Assessment of the Water Quality and Ecosystem Health of the Great Barrier Reef (Australia): Conceptual Models

Run-off containing increased concentrations of sediment, nutrients, and pesticides from land-based anthropogenic activities is a significant influence on water quality and the ecologic conditions of nearshore areas of the Great Barrier Reef World Heritage Area, Australia. The potential and actual impacts of increased pollutant concentrations range from bioaccumulation of contaminants and decreased photosynthetic capacity to major shifts in community structure and health of mangrove, coral reef, and seagrass ecosystems. A detailed conceptual model underpins and illustrates the links between the main anthropogenic pressures or threats (dry-land cattle grazing and intensive sugar cane cropping) and the production of key contaminants or stressors of Great Barrier Reef water quality. The conceptual model also includes longer-term threats to Great Barrier Reef water quality and ecosystem health, such as global climate change, that will potentially confound direct model interrelationships. The model recognises that system-specific attributes, such as monsoonal wind direction, rainfall intensity, and flood plume residence times, will act as system filters to modify the effects of any water-quality system stressor. The model also summarises key ecosystem responses in ecosystem health that can be monitored through indicators at catchment, riverine, and marine scales. Selected indicators include riverine and marine water quality, inshore coral reef and seagrass status, and biota pollutant burdens. These indicators have been adopted as components of a long-term monitoring program to enable assessment of the effectiveness of change in catchment-management practices in improving Great Barrier Reef (and adjacent catchment) water quality under the Queensland and Australian Governments’ Reef Water Quality Protection Plan.

[1]  J. Brodie,et al.  In the other 90%: phytoplankton responses to enhanced nutrient availability in the Great Barrier Reef Lagoon. , 2005, Marine pollution bulletin.

[2]  J. Jaubert,et al.  Effect of nutrient enrichment on growth and photosynthesis of the zooxanthellate coral Stylophora pistillata , 2000, Coral Reefs.

[3]  Joelle Prange,et al.  The Impact of the Herbicide Diuron on Photosynthesis in Three Species of Tropical Seagrass , 2000 .

[4]  Jon Brodie,et al.  Spatial and temporal patterns of near-surface chlorophyll a in the Great Barrier Reef lagoon , 2007 .

[5]  J. Kleypas,et al.  Coral reef development under naturally turbid conditions: fringing reefs near Broad Sound, Australia , 1996, Coral Reefs.

[6]  J. Gilmour,et al.  Experimental investigation into the effects of suspended sediment on fertilisation, larval survival and settlement in a scleractinian coral , 1999 .

[7]  B. Riegl.  Effects of sand deposition on scleractinian and alcyonacean corals , 1995 .

[8]  T. Goreau,et al.  Reduced growth rate of Montastrea annularis following the 1987–1988 coral-bleaching event , 1990, Coral Reefs.

[9]  Glenn De'ath,et al.  IDENTIFYING ECOLOGICAL CHANGE AND ITS CAUSES: A CASE STUDY ON CORAL REEFS , 2004 .

[10]  K. Bjorndal,et al.  Global Trajectories of the Long-Term Decline of Coral Reef Ecosystems , 2003, Science.

[11]  O. Hoegh‐Guldberg,et al.  Response of a scleractinian coral, Stylophora pistillata, to iron and nitrate enrichment. , 2001, Journal of experimental marine biology and ecology.

[12]  Composition and textural variability along the 10 m isobath, Great Barrier Reef: Evidence for pervasive northward sediment transport , 2000 .

[13]  W. Dennison,et al.  Responses of seagrass to nutrients in the Great Barrier Reef, Australia , 1999 .

[14]  Bofu Yu,et al.  Sediment yield and impacts from river catchments to the Great Barrier Reef lagoon , 2002 .

[15]  Eric Wolanski,et al.  A model of the effects of land-based, human activities on the health of coral reefs in the Great Barrier Reef and in Fouha Bay, Guam, Micronesia , 2004 .

[16]  M. Shaw,et al.  Preliminary evaluation of the occurrence of herbicides and PAHs in the Wet Tropics region of the Great Barrier Reef, Australia, using passive samplers. , 2005, Marine pollution bulletin.

[17]  S. Larned,et al.  Effects of herbivory, nutrient levels, and introduced algae on the distribution and abundance of the invasive macroalga Dictyosphaeria cavernosa in Kaneohe Bay, Hawaii , 2001, Coral Reefs.

[18]  C. Downs,et al.  Shifting the paradigm of coral-reef 'health' assessment. , 2005, Marine pollution bulletin.

[19]  J. Burkholder,et al.  Review of nitrogen and phosphorus metabolism in seagrasses. , 2000, Journal of experimental marine biology and ecology.

[20]  L. McCook,et al.  Mud, Marine Snow and Coral Reefs , 2003, American Scientist.

[21]  R. Coles,et al.  Flood and cyclone related loss, and partial recovery, of more than 1000 km2 of seagrass in Hervey Bay, Queensland, Australia , 1995 .

[22]  E. Wolanski,et al.  Mixing of Burdekin River flood waters in the Great Barrier Reef , 1983 .

[23]  Len J. McKenzie,et al.  Flood related loss and recovery of intertidal seagrass meadows in southern Queensland, Australia , 2004 .

[24]  A. Heyward,et al.  Natural inducers for coral larval metamorphosis , 1999, Coral Reefs.

[25]  Michelle Waycott,et al.  Seagrass population dynamics and water quality in the Great Barrier Reef region: a review and future research directions. , 2005, Marine pollution bulletin.

[26]  D. L. Scarnecchia,et al.  Fundamentals of Ecological Modelling , 1995 .

[27]  M. Atkinson,et al.  Effects of lowered pH and elevated nitrate on coral calcification , 1999 .

[28]  R. Dodge,et al.  Coral Growth Related to Resuspension of Bottom Sediments , 1974, Nature.

[29]  J. Brodie,et al.  Current status of nutrient levels and other water quality parameters in the Great Barrier Reef , 1996 .

[30]  S. Blake,et al.  Coral assemblages and physico-chemical characteristics of the Whitsunday Islands : evidence of recent community changes , 1999 .

[31]  G. M. Branch,et al.  Effects of sediment on the energy budgets of four scleractinian (Bourne 1900) and five alcyonacean (Lamouroux 1816) corals , 1995 .

[32]  G. Hodgson.  Sediment and the settlement of larvae of the reef coralPocillopora damicornis , 1990, Coral Reefs.

[33]  D. Haynes,et al.  Great Barrier Reef water quality : current issues , 2001 .

[34]  G. De’ath,et al.  Species richness and community structure of reef-building corals on the nearshore Great Barrier Reef , 2006, Coral Reefs.

[35]  Ann E. Nicholson,et al.  Development of criteria for simplifying ecological risk models , 2005 .

[36]  W. Dennison,et al.  Seagrass survival during pulsed turbidity events : the effects of light deprivation on the seagrasses Halodule pinifolia and Halophila ovalis , 1999 .

[37]  P. Hutchings,et al.  Bioerosion experiments at Lizard Island, Great Barrier Reef , 1994, Coral Reefs.

[38]  D. Bellwood,et al.  Confronting the coral reef crisis , 2004, Nature.

[39]  Christian Lott,et al.  Sedimentation stress in a scleractinian coral exposed to terrestrial and marine sediments with contrasting physical, organic and geochemical properties , 2006 .

[40]  A. Herr,et al.  A multi-criteria approach to Great Barrier Reef catchment (Queensland, Australia) diffuse-source pollution problem. , 2005, Marine pollution bulletin.

[41]  K. Fabricius.  Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis. , 2005, Marine pollution bulletin.

[42]  G. De’ath,et al.  Changes in algal, coral and fish assemblages along water quality gradients on the inshore Great Barrier Reef. , 2005, Marine pollution bulletin.

[43]  K. Fabricius,et al.  Effects of the herbicide diuron on the early life history stages of coral. , 2005, Marine pollution bulletin.

[44]  W. Hunte,et al.  Effects of eutrophication and sedimentation on juvenile corals , 1992 .

[45]  Britta Schaffelke,et al.  Water quality in the Great Barrier Reef region: responses of mangrove, seagrass and macroalgal communities. , 2005, Marine pollution bulletin.

[46]  J. Brodie,et al.  Cyclones, river flood plumes and natural water quality extremes in the Great Barrier Reef , 1996 .

[47]  N. Stambler,et al.  Effect of ammonium enrichment on respiration, zooxanthellar densities, and pigment concentrations in two species of Hawaiian corals , 1994 .

[48]  T. Hughes.  Catastrophes, Phase Shifts, and Large-Scale Degradation of a Caribbean Coral Reef , 1994, Science.

