The role of land-based pollution in coral loss

Research is increasingly showing that land-based nutrients (from agriculture, sewage, and livestock rearing) can compromise coral health and reduce coral resilience to climate change impacts. However, the role of nutrient input in the widespread loss of corals remains unexplored due to a lack of reef water quality monitoring.

We are launching projects in the Caribbean and Central Pacific that will utilize coral and reef sediment cores to track reef nutrient pollution and coral health over the past few centuries, a period of intensifying land use change. Changes in nutrient input will be assessed from the analysis of stable isotopes of nitrogen preserved within the cores, and will be related to various measures of coral health including growth rate, bleaching, and mortality.

Sediment from the Maria Creek near Mission Beach in far north Queensland heading towards the Great Barrier Reef.
Photograph: STR/AFP/Getty Images

Results will enable reef managers to set appropriate water quality targets, inform the recovery plans of coral species protected under international and national laws, and inform the selection of sites appropriate for ongoing coral restoration efforts.