Observations on the population dynamics of Potamothrix hammoniensis (Michaelsen, 1901) (Tubificidae, Oligochaeta) in Lake Isacova in the Danube Delta (original) (raw)
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Hydrobiologia, 1994
Potamothrix alatus paravanicus Poddubnaya & Pataridze (Tubificidae) is the most abundant species of benthic invertebrate in Lake Sevan and the only species in the deep profundal. Differences in annual temperature, length of the stratification period (low oxygen content) and bottom sediment characteristics influence the population of P. a. paravanicus in different depth zones of Lake Sevan. From shallow to deep water a regular increase of the following indices was observed in 1984-1987: annual biomass from 1.2-2.0 to 8.2-17.0 g m-* wet weight; mean individual wet weight of clitellate specimens from 2.0-3.8 to 8.3-16.6 mg; total life span from one and a half to more than 20 years; the length of breeding season from 2-3 to 12 months. An important ecological distinction between P. a. paravanicus and allied Potamothrix hammoniensis (Michaelsen) is the much lower fecundity of the former species.
Hydrobiologia, 2000
Within the Danube River delta's lakes the Oligochaeta communities comprise between 7.9% and 36.2% of the total biomass of benthic fauna. Their importance in energy flow at the ecosystem level changed in relation to fast trophic transition of all shallow lakes to the hypertrophic state. The parameters of the energy budget of the dominant populations and the potential production of benthivorous fish species assessed during 1976-1994 interval support this conclusion. P/B ratio, K 1 and K 2 coefficients assessed for both the 1976-1980 and 1991-1994 intervals revealed different functional patterns of response of Potamothrix hammoniensis (Michaelsen, 1901) and Limnodrilus hoffmeisteri (Claparede, 1862) to varying trophic conditions. Changes in communities structure, size of the constituent populations and their age distribution, as well as the quantity and quality of food supply and level of hypoxia at the sediment/water interface were the main factors that affected the role of these populations as energy carrier from the huge energy pool represented by sedimented organic carbon to benthivorous fish species.
During 1991-1994, the structure of the oligochaeta communities in eight representative Danube Delta lakes consisted in 2-3 dominant species, among which Potamothrix hammoniensis frequently comprised over 85%. The long-term trends in the dynamics of these communities are assessed on the basis of a comparative analysis of the total abundance and species dominance recorded for 1982, 1986 and 1992. During 1982-1994 comparable trends were noticed in all studied lakes. These consist in mass development firstly of ubiquitous L. hoffmeisteri and, later one, of the P. hammoniensis. The changes are linked with accelerated eutrophication.
Oligochaeta of the Danube River — a faunistical review
Biologia, 2013
The aim of this work is to discuss the distribution of Oligochaeta (Annelida) in the Danube River using the collections made by the Joint Danube Survey 2007 (JDS2) on more than 2800 km of the river. The basic faunistical features of the oligochaete assemblages were analysed with regard to three main sectors of the Danube (upper, middle and lower reaches, the last with the Danube Delta). A total of 52 oligochaete taxa have been recorded. Most of the observed species are typical of the potamon-type rivers in the region, and are well adapted to moderate-to-high organic load. The highest taxa richness and frequency of occurrence were observed among the Tubificidae family. Naididae, Propappidae, Enchytraeidae and Haplotaxidae had also low frequency. The upper reach of the Danube showed the lowest species richness, while the middle reach is characterised by its highest species richness. Construction of dams and regulation of the riverbed have resulted in an increase of limno(rheo)philic taxa which prefer slow-flowing and lentic zones.
Reproduction of Potamothrix hammoniensis (Oligochaeta) in shallow eutrophic lakes
Oceanological and Hydrobiological Studies, 2018
The aim of the study was to indicate the abiotic parameters of water and bottom sediments, which significantly affect the reproduction of Potamothrix hammoniensis in 9 shallow eutrophic lakes, of which 5 were dominated by macrophytes and 4 – by phytoplankton. Samples were collected once a month from January to December 2012. The percentage of Potamothrix hammoniensis individuals with a developed reproductive system varied in individual lakes and ranged from 14 to 72%. There was no correlation between the distinguished lake types and the proportion of sexually mature individuals. The reproductive activity was not observed in summer and early autumn. Among the measured parameters, the highest values of the Pearson correlation coefficient were found between the percentage of individuals with a developed reproductive system and the conductivity (r = 0.69; p < 0.001), pH (r = 0.51; p = 0.002) and the organic matter content in the sediments (r = −0.42; p = 0.012). It is worth noting th...
Zootaxa, 2013
Lake Hazar is an alkaline oligotrophic lake of tectonic origin, located in the Eastern Anatolia region in Turkey, 1248 m a.s.l. Its surface area is 80 km 2 , the average depth 93 m and maximum depth 205 m. The lake and its surroundings are under protection as a region of historical value. During the present study (2007)(2008)(2009)(2010)(2011)(2012), samples were taken from 15 stations located at a depth of 2-200 m. Oligochaeta comprised 69% of the total invertebrate abundance. The profundal oligochaete fauna was found to consist of only three tubificid taxa, all of the subfamily Tubificinae. Potamothrix alatus hazaricus Timm & Arslan, n. ssp. was dominating anywhere down to maximum depths while Psammoryctides barbatus (Grube) and Ilyodrilus(?) sp. occurred seldom. All three are new records for Lake Hazar. Potamothrix alatus hazaricus shares the "winged" body shape in its genital region with the nominal, brackish-water subspecies P. a. alatus Finogenova, 1972, and the lateral position of the spermathecal pores and the shape of the ventral chaetae with the freshwater subspecies P. a. paravanicus Poddubnaja & Pataridze, 1989 known from Transcaucasian lakes. The mitochondrial COI barcoding gene suggests long separation between the two taxa, but the nuclear ITS region shows no variation. The generic position of Ilyodrilus (?) sp. remains obscure since its internal genitalia could not be studied.