[49]  J. Brodie,et al.  Sediments, nutrients and pesticide residues in event flow conditions in streams of the Mackay Whitsunday Region, Australia. , 2005, Marine pollution bulletin.

[50]  Harrison,et al.  Changes in gametogenesis and fecundity of acroporid corals that were exposed to elevated nitrogen and phosphorus during the ENCORE experiment. , 2000, Journal of experimental marine biology and ecology.

[51]  David Haynes,et al.  Pesticide and Herbicide Residues in Sediments and Seagrasses from the Great Barrier Reef World Heritage Area and Queensland Coast , 1999 .

[52]  C. Rogers.  Responses of coral reefs and reef organisms to sedimentation , 1990 .

[53]  D. M. Hogarth,et al.  Sugarcane : research towards efficient and sustainable production , 1996 .

[54]  Z. Dubinsky,et al.  Effects of Nutrient Enrichment and Water Motion on the Coral Pocillopora damicornis , 1991 .

[55]  O. Hoegh‐Guldberg.  Climate change, coral bleaching and the future of the world's coral reefs , 1999 .

[56]  Miles Furnas,et al.  Catchments and Corals: Terrestrial Runoff to the Great Barrier Reef , 2003 .

[57]  D. Mitchell,et al.  Nitrogen losses via subsurface flow from sugar cane on floodplain soils in the Australian wet tropics. , 2000 .

[58]  K. Anthony.  Enhanced particle-feeding capacity of corals on turbid reefs (Great Barrier Reef, Australia) , 2000, Coral Reefs.

[59]  Eric Wolanski,et al.  Effects of transparent exopolymer particles and muddy terrigenous sediments on the survival of hard coral recruits , 2003 .

[60]  B. Willis,et al.  Effects of algal turfs and sediment on coral settlement. , 2005, Marine pollution bulletin.

[61]  U. Schreiber,et al.  Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia , 2003 .

[62]  J. G. McIvor,et al.  Pasture management influences runoff and soil movement in the semi-arid tropics , 1995 .

[63]  J. Armour,et al.  Nitrate accumulation under cropping in the Ferrosols of Far North Queensland wet tropics , 2001 .

[64]  K. Fabricius,et al.  Synergistic effects of diuron and sedimentation on photosynthesis and survival of crustose coralline algae. , 2005, Marine pollution bulletin.

[65]  J. Faithful,et al.  Water quality assessment for sustainable agriculture in the Wet Tropics--a community-assisted approach. , 2005, Marine pollution bulletin.

[66]  J. Brodie,et al.  Population and major land use in the Great Barrier Reef catchment area spatial and temporal trends , 2001 .

[67]  K. Fabricius,et al.  Shifting roles of heterotrophy and autotrophy in coral energetics under varying turbidity. , 2000, Journal of experimental marine biology and ecology.

[68]  R. Bramley,et al.  Export of nutrients and suspended sediment during a cyclone-mediated flood event in the Herbert River catchment, Australia , 1997 .

[69]  A. M. Bell,et al.  Herbicides implicated as the cause of severe mangrove dieback in the Mackay region, NE Australia: consequences for marine plant habitats of the GBR World Heritage Area. , 2005, Marine pollution bulletin.

[70]  J. Cloern.  Our evolving conceptual model of the coastal eutrophication problem , 2001 .

[71]  A. Kerswell,et al.  PHYTOTOXICITY OF PHOTOSYSTEM II (PSII) HERBICIDES TO CORAL , 2003 .

[72]  G. Rayment.  Water quality in sugar catchments of Queensland. , 2003, Water science and technology : a journal of the International Association on Water Pollution Research.

[73]  P. Ralph.  Herbicide toxicity of Halophila ovalis assessed by chlorophyll a fluorescence. , 2000 .

[74]  G. Rayment,et al.  Downstream Effects of Land Use , 1996 .

[75]  S. Ward,et al.  Impact of elevated ammonium on reproduction in two Hawaiian scleractinian corals with different life history patterns. , 2002, Marine pollution bulletin.

[76]  C. Mundy,et al.  Coral recruitment: Consequences of settlement choice for early growth and survivorship in two scleractinians , 1996 .

[77]  M. Björk,et al.  Coralline algae, important coral reef builders threatened by pollution , 1995 .

[78]  Jon Brodie,et al.  Exposure of inner-shelf reefs to nutrient enriched runoff entering the Great Barrier Reef Lagoon: post-European changes and the design of water quality targets. , 2006, Marine pollution bulletin.

