bluuebunny/crossref_metadata_2025_split huggingface dataset:
A survey of the macro‐fauna of the River Cynon, a polluted tributary of the River Taff (South Wales)
Authors: LEARNER M. A. , WILLIAMS R. , HARCUP M. , HUGHES B. D. 
Published: May 2006

SUMMARY(1) A survey of the macro‐invertebrates and fish in the River Cynon, a trout stream in south‐east Wales receiving industrial and domestic wastes, and nine of its tributaries, was carried out in the summer of 1970. Its principal purpose was to describe the structure of these communities before waste treatment facilities, in course of construction, reduce the degree of pollution.(2) The macro‐invertebrate communities changed dramatically at station C4, there being a very varied fauna upstream and one dominated by chironomids and oligochaetes downstream, principally Nais barbata., Cricotopus bicinctus and Syncricotopus rufiventris. It seems likely that coal particles, influencing the substrate, are largely responsible for this change. Further downstream, and below substantial organic discharges, tubificids and the enchytraeid, Lumbricillus rivalis, became increasingly abundant. The total density of macro‐invertebrates increased from about 2000/m2 in the headwaters to over 20,000/m2 in the lower reaches.(3) The fauna of the clean tributaries, Hir (C16) and Wenallt (C19) was similar to that ofthe unpolluted upper reaches ofthe Cynon (C1‐C3) whereas that of tributaries affected by coal particles was similar to the fauna of the Cynon downstream of C4.(4) Six species of fish were recorded (bullhead, eel, minnow, trout, stickleback and stoneloach) of which tbree (bullhead, eel and trout) were confined to reaches upstream (C8 and above) of industrial eflluents at Abercwmboi. For 0–8 km downstream of these effluents the river was fishless and further downstream, to the confluence with the River Taff, fish density and biomass were reduced.(5) In the upper Cynon and its tributaries the density and biomass of trout were within the range recorded elsewhere in the British Isles. The growth rate of trout in the catchment is low. Diflerences in growth rate and shape of trout in the main river and tributaries suggest that there is little interchange between these areas, except perhaps with very young fish. 0 +* fish were only caught in abundance at two tributary stations and their numbers, even if widely distributed, could not permanently support the current density of older fish throughout the upper catchment.(6) Stone loach and minnow reached a very large size and individuals caught of the latter species approached the maximum recorded length for the British Isles.
The autecology of the chub, Squalius cephalus (L.), of the River Lugg and the Afon Llynfi
Authors: HELLAWELL J. M. 
Published: May 2006

SUMMARY(1) Seasonal variation in the intensity of feeding activity was demonstrated in two chub populations. Feeding activity was higher in summer and more pronounced in the young age‐classes. The intensity of feeding activity was significantly correlated with temperature.(2) The diet of the total chub populations embraced a wide range of food items but vegetable material predominated. Substrate material was frequently encountered which suggested considerable feeding on the river bed. Fish were the most important animal food, by volume, in the River Lugg but Trichoptera larvae were most important in the Afon Llynfi. No remains of salmon parr or trout were found in chub stomachs but grayling were eaten. The most important prey fish, by volume, was the eel but cyprinids, especially minnows, were most important by frequency of occurrence.(3) Seasonal variation in the composition of the diet could be related to availability of food organisms but some selection was shown. Vegetable foods were most important in summer; animal foods, Trichoptera larvae in particular, were important in winter.(4) Analysis of the variation in the composition of the diet with age revealed several trends, notably a decrease in the importance of plant material, aquatic and aerial insects with age and a corresponding increase in the importance of larger prey foods such as fish, frogs and crayfish.(5) The commonly held view that chub are deleterious to salmonid stocks was examined. The absence of direct predation and the small likelihood of direct competition suggests that this view is incorrect.
Phosphorus availability and nitrogenase activity in aquatic blue‐green algae
Authors: STEWART W. D. P. , ALEXANDER GAIL 
Published: May 2006

SUMMARYMetabolically active phosphorus‐starved cultures of blue‐green algae assimilate 32P rapidly in the light and in the dark. The uptake of phosphorus results in a rapid (within 15 min) stimulation in acetylene reduction by Anabaena cylindrica, A. flosaquae, Anabacnopsis circuiaris and Chlorogloea fritschii, with a response being obtained to less than 5 μg/1 of phosphorus. Uptake of phosphorus also causes a rapid increase in respiration in the dark but not in photo respiration, and the size of the cellular ATP pool and the 14CO2 fixation rate both increase more slowly. The metabolism of phosphorus‐sufficient cells, which assimilate phosphorus more slowly, shows little response when phosphorus is provided.Excess phosphorus is stored in the vegetative cells of blue‐green algae as polyphosphate bodies which may form within 60 min of adding phosphorus to phosphorusstarved cells and which serve as a source of phosphorus for the algae when exogenous phosphorus is limiting. Preliminary results from Scottish waters suggest that urban effluents are important sources of available‐phosphorus for algal growth and that the levels entering fresh waters from agricultural land are, per unit volume, lower. In both types of water the levels of available‐phosphorus are rather similar to the levels of orthophosphate‐phosphorus present. Most detergents tested serve as a source of phosphorus for nitrogen‐fixing blue‐green algae and cause a rapid stimulation in reduction when added to phosphorus‐starved cultures. Of the detergents assayed, the biological types were richest in available phosphorus. The addition of detergents may result in a rapid increase in number of polyphosphate bodies present in the algae. Detergents in general also contain an inhibitor of algal metabolism. Whether a stimu‐lation or an inhibition occurs depends on the quantities of detergent added and on whether or not the alga is phosphorus‐deficient.
The Ephemeroptera of the River Bela, Westmorland
Authors: COLLINS J. M. 
Published: May 2006

SUMMARYThough larger and more calcareous than a Lake District Beck, the River Bela now harbours a similar community of Ephemeroptera. Three species characteristic of small rivers were not recorded after the sides had been straightened and cleared of emergent vegetation and the bottom had been levelled.
The effects of sand deposition upon the macroinvertebrate fauna of the River Camel, Cornwall
Authors: NUTTALL P. M. 
Published: May 2006

SummaryErosion from a tributary of the River Camel deposited an estimated 10,000 m3 of sand in the main river over a period of 2 years. The poor incidence of plants and macro‐invertebrates from the river was associated with the unstable shifting nature of the sand deposits, rather than turbidity or abrasion caused by particles in suspension. Sand deposition accounted for the low diversity of invertebrate species below the tributary, and resulted in the elimination of several species which were frequent upstream. Baetis rhodani, Rhithrogena semicolorata, and Tubificidae were abundant where sand deposition had occurred.
An examination of subspecific differences in the merus of the fifth walking leg of the amphipod Gammarus duebeni Lilljeborg
Authors: SUTCLIFFE D. W. 
Published: May 2006

SummaryStock SL Pinkster (1970) erected two subspecies of Gammarus duebeni primarily on the basis of a difference in the relative dimensions of the merus on the fifth walking leg. The diagnostic feature was given as the ratio of merus length/width, with ratio < 2 in G. duebeni duebeni and ratio > 2 in G. duebeni celticus. It is shown here that the ratio varies with the size of the animal, and this particular ratio is therefore not valid as a taxonomic character.Regressions of log merus width on log merus length were made on large samples of G. duebeni assumed to belong to subspecies celticus and duebeni respectively. The regressions were significantly diiferent and were used to predict that the ratio log merus width/log merus length is relatively constant in both subspecies. Diagnostic values for this ratio were 0.71–0.73 in celticus and 0.74–0.77 in duebeni. The ratio was also determined in small samples of G. duebeni from other localities in western Britain.The morphological difference which characterizes celticus and duebeni was not associated with habitat salinity or with previously determined physiological characteristics. It may be an instance of cHnal variation reinforced by geographical isolation.Regressions of merus length against cephalic length suggest that the relative growth rates of the merus may also differ in the two subspecies.
Assessment of two mesh sizes for interpreting life cycles, standing crop, and percentage composition of stream insects
Authors: ZELT KENNETH A. , CLIFFORD HUGH F. 
Published: May 2006

SummaryUsing Surber‐type samplers and dip‐net samplers, we assessed the efficiency of nets having pore sizes of 720 μm and 320 μm for determining standing crop and percentage composition of the stream fauna, and for collecting representative size‐class specimens of Ephemeroptera and Plecoptera to be used in life‐cycle studies. Except for one species, samples collected with either the 720‐μm or 320‐μm dip‐net led to the same general inferences about the species' life cycle. Of fifty possible sample comparisons, there were twelve samples where the size‐class frequencies of particular species collected in the 720‐μm dip‐net were significantly different from the size‐class frequencies of the 320‐μm dip‐net; for five of these samples a deficit of large nymphs (> 5.0 mm) in the 320‐μm net mainly contributed to the significant χ2 values. On one date, we used double‐bag samplers with both th e 720‐μm and 320‐μm nets attached to either the Surber or dip‐net sampler. Approximately 50% of the insects by numbers passed through the 720 fxm mesh ofeach sampler, but only 5% by volume‐biomass. Shape of the insect as well as body length was important in assessing mesh‐size efficiencies. The 720‐μm mesh of the double‐bag dip‐net sampler retained most of the Nemoura dnctipes (having stout appendages) and Epeorus longimanus (flattened) nymphs 2.0 mm in body length and larger; whereas most Baetis (streamlined) nymphs smaller than 3.0 mm and all Paraleuctra (needle‐like shape) nymphs passed through the 720‐μm mesh.
The life cycles of Leptophlebia vespertina (L.) and L. marginata (L.) (Ephemeroptera) in Llyn Dinas, North Wales
Authors: BRITTAIN J. E. 
Published: May 2006

SummaryData is presented on the life cycles of Leptopblehia vespertina (L.) and L. marginata (L.) in Llyn Dinas, an oligotrophic North Wales lake. Both species are univoltine and growth continues throughout the winter although somewhat retarded. Except during July and August there is a clear size separation of the two species, L. marginata being larger and emerging earlier. The egg incubation period was determined directly from laboratory studies. The results are discussed in relation to previous research in the English Lake District.
Studies on Gull Lake, Michigan
Authors: MOSS BRIAN 
Published: May 2006

SummaryThe seasonal and depth distribution of phytoplankton in Gull Lake, a moderately large, temperate, dimictic, recreational lake in southern Michigan, U.S.A., is described and discussed. Diatoms (Fragilaria crotonensis, Cyclotella michiganiana, Asterionella formosa, and Synechococcus) grow mainly in summer. Diatoms grew under the winter ice, and objections are lodged to the classic explanation of seasonal growth in temperate lakes, and to a recent hypothesis concerning the `paradox of the plankton'. Two raphe‐bearing large diatom species were considered to be truly planktonic. A Synechococcus species was similar to that described previously only from Loch Leven.
A relative growth index of hybridization in sunfishes (genus Lepomis, Centrarchidae)
Authors: MISRA R. K. , HOLDSWORTH C. 
Published: May 2006

SummarySunfish specimens (genus Lepomis) collected from Pinehurst Lake, Ontario, Canada, were identified as bluegill (L. macrochirus), pumpkinseed (L. gibbosus) and their hybrids. Hybridization was studied on the basis of the constants of cross‐sectional allometry as, to the best of our knowledge, no attempt has ever been made to study hybridization quantitatively from the relative growth aspect. Two sets of data‐‐‐one on the pair Y1/X (head length/standard length) and the other on the pair Y2/X (body depth/standard length)‐‐‐ were analysed, with the following objectives: (i)A statistical method of analysing hybrid index based on cross‐sectional allometry was first presented and then Y1/X‐data analysed by this method, and (ii)data Y2/X were analysed to show that in some particular situations analysis for hybridization by methods other than the hybrid index appraoch may be more appropriate. Results of the analyses were discussed.
Further studies on the occurrence of freshwater Microturbellaria in the British Isles
Authors: YOUNG JOHNSTONE O. 
Published: May 2006

SummaryFive new British records of freshwater Microturbellaria are illustrated: Gieysztoria infundibuliformis, Castrada lanceola, Castrada neocomensis, Castrada viridis and Strongylostoma elongatum. These species together with a new species, Macrostomum johni described by Young (1972), are woven into the fabric of the existing key for the group (Young, 1970). All six species were recorded from the littoral zone of lakes in Caernarvonshire, N. Wales. The times of the recordings are indicated.
Effects of the herbicide paraquat on the ecology of a reservoir
Authors: BROOKER M. P. , EDWARDS R. W. 
Published: May 2006

SummaryThe application of paraquat (1.0 mg/l) to a fishing reservoir was successful in controlling the angiosperms, Potamogeton pectinatus and Myriophyllum spicatum, but a second application (0.6 mg/l) failed to control a replacement growth of the macro‐phytic alga, Chara globularis.Paraquat was quickly lost from the water after each application and was largely taken up by the sediments, never more than 6% ofthe initial dose being recorded from the macrophytes. Final analysis of the sediments indicated that about 36% of the total amount of paraquat applied to the reservoir was not recovered.Some changes in the chemistry ofthe water after the first application of paraquat were consistent with the death of the plants (e.g. alkalinity), but there was no evidence that the subsequent decay ofthe plants produced large increases in the concentrations of major nutrients in the water. Although there was no gross deoxygenation there were changes in the oxygen status of the water following the herbicide‐induced death ofthe angiosperms.Estimates of the biomass and net productivity of the macrophytes were made.
The biology and life cycle of Nemoura avicularis Morton (Plecoptera)
Authors: BRITTAIN JOHN E. 
Published: May 2006

SummaryData are presented on the biology and life cycle of Nemoura avicularis Morton in a North Wales lake, Llyn Dinas, and in the laboratory. Aspects of egg, nymphal and adult biology are described and discussed. Special attention is given to the early instars. The life cycle in the field was followed for a 2‐year period. Eggs hatched during April, May and the first half of June, and growth then continued more or less continuously until late January when the nymphs were fully grown. Emergence, however, did not begin until March, reaching a peak in April and continuing into the early part of May. In the laboratory N avicularis was reared through its life cycle from egg to adult. The results of the present study are discussed in relation to previous research on the biology and life cycle of N. avicularis.
Studies on mountain streams in the English Lake District
Authors: SUTCLIFFE D. W. , CARRICK T. R. 
Published: May 2006

SummaryComparisons are made of pH and the concentrations of major ions in streamwater from Brownrigg Well (the source of Whelpside Ghyll) and from the River Duddon. pH in Brownrigg Well is usually >5.7, but the concentrations of sodium, potassium and possibly calcium are near to the minima required to support the amphipod Gammarus pulex. In contrast most insect taxa are not affected by low ionic concentrations. It is postulated that these had a wider distribution in mountain streams prior to the acidification of poorly buffered waters by acid rainfall resulting from large‐scale combustion of fossil fuels.
Numerical indices applied to the results of a survey of the macro‐invertebrate fauna ofthe Tamar catchment (southwest England)
Authors: NUTTALL P.M. , PURVES J.B. 
Published: May 2006

SummaryA survey ofthe macro‐invertebrate fauna in the River Tamar revealed that a division ofthe catchment can be made which separates an organically enriched upper region from a more stable environment in the lower tributaries and reaches. Invertebrate species normally associated with organic pollution were found immediately downstream from farm waste and sewage effluent outfalls. Invertebrate species normally associated with an unpolluted condition were widely distributed throughout the catchment, and revealed that the Tamar is essentially free from gross pollution causing the continuous elimination of stream fauna. Systems used by pollution control organizations to codify biological results are reviewed and applied comparatively to the results. The Diversity index was found to be the most consistent method in assessing the biological state of the river. The Trent, Lothian, Chandler and Carpenter indices were found to give either anomalous figures or proved insensitive to conditions beyond a certain quality.
Silicon depletions in some Norfolk rivers
Authors: EDWARDS A. M. C. 
Published: May 2006

