Кариб теңізінің кораллдарындағы ақ жолақты ауру

Disease affecting marine corals

White band disease is a coral disease that affects acroporid corals and is distinguishable by the white band of exposed coral skeleton that it forms. The disease completely destroys the coral tissue of Caribbean acroporid corals, specifically elkhorn coral (Acropora palmata) and staghorn coral (A. cervicornis). These symptoms are similar to white plague, except that white band disease is only found on acroporid corals, and white plague has not been found on any acroporid corals. It is part of a class of similar disease known as "white syndromes", many of which may be linked to species of Vibrio bacteria. While the pathogen for this disease has not been identified, Vibrio carchariae may be one of its factors. The degradation of coral tissue usually begins at the base of the coral, working its way up to the branch tips, but it can begin in the middle of a branch. The band, which can range from a few millimeters to 10 centimeters wide, typically works its way from the base of the coral colony up to the coral branch tips. The band progresses up the coral branch at an approximate rate of 5 millimeters per day, causing tissue loss as it works its way to the branch tips. There are two variants of white band disease, type I and type II. Type II of white band disease can be mistaken for coral bleaching. The bacteria shifts from a dominant pseudomonad population to an increasingly dominant Vibrio carchariae population. Elkhorn and staghorn corals are two of the major reef building corals, the foundation on which the rest of the coral reef is formed.

White band disease is highly contagious through direct contact between diseased and healthy coral tissue. C. abbreviata, a species native to the region where Elkhorn and Staghorn corals are found, is able to act as a "reservoir" for white band disease, meaning that it is able to retain the disease pathogen for at least two weeks. Anthropogenic climate change is negatively impacting the world's corals and coral reef ecosystems. Over the next few decades as climate change continues, oceanic warming and acidification will accelerate and further damage the fragile reef ecosystems. Prediction of the impacts of future climate change on coral reefs can be difficult given the uncertainty in certain involved socioeconomic factors (i. e. political response, future technology, changes in human behavior, the Earth's climate system, and the realtime effects on coral reefs). Despite these uncertainties, humans could see the extinction of the coral reef ecosystem by the end of the 21st century if actions are not taken to protect them. According to forecast models of increasing oceanic temperature, mass mortality events will likely occur as early as the summer of 2030 and continue to occur on an annual basis.