Coral record of increased sediment flux to the inner Great Barrier Reef since European settlement

The effect of European settlement on water quality in the Great Barrier Reef of Australia is a long-standing and controversial issue. Erosion and sediment transport in river catchments in this region have increased substantially since European settlement, but the magnitude of these changes remains uncertain. Here we report analyses of Ba/Ca ratios in long-lived Porites coral from Havannah Reef—a site on the inner Great Barrier Reef that is influenced by flood plumes from the Burdekin river—to establish a record of sediment fluxes from about 1750 to 1998. We find that, in the early part of the record, suspended sediment from river floods reached the inner reef area only occasionally, whereas after about 1870—following the beginning of European settlement—a five- to tenfold increase in the delivery of sediments is recorded with the highest fluxes occurring during the drought-breaking floods. We conclude that, since European settlement, land-use practices such as clearing and overstocking have led to major degradation of the semi-arid river catchments, resulting in substantially increased sediment loads entering the inner Great Barrier Reef.

[1]  G. Shimmield,et al.  Monsoon climate and Arabian Sea coastal upwelling recorded in massive corals from southern Oman , 1996 .

[2]  L. McCook.  Macroalgae, nutrients and phase shifts on coral reefs: scientific issues and management consequences for the Great Barrier Reef , 1999, Coral Reefs.

[3]  K. Ogawa,et al.  Invisible but common motion in organic crystals: a pedal motion in stilbenes and azobenzenes. , 2001, Journal of the American Chemical Society.

[4]  William J. Kimmerer,et al.  Kaneohe Bay Sewage Diversion Experiment: Perspectives on Ecosystem Responses to Nutritional Perturbation , 1981 .

[5]  T. Done.  Phase shifts in coral reef communities and their ecological significance , 1992, Hydrobiologia.

[6]  P. Isdale.  Fluorescent bands in massive corals record centuries of coastal rainfall , 1984, Nature.

[7]  R. Wright,et al.  Synthesis and characterization of a digermanium analogue of an alkyne. , 2002, Angewandte Chemie.

[8]  J. Lough,et al.  Luminescent lines in corals from the Great Barrier Reef provide spatial and temporal records of reefs affected by land runoff , 2002, Coral Reefs.

[9]  P. Jutzi.  Stable Systems with a Triple Bond to Silicon or Its Homologues: Another Challenge. , 2000, Angewandte Chemie.

[10]  A. Sekiguchi,et al.  High-pressure synthesis, structure and novel photochemical reactions of 7,7,8,8-tetramethyl-7,8-disilabicyclo[2.2.2]octa-2,5-diene , 1991 .

[11]  W. J. Young,et al.  Large-scale patterns of erosion and sediment transport in river networks, with examples from Australia , 2001 .

[12]  M. Gagan,et al.  Abrupt Decrease in Tropical Pacific Sea Surface Salinity at End of Little Ice Age , 2002, Science.

[13]  T. Iwamoto,et al.  The First Isolable Dialkylsilylene. , 2000 .

[14]  E. Wolanski,et al.  Muddy coastal waters and depleted mangrove coastlines - depleted seagrass and coral reefs , 2000 .

[15]  E. Boyle,et al.  Coralline barium records temporal variability in equatorial Pacific upwelling , 1989, Nature.

[16]  G. T. Shen,et al.  Trace Element Indicators of Climate Variability in Reef-Building Corals , 1990 .

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

[18]  R. Berkelmans,et al.  Source of trace element variability in Great Barrier Reef corals affected by the Burdekin flood plumes , 2003 .

[19]  Yuan-hui Li,et al.  Desorption of Ba and226Ra from river-borne sediments in the Hudson estuary , 1979 .

[20]  P. Larcombe,et al.  Increased sediment supply to the Great Barrier Reef will not increase sediment accumulation at most coral reefs , 1999, Coral Reefs.

[21]  J. J. Mott,et al.  Building Grass Castles: Integrating Ecology and Management of Australia's Tropical Tallgrass Rangelands. , 1997 .

[22]  J. White,et al.  Porites corals as recorders of mining and environmental impacts: Misima Island , 2002 .

[23]  W. Moore.  The subterranean estuary: a reaction zone of ground water and sea water , 1999 .

[24]  P. Bell,et al.  Status of eutrophication in the Great Barrier Reef lagoon , 1991 .

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

[26]  Malcolm T. McCulloch,et al.  High resolution analysis of trace elements in corals by laser ablation ICP-MS , 1998 .

[27]  M. Jaffar,et al.  Simple and multiple trace metal concentrations correlations for some commercial fish from the Arabian sea , 1991 .

[28]  E. Wolanski.  Oceanographic processes of coral reefs: physical and biological links in the Great Barrier Reef , 2000 .

[29]  A. Chivas,et al.  A high-resolution Sr/Ca and δ18O coral record from the Great Barrier Reef, Australia, and the 1982–1983 El Niño , 1994 .

[30]  R. Taylor,et al.  On the nature and causes of luminescent lines and bands in coral skeletons , 2001, Coral Reefs.

[31]  D. Haynes,et al.  Water quality in the Great Barrier Reef World Heritage Area: past perspectives, current issues and new research directions. , 2000 .

[32]  P. Power,et al.  Synthesis and Characterization of 2,6-Trip2H3C6PbPbC6H3-2,6-Trip2 (Trip = C6H2-2,4,6-i-Pr3): A Stable Heavier Group 14 Element Analogue of an Alkyne , 2000 .

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

[34]  K. Karaghiosoff,et al.  Tetrasupersilyl‐tristannaallene and ‐tristannacyclopropene (tBu3Si)4Sn3 – Isomers with the Shortest Sn=Sn Double Bonds to Date , 1999 .