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Pressures affecting marine ecosystems

Key finding

Sediment, nutrients, chemicals and litter are the major catchment pressures that broadly impact Queensland’s marine environments.

Queensland

Pressures on Queensland's marine environments vary between different regions and are often linked to the types of land uses that occur in the catchment.

Overall, sediment, nutrients and chemicals are the major catchment pressures that broadly impact Queensland’s marine environments, but these vary in their relative importance in different areas.

Plastic rubbish pollution that washes down rivers and into the sea threatens marine biodiversity and birds.

Climate change also impacts aquatic ecosystems, particularly the Great Barrier Reef, with significant mass coral bleaching events occurring in the summers of 2016 and 2017.

Healthy Land and Water South East Queensland report card

The Healthy Land and Water South East Queensland Report Card helps us to understand what pressures are affecting ecosystem health in freshwater, estuarine and marine areas.

Historic and current land management practices have resulted in substantial erosion in SEQ. Erosion leads to sediment or mud entering waterways. This can smother seagrass, reduce water clarity, and increase nutrient availability, affecting marine habitats.

Sediment from diffuse rural (e.g. agriculture) and urban sources (e.g. construction) is the current primary threat affecting marine health. The amount and source of sediment entering waterways annually depends on the condition of catchments including extent of riparian vegetation, agricultural and urban development practices and the level of rainfall.

Nutrients from agricultural run-off and effluent from treated sewage also impact waterways.  A major program of sewage treatment plant upgrades and stream rehabilitation has significantly reduced the adverse role of effluent in waterways’ health over the past 15 to 20 years, and agricultural best management practice programs aim to reduce nutrient runoff.

More information:

    Great Barrier Reef report card

    Collective impacts of land run-off associated with catchment development, coastal development activities, extreme weather events and climate change impacts such as coral bleaching events continue to put pressure on the Great Barrier Reef.

    Key Great Barrier Reef ecosystems show declining trends in condition due to:

    • continuing poor water quality
    • cumulative impacts of climate change
    • increasing intensity of extreme weather.

    Sediment from catchments increase turbidity in the marine environment and reduce light for seagrasses and coral, reducing their growth. When this sediment settles, it can have detrimental effects on the early life stages of corals, and in more extreme conditions, can smother corals and seagrass.

    There is strong evidence for several effects of nutrients on reef ecosystems, including increased outbreaks of crown-of-thorns starfish, macroalgae abundance resulting in lower coral diversity, increased coral bleaching susceptibility, increased bioerosion and some coral diseases, reduced benthic light due to algal blooms and increased macroalgae and epiphytes on seagrass.

    Pesticides have been detected inshore at concentrations high enough to affect the health of plants and corals in the Great Barrier Reef.

    Poor water quality also affects the capacity of inshore reef ecosystems to recover from disturbance events, such as cyclones.

    More information:

      Fitzroy Basin report card

      The Fitzroy Basin—the largest catchment on the east coast of Australia—is characterised by a highly variable flow regime, ephemeral streams in its upper reaches, large tidal volumes in the estuary and periods of extensive riverine flooding. High sediment volumes and turbidity result from these characteristics. Seasonal irregularity is a defining feature of the basin, with long dry spells often followed by intense wet season rainfalls. Flood plumes discharged from large floods extend east across the Capricorn Bunker Group and north of Townsend Island, covering an area greater than 10,000km2. Plumes from average floods inundate Keppel Bay, which is home to reefs with some of the highest coral cover of any within the Great Barrier Reef. These inshore reefs are at risk from the impacts of sediment, nutrients, and chemicals, and this risk is exacerbated by climate change.

      Infestations of crown-of-thorns starfish on the Swains Reefs in the Fitzroy region have occurred for the past three decades. These outbreaks have a continued impact on the density of coral reefs in the region.

      Seagrass habitat continues to decline impacting on dugong and turtle populations.

