Pressures affecting marine ecosystems

Key Finding

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

Filter this information

Queensland or report card area:

Map
List

Healthy Land and Water South East Queensland report card
Reef Water Quality report card
Fitzroy Basin report card
Gladstone Harbour report card
Mackay–Whitsunday–Isaac report card
Wet Tropics Waterways report card
Townsville Dry Tropics report card
QCatchment Archer
QCatchment Bulloo
QCatchment Burdekin
QCatchment Coleman
QCatchment Ducie
QCatchment Endeavour
QCatchment Holroyd
QCatchment Jacky Jacky
QCatchment Jardine
QCatchment Jeannie
QCatchment Lake Eyre
QCatchment Lockhart
QCatchment Nebine
QCatchment Normanby
QCatchment Olive–Pascoe
QCatchment Paroo
QCatchment Queensland Eastern Murray Darling
QCatchment Stewart
QCatchment Warrego
QCatchment Wenlock

Water Quality report card area (select locations to filter information)
(Townsville Dry Tropics boundary is indicative only)

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 pesticides 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

Historic and current land management practices have resulted in substantial erosion in South East Queensland (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 run-off.

More information:

Reef Water Quality report card

Key Great Barrier Reef ecosystems continue to be in ‘poor’ condition. This is largely due to the collective impacts of land run-off associated with past and ongoing catchment development, coastal development activities, extreme weather events and climate change impacts such as coral bleaching events.

The decline of marine water quality associated with land-based run-off from the adjacent catchments is a major cause of the current poor state of many of the coastal and marine ecosystems of the Great Barrier Reef. Water quality improvement has an important role in ecosystem resilience.

The main source of the primary pollutants (nutrients, fine sediments and pesticides) from Great Barrier Reef catchments is diffuse source pollution from agriculture. These pollutants pose a risk to Great Barrier Reef coastal and marine ecosystems.

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 Great Barrier Reef ecosystems, including increased outbreaks of coral eating crown-of-thorns starfish, macroalgae abundance resulting in lower coral diversity, increased bio-erosion and some coral diseases, reduced benthic light due to algal blooms, and increased macroalgae and epiphytes on seagrass.

Pesticides have been detected in many rivers and creeks draining to the Great Barrier Reef, as well as some inshore coastal waters at concentrations high enough to harm organisms.

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

More information:

Fitzroy Basin report card

The Fitzroy Basin report card no longer includes a marine component.

More information:

Gladstone Harbour report card

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

Gladstone Healthy Harbour Partnership has identified a number of environmental, social, cultural and economic drivers that influence Gladstone Harbour:

floods and storms
environmental flows from catchments
climate variability
hydrological connectivity
tidal flushing
natural high levers of certain minerals and political and economic drivers

The Gladstone Healthy Harbour Partnership has identified a number of specific examples of pressures that may change the ecosystem health condition of marine ecosystems within the harbour:

episodic disturbances
urban, industrial and agricultural development (resulting in habitat loss and the mobilisation of sediment, nutrients and toxicants into waterways)
point source pollution
light pollution
boat strike
marine pests
noise and
harvesting of seafood.

Report card naming in the Queensland State of the Environment report refers to the year of report card release, which may differ from the year given in the report card title or the year data group shown on regional report card partnership websites. Only data for regional report cards released before June 30 2020 are included.

More information:

Mackay–Whitsunday–Isaac report card

According to the Mackay–Whitsunday–Isaac Healthy Rivers to Reef Partnership, the 3 high level regional drivers in the Mackay–Whitsunday Region are:

climate (including climate change and variability)
population growth
economic growth

The current pressures in the Mackay–Whitsunday Region range from those occurring on an international level to Reef-wide and localised regional pressures. Pressures relevant to the marine ecosystem include:

urban, coastal, and industrial development (habitat loss)
cyclones and episodic events (including drought and flood events)
port development and shipping
agricultural development and activities
fishing and hunting (recreational, commercial, and traditional)
tourism and recreational use
litter
diffuse source pollution (agriculture and urban, point source pollution (urban and industrial)
invasive species (flora and fauna).

Severe Tropical Cyclone Debbie’s impact on the region in 2017 has seen a decline in seagrass and coral condition in inshore marine areas. Recovery from this disturbance has been limited. A number of intervention measures have been undertaken to restore corals at key tourist sites in the inshore marine zone. The cyclone’s full impact on corals offshore was not captured in the last published report card.

Crown-of-thorns starfish outbreaks are another source of pressures on corals in the marine zone of this region. An outbreak occurred in 2019 and the effects of this on coral cover and health are yet to be determined.

More information:

Wet Tropics Waterways report card

Of the key drivers and pressures identified for the region by the Wet Tropics Waterways Partnership, those relevant to marine ecosystems include:

climate change and variability
population growth
economic growth
cyclones and episodic events (including drought and flood events)
agricultural activities and development
port development and shipping activities
urban coastal and industrial development
fishing and hunting (recreational, commercial, and traditional)
tourism and recreational use
litter
invasive species.

The region’s marine environments are within the Great Barrier Reef Marine Park which provides a degree of protection to their integrity and to the diverse habitats they support including coral reefs, seagrass meadows, estuaries, coastal islands and cays. These habitats support a vast biodiversity including many species of conservation concern. Habitats that are now determined to be in ‘poor’ condition include:

inshore coral reefs
seagrass meadows
low lying islands.

Impacts from land use include water quality, in particular nutrients, pesticides and suspended solids.

Shipping and port activities and development affect the marine environment, particularly through dredging and dredge soil dumping which can exert impacts for more than 20 kilometres. Other human activities that directly impact the marine environment in this region include commercial and recreational fishing, coastal development and tourism.

The crown-of-thorns starfish is a highly significant threat to coral reefs and outbreaks are considered to be promoted by increased nutrient run-off. Extreme weather events, sea level rise, increased sea surface temperatures and ocean acidification present a wide range of highly significant threats and impacts to the marine ecosystem as a result of climate change.

More information:

Townsville Dry Tropics report card

In terms of marine ecosystems, the Townsville Dry Tropics for Healthy Waters Partnership report card covers the inshore zones of Halifax Bay and Cleveland Bay and the offshore marine zone.

Pressures on marine ecosystem health that are common across the Dry Tropics include:

catchment run-off
dredging
boating and shipping (including boat strikes, groundings, anchor damage and noise pollution)
oil and chemical spills
overfishing
poorly managed tourism and recreation
pest and invasive species (including crown of thorns starfish outbreaks).

The main difference in pressures on the marine ecosystem is that catchment run-off has a much greater impact on inshore marine zones when compared to offshore, while the reverse is true for overfishing, boating and shipping.

Sediment associated with discharges from the Burdekin River impacts Cleveland Bay inshore areas, where deposited sediment from those plumes can be resuspended by wind and tidal currents.

More information: