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.
Crown-of-thorns starfish are one of the biggest threats to the Great Barrier Reef. Since 1985, the Great Barrier Reef has lost half its coral cover, with almost half of this coral loss due to the crown-of-thorns starfish.