Key environmental pressures
No severe climate-related pressures affected the inshore Reef over the 2020-21 summer. No major cyclone made landfall, and rainfall and river discharge were close to the long-term average.
However, environmental conditions varied between regions. Northern regions experienced a wetter wet season (Dec-April) in 2020-21 than in 2019-20, while it was drier in the southern regions with rainfall below long-term average. Cyclonic activity was mostly limited to mid-shelf and offshore reefs, although Tropical cyclone Imogen brought substantial rainfall to the central parts of the inshore Reef.
How did environmental pressures affect inshore water quality?
- Inshore water quality findings:
- Regionally, water quality was moderate in the Wet Tropics, Burdekin, and Mackay-Whitsunday regions, and good in the Fitzroy.
- Individual water quality indicators are monitored annually for compliance with water quality guideline values. The good news is that in general, concentrations of chlorophyll a and dissolved inorganic phosphorus have improved in most regions over the last five years. Additionally, total suspended solids concentrations are either improving or stable across all regions.
- Secchi depth (an indication of water clarity) exceeded guideline values in most regions. In all regions, concentration of nitrogen (nitrate/nitrite and particulate nitrogen) was well above guideline values
What is monitored and where?
- Inshore water quality is monitored for:
- total suspended solids, turbidity, and Secchi depth (indicators of water clarity)
- chlorophyll a (a measure of phytoplankton abundance, which responds quickly to nutrients)
- nutrients (dissolved and particle forms of nitrogen, phosphorus, and carbon)
- sea-surface temperature and salinity
Water quality is monitored in four regions: Cape York, Wet Tropics, Burdekin, and Mackay-Whitsunday.
Recently, the reporting of the Fitzroy region was made possible through the partnership between the Australian Government’s Reef Trust, the Great Barrier Reef Foundation, and the Australian Institute of Marine Science.