It is either a Ï bond or a lone pair on an atom of relatively high electron density in a molecule or ion, or a bond that must break during a reaction. An electron sink is an atom on a molecule or ion that can accept a new bond or lone pair of electrons.
Threats to the Reef. The Great Barrier Reef is one of the worldâs best managed reefs but, like other coral reefs, it faces threats such as: 1  Climate change. 2  Extreme weather.3  Declining water quality. 4  Coastal development. 5  Illegal fishing. 6  Crown-of-thorns starfish outbreaks. 7  Marine Debris.hreats to the Reef. The Great Barrier Reef is one of the worldâs best managed reefs but, like other coral reefs, it faces threats such as: 1  Climate change. 2  Extreme weather. 3  Declining water quality. 4  Coastal development. 5  Illegal fishing. 6  Crown-of-thorns starfish outbreaks.
The interconnected nature of the Great Barrier Reef may make it more vulnerable to the crown-of-thorns than other reefs, as it means they can spread easily. It is estimated that more than one in three reefs on the Great Barrier Reef have been affected by the crown-of-thorns starfish over the past 60 years.