In order to determine the oligochaeta fauna of Lake Sapanca (Turkey) samples were collected from 5 stations monthly, between September 2000-August 2001. As a result of the study, 13 species, which belong to 9 genera, were determined. These species are Aulodrilus limnobius, Tubifex tubifex, Tubifex ignotus, Tubifex nerthus, Limnodrilus hoffmeisteri, Potamothrix hammoniensis, Potamothrix vejdovskyi, Nais communis, Spirosperma ferox, Psammoryctides barbatus, Ilyodrilus templetoni, Psammoryctides deserticola, Paranais frici. Also some physicochemical parameters of the water (temperature, dissolved oxygen, pH, turbidity and depth) were measured at the sampling site. The average density of total oligochaetes in the benthos of the lake was 1,887 ind m-2. According to Shannon-Wiener index, Lake Sapanca was found had 2.59 richness and, 5 th station were found to have highest diversity (3.87) while 3 rd station to have the lowest (1.59). There are almost no data on the Oligochaeta fauna of this lake so far. Hence, all the determined taxa from the localities are recorded for the first time.
Scientific Annals of the Danube Delta Institute, 2019
Fish from Danube delta spawn in spring grows over the summer and in autumn season juveniles recruit to the population. Ichthyofauna was sampled in May-July (springsummer) after spawning and September-October (autumn) after the juvenile's recruitments. A number of 136 fish species are quoted in references for Danube Delta Biosphere Reserve (DDBR) (included marine species) belonging to 3 Classes, 20 Order, and 45 Families (representing more than 70% of Romania's ichthyofauna). Using 4 methods of sampling, from what two in accordance with UE fish sampling standard methods, were sampled 11 representative lakes in 249 stations: electric fishing in 55 sites (fishing effort over 9 hours), 164 sites with multimeshes size Nordic gillnets (4,920 m-net-1·night-1 meaning 29225 m²-net·night-1 fishing effort) plus 23 sites with commercial gillnets (1950 m-net-1·night-1meaning 3758 m²-net·night-1 fishing efforts) and 7 sites using seine fishing (in the Razim lake). In 2016 in 6 lake-comple...
Aquatic Oligochaete Biology VIII, 2001
The species composition of the Scandinavian freshwater oligochaete fauna is strongly influenced by its post-glacial history . Few species are likely to have survived in the core areas of glaciation and the present composition of species has thus been highly dependent upon the immigration rate of 'new' species . Active immigration into new localities has proven to be a very slow process, whereas passive transportation in running water and by rafting is much faster. Exchange of ballast water in harbours is likely to be the single most effective action by man, causing large-scale passive dispersal of the aquatic fauna and flora. Bottom water with stirred-up sediment containing oligochaetes could thereby be sucked into the tanks of ships and later exchanged in nearby and distant ports. Ponto-Caspian species among the Tubificidae, originating in the Black Sea-Caspian Sea region, are continuously dispersing to the west over Central Europe and to the north-west towards the Baltic Sea area adding to the species list of the Tubificidae. Five such species of the genus Potamothrix have quite recently reached eastern Sweden . The dispersal front presently goes obliquely across Scandinavia from the north-east to the south-west. Comparisons with results from previous bottom-sampling series in Lake Mälaren from 1915 to 1916 revealed ongoing colonization, especially in those basins of the lake which were in recent contact with the Baltic Sea and thus had brackish bottom water. One of those species, Potamothrix heuscheri, which is particularly tolerant to anoxic conditions and high salinity and is likely to have reached Scandinavia in ballast water possibly via indirect sources from the Mediterranean Sea. Its uneven distribution in Scandinavia is well correlated with historic water-ways for heavy transport, for instance via cargoes of wood pulp from Lake Munksjön to the south of Lake Vättern and to and from other cellulose industries on the Baltic coast. It is speculated that distant occurrences of P. heuscheri in Africa and South America may have been reached through passive transport in the plumage of migrating wading-birds.
2018
Bu calismada, Biga Yarimadasi akarsularindan Saricay, Karamenderes, Tuzla ve Kocabas’ta belirlenmis 15 ornekleme istasyonunda, Oligochaeta (Annelida: Clitellata) faunasi cevresel degiskenler ile birlikte mevsimsel olarak arastirilmistir. Bentik orneklemeler Hess Sampler ve Ekman Birge Grab ile gerceklestirilmis ve ornekler kantitatif olarak degerlendirilmistir. Bentik orneklemeler sirasinda, su sicakligi (T), elektrik iletkenligi (EC), pH ve cozunmus oksijen (DO) yerinde, kimyasal oksijen ihtiyaci (COD), biyolojik oksijen ihtiyaci (BOD5), PO4-P, NO3-N gibi su kalitesi laboratuvarda analiz edilmistir. Arastirma sonucunda, Naididae familyasindan 29 taksa, Enchytraeidae 2 taksa ve Lumbriculidae 2 taksa olmak uzere 33 taksaya ait toplam 340993 birey tespit edilmistir. Organik kirlilige toleransli Potamothrix hammoniensis (Michaelsen, 1901), Tubifex tubifexMuller, 1774, Limnodrilus hoffmeisteri Claparede, 1862 turlerinin alt akarsu havzalarinda yer alan istasyonlarda baskin oldugu MD San...