There is reason to believe that coral reefs won’t be surviving the impact that humans have had on the planet. In part, this is because humans have been mining coral reefs, whether so that the resulting product can be sold to tourists or so that the resulting product can be turned into building materials. However, it should be noted that other human activities are having horrendous consequences for coral reefs through both direct and indirect means. For example, construction is increasing the amount of sediment that can be found in rivers, which in turn, is leading to increased amounts of sediment in the sea. This is a huge problem because the sediment prevents sunlight from reaching the coral, thus eliminating one of the factors that it needs for its continuing survival. Likewise, other examples range from how pollution is causing a similar problem by encouraging the overgrowth of algae to how certain fishing practices such as bottom trawling are straight-up destroying coral reefs. However, the single most infamous example of humanity’s negative effect on coral reefs might be climate change, not least because it seems like something inevitable at this point in time.
For those who are unfamiliar with the issue, climate change is causing an increase in the sea’s temperature, which is problematic because the current species living in the sea are most suitable for living under the previous range of temperatures. As a result, it should come as no surprise to learn that the increase in the sea’s temperature has caused a phenomenon called coral bleaching, which is when the coral expels the algae that is supposed to live in symbiosis with it because the coral is no longer capable of meeting the algae’s needs. In other words, coral bleaching is the coral’s strategy for surviving a short-term problem, which won’t help because climate change isn’t exactly a short-term problem with short-term consequences. This is particularly true because coral gets most of its energy from the algae’s photosynthesis, which explains why coral bleaching so often leads to nothing but dead coral. Even worse, climate change is causing the acidification of the ocean, which is making it harder and harder for coral reefs to persist without a strong, healthy population of coral to maintain them.
Summed up, it is no wonder that huge percentages of the world’s coral reefs are not expected to outlast the century. In turn, this explains why there are a lot of people interested in coming up with a way to help coral reefs cope with their new circumstances, which leads to the latest research on why some coral reefs are handling this particular problem better than others.
What Did Researchers Learn About the Microbes That Exist in Symbiosis with Coral?
In short, a research team exposed two species of coral to the sort of conditions that scientists are expect by the end of the century. One of the species experienced coral bleaching. In contrast, the other species did not. At this point in time, the research team is still unsure why one species of coral was so much more resilient than the other species of coral under the same circumstances. However, they made some other interesting observations as well, which was that the coral that bleached suffered a fall in the number of bacteria as well as the range of bacteria that lived on its exterior whereas the coral that did not bleach did not. Unfortunately, the research team are uncertain whether this is a case of correlation or causation, meaning that it is still unclear whether the bacteria was somehow responsible for the different outcomes for the different species of coral or whether there is some other unknown factor behind both sets of outcomes.
Regardless, the observation is interesting because there is evidence to suggest that the bacteria living on coral can help it overcome a wide range of stresses, thus making it more resilient. Furthermore, there is reason to believe that coral can survive significant changes in its environment to some extent by taking in new species of bacteria. As a result, if the bacteria was indeed responsible for the different outcomes of the different species of coral, it might be possible for scientists to introduce the right combinations of bacteria to other coral species to make their more capable of surviving in the conditions of the future. Unfortunately, even if this is an option, scientists are going to have to work fast because it is clear that time for coral reefs is running out.