Nais Elinguis Research Articles

Determination of Benthic Macroinvertebrate Fauna and Some Physicochemical Properties of Balaban Lake (Menderes- Izmir)

In this study, we aimed to identify the benthic macroinvertebrate fauna and some physicochemical characteristics of Balaban Lake located in Menderes, Izmir. For this, benthic macroinvertebrate and water samples were taken from 5 stations of the lake from October 2019 to August 2020. As a result, a total of 25 taxa were identified and were classified as Annelida (Oligochaeta and Hirudinea), Mollusca (Bivalvia and Gastropoda), Crustacea and other Insecta (Trichoptera, Coleoptera and Diptera). The sampling stations were clustered by using the Bray-Curtis UPGMA analysis in terms of the distribution of the benthic macroinvertebrates. As a result of the UPGMA analysis, the 2nd and 3rd stations (88%) were the most similar to each other. The second most similar stations to each other were determined as the 1st and 4th stations (75%). This situation can be explained by the bottom structure (rich vegetation) of these stations. According to Pearson Correlation, there is a strong positive correlation (p<0.01) of TU, EC, TDS and TP with Nais communis, while there is strong positive correlation (p<0.05) of TU, EC and TDS with Nais elinguis. On the other hand, there is a strong negative correlation (p<0.01) of TU, pH, EC, TDS and TP with Gammarus sp. This study is the first study for determining Balaban Lake benthic fauna. That’s why all the taxa diagnosed in the stream has been recorded for the first time. 

First record of the alien aquatic oligochaete species Monopylephorus limosus (Hatai, 1898) (Annelida) in Central Europe

Abstract The paper reports on the first record of the Asian aquatic oligochaete species Monopylephorus limosus (Hatai, 1898) in Central Europe. The species was found in the lower course of the Bolina River (S Poland), which is contaminated with saline mine waters. One immature individual was collected in the late summer of 2017. M. limosus co-occurred with Paranais litoralis, Nais elinguis and juvenile Enchytraeidae. To date, M. limosus is one of the 29 non-native annelids that are known to occur in Poland.

First record of Nais elinguis Müller, 1773 (Annelida: Oligochaeta: Naididae), Spatio-temporal patterns of its population density and biomass production along two estuaries in the South Caspian Sea, Mazandaran Province, Iran

The cosmopolitan oligochaete worm, Nais elinguis, is common to fresh and brackish water habitats. This species was found while investigating the limnology of two rivers alongside the Iranian coasts and has not been reported in the Iranian freshwater fauna and Caspian Sea before. N. elinguis was collected bimonthly from Cheshmehkileh and Sardabrood estuaries using a Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) with three replicates from 6 stations from November 2014 through September 2015. The results of temporal distribution showed that the highest and lowest density and biomass of this species were in January (242.2±84.45 ind m-2 and 0.105±0.035 g m-2) and in September (33.35±23.5 ind m-2 and 0.010±0.006 g m-2) respectively which were significantly different (p<0.05). Among the sampling stations, station (S1) within the river with freshwater showed higher density and biomass (273.5±87.35 ind m-2 and 0.116±0.036 g m-2) than riverine brackish station (S2) within the mouth (39.8±22.6 ind m-2 and 0.013±0.006 g m-2) and marine brackish station (S3) (0±0 ind m-2 and 0±0 g m-2) which were significantly different (p<0.05). Density and biomass of this species in Cheshmehkileh River and estuary were more than that in Sardabrood. A significant correlation (p<0.05) between the density and biomass of N. elinguis with environmental variables was found.

