Excessive nutrients from land can cause coral bleaching: Study
A recent study has identified new causes for coral bleaching: Excessive nutrients from fertilisers
and storm-water runoff. Coral reefs are among the most diverse ecosystems in the world. They provide shelter and nourishment to fish and other marine organisms. Vibrant and healthy reefs form when a coral and an algae — zooxanthellae — start a symbiotic relationship. The coral provides protection & compounds zooxanthellae need for photosynthesis. The algae produces carbohydrates and helps remove the coral’s waste. But when the corals are stressed due to
change in temperature, light & nutrients they expel the algae and turn white. Corals will die if such bleaching extends. ARC Centre of Excellence for Coral Reef Studies examined skeletal cores of long-living corals in the Red Sea. Corals bleach only when high sea surface
temperatures couple with high nutrient levels. Nutrient stress on corals is difficult to measure though. So, only temperature based stress were considered to predict coral bleaching.
Incorporating nutrient-supplying ocean currents into coral bleaching forecasts can enhance the predictions, the researchers said.