It's not just shallow ocean corals that are threatened, according to an international group of marine biologists, there's concern about damage to deep reefs, which can be thousands of metres below sea level.The warning is published ahead this week's U/N. Biodiversity Conference COP 15 in Montreal, Canada.

It's not just shallow ocean corals that are threatened, according to an international group of marine biologists, there's concern about damage to deep reefs, which can be thousands of metres below sea level.The warning is published ahead this week's U/N. Biodiversity Conference COP 15 in Montreal, Canada.