Genetic and chaetal variation in Nais worms (Annelida, Clitellata, Naididae)

The genus Nais is a group of oligochaetous clitellates, common in eutrophic freshwater habitats. About 30 species are described. Species identification is based primarily on chaetal characters, which are often subtle, inconsistent, and even overlapping between nominal species. We investigated the correlation between genetic variation and chaetal morphology in this genus. Eighty-one individuals from Europe, North America, and China were included in the study. Seventy-five of these were preserved as vouchers. They were scrutinized with regard to chaetal morphology, and ten different morphotypes were identified. Three molecular markers, two mitochondrial (the COI gene and 16S rDNA) and one nuclear (the ITS region), were used to establish the genetic lineages in the material. Genetic variation was found to be largely congruent with chaetal character patterns. However, at least nine separately evolving lineages (all supported by mitochondrial as well as nuclear data) correspond to at most six nominal species. Four morphotypes/lineages are recognized as Nais barbata, Nais christinae, Nais elinguis, and Nais stolci, respectively, whereas five, or possibly more, lineages represent a morphological continuum covering the variation of the Nais communis/variabilis complex. Thus, cryptic speciation is revealed. Our results indicate that a taxonomic revision of the genus will be needed in the future.

Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia.

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L−1, respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L−1 and 9.0, 2.0, 19.9, and 36.7 μg L−1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.

On the history of chloride concentrations in the River Lippe (Germany) and the impact on the macroinvertebrates

The River Lippe is situated at the northern part of the rhenish-westphalian coal mining area, Germany and has a long history of being affected by mining water discharge. There has, however, been a massive decrease in the discharge of mining water over the past few decades. While early in the last century concentrations of up to 3500 mg l−1 of chloride were observed, the mean concentration is now below 400 mg l−1. At the same time the water quality has improved greatly so factors other than chloride concentration may be influencing the macroinvertebrate community. Macroinvertebrate data collected from three sites along the River Lippe was analyzed for a change in the occurrence of salt tolerant species in an area where mining water discharge ended in 2000. It was found that also during the period of discharges the macroinvertebrate community was dominated by freshwater species and therefore the impact of mining water discharges in the upper River Lippe is considered to be minor. It was also found that for some species (Nais elinguis, Bithynia tentaculata and Gammarus tigrinus) their proposed salinity preference did not correlate with their occurrence in the field. This may be an area that requires further research.

Sludge reduction potential of the activated sludge process by integrating an oligochaete reactor

An oligochaete reactor linked to an integrated oxidation ditch with vertical cycle (IODVC) was used to investigate the sludge reduction potential induced by worms. The presence of Tubificidae was observed in the worm reactor throughout the operational period after its inoculation, and Tubificidae was occasionally found in the IODVC. Free-swimming worms, Aeolosoma hemprichi, Nais elinguis, and Aulophorus furcatus, were found in both the IODVC and the worm reactor, but A. hemprichi was dominant. A. hemprichi reached its maximum, 322 and 339 Aeolosoma/mL mixed liquor on day 49 in the worm reactor and the IODVC, respectively. The presence of oligochaetes or the integration of worm reactor with the IODVC had little effect on sludge yield, but the worm growth was helpful for improving sludge settling characteristics. The average sludge yield and sludge volume index (SVI) in the IODVC were 0.33 kgSS/kgCOD removed and 78 mL/g, respectively. The worm presence had little impact on effluent quality of the IODVC, but it caused phosphorus release into the effluent. The average COD, NH 4 +-N, and SS concentrations in the effluent of the IODVC were 49.06, 12.82, and 58.25 mg/L, respectively. No total nitrogen (TN) release into the effluent of the IODVC occurred.

The discharged excess sludge treated by Oligochaeta

To overcome unstable worm growth, a new worm-reactor was developed for oligochaete growth. The bench scale of this worm-reactor was used to treat the discharged excess sludge from a pilot activated sludge system, and experiments were carried out to investigate the sludge reduction induced by Oligochaeta. Due to difficult getting free-swimming worms such as Aeolosoma hemprichicii and Nais elinguis, Tubifex tubifex was thus selected and inoculated in Reactor 1 at the start-up phase except the control reactor (Reactor 2). Tubifex occurred in Reactor 1 throughout the operation period after its inoculation, and mainly attached on the carriers and aggregated on the bottom of the worm-reactor. Free-swimming worms such as Aeolosoma hemprichicii, Nais elinguis, and Aulophorus furcatus were found in both reactors since the 35th day. Microscopic investigation showed that these free-swimming worms naturally produced in the pilot activated sludge system, and entered into both reactors along the discharged sludge. Results clearly showed that the average sludge reduction in Reactor 1 was 59%, much higher than that in the control. The characteristics of sludge settling was improved by worm growth, but was not too much. High ammonia nitrogen concentration in influent sludge was toxic to worms, and then inhibited worm growth. Both the total inorganic nitrogen and phosphorus releases into effluent sludge were observed in Reactor 1, but such increases were not heavy.

Temporal dynamics of meiofauna communities in two small submountain carbonate streams with different grain size

The meiofauna community (especially nematodes, oligochaetes and chironomids) in the streambed surface of two small submountain carbonate streams (Krahenbach and Korsch, Germany) was investigated from April 1998 to March 1999. The Krahenbach stream is relatively sorted and fine-grained, while the Korsch stream is more heterogeneous and coarse-grained. The streams also differ in velocity, water level, conductivity, chloride concentration and organic content of sediment. Total meiofauna density reached a maximum value of 906 individuals per 102 cm in the Krahenbach and 3166 individuals per 102 cm in the Korsch. Rotifers were the most abundant group in the Krahenbach (52% of total fauna), whereas nematodes were dominant in the Korsch (63%). Meiofauna showed one abundance peak in the Korsch and two abundance peaks in the Krahenbach. In the Krahenbach, distinct seasonal patterns at family and species level occurred, whereas in the Korsch even at high taxonomic level only one abundance peak was observed. The most abundant nematode family in both streams were Monhysteridae, followed by Tobrilidae in the Krahenbach and by Tylenchidae in the Korsch. The dominant oligochaete family in both streams were Naididae (especially Chaetogaster langi (Bretscher, 1896) and Nais elinguis (O. F. Muller, 1773)), followed by Tubificidae. The most abundant chironomid genera in the Krahenbach were Stichtochironomus and Corynoneura. Prodiamesa olivacea (Meigen, 1818) was the dominant chironomid species in the Korsch. Deposit-feeding and detritus-feeding animals were numerically dominant in both streams. The increased mean abundance of Diplogasteridae, Rhabditidae, Tubificidae and N. elinguis in the Korsch compared to that in the Krahenbach indicates an organically enriched situation.

A deterministic size-structured population model for the worm Naidis elinguis.

In this paper we model the population dynamics of the worm Nais elinguis, which reproduces by division into two unequal parts. By using renewal theory we derive the asymptotic behaviour of a Naidis elinguis population. In particular we prove a certain relation between the fraction of the population that was born small (respectively the fraction that was born large) and the inter-division times.

Oligochaete drift in a large river (French Upper Rhône): the effect of life cycle and discharge

In the framework of a macroinvertebrate drift study, the oligochaete community was analysed over one year (1989) at six sites located in a partly impounded reach of the Upper Rhone River (France). Drift composition between sites was somewhat affected by the environmental conditions. These differences were caused by significant deviations in drift rates (P 0.05) among the swimming Naididae. As the latter strongly dominated, global spatial differences in the drift were weak. Temporal changes constituted the main source of variability in drifting oligochaetes. Life cycles and reproductive ecology of four major swimming Naidid species, Nais elinguis, Stylaria lacustris, Nais christinae, and Nais barbata, explained most of the drift structure over the year. Hydrological fluctuations also affected drift structure, both for swimming and non-swimming species. Taxon richness and relative abundance in the drift were very similar to those obtained in the river benthos from a reference reach previously studied. There was a lack of stygobiont and stygophilous species that are frequent in area of groundwater seepage. Biological and environmental implications of oligochaete drift are stressed. The drift phenomenon is appropriated to provide ecological informations on oligochaete communities in fast flowing and deep, large rivers.

