The shape of things to come: Temperature's rising

Vicki Small

Glass - Fritt-de-verre

In the summer of 2010/11 water temperatures off the south-western coast of Western Australia rose to unprecedented levels. This warming event was termed a 'marine heat wave'. Surface temperatures were more than 3°C above the long term monthly average, rising to 5°C in late February /March. This led to mortality of fish and invertebrates, and also resulted in what is believed to be the first WA regional scale coral bleaching event. Coral ecosystems are a source of food for millions; protect coastlines from storms and erosion; provide habitat, spawning and nursery grounds for economically important fish species; provide jobs and income to local economies from fishing, recreation, and tourism; are a source of new medicines. A temperature about 1 °C (or 2 °F) above average can cause bleaching. Once these corals die, reefs rarely come back. When few corals survive, they struggle to reproduce, and entire reef ecosystems, on which people and wildlife depend, deteriorate. If rising temperatures continue into the future, the shape of and colour of these fragile systems will be altered forever.