Introduction to special issue

Ecology in the Underworld

Science  11 Jun 2004:
Vol. 304, Issue 5677, pp. 1613
DOI: 10.1126/science.304.5677.1613

Contents

News

Soil and Trouble

Wounding Earth's Fragile Skin

From Alaska to Yucatan, a Long-Awaited Soil Survey Takes Shape

Defrosting the Carbon Freezer of the North

The Secret Life of Fungi

Reviews

Ecological Linkages Between Aboveground and Belowground Biota

D. A. Wardle et al.

Interactions and Self-Organization in the Soil-Microbe Complex

I. M. Young and J. W. Crawford

See related Report by Vitousek et al.

In many ways the ground beneath our feet is as alien as a distant planet. The processes occurring in the top few centimeters of Earth's surface are the basis of all life on dry land, but the opacity of soil has severely limited our understanding of how it functions. As creatures of the aerial world, we have a decidedly distorted view of this nurturing underworld. For ecologists, soil fascinates and flummoxes in equal measure. The techniques and approaches of many branches of aboveground ecology don't translate well to the soil environment.

However, perspectives are beginning to change, as the articles in this special issue show. Interest in soil is booming, spurred in part by technical advances of the past decade. Molecular phylogenetics, for example, is revealing the extent of the diversity of soil microorganisms and how patterns of diversity change over time.

Advances in understanding of the mutual influences of the underground and aboveground components of ecosystems are reviewed by Wardle et al. (p. 1629). Ecologists have traditionally portrayed the inhabitants of soil as a black box labeled “decomposers”—essentially, a single trophic level through which all aboveground material, with its multiple trophic levels, is ultimately recycled. Digging deeper, it turns out that the soil food web is every bit as complex as the aboveground web, with intricate connections to its aerial counterpart.

In the subterranean world, ecology is writ small. The spatial, chemical, and biological heterogeneity within a few cubic centimeters of soil rivals that of a hectare of forest or coral reef. Young and Crawford (p. 1634) describe some of the new techniques for documenting and visualizing the microscopic complexity underfoot. In a News story, Pennisi (p. 1620) provides a stage for one unsung subsurface duet: soil fungi and plant roots.

But Earth's skin is fragile indeed. A map (p. 1614) vividly illustrates the extent of soil degradation and loss across the globe, and in a News story, Proffitt (p. 1617) previews an effort to ascertain the extent to which contaminants have infiltrated soils in North America. Kaiser (News, p. 1616) surveys soil degradation and assesses what it bodes for crop yields, and Lal, in a Viewpoint (p. 1623), outlines the management protocols that are needed to enhance the sustainability of agricultural soils and the ability of soil to sequester carbon. The prospect of massive amounts of carbon being liberated with the melting of frozen soils in the High Arctic is explored in a News story by Stokstad (p. 1618).

Human attitudes toward soil, as toward the rest of the environment, range from reverent to cavalier. The historical development of our varied relationship with soil is charted in a Viewpoint by McNeill and Winiwarter (p. 1627), and a survey of the soil fertility of an ancient agroecosystem is given in a Report by Vitousek et al. (p. 1665). Delving deeper into the hidden world of soils will surely reveal new connections to our familiar environs and make subterraneana seem far less of an alien experience.

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