摘要:

SUMMARY.Gill structure and function are brietly considered, as are the main factors affecting the oxygen content of water. The review deals with quantitative, analytical aspects of oxygen uptake related to body size, temperature, oxygen content of water, salinity, water velocity, substratum and activity ofCammarus.A theoretical model relates oxygen uptake to growth and life‐span of individuals. Several aspects of regression analysis, as applied to measurements of oxygen uptake, are examined and constructively criticized. The energetic cost of osmoregulation is calculated forG. pulex.The review concentrates on freshwater species ofGammarusbut work on brackish‐marine species is also included. A more detailed summary and conclusions are given at the end of the rev

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00168.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1.Nemurella pictetiiKlapæplek took 2 years to complete its life cycle in both the laboratory and a small stream in the English Lake District.2. Hatching time (days after oviposition for 10%. 50% and 90% of the eggs to hatch) and hatching period (days between dates for 10% and 90% hatched) decreased with increasing water temperature in the laboratory, and the relationships were well described by a power‐law. Estimates of the mean time for 50% hatching in the stream varied between 16 and 31 days after oviposition. depending on temperature.3. Larval instars numbered fifteen for males and seventeen for females with a constant ratio of 1.18 between successive instars (conformed with Dyar's rule). Larval growth was exponential at four constant temperatures in the laboratory; mean instantaneous growth rates were 0.40±0.01% day−1at 5.9°C, 0.43±0.01% day−1at 8.2°C, 0.46±0.01% day−1at 12. 1°C. 0.56±0.02%day−1at 19.8°C. No larvae survived after instar XI at 19.8°C.4. Larval growth was exponential in the stream and was scarcely affected by variations in water temperature (range 4.2 ‐14.0°C); mean growth rates for three year‐classes were 0.41±0.02, 0.43±0.08, 0.54±0.05% day−1. Their similarity to laboratory growth rates under optimum conditions suggests that the availability of resources, such as food and space, was not res

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00169.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. Variations in the haemoglobin index of two neighbouring populations ofDaphnia magnawere recorded over a range of dissolved oxygen concentrations (0.5–4.0ml O21−1, 20°C). Reciprocal transfer experiments between habitats compared haemoglobin synthesisin situ.2. An inverse relationship was found between the oxygen content of pond water and the haemoglobin indices of laboratory and natural populations.3. Significant genetic differences in the synthesis of haemoglobin were found between the two populations. Animals from the poorly oxygenated habitat (0.8±0.18ml O21−1) had consistently higher haemoglobin contents (maximum HI, 87.7±4.5) at all experimental andin situoxygen levels.D. magnafrom the well oxygenated pond (4.3±0.59 ml O21−1) had a lowered physiological ability to synthesize haemoglobin (maximum HI, 48.3±4.2). The process of ecological differentiation inDaphniapopulations

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00170.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. Invertebrates associated with four species of aquatic plants and on the adjacent substrate were investigated in a riffle/run section of a hard‐water stream.2. Invertebrates were more numerous on stones than on any species of plant (>17,000m−2versus 1000–4000 m−2). Gatherers were more abundant onRanunculus longirostris, where proportionally more fine detritus was trapped in the leaf bundles than on other plants. Scrapers were most numerous onCharu vulgaris, where attached diatoms were also most prevalent.3. Invertebrate community structure on three plant speeies was quite different from that on stones. This was not the case forPotamogeton amplifoliuswhich appeared to be used by the organisms as a mere extension of the su

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00171.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. An examination has been made of the water quality of a 50 km (Wigan to Litherland) length of the Leeds‐Liverpool canal. Regularin situmeasurements accompanied by sampling for laboratory analysis were made at seventeen stations over a 15‐month period.2. Three principal contributory water types have been recognized, and the observations have allowed estimates to be made of their relative contributions to the total water flux in the lower reaches of the system. Linear flow rates (c. 0.6 km day−1near Litherland) are consistent with previous reports.3. The combined field and laboratory measurements have been used to obtain estimates of the partial pressure of CO2in the water (Pco2), the degree of saturation of the water with respect to calcite (Ω) and the major ion speciation in the water. Because of the variable ionic compositions of the waters examined, these estimates were made using a program (WATEQ) which took account of ion‐pairing.4. Diurnal and annual cycles with respect to pH,Pco2and ω occur, these being most marked in the lower parts of the study length when, for a large proportion of the spring and summer,Pco2was below the atmospheric level and noticeable supersaturation with respect to calcite occurred. In contrast, two of the contributory water types, the River Douglas input and the Creek, showed low pH and Ω values and highPco2values throughou

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00172.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. Dissolved organic matter (DOM) was measured at 8h intervals over a 1 year period in a stream draining 51 ha of moorland with peaty soils.2. DOM concentrations increased with increasing stream discharge from low flow values of 0–3 mg 1−1to maximum values of 30 mg 1−1. There were also seasonal differences of up to 13mgl−1between August (maximum) and February, and differences of about 2.5 mg l−1between rising and falling stage samples.3. Seasonal variation was closely related to mean temperature.4. Total loss over the year was 168 kg ha−1DOM (84 kg ha−1C), larger than previous estimates for

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00173.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. Constrained cluster analysis of thirty‐five surface sediment diatom assemblages shows that Lough Erne, a complex multi‐basin lake in Northern Ireland, can be sub‐divided into four main zones.2. All areas of the lake system have planktonic diatoms typical of eutrophic lakes but the lack of smallStephanodiscusspecies in zone 4 suggests that this area of the system is least productive.3. Surface sediment diatom assemblages can be used to assess spatial variations in complex lake systems and can thereby be used as a guide to the choice of sites for water quality monitoring and sediment c

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00174.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

SUMMARY.1. In a laboratory experiment, larvae ofSimulium noelleriwere fed on polystyrene latex microspheres of a range of diameters from 5 to 100 μm.2. Examination of the particle size distribution in the water used in the experiment showed those<13μm to be the most numerous (87% of all particles present). Particles of this size made up 57±2% (mean ±SE)of the total of those in the gut of larvae.3. Comparison of particle composition in the gut contents and the water of the experiment, using Jacob's index of electivity, showed that larvae of all sizes filtered proportionally fewer of the particles52μm in diameter) and less well able to filter the smallest particles (<13μm in diameter).5. Gut retention time was longer in larger larvae.6. The biology ofS. noelleri, which inhabits lake outlets in high population densities, is considered in the light of these f

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1984.tb00175.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY