Better ways of protecting Coral Reefs?

With coral reefs being destroyed by bleaching and ocean acidification new methods of conservation must be approached.  One of these approaches is by not putting all efforts into the coral reefs directly buy by better conserving the land around the reef.  Researchers Carissa Klein, Stacy Jupiter, Matthew Watts and Hugh Possingham tested six different conservation techniques on coral reef ecosystems in Fiji.  The primary objective of each approach was to achieve terrestrial conservation or to minimize land-based runoff.  They also compared these results with other conservation plans on how well they benefit coral reef conditions.

The researchers found that when terrestrial conservation was the primary goal that the reefs benefited by  7.7-10.4% greater than other protected areas that weren't focused on terrestrial conservation.  However, 31-44% of the terrestrial conservation was not achieved which means that there could be a higher percentage of benefit if terrestrial conservation can be achieved better.  These results are being used by the Fiji's protected area committee to better define conservation boundaries on land.



Another method that is being researched is to take more of a gardening approach to the reefs.  Studies are being done on how successful coral reefs, grown in labs, that are modified to withstand current oceanic conditions.  Artificial reefs such as concrete structures are also being used.

A more abstract study looks into if electrical currents can stimulate coral reef growth.  On Vabbinfaru Island, Maldives a 12 meter metal cage that weighed 2 tonnes was placed in the ocean and a small electrical current ran through it.  The electric current stimulates a chemical reaction that draws calcium carbonate out of the water and gets deposited on the cage.  Studies have also been done that found that the electric current helps them filter and adapt to warmer conditions because less energy is needed to form a skeleton.  One of the steel cages used is hard to distinguish now because of all of the colorful reef growth on the cage.

Unfortunately using these steel cages on a global scale would be extremely costly.  The only benefit of these artificial reefs would be from tourist areas or areas that are hit by temporary damage such as oil spills or boat impacts.  Many of the coral reef researches believe the only way to save the reefs is to greatly slash carbon dioxide levels across the globe, but they don't see that being accomplished.  Researcher Peter Sale said "By 2050, we may still have corals, and things we'll actually call 'reefs', but they will be massive limestone structures that were built in the past, with tiny patches of living coral struggling to survive on them." He adds "The world will go on without reefs, but its going to be very much inferior to the planet we have now."

References:
http://www.sciencedaily.com/releases/2013/12/131217155329.htm
http://www.sciencedirect.com/science/article/pii/S0308597X13002261#
http://www.bbc.com/future/story/20120905-save-our-dying-coral-reefs

Invasive Sea Anemones Threaten the Health of Coral Reefs Due to Sunken Ships

Healthy coral reef- Picture by Kydd Pollock

 

Iron leached out from sunken ship with surrounding invasive sea anemone- Picture by Jim Maragos, USFWS 

 

In 2008, scientists began to notice the declining health of the Palmyra Atoll coral reef in the central Pacific due to several shipwrecks in the surrounding area.  Warming seas and ocean acidification were already affecting the health of the reef, but excessive growth of Rhodactis howesii due to leached iron from sunken ships further reduced the quality of the coral reef.  Iron is an essential element for many marine organisms, but in excess, invasive species like R. howesii can thrive.

R. howesii is a type of sea anemone that is very aggressive.  When excess nutrients like iron are available with no predators to keep populations in check, the anemones thrive.  R. howesii also preys upon coral, which further degrades the health of the coral reef. 

In September 2007, USGS researcher Dr. Thierry Work, Dr. Greta Aeby from the Hawaii Institute of Marine Biology, and Dr. James Maragos from U.S. Fish and Wildlife Service studied a shipwreck from 1991 on Palmyra Atoll in the Pacific Ocean.  The researchers discovered that R. howesii was growing in high densities surrounding the ship, and densities steadily decreased with distance from the wreck.  Since the atoll is isolated, runoff from agricultural or industrial activities is unlikely, so the shipwrecks are the only logical source of excess nutrients. 

With the sea anemone growing rapidly, it causes a change in the dominant life form of the reef and is referred to as ‘phase shift’.  Even though phase shifts can have long-term negative effects, eliminating organisms like R. howesii are an impossible feat, especially over a large area.  Rapid removal of shipwrecks to prevent reefs from being overgrown by invasive species like R. howesii is crucial to reef health. 

Remediation projects are currently being implemented to evaluate the resiliency of coral reefs after shipwrecks removal. On January 29^th 2014, the Fish and Wildlife Service completed a $5.5 million conservation project to remove three wrecked ships, weighing a total of one million pounds, from protected wildlife areas in the Pacific Remote Islands National Wildlife Refuge. The shipwrecks caused miles of damage to the Palmyra Atoll and Kingman Reef.  With the reefs being home to 176 species of coral and 418 types of reef fish, protecting the damaged reef from further destruction was vital.  A team of 16 people cut and removed the wreckage from the coral reefs without causing further damage, bringing the salvage to California to be recycled. 

A representative of the remediation project stated, "We know Palmyra Atoll is resilient; it's one of the last remaining healthy coral reefs.  We've done some experiments with removal, and within three weeks we saw new species coming back to the area—mainly microscopic coral recruits.  These resilient areas can heal themselves when they get back on track."

Using Palmyra Atoll and Kingman Reef as controls, scientists can begin to understand how coral reefs heal.  It is possible that these examples can teach scientists in other parts of the world how to restore coral reef health.

New Reasearch on Coral Deaths

A new mathematical tool has been created to help biologist determine how disease and bleaching can kill corals. The researches from Cornell University are now using this model to better understand the causes of coral disease and bleaching. It has been proven that warmer waters are the cause of the bleaching and disease in areas such as the Caribbean. Mucus layers on the surface of the coral protect it from disease by preventing bacteria from invading the coral. Under warmer waters the corals become stressed and that protective technique declines which allows invasion of the bacteria. The new models were used to stimulate the bacterial community within the surface of the coral mucus under normal water conditions and warmer water conditions. The researchers have also found out that once the bacteria establishes in the coral they continue to destroy the coral even if the water cools down. At that point the corals are to damaged to recovery too. Reducing poor water quality was one idea the researchers suggested to allow coral to be less invaded by pathogens.

Reading the full article will give more information on the new model and how the researchers at Cornell University are continuing their research.

• Coral Deaths
• Picture: Partially bleached coral at Looe Key Reef in Florida Keys National Marine Sanctuary. Credit to Eric Bartels