Overview
- An AIMS-led team reported in Communications Biology that reefs exposed to higher CO2 showed progressive replacement of corals and calcifying algae by fleshy algae.
- Sampling across 37 sites along a roughly 500‑meter gradient found no single tipping point, with community structure shifting steadily as CO2 rose.
- High‑CO2 zones hosted far fewer juvenile corals, indicating slower growth and reduced capacity to recover from cyclones and bleaching.
- The findings from Milne Bay, Papua New Guinea, are being used to caution that the Great Barrier Reef and Ningaloo could evolve toward smaller, less colorful, algae‑dominated corals by century’s end.
- Researchers note ocean acidity has already increased about 30 percent and could reach around pH 7.8 by 2100, threatening reef complexity, biodiversity, fisheries and tourism.