SummaryWater samples collected weekly from the rivers Yare, Tud, Wensum and Tas in Norfolk, England, displayed marked depletions in the spring and summer of the concentration of dissolved silicon. These were unconnected with any hydrological event and were assumed to be due to the assimilation of silicon by diatoms. Equilibrium concentrations were maintained in the Yare and Tud during the weeks prior to and following the spring bloom. It was estimated that 35 Mg (51%) of the predicted load were removed from the Yare during the 11 weeks of this depletion and 6‐0 Mg (45%) from the Tud. The lowest observed concentration (0‐4 mg/l) occurred during the first week in May when over 90% of the silicon had been removed. However, the maximum amount of removal and hence maximum diatom productivity occurred earlier at a time of higher water discharge. A similar pattern was observed in the Yare during the spring of 1971. Two small blooms occurred later in the summer of 1970 in the Yare and Tud. It was estimated that 15% ofthe Yare's dissolved silicon load of 263 Mg was in the assimilated form and 12‐5%of the Tud's output of 56‐6 Mg. The weathering of silicate minerals was probably the source of almost all the silicon and the outputs represented a silicon erosion rate of 1‐15 Mg/km2/year for the Yare and 0‐77 Mg/kmVyear for the Tud.
Studies on energy transformation in the freshwater snail Pila globosa
Authors: VIVEKANANDAN E. , HANIFFA M. A. , PANDIAN T. J. , RAGHURAMAN R. 
Published: May 2006

SummaryThe effects of eleven chosen feeding levels ranging from 0 to 198 mg damp dry (plant) Ceratophyllum/g live snail/day on the absorption, conversion and metabolism of the snail Pila globosa (of 1 ‐9 g body weight) have been studied. Absorption rates increased from 3‐0 to 21‐0 mg dry food/g live snail/day in snails fed 3‐4‐28‐8 mg dry food/g live snail/day. In these snails, absorption efficiency decreased from 87.5 to 73.0%. Conversion rates increased from 0‐3 mg/g/day for snails receiving 23‐4 mg/g/day to 2‐7 mg/g/day for those fed maximum amounts, and the efficiency (K2) also increased from 1‐9% to 130%. When compared to other gastropods, Pila globosa appears to be a poor convertor. During 30 days' starvation, the test individuals lost 4.4 mg dry body substance/g/day i.e. the maintenance cost was 14‐7 cal/g live snail/day. The SDA increased by four times for those feeding on maximum rations in comparison to those receiving about 5 mg/g/day, i.e. the energy cost for converting food was increased four times.
Effect of a fulvic acid fraction on the growth of aPseudomonasfrom Tjeukemeer (The Netherlands)
Authors: DE HAAN H. 
Published: May 2006

SummaryIn this paper the effect of a fulvic acid fraction on the growth of a Pseudomonas sp. from fresh water is reported. The presence of fulvic acid in the culture medium caused an increase in the cell yield and in the cell yield per μl O2taken up by the Pseudomonas. The observed stimulating effect has been explained in terms of co‐metabolism of fulvic acid by the Pseudomonas.
The metazoan fauna of a sewage‐carrying wadi, Nahal Soreq (Judean Hills, Israel)
Authors: BROMLEY H. J. , POR F. D. 
Published: May 2006

Summary(1) An analysis of the metazoan fauna of Nahal Soreq was made at several sampling stations from October 1970 to August 1971. Relative abundance of each species or group of species was estimated by semi‐quantitative sampling, and population structures are given here in the form of percentage tables. (2) A succession of three zones, indicating three degrees of pollution, were recognized: a ‘Nematode zone’ in the most polluted waters, a ‘Chironomus zone’, where purification has progressed a little, and a ‘Proasellus (and ostracod) zone’, where purification is nearing completion. (3) These zones of indicator organisms roughly correspond to three zones classified in a ‘Saprobien System’ manner: a polysaprobic zone (Nematode zone), a mesosaprobic zone (Chironomus zone), and an oligosaprobic zone (Proasellus zone). A state of complete purification or recovery is not reached, and the purification process is stopped in the oligosaprobic condition by the disappearance of the stream underground. The other invertebrates characterizing these three zones are given. (4) A comparison is made of the saprobic zones and their corresponding fauna with findings reported elsewhere‐‐‐Europe, North America and South Africa. The successional changes are generally similar to European findings with some notable absentees, and there are also some similarities with polluted South African streams. (5) Seasonal changes in species composition and the position of these species along the stream are discussed. There are small changes which appear to be a result of life cycle habits in some air‐breathing dipterans and a slight change in the position of chironomids downstream, which is correlated with the winter rain floods. (6) The faunal types and numbers occurring downstream are compared with the increase in algal species diversity, dissolved oxygen and coli bacterial counts. It is suggested that the degree of pollution is the primary factor in the establishment and population build‐up of any particular species, but that presence of suitable substrates, availability of food and presence of predators play a larger part where the water is cleaner.