Scales of Biogeoscience

Biogeoscience spans an immense range of size, from infinitesimal atomic-scale interactions to seemingly infinite planetary-scale interactions (see figure below).

• At 10^-10 to 10^-5 meters - Atoms and molecules react to form nucleic acids, proteins, and crystal nuclei. Biochemically orchestrated reactions organize simple, organic building blocks into microorganisms. Geochemically controlled processes arrange inorganic subunits into minerals. At this scale enzymes catalyze reactions between substrates such as sugars to form products like carbon dioxide; prokaryotic organisms produce compounds that may enhance mineral growth or biomineralization reactions; mineral dissolution produces nutrients required by microorganisms for reproduction; solid surfaces like metal-oxyhydroxides catalyze the transfer of electrons to or from humic substances; and intermolecular forces control the interactions between functional groups on bacteria and structural features on mineral surfaces.

• At 10^-4 to 10¹ meters - Smaller subunits collect to form multi-cellular organisms and multi-phase rocks. Plants and animals are formed by the coordinated interactions between single-cell-like units, which work together through complex signal transduction pathways. Rocks are formed by chemical and structural reactions between individual mineral phases. At this scale, organisms like fungi, algae, and trees produce organic compounds that attack exposed rock units; dust particles and colloids are mobilized in the atmosphere and subsurface; and water droplets begin to coalesce on the land surface.

• At 10² to 10⁷ meters - Ecosystems are formed by cooperative and competitive interactions between simple and complex life forms. Igneous, metamorphic, and sedimentary processes begin to shape entire lithospheric regions. At this scale humans alter hydrological weathering patterns by creating power plants; automobiles produce greenhouse gases; terrestrial and oceanic plates collide to form volcanic chains; ocean tides rise and fall along the coast; and streams create various erosional and depositional environments.

• At 10⁸ to 10¹³ meters, energy and matter combine at such a magnitude to form planets and solar systems. Biological and geological processes are interlinked by physical and chemical attributes. At this scale civilizations are distributed across the Earth; stars are born; the search for life is pursued on distant planets; and the origins of the solar system are explored.

Biogeoscience is clearly a field that incorporates all spatial scales. A key challenge is to determine the way in which these scales are connected through space and time.