For several months in 2023, global sea surface temperatures reached record-high levels, fueled by decades of human-caused climate warming and a recent boost from the natural climate phenomenon El Niño.
For several months in 2023, global sea surface temperatures reached record-high levels, fueled by decades of human-caused climate warming and a recent boost from the natural climate phenomenon El Niño. Some areas—including the seas around Florida, Cuba, and the Bahamas—saw particularly high temperatures, with implications for the health of coral reefs.
Corals thrive within a small range of temperatures and become stressed when water is too hot or cold. Bleaching occurs when stressed corals expel the algae that live inside them, stripping corals of their color. Extreme bleaching can leave a reef susceptible to starvation, disease, and even death. Observations made by divers in the Florida Keys found that the marine heatwave in summer 2023 caused widespread bleaching.
Stress on corals can also be detected using data from satellites. This animation shows the evolution of accumulated heat stress from July through September 2023. The colors depict “degree heating weeks” (°C-weeks)—a measure that provides an estimate of the severity and duration of thermal stress. Data for the product are compiled by NOAA’s Coral Reef Watch, which blends observations from polar orbiting satellites such as the NASA-NOAA Suomi NPP, and from geostationary satellites such as GOES, with computer models.
Read more at NASA Earth Observatory
Photo Credit: xiSerge via Pixabay
