Grading statements — Physical, chemical, and ecological processes
There are no significant changes in processes as a result of human activities.
There are some significant changes in processes as a result of human activities in some areas, but these are not to the extent that they are significantly affecting ecosystem functions.
There are substantial changes in processes as a result of human activities, and these are significantly affecting ecosystem functions in some areas.
There are substantial changes in processes across a wide area as a result of human activities, and ecosystem functions are seriously affected in much of the area.
or
Borderline Indicates where a component or criterion is considered close to satisfying the adjacent grading statement.
Confidence
Adequate high-quality evidence and high level of consensus
Limited evidence or limited consensus
Inferred, very limited evidence
The chemical processes within the Reef are generally in good condition. However nutrient cycling continues to be affected by land-based run-off. Ocean pH has decreased as a result of climate change.
Although substantial and ongoing changes to nutrient cycling since European settlement continue to affect inshore habitats, this process is understood to have been generally stable since 2019. There have been important advances in our understanding of nutrient cycling and in its integration into decision-making through improved models since 2019.
Ocean pH has declined within the Region, in line with global and Australian trends. It is likely that the rate of decline has increased in recent decades, driven by progressive ocean uptake of carbon dioxide due to increasing emissions. Ocean acidification has significant implications for coral reef ecosystems.
Wider ocean patterns suggest that salinity may slowly increase in offshore areas within the Region, while inshore areas are subject to seasonal decreases in salinity as a result of freshwater input. Over the past 5 years, freshwater influence has been slightly above average overall with regional variation.