摘要:

SUMMARY.This review deals with culture techniques in use to estimate individual growth, development and reproduction of copepods and cladocerans in cultures. The conceptual aspects of growth, reproduction and feeding behaviour are briefly summarized. Marine copepods are included, because the techniques employed for the cultivation of these animals are often more advanced than those used for freshwater crustaceans. Most of the studies reviewed here were carried out under defined laboratory conditions, but a few were under field conditions, generally in smallin situenclosures. The culture methods described in this review are based on 272 studies published between 1910 and 1987. A large number of different culture systems are critically discussed in relation to culture conditions and culture techniques and the taxa used. Particular attention is given to the effect of food quality, and the problem of how to apply laboratory measurements to field populations so as to limit errors to the minimum. A more detailed summary is given in the section on ‘Recommendations’ at the end of the rev

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01369.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. Profundal macroinvertebrates and water chemistry of sixty‐eight nutrient poor, poorly buffered lakes were sampled in 1983 or 1986. Assemblages of profundal zoobenthos were classified using two‐way indicator species analysis (TWINSPAN), ordinated by canonical correspondence analysis (CCA), and related to physico‐chemical factors using CCA. discriminant analysis, and regression.2. 90% of zoobenthos (TWINSPAN) groups were classified correctly using discriminant analysis. Depth (Function 1), soluble reactive Si(OH)4and HCO3, ‐(2), and phytoplankton biovolume and pH (3) were the strongest correlates with the three discriminant functions.3. Regression analysis showed that depth, KmnO4, consumption, and phytoplankton biovolume were the best estimators of zoobenthos biomass in the profundal.4. Multivariate analyses showed species assemblages amongst the profundal zoobenthos to be good indicators of lake type, particularly depth, pH, and phytoplankton bi

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01370.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. Adult Trichoptera were caught for 1 year (May 1986 to June 1987) on the banks of the Danube at Altenwörth, Lower Austria, using a set of three Jermy‐type light traps. From a total of 62,693 specimens caught, the most abundant species wereBrachycentrus subnubilusCurtis (Brachycentridae), the two hydropsychidsHydropsyche bulgaromanorumMal. andHydropsyche contubernalisMcL.,Tinodes waeneriL. (Psychomyidae) and the leptoceridCeraclea dissimilisSteph.2. The total catch included sixty‐five of the 278 Austrian species from thirteen families.Hydroptila pulchricornisPictet andOecetis notataRamb. were new to the Austrian fauna.3.Of the meteorological parameters tested, only air temperature seemed to influence flight activity.4. Twenty‐four species were studied in detail;Halesus tesselatusRamb. was the only autumn species, the remainder being summer species. InTinodes waeneri, the flight period was divided into two well‐defined peaks.5. Of the total, 49.9% were caught during the first third of the night, 39.1% in the second and 11.0% in the last third.6. In seventeen species the sex ratio was significantly different from 1:1, and it changed during the night.7. The indication of water quality by light trap catches of caddisflies is d

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01371.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. The overlying water of intact sediment cores was constantly stirred with an impeller at a rate sufficient to mix turbulently the water column and maintain the diffusive boundary layer at a determined thickness. The system allowed standardization of water circulation in laboratory sediment core experiments.2. Both oxygen concentration and oxygen penetration depth in the sediments decreased, the former by 70% and the latter from 4.2 mm to 2.0 mm, when the overlying water was not stirred for 24 h, as measured with oxygen microelectrodes in a lake sediment core.3. Oxygen profiles measured in sediment cores in the laboratory were similar to those measuredin situwhen the overlying water was stirred with an impeller at such a rate that a similar thickness of the diffusive boundary layer at the sediment‐water interface developed in the laboratory as thatin situ.4. Sediment oxygen consumption was calculated from: (1) measured oxygen profiles in the diffusive boundary layer and the molecular diffusion coefficient for oxygen in water; (2) the measured oxygen decrease in the top of the sediments and the estimated diffusion coefficient in the sediment; and (3) by oxygen differences in the overlying water after incubation of sediment core

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01372.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.. 1. The resistance to passive entry into the drift of first to fifth instar larvae ofAllogamus auricollis(Pictet, 1834), a case‐bearing caddis‐fly, was investigated in the laboratory using an artifical stream channel.2. Dead larvae in their cases were exposed to different current speeds. When the heads of the larvae were directed towards the water flow (frontal position), the current necessary to wash larvae away ranged from 3 cm s‐l(first instars) to 21 cm s‐1for fifth instars. When the larvae were at right angles to the current (lateral position), these speeds were 2 and 9cm s‐1, respectively. In terms of force (Newtons), this passive resistance to drift ranged from 0.3x10‐6N (first instar, frontal position) to 307.0x10‐6N (fifth instar, frontal position). The data obtained in the experiments were in good agreement with values calculated from hydrodynamic equations, using biometric parameters of the larvae.3. Total resistance to drift was studied by exposing living larvae to different current speeds. The speed just sufficient to wash larvae away ranged from 13 cm s‐1in the first instar to 27.9 cm s‐1in the fifth instar (frontal position). In terms of force, the total resistance to drift varied between 5.3x10‐6N (first instar) and 547.5x10‐6N (last instar).4. The difference between total and passive resistance to drift was defined as‘active resistance to drift', and is due to the effectiveness of a larva's attachment to the substrate. It ranged from 3.5x10‐6N (first instar) to 2

