Marine Heat Wave Threatens Florida Coral Reefs with Unprecedented Bleaching Event
(CNN) A sudden marine heat wave off the coast of Florida has shocked scientists with its extreme temperatures, posing a severe threat to one of the state’s most significant coral bleaching events ever recorded. Sea surface temperatures have reached unprecedented levels since satellite data collection began. The alarming rise in temperatures is occurring much earlier than normal, highlighting the amplified impact of human-caused climate change on ocean heat.
Derek Manzello, coordinator of the Coral Reef Watch program at the National Oceanic and Atmospheric Administration (NOAA), expressed his surprise, stating, “We did not expect this warming to occur so early and to be so extreme. This appears to be unprecedented in our records.” Some areas have experienced water temperatures as high as 36.1 degrees Celsius, which is an alarming climate record for the region.
The survival of coral reefs depends greatly on the duration and intensity of extreme ocean heat. Prolonged exposure to high temperatures causes coral to bleach, turning them a pale white as they expel their vital algae food source and eventually starve to death. Although bleached coral can recover under suitable conditions, the likelihood of death increases with higher and more prolonged temperatures.
According to Manzello, a sea surface warming of just 1 degree Celsius beyond the reef’s highest normal temperature is enough to trigger bleaching. Currently, sea surface temperatures around Florida are more than 2 degrees Celsius above the normal range and have maintained these levels for the past week or two.
Buoy measurements off the Florida coast revealed water temperatures reaching 36 degrees Celsius, reminiscent of a hot tub, on Monday in the shallow, heat-prone bay between the southern tip of Florida and the Keys. While the most vital coral reefs lie east and south of the Florida Keys, the buoy measurements indicate the extraordinary and unusual heat observed in Florida during early summer.
Typically, ocean temperatures around Florida increase gradually throughout the summer, peaking in late August or September. Therefore, there is a possibility for further temperature rise, potentially leading to “significant and severe” bleaching in the coming weeks and the potential death of coral reefs within a month, warned Manzello.
Already, bleaching has been observed in the Florida Keys, home to thousands of individual reefs. The Mote Marine Laboratory confirmed eleven cases of partial bleaching in June, with experts projecting a considerable increase in the following weeks.
Katey Lesneski, monitoring coordinator for the Mission: Iconic Reefs project, witnessed initial stages of coral bleaching during her snorkeling expedition near Islamorada in northern Florida Keys. She described the corals as unusually light in color, resembling the effect of lye being thrown at them. A NOAA study published last year revealed that climate change has already eroded 70% of Florida’s coral reefs, causing disease and bleaching. The restoration program aims to revive seven iconic reefs that have experienced a drastic decline in coral cover, from over 50% to a mere 2% since 2019.
The demise of coral reefs has dire consequences beyond the loss of marine biodiversity. The reefs generate billions of dollars for Florida’s economy through fishing and tourism activities. Around 25% of marine species rely on coral reefs at some point in their lives, highlighting the significance of these ecosystems to various ecosystems and industries.
Florida’s coral crisis is merely one symptom of the broader threat posed by climate change. A recent study predicts the potential extinction of all global coral reefs by 2100. Manzello described the current situation as “another cut in a death by a thousand cuts.” With ocean warming intensifying and bleaching events becoming more frequent, this crisis poses an existential threat to coral reefs as we know them.
As the world continues to grapple with the consequences of climate change, urgent action is needed to mitigate its effects on vulnerable ecosystems like coral reefs. Otherwise, these remarkable underwater marvels may soon become nothing but a memory.