摘要:

SUMMARY.The life histories of twelve abundant species in the River Coquet are given together with notes on certain scarce species. The life histories are compared with those recorded for other river systems and major differences in findings between studies are related to geographical location and temperature. Catastrophic mortalities noted for some populations coincided with the presence of slush‐ice in the river bed and subsequent winter spates caused by meltwaters. Extended hatching periods are apparently adaptive and compensate for such losses. Life histories are also compared along the length of the R. Coquet. Hatching periods, growth rates and emergence periods show regional differences which are apparently dependent on altitudinal variations in temperature regim

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01185.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.The seasonal and depth distributions of dominant phytoplankters,in situprimary productivity, organic carbon, and major chemical variables are described for Gull Lake, Michigan for the years 1971–74. Despite efforts by residents surrounding this moderately large dimictic lake to reduce phosphorus loading, all indications are of progressive eutrophication over the period. Previously dominantCyclotella michiganianahas almost completely disappeared while araphidinean diatoms have increased greatly; certain blue‐green algae that were absent previously are becoming characteristic. The ratio of araphidinean to centric diatoms in recent sediments has also increased. Primary productivity and particulate and dissolved organic carbon concentrations have also increased. Voluntary attempts to reduce nutrient loading have apparently been inadequate to arrest increasing rates of eutrophicat

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01186.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.The accumulation of cadmium from an experimental medium by the freshwater amphipodGammarus pulexis described.Much of the uptake is internal as opposed to adsorption on the body surface, and after an apparent saturation of the exoskeleton the hepatopancreas becomes an increasingly important site of cadmium storage. The haemolymph cadmium concentration reaches a high level compared with marine crustaceans, achieving a concentration factor (ratio of internal Cd/ external Cd) of 100 after about 60 h uptake.The cadmium uptake process is severely inhibited after exposure of experimental animals to 0.5 mM 2:4 Dinitrophenol, indicating the mediation of an active process. This fact together with the negative relationship between cadmium uptake rate and the calcium concentration of the animal suggests that cadmium accumulation by this species may be at least partially accounted for by a process of ‘accidental’ active cadmium uptake, with cadmium substituting for calcium on a calcium regulatory mechanism.As yet it has not been possible to establish a true stoichiometric relationship between the two metals. Although calcium influx and cadmium uptake (influx) rates are similar over a wide range of external concentrations, calcium influx is clearly inhibited by a low external ratio of cadmium to calcium. This indicates that the relationship between the two metals is far from an equimolar one and the possibility of non‐competitive inhibition of calcium influx by cadmium cannot be elimi

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01187.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.A 1‐m water sampler is described together with results obtained from sampling a vertically stratified phytoplankton population ofCeratium hirundinella. These results were analysed using a one‐way analysis of variance to partition the total variance into two components. Population estimates from 1‐m sections taken sequentially from the surface waters to 5‐m depth and integrated, were not significantly different (P>0.05) from those obtained using a 5‐m vertical tube sampler: replicate sampling units taken with both samplers showed thatCeratiumwas contagiouly distributed in the vertical wat

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01188.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.The effects of pollutants from the coal industry on the macroinvertebrate fauna of a small river in the South Wales coalfield were investigated during 1972 and 1973.Three major types of pollution, each spatially separate, affected the river and its tributaries. The upper reaches received acidic drainage from coal stockpiles. The lower reaches received a discharge from a drift mine, bearing high loads of suspended coal particles which caused siltation of the river bed downstream to its confluence with the R. Taff (3.5 km). The largest tributary was subjected, under neutral pH, to siltation by ferric hydroxide, derived from seepage from an abandoned mine.In the upper reaches, a few acid‐tolerant invertebrate species survived in low numbers. Downstream recovery was not complete before the discharge of coal particles. In the reaches silted by ferric hydroxide or coal there was a pronounced reduction (80–90%) in faunal abundance. Clear differences in sensitivity of invertebrate groups to these types of siltation were apparent.The data are used to assess the various methods of biological surveillance involving invertebra

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01189.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.Diel vertical migrations of a dinoflagellate,Ceratium hirundinella, were induced in a laboratory tube (1.63 × 0.15 m) under a light‐dark cycle. The timing of vertical migrations differed between cultures in the exponential and stationary phases of growth; the latter showed a greater coincidence with the light regime.Migration of cells into the surface layers occurred at low values of surface irradiance (1300 μE m−2s−1) there was a marked avoidance of surface waters, and population maxima were found at depths associated with a relative irradiance level of 10% orc.150 μE m−2s−1). Thermal stratification restricted downward movement of cells into the cooler layers. The combination of high surface irradiance and thermal stratification resulted in large, stable, sub‐surface maxima ofCeratium, similar to those observed in natural waters under comparable envir

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01190.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

SUMMARY.Keys are provided to identify those British limnephilid larvae which are characterized by having gill sites occupied solely by single filaments at the final instar. Most species can be identified at the final instar but many species can also be identified at the earlier instars. A key is also supplied to distinguish the early instar larvae as a group from other limnephilid larvae. Brief notes on distribution and habitat are given. The species identified at least at the final instar are:‐Apatania wallengreni, A. auricula, A. muliebris, Drusus annulatus, Ecclisopteryx guttulata, Potamophylax latipennis, P. cingulatus, P. rotundipennis, Melampophylax mucoreus, Allogamus auricollis, Hydatophylax infumatus, Chaetopteryx villosa. It was not possible to segregateHalesus radiatusfromH. digitatus, Stenophylax permistusfromS. vibex, orS. lateralisfromS. sequa

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01191.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Koste W. (1978)Rotatoria: Die Rädertiere Mitteleuropas. Superorder Monogononta.Pontin, Rosalind M. (1978)A key to British freshwater planktonic Rotifera.Russell, Sir Frederick S.&Yonge, Sir Maurice(Eds)(1979)Advances in Marine Biology, Vol. 15.Jenkins S.H.(Ed.)(1978)Water Pollution Research.Good, R.E., Whigham, D.F., Simpson, R.L.&Jackson, C.G. (1978).Freshwater Wetlands—Ecological Processes and Management Potenti

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01192.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1980.tb01193.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY