Threats to Coral Reefs include:
Pollution Disease Over-fishing Dynamite and cyanide fishing Sedimentation Bleaching caused by rising ocean temperatures
Ask yourselves what can we do to make threats to coral reefs better?
As far as pollution goes, 80% of sea water pollution comes from land based sources! Water table draining fertilisers to the sea or sewage or industrial waste runoff or deliberate dumping into the ocean as well as sea water debris mainly plastic! Eat organic! Force farmers to take a turn to the normal accepted way of mass producing food and ground water pollution at the same time! Take a stand and protest local sea water pollution from local unregulated industry and boycott their products! Make them listen! Last but not least, whenever you dive clean the dive site and never ever throw waste into the sea! Plastic lasts forever or close enough!
Remember, the Oceans are connected! Don’t think for a second that what you do near your home does not effect anyone…take a look at how floating debris travels around the globe and congregates in a Pacific Area dubbed The Great Pacific Garbage Patch.
Being colonies of millions of living organisms it stands to reason that Coral Reefs fall prey to a number of diseases which threaten them some of them are:
Aspergillosis, caused by the fungus Aspergillus sydowii, affects Gorgonian soft corals commonly known as sea fans.
Black Band Disease, caused by a microbial consortium dominated by the cyanobacteria Phormidium corallyticum.
White Band Disease, the cause of this disease remains unknown.
Black Necrosing Syndrome, affects gorgonian from the Great Barrier Reef, possibly a fungal pathogen similar to aspergillosis.
Brown Band Disease, reported only from the Great Barrier Reef, etiology at current unknown although the dense brown band preceding the disease lesion contains the presence of ciliates (although not to be mistaken with Helicostoma nonatum - see Willis et al. 2004).
Dark Spots Disease, etiology currently unknown, possibly an environmental stressor rather than a true pathogenic disease.
Rapid Wasting Syndrome, possibly caused by a fungus growing on areas damaged by feeding action of the parrotfish Sparisoma viride.
Skeletal Eroding Band, associated with the ciliate Halofolliculina corallasia.
White Plague, caused by the bacterium Aurantimonas coralicida.
White Pox Disease, caused by the bacterium Serratia marcescens.
Yellow-Band Disease AKA Yellow blotch disease, thought to be caused by Vibrio spp.
Take a look at this video. We could go on and on on this subject but nothing sums it in a more rounded and resonant way than these video we have stumbled upon by our friends over at OCEAN2012
Dynamite and Cyanide Fishing
In our day and age? Still? You bet! More than ever in fact! Divers, often SCUBA divers squirt fish and coral with Potassium Cyanide to stun and capture rare and exotic fish. They usually spray it onto living coral which kills it of course and stuns/kills any fish hiding or nesting in the immediate vicinity, as well as any other living thing! Most fish caught this way don’t even make it to the aquarium or restaurant tanks! Four fish in ten caught this way perish before they reach their aspiring new owners! Ranked second in the international illegal trade list, second only to the drugs, trading in exotic fish and animals is very profitable made so by the millions of consumers who wish to own one of these special exotic reef fish for their home aquariums! Sad! Added to this the fact that more than two in ten perish in captivity due to the very narrow environmental niche they require to survive especially fish such as Sea Horses makes this doubly sad!
Dynamite fishing occurs the world over. The effects as you might expect are catastrophic. Especially since most times the reef in question is dynamited twice! Once to kill the small fish…which in turn attract the larger predatory fish…which are the main target for the second round of charges! Dynamite is made at home most of the times with the greater culprit being fertilizer charges! As such is very hard or impossible to regulate! It can take upward of 100 years for reefs to recover once damaged by dynamite! Its amazingly destructive!
Both these methods of fishing are illegal the world over and while difficult to regulate local authorities rely on first hand reports. We as divers have a duty to report any such activity that might fall into our attention no matter the area of the world we are diving. We try to preserve the dive sites we enjoy today for our children!
We are hard pressed to believe that this can also be a factor of endangering coral reefs! Beach side property is at an all time premium but while development and economical opportunities are a wanted situation for any place around the world, limits need to be placed to protect that which is truly irreplaceable in an economy! Take a look at this NOAA Chart which depicts the breakdown of component values that contribute the the global annual value of coral ecosystems. Look at the real value of coral reefs! Something people are not always aware of!
Construction, mining, logging and farming along coastal areas or rivers near active coral reefs create mobile sediment which in turn ends up resting on top of coral reefs! This chokes corals and lowers the sunlight reaching them depriving them of nutrients necessary for growth and survival! In certain areas where naturally occurring filter mechanisms have long since been in place have seen their own destruction compounding the problem of coral reef sedimentation. A great example of this are Mangrove Forests, once the great filters in river deltas across the US now cut down and destroyed minimizing their effectiveness and allowing millions of tons of sediment to escape the river deltas into the sea every year!
Although not a threat to coral reefs, but an effect caused by the global rise in sea temperatures and many other factors, coral reef bleaching has been recorded across the globe and it effects have been known to be devastating. Although a result of multiple stresses onto coral reefs and while theorised that it gives way to more resistant coral reefs often repopulated from the deep with hardier coral in most cases the widespread damage that is caused from the coral reef is so large that bouncing back takes many years and can be devastating to local economies relying on the good health of their local coral reef!
Bleaching occurs when zooxanthellate invertebrates die off or loose their photosynthetic pigments. If the stress is momentary or short lived the coral affected will recover in a matter of weeks or months. If however the stressor is continuous or prolonged the affected coral will not recover and will eventually die off!
Stress factors that cause bleaching include water temperature variations (1-2 degrees Celsius for 5-10weeks ie Summer), solar irradiation during the summer months and due to ozone depletion, inorganic nutrients (while increasing Zooxanthellate populations initially the created imbalance crashes the system in the end causing bleaching), fresh water dilution from runoff from rainwater from untimely and greater than normal rainfall due to climate change.