摘要:

AbstractThe impact of selective predation in freshwater zooplankton communities is examined with special emphasis on the ecological and evolutionary consequences for the prey. The behavioral interactions between predators and prey are reviewed, and the general patterns in age‐ and size‐selective predation are derived in a semi‐quantitative model. The final section explores the life history adaptations that zooplankton have evolved in response to these different patterns of selective pred

ISSN:0020-9309    

DOI:10.1002/iroh.19830680302

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19830680303

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractThe dependence of the specific growth rate ofMicrocystis aeruginosa(KÜTZ);KÜTZf.aeruginosaupon temperature and light intensity was determined under continuous illumination in batch cultures. The result can be well described by the function:where μmax= 3.44.d−1, Topt= 33.2°C, Tmin= 18.3°C and KI= 71.4 Wm−2. The validity of this function is limited to the range of 10–28 °C and light intensities from 5–25 Wm−2. The dependence of the specific growth rate on the nutrient concentration was investigated a t 25°C and 24 Wm−2light intensity by means of chemostat cultures. The half saturation constants related to the maximum specific growth rate of 1.1 d−1measured under these conditions were 0.44 μmol.I−1, 4.3 μmol.I−1and 26.5 μmol.−1for orthophosphate, nitrat

ISSN:0020-9309    

DOI:10.1002/iroh.19830680304

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractA Monte Carlo model of a multi‐species community with a single trophic level, with nutrients supplied randomly in space and time, demonstrates an irreducible variability in species number and composition. Competition between closely similar species does not necessarily proceed to the elimination of the less efficient species because the variability in food supply becomes a more important factor in survival than does even a fairly large difference in efficienc

ISSN:0020-9309    

DOI:10.1002/iroh.19830680305

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractPopulation changes ofSida crystallina, a filter feeding microcrustacean which attaches to aquatic macrophytes, were examined in Cochran Lake, Michigan during June and July, 1979. Population estimates were derived from organisms present in 10 samples of leaves of the water lilyNymphaea odoratacollected every 3 days.Population densities ofSidaresponded both to food and predation by fish. Declines in average clutch size were associated with decreasing phytoplankton biomass and the increasing dominance of colonial green and blue‐green algae, but were not significantly influenced by the densities of invertebrates on the plants. Largemouth bass fry (Micropterus salmoides) dramatically reduced the numbers ofSidaand altered the age structure of the population in late Jun

ISSN:0020-9309    

DOI:10.1002/iroh.19830680306

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution and abundance of larval chironomids in Lake Hayes were studied from December 1973 to March 1975. The mean annual production of the two dominant species,Chironomus zealandicusandChironomussp. a, was 29.2 g m−2dry weight which is approximately 4.3 % of the average annual phytoplankton production in the lake. A high annual P/B ratio of 18.5 is consistent with the multivoltine life cycle ofC. zealandicus.Larval chironomid production in the second summer whenAnabaenablooms were absent was only one quarter of that in the first summer and is consistent with the hypothesis that the production of benthic chironomids in Lake Hayes is closely linked to that of the phytoplankton through the sedimentation of autochthonous organic matte

ISSN:0020-9309    

DOI:10.1002/iroh.19830680307

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19830680308

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractThe zooplankton community of two ponds in an alkaline marsh in central Pennsylvania were studied. The ponds were found to be distinctly different from one another with regard to species but similar when only zooplankton types are considered. The ponds were quite similar with respect to a number of physico‐chemical characteristics but differed significantly with respect to alkalinity, conductivity, habitat type, vegetation, depth, and predation pressur

ISSN:0020-9309    

DOI:10.1002/iroh.19830680309

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19830680311

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of filter‐feeding zooplankton on phytoplankton was investigated in two fish ponds near Blatná (southwestern Bohemia, Czechoslovakia) using enclosures of 50 liters volume. Filter‐feeding activity had a positive effect on the growth of individual net phytoplankton (>40 μm) species except forAphanizomenon flos‐aquaeandMelosira granulata.Except forSchroederia setigerananoplankton species (<40 μm) were suppressed by the filter‐feeding zooplankton. In bags without zooplankton the addition of nutrients induced growth of nanophytoplankton species, but no significant differences were noted in bags with z

ISSN:0020-9309    

DOI:10.1002/iroh.19830680312

出版商:Akademie Verlag, Berlin    

年代:1983

数据来源: WILEY