing them. Worldwide, 30% of coral is severely damaged. The Great Barrier Reef has lost 20% of its coral in the last 60 years; Eighty percent of the Caribbean reef coral has died in the last 30 years.

Forest goes through all of the threats to corals, including temperature and acidity changes due to increased carbon dioxide in the atmosphere, and finds that overfishing is the main culprit in killing corals.  Simply put, no sharks, no corals.

The process is somewhat complex, but once it gets started it feeds itself in a positive feedback loop.  Overfishing down the food web from sharks to herbivores increases the amount of algae on a reef, which in turn releases large amounts of sugars and carbohydrates (something he calls dissolved organic carbon or DOC), which feed microbes, which smother and kill coral.  When the coral dies, it creates more space for the algae to grow, resulting in even more sugars and carbohydrates in the water, more microbes, and more coral death, until the ecosystem flips from a coral-dominated ecosystem with lots of fish, to an algae-dominated ecosystem with very few fish.  Adding nutrients from agriculture runoff and sewage only fuels the process, as nitrogen and phosphates increase algal growth.

The book is a must read for anyone working on coral reefs today.  Forest's recommendations at the end of the book are to protect large predators and herbivores, such as sharks and parrot fish, create marine protected areas, and reduce pollution.

1 comment:

Joseph Shaul said...

I love your work, but you need better slogans. Less syllables, more snap!