Marine biogeography, climate change and societal needs

Abstract

Pelagic biogeography deals with the large scale distributional patterns of pelagic organisms in the world's oceans, their origins through evolution and the changes in ocean morphology during the geological past, and the factors which currently control and maintain them. The knowledge it generates has a wide variety of uses in science, both basic and applied, and in socio-economics. Its products include: (1) Distributional data compiled in data bases, maps and atlases; (2) Explanatory scientific and non-scientific publications on the distributions and their implications; (3) Standardisation of methodologies; (4) Trained specialists; (5) Advice to society on oceanic aspects of global resource management; and (6) Assessments of oceanic biodiversity in relation to the Biodiversity Convention. The immediate users of this knowledge include oceanographers in other disciplines, ecologists, applied scientists and engineers, resource managers, fishermen, environmentalists, teachers, international lawuers and policy-makers. At present the largest users are the natural resource managers seeking to optimise and to sustain the resource for which they are responsible. There is a considerable body of national and international legislation which is underpinned by biogeographical information. Similarly much of our understanding about past climate which is being used to predict future trends, is based on applying information on present-day distributional patterns to the interpretation of the fossil record in marine sediments. Global change, in the ocean, the atmosphere and on land, is strongly modulated by the feedback between marine organisms, nutrients and greenhouse gases. The marked coherence observed between the distributions of physical, chemical and biological patterns suggest that the process involved in this feedback are linked with pelagic community structure. Remote sensing of sea-surface properties and the heat content of the mixed-layer, offer considerable potential for linking ecological and biogeographical processes to large scale features of ocean circulation and climatology. The long-term monitoring of the ocean in the Global Ocean Observing System will need to integrate physical, chemical and ecological data, if the models used to predict future change are to achieve adequate precision. The future use and resource management of the oceans has to involve biogeographical information. Traditional sampling methods, even when supplemented by large scale surveys such as CALCOFI and the Continuous Plankton Recorder surveys, will never provide sufficient data, so new techniques for intensive sampling and monitoring are being sought. Some surrogate measures such as chlorophyll fluorescence are already well established as standard oceanographic methodology; others involving acoustics and optical properties have the potential for sampling the biological characteristics at the same time/space scales as the physicochemical properties of the oceans are being studied. However, the calibration of these new techniques against traditional sampling and observational methods remains problematic. Information technology is beginning to be used, not only to unify the systematics of many taxonomic groups, but also to improve information exchange. Improvements in digital data bases will lead to freer exchange of information, and also facilitate the production of maps and interpretations customized for other users. The scientific resources being devoted to pelagic biogeography are declining with potentially serious consequences. This trend can only be reversed if the biogeographers themselves make their output more accessible and user-friendly for non-scientists, and take advantage of the new technologies which promise to re-vitalise the field.