Potential effects of a cyclone on benthic algal production and yield to grazers on coral reefs across the central Great Barrier Reef

Rates of production of the epilithic algal community (EAC) and rates of yield to large herbivorous grazers were measured on inshore, mid-shelf and outer-shelf coral reefs in the central Great Barrier Reef (GBR) in February 1985 and February 1986. In February 1985 rates of production and yield were significantly lower inshore (approximately 10 km from the coast) than on the mid-shelf (approximately 50 km from the coast) and outer-shelf (approximately 100 km from the coast). In February 1986 cyclone Winifred passed through the central section of the GBR, causing extensive disturbance of shallow-water sediments inshore and substantially increasing both rainfall and run-off from the major river systems in the area. Inshore rates of both production of the EAC and yield to large grazers increased by a factor of five between February 1985 and February 1986. This resulted in production and yield inshore not significantly different from that on the mid-shelf and outer-shelf in February 1986. Compared to February 1985, the EAC inshore in February 1986 had a significantly lower carbon/nitrogen ratio, a significantly higher standing crop of nitrogen and a significantly higher yield of nitrogen to grazers. It is suggested that reworking of mineralized organic nitrogen from inshore sediments and increased river run-off, both due to the cyclone, increased the availability of nutrients on inshore coral reefs. These nutrients were incorporated into benthic algal production and passed rapidly to the next trophic level. These results are not consistent with the idea that high biomass of algae on inshore reefs is due to higher production, in turn due to higher nutrient input to those reefs. This conclusion has important implications for the interpretation and management of cross-shelf differences in reef benthos.

[1]  T. Walker,et al.  Observations on nitrate, phosphate and silicate in Cleveland Bay, northern Queensland , 1981 .

[2]  D. Klumpp,et al.  Nutrient-limited growth of the coral reef macroalga Sargassum baccularia and experimental growth enhancement by nutrient addition in continuous flow culture , 1998 .

[3]  L. McCook,et al.  Macroalgal distributions on the Great Barrier Reef: a review of patterns and causes , 1997 .

[4]  B. Hatcher,et al.  Coral reef primary productivity: A beggar's banquet. , 1988, Trends in ecology & evolution.

[5]  R. Carpenter,et al.  Relationships between primary production and ii radiance in coral reef algal communities1 , 1985 .

[6]  N. Polunin,et al.  Algal production, grazers and habitat partitioning on a coral reef: positive correlation between grazing rate and food availability , 1990 .

[7]  T. Done,et al.  Effects of tropical cyclone waves on ecological and geomorphological structures on the Great Barrier Reef , 1992 .

[8]  R. Carpenter.  PARTITIONING HERBIVORY AND ITS EFFECTS ON CORAL REEF ALGAL COMMUNITIES , 1986 .

[9]  Fj Scott,et al.  EFFECTS OF GRAZING ON SPECIES COMPOSITION OF THE EPILITHIC ALGAL COMMUNITY ON CORAL REEFS OF THE CENTRAL GREAT-BARRIER-REEF , 1987 .

[10]  P. Doherty,et al.  The replenishment of coral reef fish populations , 1988 .

[11]  L. McCook.  Effects of herbivory on zonation of Sargassum spp. within fringing reefs of the central Great Barrier Reef , 1997 .

[12]  Harthoorn Am,et al.  Response of herbivorous fishes to crown-of-thorns starfish Acanthaster planci outbreaks. II. Density and biomass of selected species of herbivorous fish and fish-habitat correlations , 1996 .

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

[14]  B. Lapointe.  Phosphorus- and nitrogen-limited photosynthesis and growth of Gracilaria tikvahiae (Rhodophyceae) in the Florida Keys: an experimental field study , 1987 .

[15]  C. Davies.  Patterns of movement of three species of coral reef fish on the Great Barrier Reef , 1995 .

[16]  M. Sandstrom,et al.  Direct determination of organic carbon in modern reef sediments and calcareous organisms after dissolution of carbonate , 1986 .

