bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coidingham Loch, S.E. Scotland
Authors: BAILEY‐WATTS A. E. , KIRIKA A. A. LYLE. A. , WISE* E. J. 
Published: May 2006

SUMMARY. 1. Coidingham Loch (Berwickshire. Scotland) (area. 8.4 ha, mean depth 2.9 m, max. depth 12.3 m) belongs to Hakansson's convex shape category. It lies in a basin of Silurian Greywackes rock within 0.25 km of coastal sea cliffs (c. 133 m a.s.l.). The theoretical hydraulic replacement time is 3.17 years.2. The loch stratifies intermittently in summer. Fluctuations in oxygen concentration generally correspond to spells of mixing and stratification; low values of 10% saturation occur at the bottom.3. The sum of the concentrations of major cations (Na+, K+, Ca2+, Mg2+) is in accordance with measured conductivities ranging between 380 μS cm−1 and 420 μS cm−1 (k.25). The ratios (by equivalents) of Na+/Cl− (0.04) are similar to those in sea‐water, whilst values for Ca+2+/Cl− (0.85–1.01) and Mg2+/Cl− (0.79–0.88) reflect the bedrock.4. Nitrate concentrations were lowest (<0.05 mg N1−1) in summer following losses from the column of 107 mg N m−2 1−1, a rate corresponding well with published figures on microbial nitrate reduction. Nitrate increased at a rate of 8μg N I−1 d−1 to a winter maximum of 1.55 mg N I−1. Mass balance calculations show that if this rise is attributed to run‐off from surrounding land, a loss rate of 11.1 kg N ha−1 yr−1 would be required; this value is also commensurate with published figures.5. Changes in phosphorus and factors controlling them contrast markedly with those of nitrate. The minimum concentration of 55 μg total P l−1 (mainly in soluble reactive form) occurs in spring. An increase to the maximum ofc. 300 μg l−1 in summer is sustained mainly by release from the sediments at a regular rate of 3 μg P l−1 d−1 (8.7 mg m−2 d−1). Adsorption by the sediments is considered to be the major process accounting for autumnal losses of phosphorus of 2.6 mg P M−2d−1.6. Silica showed a less regular seasonal pattern, but varied some 45‐fold with a maximum of 2.25 mg SiO2, l−1 in August.
The biology and life cycles of Lipsothrix spp. (Diptera: Tipulidae) inhabiting wood in Western Oregon streams
Authors: DUDLEY TOM L. , ANDERSON N. H. 
Published: May 2006

SUMMARY. 1. The immature stages of the craneflies Lipsothrix nigrilinea and L. fenderi are spent in galleries within decayed red alder (Atntts rtibra), in low order streams of the Pacific Northwest. L. fenderi also occurs in some coniferous wood and wood in semi‐terrestrial sites at stream margins. Larvae of both species feed on the wood and are important degraders of this material.2. The immature stages are briefly described and behaviour of the two species is compared.3. L. nigrilinea has a predominantly biennial life cycle. It emerges from April to August in response to receding water level. The absence of this cue results in an extension of the life span to 3 or more years. The non‐deterministic life cycle results in high variability of juvenile and adult weights.4. L. fenderi is basically a biennial species, with a more synchronized autumn emergence. A portion of the population may emerge after 1 year if oviposition occurs early enough to allow autumnal growth of larvae or if growth is relatively rapid.5. The extended life cycle of Lipsothrix spp. and the broad emergence of L. nigrilinea are concluded to be adaptations to a habitat/resource which is relatively stable and allows long‐term association.
Variability In the rate of egg development of the stonefly, Nemoura cinerea (Plecoptera)
Authors: EBRITTAIN JOHN , LILLEHAMMER ALBERT 
Published: May 2006

SUMMARY. 1. The egg development of the widely distributed European stonefly. Nemoura cinerea Retzius. was investigated in the laboratory. There was a significant relationship between water temperature (T°C) and incubation period (Ydays), expressed by the regression equation: Y= 239 T−0.85 (r2= 0.85. P<0.001).2. The number of day‐degrees above 0°C required for hatching showed a curvilinear relationship with water temperature, with a minimum requirement around 12°C.3. Nemoura cinerea shows more variation in the rate of egg development than most other stoneflies. This, in part, explains the wide size range in nymphal populations and the species’ extended emergence period. Flexibility in life cycle and asynchrony in egg development enable this species to colonize a wide range of freshwater habitats.
Importance of hydrogen ions and aluminium in regulating the structure and function of stream ecosystems: an experimental test
Authors: HALL RONALD J. , DRISCOLL CHARLES T. , LIKENS GENE E. 
Published: May 2006

1. Experiments simulating spring acidic snowmelt episodes were conducted to determine the effects of short‐term inputs of H+and Al on the chemistry and biology of a poorly buffered mountain stream. HC1 and A1C13were added in separate experiments to first‐ to third‐order reaches of a New Hampshire stream.2. Cation exchange and Aln+dissolution reactions neutralized experimentally added H+, whereas groundwater dilution was insignificant. Mobilized Ca++, Mg++and Aln+concentrations progressively increased from third‐ to first‐order reaches during HC1 additions. Mobilization of Ca++and Mg++was greater during A1C13than HC1 addition.3. Total phosphorus was mobilized from stream sediments during both HCI and A1C13addition. Dissolved organic carbon (DOC) decreased during A1C13addition in the second‐order but not in the third‐order reach. DOC concentration decreased during HCI addition only when Aln +mobilized from the stream bottom was >0.28 mg AI 11.4. Production of foam at the water surface during AlCl3addition to a second‐order and HCl addition to a first‐order reach indicated a reduction in surface tension of the streamwater and may be related to complexation reactions between Al and DOC at low pH (4–5).5. Mayfly nymphs and blackfly and chironomid larvae drifted at greater rates from HCl‐ and AlCl3treated sections of first‐ and second‐order streams than from corresponding reference areas.6. When stream pH was lowered to 5.25–5.5 by HCI alone (15 μg monomeric inorganic Al l−1), the behaviour of aquatic invertebrates did not change, but pH reduced to the same range during Al additions (280μg Al 1−1) did affect it. Therefore, fluctuating aluminium concentrations in low‐order streams at a pH range of 4.5–5.5 may alter the biology and geochemistry of poorly buffered waters.
The diversity of macro invertebrate and macrophyte communities in ponds
Authors: FRIDAY LAURIE E. 
Published: May 2006

SUMMARY 1. The range of factors which may influence the wide variation in the structure of pond communities is reviewed.2. Factors explaining the variation in numbers of macro invertebrate and macrophyte taxa are investigated, using multiple regression analysis, for a group of ponds in which biogeographical effects are likely to be minimal.3. Numbers of macro invertebrate taxa in these ponds are highly correlated with pH and probably, therefore, with other associated aspects of water chemistry,4. Many invertebrate taxa, from species to entire phyla, were not found below pH 5.5, but few characteristically‘acidophilic’taxa were apparent.5. Details of species composition of the macro invertebrate fauna differ widely even between ponds of similar pH.6. The diversity and composition of macrophyte communities are not adequately predicted by any of the factors investigated.
The role of drift and effect of season on macroinvertebrate colonization of implanted substrata in a tropical Australian stream
Authors: BENSON L. J. , PEARSON R. G. 
Published: May 2006

SUMMARY 1. Experiments using implanted substrata were conducted in Yuccabine Creek, a n upland stream in north‐eastern Australia which exhibits a strong seasonal pattern of discharge and temperature. The implanted substrata were either set in the stream bed or were raised in the water column. Three experiments were run, at different times of the year.2. Colonization rate was dependent on benthic abundance, mobility of the fauna and distribution of resources. The rates on embedded trays were similar in the late wet season and mid dry season, but colonization rate in the late dry season was greater.3. Drift alone could have accounted for all colonization in the late wet season, 63% of colonization in the mid dry season and less (unmeasured) in the late dry season. Drift acts to disperse early instars to patches of suitable habitat after the summer wet‐season peak in reproduction.4. Following the wet season, stream discharge decreases, benthic abundance increases, resources become more concentrated, and movements of animals in contact with the substratum play an increasingly important role in colonization.
Sizes and daily growth rates of two algal phytoplankters in the field
Authors: COBELAS M. ALVAREZ , VELASCO J. L. , RUBIO A. , ACOSTA F. J. 
Published: May 2006

SUMMARY 1. Measurements of daily growth rates, colony widths and lengths and cell widths and lengths were made on Fotterella tetrachlorelloides Buck and Staurastrum longiradiatum West & West (Chlorophyceae), collected from an eutrophic reservoir close to Madrid (Spain) on nine consecutive days of June 1983.2. F. tetrachlorelloides exhibited growth followed by a period of decay, whilst S. longiradiatum grew more or less continuously throughout the observations.3. A colony length‐width relationship was statistically significant throughout the growth period of F. tetrachlorelloides, but not when the population was decaying. This relationship was always statistically significant in S. longiradiatum. There was an inverse relationship between volume and daily growth rate in S. longiradiatum, but no such correlation was found in F. tetrachlorelloides.4. The time course of statistical volume distributions and daily growth rates suggested that F. tetrachlorelloides was undergoing clonal ageing during the study.
Lake sediment microlaminae and annual mortalities of photosynthetic bacteria in an oligomictic lake
Authors: DICKMAN MIKE 
Published: May 2006

SUMMARY 1. A novel mechanism of microlamina formation in oligomictic lakes is proposed. During spring and summer in Zaca Lake, an oligomictic lake in Santa Barbara, California, a light‐coloured microlamina is formed. During winter, a mass mortality of sulphur‐rich phototrophic bacteria occurs following the ventilation of the chemocline or the overturn of the lake. When this occurs, oxygen is introduced into the chemocline killing most of the anaerobic bacteria. When these sulphur‐laden bacteria die and settle to the bottom of the lake, they form a black microlamina which is rich in ferrous monosulphides.2. The varved stratigraphy of the Zaca Lake sediment core presents an opportunity to correlate stratigraphic events in the lake's varved sediments with events reported for its catchment over the last 200 years.3. Colonization by Europeans dates back to the 1760s, making this one of the best‐documented histories for a small lake in North America. A number of events have been correlated with stratigraphic information from the lake's varved cores.4. Eutrophic diatom indicator species disappear downcore, where they are replaced by meso‐ and oligotrophic indicators. In addition, pollen from exotic trees planted in the lake's catchment appears at specific core depths associated with their pollen production stage.
Distribution and life cycles of cladocerans in temporary pools from Central Italy
Authors: CROSETTI D. , MARGARITORA F. G. 
Published: May 2006

SUMMARY 1. A study of twenty‐nine temporary pools located in a nature reserve in Central Italy was carried out for two successive years (1982–83 and 1983–84) to determine the distribution and life cycles of the cladocerans they contained.2. The pools followed a typical autumnal cycle, filling up in early autumn and drying up in late spring. They differed in morphology (size, depth, type of soil) and in the length of the wet phase.3. Nineteen cladoceran species were found. A few of these are early species, appearing at the beginning of the wet phase, whereas others appear much later in spring and these populations persist for a shorter time.4. Species distributions did not show any clear correlation with the ponds’morphological features, and the life cycles of individual species were similar in all ponds. Thus populations did not adapt life history patterns to match conditions in particular ponds.
Effects of predation by Chaoborus flavicans on crustacean zooplankton of Lake Lenore, Washington
Authors: LUECKE CHRIS , LITT ARNI H. 
Published: May 2006

1. After Chaoborus flavicans became established in 1974, the species composition of zooplankton in Lake Lenore changed. Diaptomus nevadensis disappeared and densities of Diaptomus siciliswere reduced.2. A transplant experiment showed the D. nevadensis could survive in Lake Lenore water in the absence of Chaoborus. The disappearance of D. nevadensis was probably a consequence of Chaoborus predation.3. Although densities of Daphnia pulicaria† were similar before and after the colonization of C. flavicans, juvenile D. pulicaria began producing neck‐teeth during the first summer Chaoborus was present.4. The seasonal pattern of neck‐teeth production by juvenile D. pilicaria did not correlate with density of Chaoborus but rather with a combination of water temperature and Chaoborus density, suggesting that metabolic processes are a component of induction of neck‐teeth in this species.
Population growth in some Mesostoma species (Turbellaria) predatory on mosquitoes
Authors: KOLASA JERZY 
Published: May 2006

