Factors Mediating Interspecific Aggregation of Tubificid Oligochaetes

1974 ◽  
Vol 31 (4) ◽  
pp. 460-462 ◽  
Author(s):  
R. O. Brinkhurst

Tubifex tubifex and Limnodrilus hoffmeisteri are both attracted to the feces of T. tubifex rather than to those of L. hoffmeisteri or a control sediment. This substantiates the hypothesis that lowered respiration and increased growth caused by mixing the two species could be due to an increase in time spent burrowing, rather than feeding, when isolated species are removed from their preferred food, the feces of another species of worm. It also helps explain the inter- and intraspecific clumping that characterizes their normal distribution.

2014 ◽  
Vol 11 (3) ◽  
pp. 1397-1404 ◽  
Author(s):  
Baghdad Science Journal

A total of 60 species of aquatic oligochaetes were identified in different sites within Tigris-Euphrates basin / Iraq, including River Tigris, River Euphrates, Southern marshes ( Al-Haweiza , Al-Hammar and Al-Chebaiesh ) , Shutt Al-Germa, and Shatt Al-Arab. In River Euphrates 39 species were identified, 40 species from River Tigris and 32 species from Shatt-Al-Arab and southern marshes.The identified species were classified as four species of Family Aeolosomatidae, 54 species of Naididae ( 31 Naidinae , 8 Pristininae and 15 Tubificid worms), one species of each of Lumbriculidae ( Lumbriculus variegates ) and Lumbricidae ( Eiseiella tetraedra). Among Aeolosomatidae , Aelosoma aquaternarium, A. Liedyi, A. variegatum and A. hemprichi, in which, A. variegatum was the most frequent species, found in Euphrates river. Naidinae community were represented by five species of genus Chaetogaster, two species of each of Paranais, Slavina, & Stylaria, four species of Allonais , and seven species of each of Dero and Nais, in addition to Stephensoniana trivandrana, Specaria josinae and Ophidonais serpentina. Nais variabilis was the most abundant and frequent species in River Tigris while Stylaria lacustris & Ophidonais serpentina are abundant in River Euphrates . Species of Pristininae were representative by four species of genus Pristina and three species of genus pristinella, among them Priatina longiseta is the most abundant species.Tubificid worms, Branchuira sowerbyi and Limnodrilus hoffmeisteri were the most frequent and abundant species in the surface sediments of Iraqi waters. Beside L. hoffmeisteri , other five species of Limnodrilus, two species of Potomothrix, and a single species of Tubifex tubifex , Embolocephalus velutinus, Aulodrilus piguetia, Psammoryctides moravicus and Rhyacodrilus coccineus were recorded.


1972 ◽  
Vol 180 (1061) ◽  
pp. 407-419 ◽  

A number of detailed studies of the effects of heated discharges from power stations on the temperature, chemistry and ecology of British rivers have been carried out since 1965. This paper deals mainly with the Rivers Severn and Trent. In the Severn, a relatively clean river, temperatures up to 28°C below Ironbridge Power Station outfalls have not affected the diversity of the invertebrate fauna. There were slight alterations in the hatching of insect nymphs which may have been attributable to temperature, though natural variations from year to year were much more obvious. Emergence of adult Ephemeroptera and Trichoptera was not affected by temperatures of 26 to 28°C. The River Trent is used for cooling by some 14 power stations. There are no obvious changes in the diversity of the invertebrate fauna which can be related to temperature, though pollution from other sources causes very marked changes. At Drakelow, in the most polluted reach, changes in the Oligochaete community were possibly attributable to temperatures below the outfall. Experiments showed that Limnodrilus hoffmeisteri had a wider temperature range for reproduction than Tubifex tubifex . Studies of fish populations at Peterborough have shown that many coarse fishes can withstand quite sudden and wide temperature fluctuations.


1973 ◽  
Vol 30 (5) ◽  
pp. 617-622 ◽  
Author(s):  
K. E. Chua ◽  
R. O. Brinkhurst

Determination of respiration of Tubifex tubifex, Limnodrilus hoffmeisteri, and Peloscolex multisetosus in the laboratory provided evidence of interspecific interactions between two tubificid species. The same individuals in mixed species culture respire significantly less than in pure culture. The effector of the interaction in the one interaction between T. tubifex and L. hoffmeisteri is waterborne, smaller than 0.45 μ, and it is rendered ineffective by heating at 60 C for 20 min.


1980 ◽  
Vol 37 (4) ◽  
pp. 656-663 ◽  
Author(s):  
Lakeram Chatarpaul ◽  
John B. Robinson ◽  
Narinder K. Kaushik

Labeled nitrate-N in the form of K15NO3 was used to determine the effects of the tubificid oligochaetes, Tubifex tubifex and Limnodrilus hoffmeisteri, on the N transformation processes in stream sediment contained in laboratory columns. Denitrification and nitrification occurred simultaneously and were enhanced significantly in the presence of the worms. The denitrification rate over 48 d at 15 °C in the sediment that contained the worms was 90 mg N/m2∙d−1; the simultaneous rate of nitrification was 69 mg N/m2∙d−1. The corresponding rates for denitrification and nitrification in sediment without worms were 50 mg N/m2∙d−1 and 29 mg N/m2∙d−1. The rate of CO2 evolution from sediment containing worms and overlain with nitrate-N solution was about 21% greater than that of sediment with worms overlain with distilled water. It was concluded from experiments using chloride as tracer that denitrification could be enhanced by the worms at least in part as a result of accelerated movement of nitrate-N into the sediment. However, when a column of glass beads was used as substrate for worms, and with no organic matter present, the concentration of nitrate in an overlying solution declined at an appreciable rate. This suggested that denitrification occurred in or on the worms, a possibility supported by the observation that denitrifying bacteria could be isolated from both the exterior and the gut contents of the worms.Key words: tubificid worms, stream nutrient cycling, denitrification, nitrogen cycling


2013 ◽  
Vol 10 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Baghdad Science Journal

The present investigation is concerned primarily with sorting and identification of subfamily Tubificinae from River Tigris and some water surface in Baghdad /Iraq . For this purpose six study sites were chosen, including a Al- Kadhemyia drainage canal, North Baghdad; three sites on the shore of River Tigris; in addition to site in Al-Jaish canal , East Baghdad, finally the sixth site was from pond in Al-Zawra'a park , within the center of Baghdad .These sites were characterized by sediment rang from clay, silty-clay to silty with a percentage of organic matter ranged between 0.7% - 9.9% . According to water temperature, salinity and pH values, they were nearly identical in all study sites, the water temperature was ranged through the study period between 12.5 – 300 C , while electrical conductivity and salinity values were ranged beteen 733.5-1227.5 ?s ,which equivalent to 0.469-0.787 ‰ salinity. All sites were slightly alkaline ,so the pH values were ranged between 7.5-8.1. 3628 individuals were sorted from 24 samples collected from different study sites.. Twelve species were identified belonging to seven genera, including , Limnodrilus hoffmeisteri, L. claparedeianus, .L. profundicola, . L.udekemianus , L. silvani, Tubifex tubifex, Branchiura sowerbyi, Potamothrix. 2013 )2( ???? ????? ?????? ???? 10 982 bavaricus, , P. hammoniensis, Psammoryctide moravicus, Monopylephorus irroratus, and Rhyacodrilus coccineus. The result revealed that Al-Jaish canal and Tigris River / al-Sarafyia were considered as the richest sites according to the number of species recorded, where 8 species were recorded in each of them, but Al-Jaish canal had higher individual number of 1346 individuals , followed by Al-Kadhemyia drainage canal recorded only three species with high total individual number of 606 individual. The lowest total individual number was recorded in Tigris River / Al- Zaafaranyia of 326 individual. L. hoffmeisteri, records higher individuals number of 1870 individual , followed by B. sowerbyi which records 946 individual. Both species recorded highest percentage occurance of 100% followed by 79.16% recorded by L. profundicola. High densities of Tubificinae were recorded during all study period. The highest density was during March-April, reached between 2109 -534.9 ind/m2 in Tigris River sites , 7270.5 ind/m2 in Al-Jaish canal and 2419.8 ind/m2 in Al-Zawra'a pond. The .results of relative abundance revealed that L. hoffmeisteri was the dominant species in site Tigris River/Al- Jaderyia, and abundant in other study sites. B. sowerbyi was abundant in all study sites, while other species were recorded between few to rare species except L. udekemianus which was abundant in site Al-Jaish canal, and T. tubifex in site Tigris River / Al- Zaafaranyia.


1989 ◽  
Vol 46 (2) ◽  
pp. 223-231 ◽  
Author(s):  
J. A. Robbins ◽  
T. Keilty ◽  
D. S. White ◽  
D. N. Edgington

Sediment cores taken at 15 sites within the three main depositional basins of Lake Erie from 1976 to 1982 were sectioned in 1-cm intervals and analyzed for the abundance and vertical distribution of benthic organisms, 137Cs, and 210Pb (in some cores) and for surficial (upper 2 cm) organic and inorganic carbon. Zoobenthos populations were dominated (>85%) by tubificids (Limnodrilus hoffmeisteri, Quistadrilus multisetosus, and Tubifex tubifex) and varied in abundance from 6600 to 55 300 individuals∙m−2. The depth above which 90% of the individuals occurred correlated significantly with their abundance and with radiometrically determined mixed depths. Rates of sediment reworking by tubificids exceeded sedimentation rates by 5–80 times, indicating that worms alone can produce the observed zone of constant tracer activity at the sediment–water interface. Tubificid abundance was not significantly related to organic carbon but instead correlated strongly with the sediment accumulation rate and organic carbon flux. In Lake Erie the abundance of tubificids may be limited by the rate of supply of nutrients as measured roughly in terms of the organic carbon flux.


1970 ◽  
Vol 27 (11) ◽  
pp. 1971-1982 ◽  
Author(s):  
A. G. Appleby ◽  
R. O. Brinkhurst

The defecation rate of three tubificids is affected by temperature but the effect differs from species to species. Information on defecation rate and weight change at each experimental temperature suggests an optimum temperature range of 14 C for Peloscolex multisetosus, 18 C for Tubifex tubifex, and greater than 20 C for Limnodrilus hoffmeisteri. Downward trends of defecation rate with time were recorded for P. multisetosus, but these were probably due to lowered activity prior to the observed mortality. Upward trends in defecation rate with time in L. hoffmeisteri may indicate continuing acclimation to experimental conditions beyond their 10- to 14-day duration, or a need to process increasing amounts of less nutritious mud because of selective feeding on the richer fractions at the beginning of the assay period. Data on the relative abundance and distribution of species in Toronto Harbour is used to estimate defecation rates of the tubificid populations in the field.


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