365 Days of Climate Awareness 196 – Decline of the Great Barrier Reef, Introduction

The Great Barrier Reef is the world’s largest coral reef system, comprised of more than 2900 individual coral reefs and 900 islands off Australia’s northeastern coast. It stretches more than 2300 km/1400 mi, and is roughly 344,000 km²/133,000 mi² in area, and is bordered to the northeast by the Coral Sea region of the South Pacific.

Australia and surrounding ocean, with the Great Barrier Reef. 

Coral reefs are the structures built from the exoskeletons of coral polyps, which over many successive generations create broad or wall-like mounds which become home to a huge range of marine life. In this way coral polyps, which feed off of photosynthesizing algae, are the physical (if not primary producing) foundation of massive marine ecosystems. The Great Barrier Reef is the largest of these.

Closer-up map of the reef extent.

Corals require warm water, between 23°C/73°F and 29°C/84°F, proximity to the sea surface for photosynthesis, and marine species which feed on other species of algae which would otherwise overrun the coral. With those basic elements present, many other species can find survival niches and so the community grows.

Closer view showing some of the reef segments, named individually.

Many thousands of species make their homes on and around the Great Barrier Reef, including more than 1620 species of fish, 300 species of mollusks and 500 species of algae (among many more). However, most of this region and the life on it is under increasing threat from many sources, including marine pollution, rising water temperatures and increasing ocean acidity.

Tomorrow: main threats.

Be brave, and be well.