We have heard and seen it all before and will continue to do so unfortunately! Headlines…Our reefs of the world are being decimated due to increased water temperatures, or oil tanker crashes into reef spilling 50,000 gallons of oil into the ocean. These are just a couple of the cold, hard facts that most people are aware of on a consistent basis thanks to news briefs. Compile these factors with the lesser known factors that are a day in and day out and we have really got a problematic situation on our hands. All to often we, as a whole, do not care or are not aware of the progressive chain of events that will provide detrimental consequences down the not so distant road. These categories below; physical damage, sediment damage, animal damage, algal destruction and diseases/viruses all play a part in the prolific coral mortality that can and will continue to decimate the reefs of our world unless something is done rather quickly and we show some compassion and become conscientious and knowledgeable as to what is taking place in our marine world.
Physical damage is just that, damage inflicted by our error for the most part. Yes, I guess you could place such acts of nature like hurricanes and typhoons and earthquakes under this category as they will impact a coral reef on a very large scale due to the force associated with these turbulence’s. Ship wrecks, boat anchors, snorkel or diving carelessness from the collecting, standing on or touching areas of our reefs that took years to create. These impact our reefs on such a grand scale. On a smaller scale, within the confines of our reef tanks we have to deal with some of these same issues that plague or oceans. Rocks, power heads, heaters etc. falling on our corals or carelessness regarding shipping, handling and transferring corals from place of collection to our tanks.
Sediment damage can be associated with the violent storms, flooding as well as land-based and river run off. These can potentially cause mass destruction. eroded soil and substrate can and will cause the mortality of corals as well as Trudging clams especially due to the accumulation of these on the delicate tissue reducing the amount of available light to its symbiotic sixthly. These factors will also affect water quality as well as affect the carbon dioxide and oxygen gas transfer(anorexia-oxygen deprivation), possibly causing suffocation. In our tanks this also hold true as many fish species or the flow of power heads can ultimately disturb the Bentham areas of our tanks by stirring up the sand bed causing substrate to cloud our water and accumulate on our living corals and clams possibly paving the way to disease, or worse yet, death. Organic matter such as detritus can also accumulate as a result from feeding livestock, deification and decomposition. Increased bacteria and the local anorexia associated with this detritus on coral tissue can overwhelm them leading to disease as well. Some corals are able to handle this type of situation by forming a mucus net that they can slough from time to time as a natural means of ridding detritus and sediment on their delicate tissue.
Algae growth is another big problem which can effect corals. It can deter coral growth by reducing available light or reacting negatively with their tissue. Also, algae will quickly form on areas of the coral that have been affected by injury, damaged or weakened for what ever reason.
Animal predation takes place non stop, 24/7. Whether it be a Hawks bill Turtle grazing on Uphill Angora, Crown-of Thorns Sea star voraciously consuming stony corals, Queen Angel picking on polyps and sponges or a parrot fish devouring tons of coral on a daily basis, it is an ongoing event. Certain Subbranches, Long nose File fish, Nadia Sea star and Butterfly fish are also culprits in the marine Boote.
Disease and viruses can result as a result of stress factors(lighting, water flow, water parameters, sediment, salinity or temperature) etc. Unfortunately, their is little known about the causes and origins(etiology) of these pathogens that are plaguing our corals, not to mention ways to treat these outbreaks that are causing mass destruction. Exotics( animal kingdom equivalent to human epidemics) have caused widespread destruction to not only corals but invertebrates and fish as well as entire ecosystems have become devastated due to bacteria, diseases and viruses. Humans are partly at fault regarding these etiology and pathogenesis developments effecting our reefs as well as within the confined closed systems in our tanks. It is documented, the widespread bleaching events that took place back in 1983 and 1987 and the destruction of 95% of the Atlantic acropora coral species due to white and lack band disease as a result. Whether or not coral death is a direct result of tissue death or a dysfunction of the symbiotic relationship between coral and its host zooxanthellae. It seems as if their are different diseases and viruses that affect different parts of the coral. Some are associated with the attacking of the corals polyps, while others affect the host zooxanthellae. In any event they both have a negative impact on the coral as a whole and will ultimately lead to the death of at least part of the coral if not the colony as a whole. The various so-called Band diseases, Tissue Necrosis, Brown Jelly, White Pox, Yellow Blotch, Aspergillosis, White Plagues are all some of the diseases encountered with corals. Bacteria such as Beggiatoa, and Desulfovibrio are also associated with coral and their demise. Protozoans like Nematopsis, Gemmocystis cylindrus and amoebae can also hinder corals by causing atrophy, tissue necrosis and bleaching. With the myriad of potential diseases, protozoans, viruses, tumors, and other unfavorable conditions affecting corals, it is our job as conscientious marine hobby enthusiasts as well as marine biologist, scientists and oceanographers to decipher the causes, reasons and possible cures to limit the mass destruction that can invade our reefs as well as our tanks.
You can even take it one step further and include the parasitic organisms that will also disrupt, stress and kill corals in our tanks as well as in the wild. Cryptofauna organisms are often associated with corals. Many of these are commensal seeking the refuge within the confines of the skeletal structure and tissue of corals, either temporarily or for a very long period of time. Some are predatory or parasitic causing injury to the coral whereas others are often harmless and beneficial. Corkscrew, Aiptasia and Mojano anemones are some of the more damaging commensal organisms that will kill neighboring areas or corals as a whole with their strong sting. Crabs, and other invertebrates along with polychaete worms (boring and parasitic flatworms for example) can also be a hindrance or benefit to the various corals of the world.
As you are aware by now, there are many different variables that factor in to whether or not a particular coral or coral reef will survive or be completely wiped-out. We need to be enlightened and educated as to the potential problems that can effect our reefs and make the right decision to help our diverse and fragile marine ecosystem so that it will be able to flourish as it once did not too long ago. Unfortunately not everything can be controlled or dictated by human intervention as we cannot control many of harsh and dramatic warefare situations evident in the underwater realm, but if we each play our part, we will be able to give our reefs and the corals within our tanks a chance of life to grow, flourish, evolve and diversify for not only us at the present time, but for our kids and theirs as well.