Greenpeace's Sue Mayer (THES, August 25) chose to misinterpret some of my written words and to quote others out of context.

In my Brent Spar article (THES, August 11) I did not write that "dumping waste, like Brent Spar, in the deep oceans" was "part of the solution to the survival equation". I did write "that to ignore the oceans in trying to solve our survival equation would be quite irresponsible". A subtle, but crucial, difference by which I stand.

Dr Mayer goes on to try to demonstrate an inconsistency in my argument by quoting from an article I wrote in 1992 in which I maintained that we were unable to predict the effects on deep-sea communities of anthropogenic disturbance. But she failed to point out two further salient points.

First, the 1992 article was prompted by another piece in the same magazine (Ocean Challenge) summarising the results of the only major man-made deep-sea disturbance experiment currently being conducted. This experiment, in which more than ten square kilometres of the abyssal South Pacific has been ploughed up with a modified agricultural harrow, attempts to mimic some of the potential effects of any future manganese nodule mining.

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Interestingly, in view of the violent opposition of the German population to the Brent Spar affair, this deep-sea impact is masterminded by my friend Hjalmar Thiel from the University of Hamburg, while a co-author of the Ocean Challenge article was Christian Bussau, now working for Greenpeace in Germany, whose PhD was based on the disturbance experiment.

Second, my 1992 article dealt specifically with potential largescale impacts such as those from metalliferous mud and manganese nodule extraction, and the disposal of bulky materials such as municipal wastes, dredge spoils and sewage sludge. My argument was, and is, that before such activities could even vaguely be considered, properly monitored large-scale impact experiments would be absolutely essential.

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This is not true for Brent Spar. We do know enough to be certain that the impact of the disposal of this structure would be negligible. This is true even for the rather silly choice of disposal site by Shell and their advisers, and despite the valid criticisms of the Best Practicable Environmental Option document by our Scottish Association for Marine Science colleagues.

But I agree totally with Dr Mayer that Brent Spar stands for a much broader and more important issue, where we should at least consider all the options (including the deep sea) in what I have called the survival equation.

Greenpeace's answer is an emphatic "no", and Sue Mayer's letter graphically confirms that this view is based on "principles and values" rather than on rational argument. Indeed, she castigates me for "wrapping this up as a scientific debate". I plead guilty. If you wish to base crucial environmental decisions on dogma and emotion, do not look for my support.

Finally, I am accused of naivety in trying to treat Brent Spar in isolation. If the deep-sea disposal of the Spar went ahead, it is said, the disposal of the next 50 installations would go through "on the nod" so to say. If you believe that, just watch this space.

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TONY RICE

Institute of Oceanographic Sciences Deacon Laboratory Wormley, Surrey