Abstract
Coral reef flushing times at an individual reef scale are specified and a general formula to determine these times is developed. The formula is confirmed by comparison with residence times predicted by numerical small-scale reef models, including those from a 4 month unsteady current simulation of John Brewer Reef on Australia's Great Barrier Reef. The method proves to be a satisfactory alternative to the numerical modelling. When neutrally-buoyant material around a reef is removed by the currents, the concentrations decay exponentially. The decay rate depends primarily on free stream current and reef dimensions. Secondary factors are the tidal excursion, shelf depth, lagoon size and residual current in the lee of the reef. These factors, when combined into a decay coefficient, specify the rate of loss of neutrally-buoyant material (e.g. some larvae, pollutants and sewage) from a coral reef and its surrounds. The analytical formula can be used to predict the flushing rates or the percentage of material still remaining on a reef after a selected time interval. We demonstrate that material can remain on or near typical reefs in common weather conditions for several weeks.
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References
Black KP (1988) The relationship of reef hydrodynamics to variations in numbers of planktonic larvae on and around coral reefs. Proc 6th Int Coral Reef Symp 2:125–130
Black KP, Gay SL (1987a) Hydrodynamic control of the dispersal of Crown-of-Thorns starfish larvae. 1. Small-scale hydrodynamics on and around schematised and actual coral reefs. Vict Inst Mar Sci Tech Rep No 8, Melbourne, Australia
Black KP, Gay SL (1987b) Eddy formation in unsteady flows. J Geophys Res 92(C9):9514–9522
Black KP, Gay SL (1990) A numerical scheme for determining trajectories in particle models. In: Bradbury RH (ed) The Acanthaster phenomenon: a modelling approach. Lecture Notes in Biomathematics (in press)
Church JA, Andrews JC, Boland FM (1985) Tidal currents in the central Great Barrier Reef. Cont Shelf Res 4:515–531
Dight IJ, James MK, Bode L (1990) Modelling the larval dispersal of Acanthaster planci. II. Patterns of reef connectivity. Coral Reefs 9:125–134
Dyer KR (1973) Estuaries: A physical introduction. Wiley-Interscience, London
Gay SL, Andrews JC, Black KP (1990) Dispersal of neutrally-buoyant material near John Brewer Reef. In: Bradbury RH (ed) The Acanthaster phenomenon: a modelling approach. Lecture Notes in Biomathematics (in press)
Healy TR, Black KP, de Lange WP (1987) Field investigations required for numerical model studies of port developments in large tidal inlet harbours. Int Geomorph 1:1099–1112
Heathershaw AD, Simpson JH (1978) The sampling variability of the Reynolds stress and its relation to boundary shear stress and drag coefficient measurements. Estuarine Coast Mar Sci 6:263–274
Lee TT, Black KP (1978) The energy spectra of surf waves on a coral reef. 16th Int Conf Coast Eng, Hamburg 1:588–608
Olson RR (1987) In situ culturing as a test of the larval starvation hypothesis for the Crown-of-Thorns starfish, Acanthaster planci. Limnol Oceanogr 32:895–904
Pickard GL (1986) Effects of wind and tide on upper-layer currents at Davies Reef, Great Barrier Reef, during MECOR (July–August, 1984). Aust J Mar Freshwater Res 37:545–565
Reichelt RE, Loya Y, Bradbury RH (1986) Patterns in the use of space by henthic communities on two coral reefs of the GBR. Coral Reefs 5:73–79
Williams DMcB, Wolanski E, Andrews JC (1984) Transport mechanisms and the potential movement of planktonic larvae in the central region of the Great Barrier Reef. Coral Reefs 3:229–236
Wolanski E, Imberger J, Heron ML (1984) Island wakes in shallow coastal waters. J Geophys Res 89(C6):10553–69
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Black, K.P., Gay, S.L. & Andrews, J.C. Residence times of neutrally-buoyant matter such as larvae, sewage or nutrients on coral reefs. Coral Reefs 9, 105–114 (1990). https://doi.org/10.1007/BF00258221
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DOI: https://doi.org/10.1007/BF00258221