New aspects of the possible sites of ultrafiltration in annelids (oligochaeta)

Electron microscopic investigations of blood vessels were conducted to show sites of filtration such as podocytes or fenestrated endothelia. The endothelia of the blood vessels of Aelosoma hemprichi, Nais elinguis, Dero obtusa and Enchytraeus buchholzi consist of myoendothelial cells, chloragocytes and podocytes. The podocytes form large archs over a considerable area of the vessels. On the lumen side of the vessel there are several columnar processes which split into numerous small pedicels. The gaps between the adjacent pedicles are bridged by slit membranes. The podocytes are restricted to the front part of the ventral vessel. They are presumed to form a filtration surface. Furthermore, some parts of the ventral vessel are formed by a fenestrated endothelium, mainly in Enchytraeus buchholzi. In the vascular system of E. buchholzi two separate filtration sites were found. Additionally to the filtration site between ventral vessel and coelomic cavity a second filtration site was found in the front part of the body between blood sinus and coelomic cavity. In such areas the basement membrane is the only continuous layer between the blood vessel and the coelomic cavity. Its thickness is in the range of 40 nm. Possible filtration sites in the form of podocytes and irregular fenestrations could be localized at the border between the blood compartment and the coelomic compartment. It can be presumed that the primary urine may be formed by ultrafiltration of blood.

Modelling the growth of an oligochaete on activated sludge

A dynamic energy-budget model (DEB model) was extended to describe the growth of Nais elinguis, a common oligochaete species frequently occurring in sewage treatment plants. Nais elinguis reproduces asexually by dividing into an anterior and a posterior naidid. The daughter naidids initially have different growth rates due to differences in energy reserves. The fit of the model showed a good description of the length measurements. The parameters of the model, such as maintenance rate coefficient and energy conductance, which represent physiological features of the organisms, facilitate insight into the processes underlying naidid growth. A numerical method was developed to predict asexual reproduction. The presented model is a first step towards a more comprehensive knowledge and modelling of organisms in an activated sludge plant and is therefore interesting from a wastewater management point of view.

The Influence of Environmental Factors and Microhabitat Availability on the Distribution of an Aquatic Oligochaete Assemblage in a Mediterranean River Basin

AbstractSome aquatic oligochaete species, mainly certain naidids and tubificids, are often associated with polluted environments, with high levels of organic matter and oxygen deficit. However, in the stations sampled in the Guadaira river basin, which can be arranged on an axis of organic pollution, the main aquatic oligochaete species (Nais elinguis and Tubifex tubifex) inhabiting these environments do not show a distribution pattern significantly related to the water physico‐chemical characteristics measured. Nor, have we registered any association between these species and any kind of microhabitat, defined here: water current, presence of different types of vegetation, substrate coarseness and presence of anoxic sediments. Paranais litoralis is the exception, being related to areas without water current, located at higher altitudes, with high levels of dissolved organic matter and an anoxic substrate made up of fine particles.These results can be explained by the highly fluctuating nature of Mediterranean ecosystems and by the marked generalist character and ubiquity of the oligochaete assemblage species, able to colonize any kind of environment.

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.

Littoral sand zoobenthos and its relation to organic pollution in Lake Nemi (Central Italy)

The results of a study on the littoral sand zoobenthos in the polluted Lake Nemi are reported and the role of this community in the evaluation of water quality in lakes is discussed. The fauna was composed of 65 taxa belonging to 15 zoological groups. Oligochaeta were dominant, followed by Diptera: Chironomidae, Crustacea and nematoda. Oligochaeta, including 21 taxa, had the maximum percentage occurrence in the discharge zones, with prevalence of species (Potamothrix heuscheri, Limnodrilus hoffmeisteri, Nais elinguis) very tolerant to organic enrichment. On the contrary, Chironomidae showed a depletion in the same zones, where we also observed the absence of Tanytarsini, typical of oligo-mesotrophic conditions, and the exclusive presence of Diptera: Psychodidae, considered as indicators of pollution. The community structure is related to the pollutional status at the sampling points, in a similar way as can be observed in profundal macrobenthos.

A choice chamber experiment on the selection of algae as food and substrata by Nais elinguis (Oligochaeta: Naididae)

SUMMARY. A choice chamber experiment was performed in the laboratory to quantify the selection of benthic algae as food and substrata by Nais elinguis. Most worms actively chose filamentous algae and/or diatoms as substrata whereas unicellular or colonial chiorophycean algae were discriminated against. Diatoms were selected in preference to latex beads but the worms could not discriminate between living filaments and nylon monofilaments. A thigmotactic response to filaments and a chemotactic response to diatoms may be implicated. The worms ingested unicellular algae at a greater rate than colonial and filamentous algae. The rates at which the algae were ingested were negatively correlated with the lengths of the algae. A filament 200 μm long was the largest item ingested, representing about 63% of the length of the pharynx of the worm. Ivlev's electlvity indices were positive when the rates at which the algae were ingested exceeded about 20 individuals h‐1. The index was negatively correlated with the lengths of the algae, but the time periods spent by the worms in association with the algae were unrelated to the electivity index. The data confirmed previous observations on the selection of algae as food and substrata by Nais elinguis in a natural habitat.

The ingestion and assimilation of algae by Nais elinguis (Oligochaeta: Naididae).

Nais elinguis was offered equal densities of three algal species under controlled conditions. Colonies of Scenedesmus quadricauda were ingested at significantly lower rates than cell of Nitzschia kutzingiana and Chlorella vulgaris. Labelled cells of N. kutzingiana were more rapidly and more efficiently assimilated than those of the other algae. Cells of S. quadricauda were viable in the faeces.This work confirmed conclusions from other studies with respect to the role of algae in the nutrition of Nais elinguis and other freshwater benthic herbivores.

The breeding behaviour of Gammarus duebeni

The breeding behaviour of a population of Gammarus duebeni is investigated. The breeding system includes a precopulatory guarding phase by a male of a female and the length of this phase varies markedly over the season. Large size is not of as great advantage in reproductive competition between males as in a stream population of G. pulex. In the spring of 1981 oligochete worms, Nais elinguis, were found in the brood pouches of some females; eggs were seldom present with the worms but rather amorphous debris. The occurrence of the worms and the debris in the females' pouches coincided with the pattern of abundance of the worms previously reported.

Ecophysiology of Nais elinguis (Oligochaeta) in a brackish-water lagoon

Population densities of Nais elinguis Müller were determined in Swanpool, a brackish-water lagoon at Falmouth, Cornwall, U.K., over a four-year period. High densities were found only from January to May, usually with a peak in March. Significant negative correlations were shown between population density and both salinity and temperature. In laboratory tests, feeding rates remained unchanged from freshwater to 20‰ salinity (S), but declined above this salinity. Nais elinguis was shown to be a good osmoregulator, remaining hyperosmotic below 7‰ S, and hypo-osmotic above this. Feeding rate showed a Q 10 of approximately 2 from 1 to 25°C, but above this the rate declined. Feeding rate was unaffected between pH 6 and 11. Increased salinity to (10‰ S) did not influence the effect of temperature on feeding rate. This high salinity did reduce feeding rate at a pH of 10 and above. It is concluded that the physical and chemical variables considered are unlikely to be direct causal factors limiting populations of N. elinguis in Swanpool. The influence of food supply, competition, predation and changes in reproductive mode are discussed as possible controlling factors. It is shown that the population decline of N. elinguis in early summer usually coincides with the rise of populations of chironomid larvae.