This week would certainly not be the first time we’ve brought you news of a heat wave, but it is the first time we are reporting one over an ocean. The problem here is not harmful effects to health, clearly, rather harmful effects to reefs. Coral is the mainstay of reefs. Other zooplankton have an important role to play, but without a healthy supply of coral to deposit exoskeletons to make the rock-like structures of a reef, there is great harm to any reef. Some fish have evolved jaws to eat coral skeletons, but they leave the bulk of living colonies intact. Most of what we think of as coral is actually dead. Only the head of coral is living. The rest is the calcium carbonate skeletons they leave behind. Zooplanktons like corals are animals, so like all animals they need to eat. This is where bleaching becomes a problem.

 

Corals, loosely speaking, eat algae. Algae have what corals lack, the ability to photosynthesize. It’s actually a bit more complicated than that. Corals host these algae intracellularly. They derive energy from them non-destructively.  The algae in turn use the host corals’ carbon dioxide and nitrogenous waste for photosynthesis. In addition, integrating with a coral provides some measure of safety for the algae. When the corals suffer physiological stress, however, they eject the algae. The algae are colourful, but the coral is always white, clear, or brown. Therefore, the event is called bleaching.

 

Though the mechanism that causes bleaching is technically called ejection, the corals are less the agents than the algae. The coral effectively loses its symbiote. Corals lacking algae are liable to starve, because while they eat phytoplankton and other zooplankton, destructively, the corals rely mostly on the symbiotic relationship they maintain with algae.   Corals and reef organisms that are dependent on corals are used extensively in medicine. Many drugs used to treat various diseases, including arthritis, asthma, HIV and possibly even cancer. A loss of biodiversity could cost us lost opportunities for creating new drugs. Critically though, corals are the base of the ecosystems edible fish inhabit. Young fish spend their time in the relative safety of reefs before venturing out into open ocean. It is where they start their life cycle. About 30 million people, (which is just lower than the population of Canada,) depend on coral reefs for their survival, mostly because they consume a heavily fish based diet.

 

In other news, serious flooding has affected North and South Carolina, with a death toll of at least 19 people. The historic flooding caused over a billion dollars in damage. In South Carolina, 14 dams failed. The Columbia Canal also breached, prompting the National Guard to drop 3,000lb (1,136 kg) sand bags into the canal.

Unfortunately, the tragic events we reported on are in no way a full reflection of what has been going on in the world.  If you would like to see all of our headlines from the past week, please click here.

 

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