Sea Fan Disease – Aspergillosis of sea fan corals


I had noticed last time I was in Pepper Park and Lauderdale by the Sea that the sea fans were looking much better in central Florida. I started my search to see why they growth seemed to be occuring more and was ever so dismayed to learn of the problems they are having in the Florida Keys. I have decided to go on a journey to learn more. Knowledge is power after all.

The reefs are a large part of why I dive, that and to escape the human element found onshore. Finding a new creature or experiencing something new these fabulous little creatures do is a big part of why I try to spend as much time in the water as possible when it is warm. Other than equipment issues that may arise time to time, I find it extremely relaxing and a fabulous destressor and quick way to declutter my brain. Let’s face it, reefs are wrecked when humans treat them irresponsibly. It is shameful, but I have contributed in some bad way, even if it was the bug killer I put on my lawn that may have run off in a rain storm into the drains and into the Indian river that eventually found it into the ocean. I am ashamed and will try to do my best to educate myself better on how to protect our friends in the ocean. With that said, let’s start our journey….

Gorgonia ventalina is a unique coral that grows in the shape of a fan and has a very distinctive purple coloring. They may also be brown or yellow (which is much rarer). Their branches tend to be round and compressed into a fan shape. In 2-5 years they can grow to 180cm tall by 150cm wide. They will continue to grow longer but at a much slower rate of growth. It can can be found in many environments and varying depths throughout the Florida, Caribbean and Bermuda reefs. With their surface sclerites and chemical compounds they are able to defend off predators and diseases. Keep in mind before you remove this from the ocean if you are in the Bahamas, that it is protected so by the Coral Reef Preserve Act of 1966.
The sea fans flourish in water with good flow that allow for feedings and respiration seasons. They generally die from wave energy, boat propeller destruction and overgrowth of their surface by other micro organisms like Millepora alcicornis and some encrusting bryozoans. Nudibrachs love this tasty treat. The nudi’s feed on this sea fan for the reason of acquiring its chemical compounds which are then incorporated in its body to defend against predators. Now it appears however, they have a new enemy and killer! Check these two videos out. Aspergillosis of sea fan corals is puzzling. Aspergillosis is caused by the fungus Aspergillus sydowii which originates in soil and is also known as a food contaminant and occasionally as human pathogen. The symptoms of this disease in sea fans black or brown lesions, galling, and purpling of the tissue, which can together lead to the sea fan dying. Aspergillosis, like any disease, is dependent on different factors for infection: host of health, colony size, and chemical compounds. It is generally a land based disease that humans can also get. Why is it infecting marine life in Florida?

There are a few popular theories of why it is happening are:

Water run off – is this causing chemical damage? Gorgonians have secondary compounds within their tissue to defend against predators and it is ta common belief that these same chemicals also protect against disease. If these chemical compounds were decreased because of outside factors then their defense against the disease would lessen and infestation is a greater risk. Are we polluting our soil with chemicals that run off and are we dumping unclean water directly into our oceans and rivers.

The African dust theory – microorganisms carried from Africa and deposited on reefs. Each year hundreds of millions of tons of dust is transported from the Sahara desert to the Caribbean. There are indications that the volume of dust has increased as the Sahara expands and atmospheric conditions and wind patterns change. The idea is that African dust can cause or exacerbate coral epizootics by depositing nutrients and trace elements that benefit pathogens or by transporting pathogens from terrestrial African habitats to Caribbean coral reefs. Past studies have indeed found Aspergillus . in dust samples collected from the Caribbean, but none have identified the fungi to species, making it inconclusive. Or has it always been there and we have never seen it. Is it because of global warming? The water temps are at their warmest and we know this affects lifespan and longevity of corals. Warmer water temps cause the sea fans to become stressed from the lack of nutrients; therefore infection chances are increased. Some researchers speculate that multiple stresses, like bleaching, sedimentation and pollution, have pushed corals to the breaking point so that they are now unable to fend off diseases that they have fought off in the past.

Is the the size of the colony? Larger colonies seem to be more highly infected. This could be because of a positive relationship between surface area and probability of infection, a greater age and therefore longer exposure time to sea fans or that smaller sea fans have greater chemical, cellular, and/or structural resistance to disease.

Ways to cure, fix or identify this alarming issue:In order to make identification of diseases more straightforward, some researchers are trying to develop molecular tests for coral diseases. Some biologists are trying to create at test like a DNA fingerprint of the pathogen that would allow researchers who suspect that a coral has the disease to test DNA from the infected area and find out definitively if the fungus that causes sea fan disease is present. This would be an awesome way to prevent the disease before it spreads through a whole colony of sea fans. As scientists struggle to identify illnesses, cures for sick corals appear to be a long way off. Do you apply antibiotics to the reefs? If you do so, what are the hazards that may occur to perfectly normal coral and sea creatures living in this habitat? Would they destroy useful bacteria as easily as harmful bacteria. What if you use an antibiotic and the pathogen turns out not to be bacteria at all? The best results from treating this devastating disease so far has been by vacuuming off the diseased band of tissue that gives the illness its name. This is enormously time-consuming and almost impossible in some areas where the disease is ravaging the sea fans.

Reefs are wrecked when Humans treat them irresponsibly.

Be a responsible diver or snorkelers and remember why all those cute little fish are on that reef. It is their home. You can help these beautiful creatures! Dive responsibly. That means stay neutrally buoyant, make sure your equipment doesn’t drag on the reef and don’t touch coral reefs or stir up sediment. Snorkelers too can help coral reefs by not touching coral, putting your feet down on a coral reef or stirring up sediment. You can also support reef-friendly dive operators. If you are out on a dive boat and he rips through low coral, you have the POWER! Don’t use him again. You can also not take live coral or purchase coral souvenirs. Invest in an underwater camera. Take pictures instead. (HUBBY if you read this…my number one thing on my dive wish list. ) You can also volunteer for a coral reef clean-up, conservation or research project. I have yet to do one of these but I am going to slate a few in this year. Another great way to help out oceans it to pack out your plastics and batteries when visiting tropical islands and try to support hotels and resorts that properly treat their sewage and waste. Many little islands (Corn Islands included) do not have proper waste facilities. They burn their trash and plastics and batteries can not be disposed of this way. Last, leave only your footprints when you leave your favorite shore diving site. Pick up your trash, wrappers, and all dive gear.

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About daniellesdives

diving enthusiast
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