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        Gladstone Harbour report card

        Gladstone Harbour and its associated waterways are used for many wide-ranging activities—from agriculture and industrial and urban development to fishing, dredging and shipping.  These activities exert pressure on the harbour’s ecosystems and species.

        Specific examples of pressures that may change the environmental condition of the harbour are the release of toxic material, physical disturbance of habitats such as mangroves or seagrass, and alterations to the coastline.

        Excess levels of nutrients, such as nitrogen and phosphorus, are pressures on marine environments. Dissolved metals, such as aluminium, lead, manganese, nickel, zinc and copper also impact marine environments.

        More information:

          Mackay–Whitsunday report card

          Pressures in the Mackay-Whitsunday region range from those occurring on an international level such as climate change to reef-wide and localised regional pressures, among them coastal, port and agricultural development, tourism and litter.

          Activities in the catchment strongly influence waterway health scores.

          Mackay–Whitsunday region is a major agricultural area with a significant area of the catchment under sugarcane production: catchment runoff of pollutants, particularly nutrients and pesticides, present a major pressure, notably in the Pioneer and Plane river basins.

          Rainfall is a key driver of water quality. The region was heavily impacted by Severe Tropical Cyclone Debbie in 2017. Its effects will be captured in the 2017 report card.

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            Wet Tropics report card

            Significant industries in the Wet Tropics region — which includes 2 World Heritage Areas — are tourism, agriculture, ports, aquaculture, fishing, urban and heavy industry.

            The main agricultural sectors — grazing, sugarcane and banana growing — collectively contribute nutrients, sediment and pesticides to agricultural runoff which impacts rivers, estuaries and the marine areas. Whilst plumes of sediments, nutrients and pesticides from river discharge impact the inshore marine areas, the offshore zone is less affected as it is typically a minimum of 20km for the mainland (14km at closest point, Cape Kimberley, just north of the Daintree).

            Seagrass decline, resulting from regional climate patterns compounded by cyclones and storms, has impacted inshore marine grades.

            Coral cover and health is also impacted by cyclones and storm events, as well as coral bleaching events.

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              Condamine Catchment report card

              Marine ecosystems not analysed in report card publication.

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              QCatchment Bulloo

              Marine ecosystems not analysed in report card publication.

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              QCatchment Paroo

              Marine ecosystems not analysed in report card publication.

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              QCatchment Warrego

              Marine ecosystems not analysed in report card publication.

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              QCatchment Nebine

              Marine ecosystems not analysed in report card publication.

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              QCatchment Lake Eyre

              Marine ecosystems not analysed in report card publication.

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              QCatchment Archer

              Marine ecosystems not analysed in report card publication.

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              QCatchment Coleman

              Marine ecosystems not analysed in report card publication.

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              QCatchment Ducie

              Marine ecosystems not analysed in report card publication.

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              QCatchment Endeavour

              Marine ecosystems not analysed in report card publication.

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              QCatchment Holroyd

              Marine ecosystems not analysed in report card publication.

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              QCatchment Jacky Jacky

              Marine ecosystems not analysed in report card publication.

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              QCatchment Jardine

              Marine ecosystems not analysed in report card publication.

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              QCatchment Jeannie

              Marine ecosystems not analysed in report card publication.

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              QCatchment Lockhart

              Marine ecosystems not analysed in report card publication.

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              QCatchment Normanby

              Marine ecosystems not analysed in report card publication.

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              QCatchment Olive–Pascoe

              Marine ecosystems not analysed in report card publication.

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              QCatchment Stewart

              Marine ecosystems not analysed in report card publication.

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              QCatchment Wenlock

              Marine ecosystems not analysed in report card publication.

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              Indicator: Pressures identified in report card area

              Pressures identified in various water quality report cards across Queensland.

              Last updated 8 January 2019

              Assessment summary

              See an overview of gradings for estuarine and marine ecosystems in the assessment summary.