10 key facts from the Scientific Consensus Statement

  1. The 2017 Scientific Consensus Statement is the most authoritative synthesis of Great Barrier Reef water quality science which draws on independent, peer reviewed research from more than 1600 reports. A panel of 48 experts from a range of disciplines (for example biology, ecology, economics and social science) compiled the document. TropWATER, James Cook University, led the project.
  2. The Great Barrier Reef lagoon and catchments are a dynamic interconnected system which includes fresh and marine ecosystems such as seagrass meadows, wetlands, coral reefs, estuaries, mangroves and saltmarshes.
  3. Key Great Barrier Reef ecosystems continue to be in poor condition. This is largely due to the collective impact of land run-off associated with past and ongoing catchment development, coastal development activities, extreme weather events and climate change impacts.
  4. Water quality plays an important role in Great Barrier Reef ecosystem resilience.  Unlike global challenges like climate change, we can work together locally and quickly to improve water quality through targeted actions.
  5. Greater effort to improve water quality is urgently needed to reduce the amount of sediment, nutrients and pesticides reaching the Great Barrier Reef in run-off. Changes to farming and land management practices can be accelerated by addressing social and economic factors, better targeting and prioritisation, exploring alternative management options and providing increased support and resources.
  6. The main pollutants posing a risk to Great Barrier Reef ecosystems mostly come from agriculture. They are:
    • fine sediments from soil erosion
    • nutrients from fertiliser use
    • pesticides used to protect against pests.
  7. The effects of nutrient run-off include increased outbreaks of coral-eating crown-of-thorn starfish, lower coral diversity, algal blooms, increased susceptibility to coral bleaching and some coral diseases. Dissolved inorganic nitrogen is of greatest concern because it is immediately and completely available for uptake by marine plants and algae. The main source of dissolved inorganic nitrogen is fertiliser run-off from cane farms.
  8. Fine sediments cause turbidity which reduces the amount of light available to seagrasses and inshore coral reefs, stunting their growth and even smothering them when present for extended periods. Grazing lands are the major contributor of sediment in Reef ecosystems.
  9. Pesticides are a threat because what they are designed to do on land – kill pests such as weeds and insects – means they also impact plants and animals in rivers and creeks, as well as some coastal and inshore areas. Pesticides including herbicides, insecticides and fungicides are generally not found in the natural environment and can take months or even years to break down.
  10. Better monitoring and modelling of river pollutant loads has significantly improved our understanding of the source and quantities of pollutants discharging to the Great Barrier Reef and is helping improve water quality programs.
Last updated
14 February 2019