SUMMARY 1. Turbellarian predators of the genus Mesostoma prey on the aquatic stages of mosquitoes. In order to evaluate their potential as control agents, a comparison of population parameters has been made on three species from Australia, Africa and Papua New Guinea: M. appinum, M. zariae and M. timbunke.2. The life cycle of these species is relatively short at higher temperature ranges (22–30°C) and varies from 12 to 35 days, depending on the temperature. M. appinum does not increase in numbers at 30°C, white M. timbunke is unable to reach sexual maturity at 15°C. M. appinum, but not M. zariae, multiplies slowly at 15°C, although both species survive at this temperature. The fastest population growth was obtained for M. appinum at 22°C, and for M. zariae and M. timbunke at 30°C. The doubling time for the population is about 6–7 days in the multivoltine species, M. appinum and M. zariae, and about 18.5 days in univoltine M. timbunke.3. A significant part of the growing population is composed of immature individuals, which corresponds to the high values of the reproductive parameters Ro and rm. In M. appinum and M. zariae, individuals rarely produce dormant resting eggs except under deteriorating conditions. M. timbunke produces only dormant eggs, and in this respect resembles arctic and subarctic species. A convergence of the reproductive modes between this equatorial species and the high latitude species might be interpreted as adaptation to harsh environments.4. The overall population growth of all Mesostoma spp. is several times faster than in Dugesia dorotocephala and D. trigrina, other flatworms studied as potential biological control agents of mosquitoes
Production and litter processing by crayfish in an Appalachian mountain stream
Authors: HURYN ALEXANDER D. , WALLACE J. BRUCE 
Published: May 2006

SUMMARY 1. Mean annual density and biomass (B̄) of Cambarus bartonii in an Appalachian mountain stream (U.S.A.) was 12 individuals m−2 and 1669 mg (ash‐free dry weight) m−2.2. Annual production (P) of C bartonii was 961 mg AFDW m−2. Despite high biomass, low growth rates resulted in low production and a low P/B̄ ratio of 0.58.3. While C bartonii constituted 61% of the total macroinvertebrate biomass, it contributed only 13% of annual community secondary production.4. Litter processing was positively related to temperature and crayfish size. Cambariis bartotnii was estimated to comminute 36 g m−2 y−1 of leaf litter (>1 mm2) to 24 g m−>2 y−1 fine particulate material (<1 mm2). The annual pattern of litter comminution by crayfish was regulated by temperature. As a result, >5()% of shredding activity by crayfish occurred from June to September which was also the period of lowest litter standing crops and activity of other shredding macroinvertebrates.5. We speculate that during summer crayfish play an important role in temperate woodland streams by converting slowly processed leaf litter species (e.g. Rhododendron) to fine particles which are then available to collector‐gatherers (e.g. Chironomidae, Oligochaeta).
Production of the three‐spined stickleback, Gasterosteus aculeatus L., in the River Weaver, England
Authors: O'HARA K. , PENCZAK T. 
Published: May 2006

1. The production of three‐spined sticklebacks, Gasterosteus aculeatus, estimated in the margin of a large channelized lowland river, averaged 42.3 g m−2 yr−1 and the P/B ratio was 3.7. The production value greatly exceeds those previously recorded for G. aculeatus and results from the very high population densities.2. Life‐bistory tactics of the sticklebacks included both r‐ and K‐selected traits.3. The fish were carnivorous in the summer months but predominantly detritivorous in the winter.
Effects of chronic chlorine exposure on litter processing in outdoor experimental streams
Authors: NEWMAN RAYMOND M. , PERRY JAMES A. , TAM ERIC , CRAWFORD RONALD L. 
Published: May 2006