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01373.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. The impact of parasitism by a fungusAphanomycessp. (Phycomycetes: Saprotegniaceae) on a population ofBoeckella hamatain Lake Mahinerangi in New Zealand was studied over 20 months. The incidence of infection among adult female copepods exceeded 12% throughout winter (May‐October) and was highest in autumn (46%) when population birth rates were depressed by 48.8%. During most of the study, parasitism lowered the rates of population recruitment and growth by more than 10%. These effects on theB. hamatapopulation exceeded those ofAphanomycesonBoeckella dilatataSars in another study.2. It is hypothesized that the high incidence of parasitism byAphanomycesand its importance at times in regulating populations ofBoeckellain New Zealand lakes may be an ecological consequence of life in predator‐poor ecosyst

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01374.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. Copper(II) complexation in the eutrophic. humus‐rich Lake Tjeukemeer was measured fortnightly for several years by copper titration (Ion Selective Electrode) and by copper solubilization. Additionally, the copper speciation during titration was followed by ultrafiltration.2. The Tjeukemeer showed high ligand concentrations able to complex up to 8.5X10‐5M Cu.3. Scatchard plots and affinity spectra of the titration data allowed the discrimination of at least three different binding sites. In Scatchard plots logKvalues ranged from 5 to 9, in affinity spectra from 4.5 to 8.4. The highest logKvalues coincided with relatively low humus concentrations and blooms of algae, mainly Cyanobacteria.5. The ultrafiltration experiments indicated that relatively small size fractions (<10 nm) have the highest copper binding affin

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01375.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. Cyst distribution and a possible excystment site of the dinoflagellatePeridinium penardii(Lemm.) Lemm. in a reservoir were surveyed.2. The presence of vegetative cells ofP. penardiifrom all lake bottom mud samples, taken from several sites throughout the reservoir and culturedin vitro, showed that viable cysts ofP. penardiiwere ubiquitous on the bottom of the reservoir.3. Culture bottles containing bottom mud with cysts ofP. penardiiwere suspended at several depths at four stations in the reservoir. Vegetative cells ofP. penardiiwere found in all bottles suspended at 0.5 m and almost none deeper than 20.0 m. Water depth was a critical environmental factor in preventing excystment.4. The place whereP. penardiifirst excysts annually was predicted to be at the head of the reservoir using the data of cyst distribution, excystment conditions and morphology of the lake basin.

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01376.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. Standard hemispheres of identical size and surface but different densities were exposed on a horizontal plane at the bottom of streams. The heaviest hemisphere moved was used as an indicator of flow conditions close to the substrate.2. Techniques of manufacture, maintenance, and use of the equipment were considered in detail.3. The method was an easily applicable and integrated indicator of key hydraulic characteristics (turbulence or force of flow prevailing at the stream bottom) previously measured in lotic benthos research, and can replace these more laborious techniques.4. The hemispheres enabled a rapid flow characterization in stream reaches, in smaller areas where the benthos was being quantitatively sampled, and in en/exclosure cages used in experimental studies.5. The method also has the potential to characterize and compare physics of flow in individual running water segments with regard to frequencies and intensities of disturbances caused by long‐term variations in discharge.6. The hemispheres could be used as a standard in benthic research. since they offer a well defined scale that is directly comparable not only between studies in running waters but also in wave‐exposed shores of lakes and oce

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01377.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY.1. The impact of different predation regimes of zooplanktivorous larval tiger salamanders,Ambystoma tigrinum nebulosum, on the vertical temporal distributions ofDaphnia pulex, Diaptomus nudusand larvalChaoborus flavicanswas studied in limnetic enclosures in a pond in east‐central Arizona. Zooplankton densities were monitored 1‐2 h before sunset, at sunset, and 1‐2 h after sunset at three depths (0‐0.4, 1.0 and 2.0 m) in four salamander treatments (0, 20, 40 salamanders per enclosure, and unenclosed limnetic areas).2. Densities and body size ofDaphnia pulexwere consistently greater in salamander‐free enclosures than in other treatments. MoreDaphniawere generally nearer the surface (0‐1.0 m) than along the bottom before and at sunset than after sunset in enclosures without salamanders. After sunset,Daphniawas by far most dense along the bottom. Densities were uniform among depths and sample times in treatments with salamanders. Salamanders moved throughout the water column. Frequencies ofD. pulexspined morphs (with prominent dorsal crest) did not differ among salamander treatments.3.Chaoborusdensities were positively correlated withD. pulexdistributions among depths and sample times in treatments. Spatio‐temporal distributions ofChaoboruswere influenced more by their daphnid prey than by risk of predation from larval salamanders.4. Densities ofDiaptomus nuduswere highest in open water controls and lowest in enclosures without salamanders.Diaptomuswas generally more dense between 0 and 1 m than at 2.0 m depths in all treatments, and vertical distributions were not dependent on salam

ISSN:0046-5070    

DOI:10.1111/j.1365-2427.1989.tb01378.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY