Worm burrows

Preferential flow through root-mediated soil pores has been demonstrated for chloride, nitrate, and other ions that are not sorbed onto soil organic matter and clays. However, pesticide sorption onto soil affects both mobiUty of the pesticide as well as its residual life in the soil. Pesticide sorption onto root organic matter or organic linings of worm burrows may also slow transport of pesticides relative to water (72), thus countering the effects of increased permeabihty caused by roots. 

Figure 2.11 Distribution of worm burrows and cylinders of influence represented by boundary conditions for Equation (2.37)...

T cell and cytokine regulation of enterocyte apoptosis may also be important in the expulsion of nematodes, in particular T. spiralis and T. muris, which inhabit an intracellular niche. Certainly an increase in the number of apoptotic cells within the epithelium is observed around the period of expulsion of T. muris in resistant mouse strains (D. Artis, C.S. Potten and R.K. Grencis, unpublished). Apoptosis of host enterocytes may dislodge the nematode or perhaps expose vital feeding organs to immune attack, and so enhance expulsion. Whether enterocyte apoptosis results from the burrowing action of the worms or a tissue repair mechanism, or is involved in expulsion, remains to be investigated. 

Compound 1080 was also effective against jackrabbits, foxes, and moles. Baits containing 0.05 to 0.1% 1080 on vegetables were used in California to kill jackrabbits (Lepus spp.) and various rodents (Schitoskey 1975). The Arctic fox (Alopex lagopus), intentionally introduced onto the Aleutian Islands in 1835 (Bailey 1993), almost eliminated the Aleutian Canada goose (Branta canadensis leucoparlia) by 1967. 1080-tallow baits were successfully used to control fox populations (Byrd et al. 1988 Tietjen et al. 1988 Bailey 1993). Earthworm baits are used to kill moles. The earthworms are soaked for 45 min in a 2.5% solution of 1080 and placed in mole burrows. The solution can be used several times for additional lots of worms however, the use of the manure worm (Eisenia foetida) should be avoided because it is seldom eaten by moles (Peacock 1964). 

Note that the sensitivity of the net flux between the soil and water to the worms activities depends on the relation between the rate R and the solute concentration. For the calculations in Figures 2.13 and 2.14, R varies linearly with concentration as specified in Equation (2.40), and the flux is sensitive to worm activity. But where the rate is independent of concentration, as for NH4+ formation in Equation (2.39), the net flux, which in this case is roughly Ro/a + LRi, is necessarily independent of worm activity, though the distribution of the flux between burrows and the sediment surface and the concentration profile are not. In practice the rate will always depend to some extent on concentration. But the predictions here for the idealized steady state indicate the expected sensitivities. 

Steward CC, Nold SC, Ringelberg DB, White DC, Lovell CR (1996) Microbial Biomass and Community Structures in the Burrows of Bromophenol Producing and Non-Producing Marine Worms and Surrounding Sediments. Mar Ecol Prog Ser 133 149... 

Oligochaete worm, deep burrower and relatively tolerant to anoxia. Volume 1(12). 

Teredo—A kind of mollusk with a worm like body, which burrows through wood and other materials on ships. 

In addition to body fossils, paleoecologists study trace fossils. These are things like footprints, gopher burrows, or worm trails preserved in sediments. Trace fossils indicate the behavior of the organism that made the trace and physical factors about the environment. For example, a trail of dinosaur footprints preserved in stream bed sediments provides evidence of how fast the dinosaur was moving, based on spacing of the prints. The depth of the footprints suggests how soft the sediments were, and hence, whether the stream bed was dry at the time the dinosaur traversed it. 

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