Nematodes from river drift and surface drinking water supplies in southern Ontario

Abstract

Sixty-six genera'of nematodes representing 37 families were collected over a 13-month period from untreated and treated water from three water treatment plants in southern Ontario. Two plants receive water from the Grand River which drains agricultural, residential and industrial regions, the third from a small stream in an agricultural district. Specimens were isolated by filtration from weekly samples of untreated and treated water, most were identified to genus but a few to species.Estimated mean density in the organic drift of the river ranged from 0.58 individuals per litre in winter, when it was under ice, to 10.57 per litre during the spring thaw. Most of the 66 genera found passed through the treatment plants and over 50% of these were still motile.Eleven genera were abundant at some time of the year, six known only from soil-dwelling forms and five from aquatic or soil/ aquatic species. There was no indication that sewage purification works were a major source of any genus. There were a few plant parasites.Aquatic nematodes occurred during most of the year although they were more abundant during the warmer months, high densities of soil nematodes were a feature of the spring thaw and rains and during heavy autumn rains. More than 50% of the specimens were juveniles and some common genera lacked males.

Seasonal distribution of free-living nematodes in the Körsch, a coarse-grained submountain carbonate stream in southwest Germany

“…As in the Krähenbach (Beier & Traunspurger, 2003b), the Adige (Andrássy, 1959), the Danube (Andrássy, 1962) and the Grand River (Mott & Harrison, 1983), the nematode population of the Körsch shows a high percentage of females and juveniles and a low percentage of males. The low percentage of males in all these systems can have no signi cant impact on reproductive output since most of the lotic nematodes reproduce parthenogenetically.…”

Revisiting the meiofauna paradox: dispersal and colonization of nematodes and other meiofaunal organisms in low- and high-energy environments

“…It has been frequently suggested that meiofauna depend on external forces to become suspended in the water column and carried to distant habitats (Hagerman & Rieger, 1981;Mott & Harrison, 1983;Fleeger et al, 1984;Fegley, 1985;Armonies, 1988;Palmer, 1988;Bertelsen, 1998;Powers, 1998). One would thus expect to encounter more meiofauna in the water column of high-energy environments than of more protected ones.…”

“…Although nematodes have been collected from plankton samples (Hagerman & Rieger, 1981;Sibert, 1981) and marine snow (Shanks & Walters, 1997), they are poor swimmers (Fegley, 1985) and likely become suspended in the water column via external forces (water currents or bioturbation), as is assumed for most meiofaunal taxa (Hagerman & Rieger, 1981;Mott & Harrison, 1983;Fleeger et al, 1984;Fegley, 1985;Armonies, 1988;Palmer, 1988;Bertelsen, 1998;Powers, 1998;Fonseca-Genevois et al, 2006). Many harpacticoid copepods, however, are much better active dispersers than nematodes (Widbom, 1983;Ó lafsson & Moore, 1990Ó lafsson & Moore, , 1992 and occasionally enter the water column under their own power (Alldredge & King, 1980, 1985Bell et al, 1988;Kurdziel & Bell, 1992;Walters and Bell, 1994;Teasdale et al, 2004).…”

Drinking Water Microbiology

“…Most adult forms are about 1 mm long (Nicholas, 1975;Croll, 1977). Nematodes found in untreated drinking waters originate from animals drifting into the water distribution system (Mott and Harrison, 1983). In treated drinking water, the source of nematodes is likely to be either drifting or colonization and breeding within the water treatment plant (Cobb, 1918;George, 1966;Tombes et al, 1979).…”