Toxicity of copper, mercury and lead to a marine nematode

Abstract

Toxicity of copper, lead and mercury to the nematode Diplolaimella spec 1 is studied. Mortality responses obtained demonstrate high resistance to heavy metals. Population growth parameters as the intrinsic rate of natural increase and net-reproductivity are significantly depressed at copper-concentrations which cause no juve~ile mortality. The lowest concentrations tested caused significant inhibition of development rate in both sexes. For this particular nematode species suppression of fecundity and developmental inhibition are more reliable criteria, determining non-exceedable limits with regard to environmental safety. Our tests show that nematode productivity may be significant1y depressed at copper levels found in some areas of the North Sea. 173. 2. INTRODUCTI ONMarine nematodes are the most abundant anima1s in marine sediments and have severa1 features that are advantageous in ecotoxicological research in the laboratory : they have a short 1ife-span (Vranken & Heip, in press), a high fecundity (Vranken &Heip, 1983), represent several trophic levels (herbivores, bacteria1 feeders and carnivores) and at least some species are easi1y cultured (Heip et al., 1985).However, the effect of on1y a very limited set of chemical agents to on1ya few species has been tested up till now (Bogaert et a1., 1984; Howell, 1934; Vranken et al., 1934b). From these few experiments it appears that nematodes are relatively resistant to pollutants. This is corroborated by evidence from field surveys which have shown that nematode density is not affected substantia11y by raw domestic sewage (Vidakovic, 1983), heavy metals (Tietjen, 1977(Tietjen, , 1980 and acid iron waste (Lorenzen, 1974).In this paper we present results from tests on the species Dip101aimella spec I, a new species described by Jacobs &Vranken (in prep.) and misidentified as Monhystera microphthalma in previous papers.First, aseries of dcute (static) and sub1etha1 (chronic) tests on the toxicity of copper, mercury and lead is described, in which both mortality and deve10pment rate are studied simultaneous1y. Nematodes moult four times before becoming adult and the success in reaching a particular stage has been proposed as a sensitive indicator of toxicity (Samoiloff et a1., 1980). We used a slightly different approach and have determined generation time and preadult mortality as a function of metal concentration. These tests are presented as a supplement to the few data available and are intended to check whether the resistance of nematodes to toxicants is indeed true. Second, we will also report on sublethal effects of copper on fecundity, because mortality is not a 174 • very sensitive index of toxicity. Fecundity, the number of eggs produced, has been used because it is known to be a sensitive criterion in toxicity testing (Bryan, 1980;Reish &Carr, 1978).As a combination of fecundity and deyelop~ent rate (generation time) the intrinsic rate of natural increase r m of the population can be calculated. This has been done by Tietjen &Lee (1984) to measur...

Observed Differences in Life History Characteristics of Nematodes Aphelenchus and Acrobeloides upon Exposure to Copper and Benzo(a)pyrene

“…Development inhibition may be a much more sensitive index of toxicity than mortality of nematodes (Samoiloff et al, 1980;Vranken and Heip, 1986;van Straalen and van Gestal, 1993). However, this may not be the case for all nematode species.…”

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

“…A study about the impact of heavy metals on nematodes from the Swartkops Estuary (Port Elizabeth, South Africa) revealed that nematode community structure was significantly impacted, with dominance of Monhystera and Theristus coloniser genera in the most polluted sites (Gyedu-Ababio et al 1999). Some species, such as Enoplus communis, show low tolerance to metals (Howell 1983), while others, such as Diplolaimella dievengatensis and Halomonhystera disjuncta nematodes (Vranken and Heip 1986;Vranken et al 1991;Gyedu-Ababio and Baird 2006), as well as copepods (Burton et al 2001), can be tolerant to high levels of heavy metals. Nematodes can accumulate and tolerate higher levels of copper, cadmium, zinc and lead than other meiofaunal organisms (van der Wurff et al 2007 and references therein).…”

Patterns of sensitivity to cadmium and pentachlorophenol among nematode species from different taxonomic and ecological groups

“…Various papers have investigated the toxicity of chemicals, e.g., pesticides (Bunt 1980;K~impfe and Wischgoll 1984) and heavy metals (Vranken and Heip 1986;Williams and Dusenbery 1990;Vranken et al 1991) to nematodes. However, only a limited number of species have been tested, and routes of uptake and test conditions differed too much to allow for a proper comparison.…”