With temperatures in South Florida waters reaching above 32 degrees Celsius in mid-July, scientists are already seeing signs of coral bleaching in Central and South America. What is most concerning is that we are seeing such high ocean temperatures so early in the summer. If this extreme heat continues, it could be devastating for coral reefs.
Just like humans, corals can cope with a certain level of stress, but the longer it lasts the more damage is done. When water temperatures rise to dangerous levels, corals cannot migrate to cooler areas. They are trapped inside. For those that are very sensitive to temperature then it can be very dangerous.
A healthy coral reef ecosystem is important to humans in many ways. Unfortunately, ocean heat waves are getting more frequent and extreme and can have a devastating impact on coral reefs around the world that are already in a fragile state. Coral reefs are biodiversity hotspots. They are often referred to as marine rainforests because they contain the highest concentration of species in the ocean.
However, corals are quite sensitive to warming waters. They contain microscopic symbiotic zooxanthellae algae that photosynthesize like plants and provide food for corals. If the surrounding water warms for too long, the zooxanthellae leave the coral and the coral can become pale or white – a process called bleaching. If it continues to bleach, the coral can be damaged and eventually die.
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A recent paper by John Morris, a researcher at the Florida lab, showed that 70% of coral reefs in the Florida Keys are now experiencing net erosion, meaning they are losing more habitat than they are gaining. Global sea surface temperatures have reached record highs and large parts of the Atlantic and Eastern Pacific are exposed to bleaching warnings. At this point, the evidence points to the possibility of a very negative outcome.
Major restoration efforts are underway in the Florida Keys as part of NOAA Mission Iconic Reefs. They are also studying how individual corals behave under stress in hopes of combining large amounts of data from restoration projects and coral gardens to identify corals that are particularly resistant to stress.
In addition to the major restoration work currently underway in the Florida Keys, evaluations of stress-hardening technologies are also being conducted. For example, corals in tide pools experience large temperature changes over short periods, making them more resistant to subsequent heat stress events. We are investigating whether it is possible to reproduce this natural process in the lab before transplanting corals onto reefs for better outcomes in preparation for stressful summers in the wild.
Source: theconversation.com
