Copepod Nitocra Spinipes Research Articles

Oestrogens have no Hormonal Effect on the Development and Reproduction of the Harpacticoid Copepod Nitocra spinipes

In recent years, reports have described endocrine-disruptive effects of environmental oestrogens in fish, but little is known about similar effects in crustaceans. The objective of the present study was therefore to examine whether the oestrogens 17-β-oestradiol, 17-α-ethynylestradiol and diethylstilbestrol (DES), could affect mortality, larval development rate, fecundity and sex ratio in the sexually reproducing harpacticoid copepod Nitocra spinipes. Newly released nauplii (<24-h old) were exposed to 1/1000, 1/100 and 1/10 (nominal concentrations) of each oestrogen's 96 h-LC 50 value for ≤18 days at 22±1°C. The percentage of gravid females and the number of developed copepodites were both reduced at 0.03 mg l −1 DES, although the latter response was not significant. None of the other two oestrogens induced any measurable effects. Since the only observed significant response appeared at a DES concentration no more than 10 times below the 96 h-LC 50 value, there is no evidence of endocrine-disruptive activity in N. spinipes exposed to oestrogens.

Development and lipid composition of the harpacticoid copepod Nitocra spinipes reared on different diets

Development and lipid composition of the harpacticoid copepod Nitocra spinipes reared on different diets

Precision of the nitocra spinipes acute toxicity test and the effect of salinity on toxicity of the reference toxicant potassium bichromate

AbstractThe precision of the 96‐h LC50 test with the eurohaline copepod Nitocra spinipes was evaluated from a data set containing 85 tests with the reference toxicant potassium bichromate conducted at 12 laboratories during a 12‐year period. The overall mean was 30 mg/L as K2Cr2O7 with a coefficient of variation (CV) of 47% (N = 85). Since salinity differed between tests (7–33 o/oo), it explained part of the variation (ca. 25%; Pearson two‐tailed test r = 0.49; p = 0.0000; N = 85). The effect of salinity on Cr(VI) toxicity was confirmed in an experiment with 4 salinities (3.4, 6.8, 14.6, and 27 o/oo) and was explained to 99% by the equation 96‐h LC50 (mg/L) = 2.58 + 1.79 × salinity (o/oo). Intralaboratory CVs for corresponding salinities ranged from 8 to 35% (repeatability). Interlaboratory CVs at two salinities were 42% (N = 11) at 7–9 o/oo and 47% (N = 4) at 15–16 o/oo. © 1993 John Wiley &amp; Sons, Inc.

A flowthrough fecundity test with Nitocra spinipes (harpacticoidea crustacea) for aquatic toxicity

A sublethal flowthrough fecundity test with the euryhaline harpacticoid copepod Nitocra spinipes has been developed as a complement to the acute toxicity test (for 48 or 96 hr LC 50) with the same species (B-E. Bengtsson, 1981, Mar. Pollut. Biol., 9, 238–241). Bacterial suspension as feed and test water are continuously fed by a peristaltic pump to the systeem. Newly fertilized females with ovigerous bands are harvested from laboratory cultures and put into the test vessels at the start of the experiment. They are then exposed to a series of concentrations of chemicals or industrial effluents for 13 days. The amount of live offspring (metanauplia and copepodids) are recorded and an EC 50 for fecundity is calculated. The report gives a detailed technical description of the test system and presents the results from 11 tests with pure chemicals (Zn, Cd, As, and pentachlorophenate) and six industrial effluents (pulp industry, textile industry, and refinery) in salinities ranging from 3 to 25‰

Fluctuations in the meiofauna of the Aufwuchs community in a brackish-water lagoon

The organization of the Aufwuchs community in a brackish-water lagoon (Swanpool, Falmouth, U.K.) is described. Changes in the population densities of encrusting bryozoans and mobile meiofauna are described for a period of 3 years. Most meiofaunal species reached peak densities in the spring (January–March). These included tardigrades ( Macrobiotus sp.), oligochaetes ( Nais elinguis, Chaetogaster diaphanus), the harpacticoid copepod Schizopera clandestina, ostracods, the nematodes Dichromadora geophila and Theristus spp., and possibly the nematodes Chromadorina germanica and Atrochromadora microlaima. Other meiofaunal populations peaked in summer (July–September), and these included the chironomid Chironomus salinarius, the harpacticoid copepod Nitocra spinipes and the nematode Adoncholaimus thalassophygas. Two further species, the mite Halacarus balticus and the nematode Aphelencoides sp., showed irregular bursts in numbers. It is concluded that the spring-peaking species increased in numbers dependent upon the growth of the Aufwuchs, and particularly of the surface film of diatoms, while the summer-peaking species may have been controlled more by limiting values of salinity and temperature. These conclusions are contrasted with the general view of salinity as the over-riding factor in brackish-water ecosystems.

Molecular structure and aquatic toxicity — An example with C 1 - C 13 aliphatic alcohols

The acute aquatic toxicity of a series of primary aliphatic alcohols (C 1 - C 13) has been tested on the harpacticoid copepod Nitocra spinipes, Boeck, and the bleak, Alburnus alburnus L. The results showed that the toxicity was highly correlated to the number of carbon atoms, ie increasing toxicity with increasing number of carbons. The results are discussed in relation to interspecies differences in sensitivity, correlations between hydrophobicity (log P ow) and toxicity, and the use of solvents in bioassays.

Use of a harpacticoid copepod in toxicity tests

The harpacticoid copepod Nitocra spinipes has been tested for acute toxicity of 12 metal chlorides in brackish water. Their order of toxicity, expressed as 96 h LC 50, was in good agreement with other investigations performed in freshwater and seawater. The 96 h LC 50-values were of intermediate levels compared to these two environments. The organochlorines p, p′-DDE and p, p′-DDE methyl sulphone were tested for effects on reproduction and mortality during two weeks, and it was found that p, p′-DDE was the most toxic. It is concluded from the investigation that N. spinipes is a suitable toxicity test organism in brackish water.