Studies of the life-history and energetics of marine and brackish-water nematodes

Abstract

Summary. Aspects of the demography of Monhystera disjuncta were investigated at different temperatures (in agnotobiotic cultures) and in different feeding conditions (monoxenic cultures with different bacterial strains, and different densities in the feeding suspension with one strain). Embryonic development time, minimum generation time, egg deposition rate and adult longevity depend on temperature, quality and quantity of food offered. Body mass at maturity is an allometric function of food density. It is shown that a previously inferred selectivity in food uptake is an artifact of culture conditions, pH buffering and addition of sterols permit culture of the species on a wide variety of bacterial strains. M. disjuncta is less well adapted to take advantage of high food density than are nematodes from polysaprobic environments. The animals channel surplus energy intake into a larger body mass, without being able to increase their rate of population growth accordingly.

Ecology and Biogeography of Free-Living Nematodes Associated with Chemosynthetic Environments in the Deep Sea: A Review

“…H. disjuncta is further known as a fast colonizer in shallow waters, successfully exploiting organically enriched substrata, such as sediments from estuarine mudflats or decomposing algal thalli. The species occurs in shallow water along the European coast from both the North Sea, south of Norway [83] and the White Sea, northeast of Norway [84]. H. disjuncta , found at the Belgian and Dutch coast, is represented by at least 5 cryptic species [85] with subtle morphological differences [86].…”

“…The specimens were identified as morphologically similar to Terschellingia longicaudata , although molecular evidence is lacking so far. Like H. disjuncta , T. longicaudata has an extensive geographical range including estuarine sediments off the North Sea [82], [83], [87], mangrove mudflats off northeastern Australia [88]–[90], the southeast coast of India [91], off the Atlantic coast of France, in the Black Sea [92] and the Gulf of Mexico, off eastern China (Qingdao province [93]) as well as New Zealand and the Solomon Islands [94]. In [95] a broad ecological and geographic range is suggested based on molecular evidence.…”

Possible effects of global environmental changes on Antarctic benthos: a synthesis across five major taxa

“…On the species level, information on nematode responses to environmental change for the SO is lacking, but experimental laboratory studies on species from coastal and estuarine areas in temperate regions indicate that rising temperatures, food quality and quantity, and salinity changes may have significant effects on the life history, reproduction, and feeding characteristics of many species (see Table 2, Forster 1998; Gerlach and Schrage 1971; Heip et al 1978, 1985; Ishida et al 2005; Kim and Shirayama 2001; Moens and Vincx 2000a, b; Pascal et al 2008a, b; Price and Warwick 1980; Takeuchi et al 1997; Tietjen and Lee 1972, 1977; Tietjen et al 1970; Vranken and Heip 1986; Vranken et al 1988; Warwick 1981; Wieser et al 1974; Wieser and Schiemer 1977; Woombs and Laybournparry 1984). Even though the effect ranges tested in these studies go well beyond the expected environmental changes in the Antarctic and the magnitude of effects of similar temperature shifts may vary depending where along the temperature spectrum they occur, species responses are very likely under the predicted scenarios.…”

Temperature and salinity induce differential responses in life histories of cryptic nematode species

“…In the area of this study, maximum daytime temperatures can range from below 0°C to above 25°C. Increasing temperature has been shown to increase the fecundity and decrease the development time of marine and brackish-water nematodes (reviewed in Heip et al, 1985;Vranken et al, 1988). Moreover, the development time of L. marina was strongly affected by temperature (Moens and Vincx, 2000).…”