This work was developed on the suggestion of A. Bakun, who also offered help and guidance during the course of the study. The activities of Working Group 98 of the Scientific Committee on Ocean Research (SCOR) provided important motivation and background ideas and it is hoped that the concepts and hypotheses generated in this study may in turn contribute to the ultimate findings and conclusions of SCOR-WG98. E. Glazier's editorial work on the English language version is also gratefully acknowledged.