[79]  R. Grosberg,et al.  Climate Change, Human Impacts, and the Resilience of Coral Reefs , 2003, Science.

[80]  Jamie Oliver,et al.  Natural turbidity variability and weather forecasts in risk management of anthropogenic sediment discharge near sensitive environments. , 2004, Marine pollution bulletin.

[81]  Mark Ridgley,et al.  A Fuzzy Logic Model to Predict Coral Reef Development under Nutrient and Sediment Stress , 1998 .

[82]  Russ Babcock,et al.  Effects of sedimentation on settlement of Acropora millepora , 2004, Coral Reefs.

[83]  G. De’ath,et al.  Predicting the impact of present and future human land-use on the Great Barrier Reef , 2005 .

[84]  M. Stafford-Smith.  Sediment-rejection efficiency of 22 species of Australian scleractinian corals , 1993 .

[85]  W. Dennison,et al.  ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions. , 2001, Marine pollution bulletin.

[86]  W. Goldberg,et al.  Effects of turbidity on the photosynthesis and respiration of two south Florida reef coral species , 1995 .

[87]  K. Fabricius,et al.  Rapid Smothering of Coral Reef Organisms by Muddy Marine Snow , 2000 .

[88]  A. M. Bell,et al.  Effects of Photosystem II inhibiting herbicides on mangroves--preliminary toxicology trials. , 2005, Marine Pollution Bulletin.

[89]  Langdon,et al.  Geochemical consequences of increased atmospheric carbon dioxide on coral reefs , 1999, Science.

[90]  J. Brodie,et al.  Catchment management and the Great Barrier Reef. , 2001, Water science and technology : a journal of the International Association on Water Pollution Research.

[91]  K. Anthony.  Coral suspension feeding on fine particulate matter , 1999 .

[92]  Jon Brodie,et al.  Are increased nutrient inputs responsible for more outbreaks of crown-of-thorns starfish? An appraisal of the evidence. , 2005, Marine pollution bulletin.

[93]  M. Ridgley,et al.  Optimization of economic policies and investment projects using a fuzzy logic based cost-effectiveness model of coral reef quality: empirical results for Montego Bay, Jamaica , 1999, Coral Reefs.

[94]  H. Marsh,et al.  The outstanding universal value of the Great Barrier Reef, World Heritage area , 1997 .

[95]  T. Walker.  The state of research on chondrichthyan fishes , 2007 .

[96]  G. Shaw,et al.  Pesticides in Sediments From Queensland Irrigation Channels and Drains , 2000 .

[97]  Jon Brodie,et al.  Regional scale nutrient modelling: exports to the Great Barrier Reef World Heritage Area. , 2005, Marine pollution bulletin.

[98]  R. Berkelmans,et al.  Large-scale bleaching of corals on the Great Barrier Reef , 1999, Coral Reefs.

[99]  K. Fabricius,et al.  Photophysiological stress in scleractinian corals in response to short-term sedimentation , 2003 .

[100]  G. Brunskill,et al.  137Cs and excess 210Pb deposition patterns in estuarine and marine sediment in the central region of the Great Barrier Reef Lagoon, north-eastern Australia. , 2004, Journal of environmental radioactivity.

[101]  W. Hunte,et al.  Effects of eutrophication and sedimentation on juvenile corals , 1992 .

[102]  Ross Jones.  The ecotoxicological effects of Photosystem II herbicides on corals. , 2005, Marine pollution bulletin.

[103]  J. Brodie,et al.  Flood plumes in the Great Barrier Reef : spatial and temporal patterns in composition and distribution , 2001 .

[104]  J. Brodie,et al.  Nutrients in Australian tropical rivers: changes with agricultural development and implications for receiving environments , 2005 .

[105]  N. Duke,et al.  Herbicide contamination and the potential impact to seagrass meadows in Hervey Bay, Queensland, Australia. , 2005, Marine pollution bulletin.

[106]  M. Waycott,et al.  Variation in biogeochemical parameters across intertidal seagrass meadows in the central Great Barrier Reef region. , 2005, Marine pollution bulletin.

[107]  W. Dennison,et al.  Organochlorine and heavy metal concentrations in blubber and liver tissue collected from Queensland (Australia) dugong (Dugong dugon). , 2005, Marine pollution bulletin.

[108]  J. Brodie,et al.  Terrestrial discharge into the Great Barrier Reef Lagoon: nutrient behavior in coastal waters. , 2005, Marine pollution bulletin.