CHAPTER 7 • The Implications of Oceanographic Chaos for Coastal Management
139
ous scenarios, though it under-predicts the patchiness. These predictions, particularly if they extend to biological processes, may not be helpful to management if
they do not successfully incorporate also natural patterns of variability. Because the
biological response is often the key criterion in environment impact studies, modelling is usually seen as having failed management. Solving this problem is not trivial
because attempts to incorporate chaos and patchiness in ecosystem models are
still very much at the research stage (e.g. Hassel et al. 1991; Engbert and Drepper 1994;
McCook 1994).
More often than not, the natural variability appears chaotic to environmental engineers, they usually characterize it by computing means and standard deviations. Simplifying the system by these simple statistics destroys any chance to characterize
topographically complex coastlines and lead to unreliable predictions for important
applic~tions. Practical such cases include responses of seagrass and corals to shortterm events of high turbidity, both natural and anthropogenic. Other cases include algae in coastal waters responding to pulses of nutrients, both natural and anthropogenic.
Other practical applications include changes in recruitment patterns for fish and crustaceans in the presence of engineering structures and dredged channels. There has been
no attempt yet to quantify how a marine ecosystem already subjected to chaotic forcings
will respond to an increase or a variation in this forcing from anthropogenic effects,
present state-of-the-art practice (e.g. Gray 1996) largely ignores the natural chaos. For
environmental impact modelling to reach the desks of coastal resources managers as
practical tools in the decision-making process, these pitfalls need to be addressed as a
matter of priority.
7.9
Conclusions
Chaos is largely ignored in environmental impact studies in the coastal environment,
this may lead to meaningless predictions especially if the predictions extend to biological processes. Also, chaos needs to be better taken into account when collecting field
data. In particular in most environmental impact assessment studies for coastal developments, only the mean and standard deviation of a number of parameters are
measured occasionally at a few points. Our studies demonstrate that in a topographically complex coastal environment much more data are required in view of the chaos
in the flow, chemical and biological distributions.
Acknowledgements
This study results from 19 years of field work and modelling in the Great Barrier Reef
of Australia. This research was supported by the Australian Institute of Marine Science,
the IBM International Foundation, CRC-Reef Research, Ok Tedi Mining Limited, Kansai
Electric Power Co., Japan's Port and Harbour Research Institute and others. Special
thanks are due to Takeshi Asaeda, Tenshi Ayukai, Joe Baker, Danny Brooks, Ving Chin
Chong, Robert Cusumano, John Bunt, Eric Deleersnijder, Peter Doherty, Murray Eagle,
Keita Furukawa, Duncan Galloway, Bill Hamner, Ian Gardner, Eng Bin Lim, Ray
McAllister, Laurence McCook, Jamie Oliver, Russell Reichelt, Joe Sarsenski, Kris
Summerhayes and Ian Wood.
139
ous scenarios, though it under-predicts the patchiness. These predictions, particularly if they extend to biological processes, may not be helpful to management if
they do not successfully incorporate also natural patterns of variability. Because the
biological response is often the key criterion in environment impact studies, modelling is usually seen as having failed management. Solving this problem is not trivial
because attempts to incorporate chaos and patchiness in ecosystem models are
still very much at the research stage (e.g. Hassel et al. 1991; Engbert and Drepper 1994;
McCook 1994).
More often than not, the natural variability appears chaotic to environmental engineers, they usually characterize it by computing means and standard deviations. Simplifying the system by these simple statistics destroys any chance to characterize
topographically complex coastlines and lead to unreliable predictions for important
applic~tions. Practical such cases include responses of seagrass and corals to shortterm events of high turbidity, both natural and anthropogenic. Other cases include algae in coastal waters responding to pulses of nutrients, both natural and anthropogenic.
Other practical applications include changes in recruitment patterns for fish and crustaceans in the presence of engineering structures and dredged channels. There has been
no attempt yet to quantify how a marine ecosystem already subjected to chaotic forcings
will respond to an increase or a variation in this forcing from anthropogenic effects,
present state-of-the-art practice (e.g. Gray 1996) largely ignores the natural chaos. For
environmental impact modelling to reach the desks of coastal resources managers as
practical tools in the decision-making process, these pitfalls need to be addressed as a
matter of priority.
7.9
Conclusions
Chaos is largely ignored in environmental impact studies in the coastal environment,
this may lead to meaningless predictions especially if the predictions extend to biological processes. Also, chaos needs to be better taken into account when collecting field
data. In particular in most environmental impact assessment studies for coastal developments, only the mean and standard deviation of a number of parameters are
measured occasionally at a few points. Our studies demonstrate that in a topographically complex coastal environment much more data are required in view of the chaos
in the flow, chemical and biological distributions.
Acknowledgements
This study results from 19 years of field work and modelling in the Great Barrier Reef
of Australia. This research was supported by the Australian Institute of Marine Science,
the IBM International Foundation, CRC-Reef Research, Ok Tedi Mining Limited, Kansai
Electric Power Co., Japan's Port and Harbour Research Institute and others. Special
thanks are due to Takeshi Asaeda, Tenshi Ayukai, Joe Baker, Danny Brooks, Ving Chin
Chong, Robert Cusumano, John Bunt, Eric Deleersnijder, Peter Doherty, Murray Eagle,
Keita Furukawa, Duncan Galloway, Bill Hamner, Ian Gardner, Eng Bin Lim, Ray
McAllister, Laurence McCook, Jamie Oliver, Russell Reichelt, Joe Sarsenski, Kris
Summerhayes and Ian Wood.