coral reef

Fascinating: “Coral reefs produce a volatile substance called dimethylsulphide or DMS which oxidizes in the atmosphere to produce cloud condensation nuclei (CCN). These are tiny sulphur aerosol particles around which water vapor condenses to form clouds, and lead to precipitation. Yet Jones has discovered that even a slight rise in ocean temperatures could affect this natural process, making climate change a significant threat to clouds (and precipitation) seeded by coral reefs. What this suggests is that fewer CCN (cloud condensation nuclei) are produced over coral reefs during high sea surface temperatures and so cloud cover could be expected to be lower or non-existent during high seas surface temperatures. This is a feedback system where the warmer temperatures decrease cloud cover through shutting down the coral’s production of DMS, which in turn further warms the ocean since more sunlight reaches the sea surface. Once the sea surface temperatures exceed the coral’s tolerance level, the corals suffer bleaching, which leads to wide-spread coral stress and even mortality.