SUMMARY 1. The effects of chlorine on litter (Potamogeton crispusL.) processing were examined using six outdoor experimental streams. Downstream portions of two streams were dosed at c. 10 μg l−1 Total Residual Chlorine (TRC), one stream at 64 μgl1, and one stream at 230μg l−1. Two control streams were not dosed; upstream riffles of each stream served as instream controls.2. Two 35 day litter breakdown (per cent AFDW remaining) experiments indicated significantly lower decay rates in the high dose riffle. No other concentration of chlorine significantly affected decay rate.3. A third experiment, conducted in medium and high dose streams, indicated that high dose chlorine exposure reduced litter decomposition rates significantly, and reduced microbial colonization, microbial electron transport system activity, and microbial litter decomposition after 4 days but not after 11 days of exposure. The number of amphipod shredders colonizing litter bags was also reduced significantly with high chlorine dose.4. A fourth experiment, after dosing was terminated, provided direct evidence that amphipod shredders were important in facilitating litter decomposition: litter bags stocked with amphipods had significantly higher decomposition rates than bags which excluded shredders.5. Overall results indicate that the high dose (c. 230 μgl−1 TRC) of chlorine reduced litter processing rates partly by reducing initial microbial conditioning, but primarily by reducing the colonization of amphipod shredders.
Laboratory breeding studies of freshwater crayfish, Austropotamobius pallipes (Lereboullet)
Authors: WOODLOCK BRIAN , REYNOLDS JULIAN D. 
Published: May 2006

SUMMARY. 1. Mature crayfish, collected from an Irish lake before breeding had started, were held in breeding combinations and their mating and brooding activities observed.2. All mating attempts were initiated by the male. A single mating led to spawning within 6 days but a subsequent mating cancelled the effects of the first. Males mated more often when there were more females present. Males lacking a major cheliped mated less often than did normal males.3. Larger males mated more often than did smaller males, and although males showed no female size preference, matings were less frequent and generally unsuccessful when males were much larger than females; the female was usually killed. Large females mated successfully with smaller males.4. Females held at high densities with a larger male mated earlier than at low densities. However, aggression also increased with density; at high densities males fought and killed females.5. Males held in pairs without females fought; in occasional mating attempts spermatophores were not positioned correctly. Paired females rarely fought; all spawned normally although unmated. Although their eggs soon died and were removed during grooming, brooding behaviour continued for at least 2 months.6. Brooding females held in pairs shed pleopodal eggs during aggressive encounters. Females held singly showed a lower initial rate of egg loss.
Effects of previous diet and frequency of feeding on development of larval damselflies
Authors: BAKER ROBERT L. 
Published: May 2006

SUMMARY. 1. Food availability during instar F‐3 affected duration of instar F‐3 of larval Ischnura vertiealis (Say) maintained in the laboratory but did not affect the increase in head width at the moult to instar F‐2.2. Food availability during instar F‐2 altered both duration in instar F‐2 and weight per unit head width of newly moulted F‐l larvae, but not the increase in head width at the moult to instar F‐1.3. Food availability during instar F‐3 had no effect on instar duration, weight per unit head width, or increase in head width of F‐2 larvae at the moult to instar F‐l.4. Survival of larval Coenagrion resolution (Hagen) reared in the laboratory was dependent on mean number of Daphnia offered per day. In addition, larvae fed less frequently, but on the same mean number of Daphnia per day. had lower survival rates than larvae fed more frequently.
Cadmium toxicity to the freshwater amphipod Gammarus pulex (L.) during the moult cycle
Authors: McCAHON C. P. , PASCOE D. 
Published: May 2006

SUMMARY. 1. The toxicity of cadmium to mature Gammarus pulex at different stages in the moult cycle is described.2. Immediate post‐moult animals are significantly more sensitive than intermoult specimens at cadmium concentrations between 1.0 and 0.1 mg 1−1 but not at 0.03 or 0.01 mg Cd 1−1.3. At a calcium concentration of 40mgl−1, post‐moult animals undergo recalcification within 7 days and thereafter there is little variation in their response to cadmium.4. External calcium concentrations of 40 and 115mg 1−1 do not affect cadmium toxicity but at 180 mg Ca1−1 the sensitivity of immediate post‐moult specimens is significantly reduced.5. The results are discussed with regard to the protection of G. pulex by present water quality standards.