Marine Biodiversity: Patterns and Processes - Review

Ecology, Jan, 1999 by Elliott A. Norse

Ormond, Rupert F. G., John D. Gage, and Martin Vivian Angel, editors. 1997. Cambridge University Press, New York. xxii 449 p. $74.95, ISBN: 0-521-55222-2.

Since the term biological diversity (Lovejoy, T. 1980. "Foreword" in Michael E. Soule and Bruce A. Wilcox, editors. Conservation biology - an evolutionary-ecological perspective. Sinauer Associates, Sunderland, Massachusetts; Norse, E. A., and R. E. McManus. 1980. Ecology and living resources: biological diversity. pp. 31-80 in Council on Environmental Quality. Environmental quality - 1980: the eleventh annual report of the Council on Environmental Quality. U.S. Government Printing Office, Washington, D.C.) and its synonym biodiversity (Wilson, E. O., editor. 1988. Biodiversity. National Academy Press, Washington, D.C.) emerged from the conservation literature into the broader lexicon, stopping biodiversity loss has become the focus of conservation worldwide and provided impetus for public funding of systematics, biogeography and ecology. Because biodiversity on land has received the lion's share of attention and books on marine biodiversity are few, I awaited this book eagerly.

I was disappointed to find that the book focuses mostly on descriptions of species diversity patterns and the processes that could shape them, giving insufficient attention to lower and higher levels of genetic diversity within species and ecosystem diversity. The relevance of such patterns to conservation is explicit in only a few chapters, which is unfortunate because many will buy this book for insights into a realm increasingly dominated by humans. Moreover, marine biodiversity patterns are frustratingly complex, and some herein are plagued by sparse data or have underlying mechanisms so obscure that the authors' best efforts cannot yet contribute much to the conceptual foundation for marine stewardship. Simply put, we do not yet have the data or theory that we need. Other chapters, however, are intriguing, well written, and highly relevant. The book's topics range broadly, from subpolar to tropical, nearshore to oceanic, benthic to planktonic, diatoms to fishes, Mesozoic to modern.

M. V. Angel's chapter on pelagic biodiversity is inexplicably narrow. Whereas the pelagic realm is home to phytoplankton, zooplankton, neuston, nekton, and flying organisms that feed near the surface, the chapter mentions only phytoplankton, crustaceans, and three small mesopelagic fishes, thereby omitting gelatinous zooplankton, squids, sharks, mackerels, tunas, bill fishes, sea turtles, seabirds, pinnipeds, and cetaceans. This is analogous to neglecting reptiles, birds, antelopes, zebras, elephants, hyenas, and lions in a chapter on African savanna biodiversity. Pelagic biodiversity is more than what plankton nets sample.

M. A. Rex et al. provide useful ideas on deepsea species diversity patterns and processes, but show how devilishly difficult it is to demonstrate broad geographic patterns in the deep sea when the total area of the seabed sampled quantitatively is only 500 [m.sup.2] worldwide. They provide evidence of a polar-tropical species diversity gradient in the northern hemisphere, but including the especially poorly sampled southern hemisphere complicates the picture. This is reinforced by A. Clarke and J. A. Crame's lucid chapter on shallow water latitudinal gradients, which explains how the greater species diversity in Antarctic waters reflects both historic and modern environmental differences from the Arctic and provides welcome comparison with the better-known terrestrial latitudinal species diversity gradient. J. D. Gage provides a thoughtful examination of disturbance in the deep sea, a realm where some places are much more dynamic than had been thought.

Nutrient status deserves far more attention from ecologists and conservation biologists. J. D. Taylor's illuminating chapter examines community differences related to ecosystems' nutrient status. Reef corals become less diverse and ultimately less abundant in waters with more available nutrients, while bioeroders (such as Lithophaga date mussels) become more active and primary production shifts progressively from animals having endozoic algal mutualists to benthic seaweeds to phytoplankton. This sequence describes an increasing proportion of coral reefs. Taylor also points out that predatory gastropods in eutrophic waters on continental shores tend to be generalist feeders on suspension-feeding barnacles and bivalves, whereas predatory gastropods in oligotrophic waters are more specialized feeders on algal-grazing polychaetes, sipunculans, or gastropods. Understanding such changes in species composition and trophic structure could alert us to degradation in nearshore assemblages. My only quibble: in three tables showing higher diversity of bivalves or other taxa on continental margins and high islands versus oceanic islands, Taylor concludes that trophic status causes this pattern without ruling out island biogeographic differences in extinction and recolonization rates.