Biogeochemical Provinces: Towards a JGOFS Synthesis

Abstract

Most people are intuitively familiar with the existenceof recognizable, bounded units of landscape with characteristic climatic regimes, land cover and animal populations — the basis of the ecosystem concept in ecology. Theophrastus (ca. 320 b.c.) documented this recognition in his ‘Inquiry into Plants’ and it is implicit much later in the writings of Thoreau, G. P. Marsh and others who by the mid-19^th century already lamented the loss of the North American primeval forests (Cronon 1983). Thus we recognize particular terrestrial ecosystems: grasslands, savannas, deserts, temperate and tropical forests, polar tundra and so on. What about the ocean? To the uneducated eye of the non-sailor, the surface of nearly three quarters of the planet is largely homogeneous, with minor differences in surface roughness and color. The featureless nature of the ocean’s upper surface is especially conspicuous offshore, away from the gradients in color resulting from terrestrial sources of organic matter and resuspended sediments found in shallow waters. Do distinct marine provinces or ecosystems analogous to the familiar terrestrial biomes exist? Many (but not all) oceanographers agree that they do, and there have been many schemes to distinguish and classify them, but there is little agreement on how many should be identified and their spatial scale. Yet most of us would agree that there are distinctive, large scale ocean regimes which also support characteristic flora and fauna, and exist in the familiar climatic regions of the planet.