[17]  R. Carpenter.  Mass mortality of a Caribbean sea urchin: Immediate effects on community metabolism and other herbivores. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[18]  McCook Lj.  Effects of herbivores and water quality on Sargassum distribution on the central great barrier reef: Cross-shelf transplants , 1996 .

[19]  G. Russ.  Distribution and abundance of herbivorous grazing fishes in the central Great Barrier Reef.11. Patterns of zonation of mid-shelf and outershelf reefs , 1984 .

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

[21]  P. Bell,et al.  Eutrophication and coral reefs—some examples in the Great Barrier Reef lagoon , 1992 .

[22]  M. Furnas.  Cyclonic disturbance and a phytoplankton bloom in a tropical shelf ecosystem , 1989 .

[23]  A. Chivas,et al.  Shelf-wide erosion, deposition, and suspended sediment tranport during Cyclone Winifred, central Great Barrier Reef, Australia , 1990 .

[24]  I. Elmetri,et al.  Ecological indicators of large-scale eutrophication in the Great Barrier Reef Lagoon. , 1995 .

[25]  David Barnes,et al.  Perspectives on coral reefs , 1983 .

[26]  G. Russ.  IS RATE OF REMOVAL OF ALGAE BY GRAZERS REDUCED INSIDE TERRITORIES OF TROPICAL DAMSELFISHES , 1987 .

[27]  D. Klumpp,et al.  Macroalgae on the GBR: causes or consequences, indicators or models of reef degradation? , 1997 .

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

[29]  L. McCook,et al.  The state of the algae of the Great Barrier Reef: what do we know? , 1997 .

[30]  D. Williams.  Temporal variation in the structure of reef slope fish communities (central Great Barrier Reef): short-term effects of Acanthaster planci infestation , 1986 .

[31]  Anthony W. D. Larkum,et al.  An experimental analysis of factors controlling the standing crop of the epilithic algal community on a coral reef , 1983 .

[32]  B. Lapointe,et al.  A comparison of nutrient-limited productivity in macroalgae from a Caribbean barrier reef and from a mangrove ecosystem , 1987 .

[33]  H. Odum,et al.  Trophic Structure and Productivity of a Windward Coral Reef Community on Eniwetok Atoll , 1955 .

[34]  R. Woesik,et al.  Effects of Cyclone 'Joy' on nearshore coral communities of the Great Barrier Reef , 1995 .

[35]  W. Wiebe,et al.  Enewetak (Eniwetok) Atoll: Aspects of the nitrogen cycle on a coral reef1 , 1975 .

[36]  V. Tunnicliffe,et al.  Hurricane Allen's Impact on Jamaican Coral Reefs. , 1981, Science.

[37]  D. Klumpp,et al.  Community structure, biomass and productivity of epilithic algal communities on the Great Barrier Reef: dynamics at different spatial scales , 1992 .

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

[39]  A. Steven,et al.  Cyclone Sadie flood plumes in the Great Barrier Reef Lagoon : composition and consequences : proceedings of a workshop held in Townsville Queensland, Australia, 10 November 1994, at the Australian Institute of Marine Science , 1997 .

[40]  T. Done,et al.  The effects of Cyclone Sadie on coral communities of nearshore reefs in the central Great Barrier Reef , 1997 .

[41]  L. McCook,et al.  Effects of sediment deposition on the seaweed Sargassum on a fringing coral reef , 1998, Coral Reefs.

[42]  B. Lapointe,et al.  Modification of tropical reef community structure due to cultural eutrophication: the southwest coast of Martinique , 1993 .

[43]  G. Russ.  Distribution and abundance of herbivorous grazing fishes in the central Great Barrier Reef. I: Levels of variability across the entire continental shelf , 1984 .

[44]  B. Hatcher,et al.  Coral reef primary productivity. A hierarchy of pattern and process. , 1990, Trends in ecology & evolution.

[45]  S. Kennelly.  An experimental approach to the study of factors affecting algal colonization in a sublittoral kelp forest , 1983 .