soil - Lublin

RELATIONS
The relations between soil organisms (especially competition and predator:prey
interactions) are of great importance for microbial community structure and diversity,
as well as for the decomposition of natural substrates and thus for biogeochemistry
of ecosystems (Mamilov et al., 1001; Torsvik and Øvreås 2002). There
are some mechanisms by which the soil microbiota and their predators are able to
coexist in soil. These mechanisms include location of the soil microorganisms in
pores of sufficiently small neck diameters to prevent access of larger predators
(mainly protozoa and nematodes) and critical prey densities (cell numbers or biomass
per unit of soil pore volume) below which too little energy is obtained by the
predator to maintain its active search for food (Ladd et al., 1996). Crawford et al.
(1993) calculated that about half of the potential habitable area for a bacterium of 5
µm diameter would be accessible to a predator of 30 µm (for example amoebal
pseudopodia can penetrate pores to gain access to bacteria). It has been generally
accepted that bacteria are protected from flagellates, nematodes, and ciliates in
pores with entry neck sizes