How far apart is "too far" for a coral colony to survive? This is the second of three micro-lectures broadcast as part of the Climate at the crossroads live lesson (see links to further videos below). 

Marine ecologist, Prof Peter Mumby from the University of Queensland, takes us beneath the waves of the Great Barrier Reef and the Pacific to explore the complex reproductive lives of corals.

He explains the symbiosis between corals and photosynthetic algae, showing how rising sea temperatures disrupt this relationship and can lead to catastrophic coral bleaching events. Moving beyond the immediate visual damage of bleaching, he introduces a critical yet overlooked threat: how population decline triggers the "Allee effect", the relationship between the spatial density of coral colonies and fertilisation rates.

The talk ends with a presentation of the results of the research, and the implications for coral conservation.

Download the Student Sheet to support class discussion

Other videos in this series

• Global carbon levels - how bad is it? by Dr Mike O’Sullivan, University of Exeter
• Tipping points - from peril to prosperity by Dr Tom Powell, University of Exeter