摘要:

AbstractIn the drinking water reservoir Římov (Southern Bohemia) bacterioplankton was studied during 1983. Special attention was given to the relationships between parameters of bacterial abundance, total and individual activity. Bacterial counts and biomass was assessed and autoradiographic determinations of the proportion of active bacteria incorporating thymidine (Th) and mixture of amino acids (AA) and total uptake rate of AA were made over a year in the surface layer and during summer stratification from the thermocline and 15 m depth. Specific activity of metabolically active bacteria (SAMAB) and specific activity per unit of biomass (SAUB) were negatively correlated with counts of metabolizing cells and with bacterial biomass, respectively. Total and individual heterotrophic activity and counts of bacteria coincided with the changes of phytoplankton biomass, whereas bacteria incorporating Th were more tightly correlated with primary production. The most significant relation of metabolically active bacteria was found to cladoceran biomass. Thus, this part of heterotrophic bacterial activity seems to be stimulated by leakage of dissolved organic matter from phytoplankton being disrupted and incompletely digested by cladocerans rather than from healthy photosynthetizing cell

ISSN:0020-9309    

DOI:10.1002/iroh.19860710502

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractDispersion of chironomid larvae between and within stands of the aquatic macrophyteRanunculus penicillatusvar.calcareuswas studied by sampling individual leaves ofRanunculus. Two of the six common species exhibited no variation in density between sites, while others had significant variations. A new probability density function was applied to the data and it was revealed that random colonization was not uncommon among these epiphytic larvae. It was suggested that stochastic factors are of some importance in the system under study.

ISSN:0020-9309    

DOI:10.1002/iroh.19860710503

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractEnergy flux to a large, deep, salt lake from phytoplankton, periphyton and macrophyte primary production as well as fluvial transport and wind‐transported terrestrial vegetation and dust were quantified. Average areal phytoplankton net photosynthesis was 511 mg C m−2d−1. Highest rates were during water‐blooms of the bluegreen alga,Nodularia spumigena. Although areal daily net photosynthesis by periphyton in Pyramid Lake was comparable to other salt lakes, annual carbon influx by periphyton was small due to the lake's graben morphology and moderate euphotic depth (mean, 11.9 m). Macrophytes were uncommon and, therefore a minor source of energy.Truckee River is the only major fluvial discharge to Pyramid Lake and dissolved organic carbon was the principal organic carbon fraction in river water. Large upstream water diversions coupled with several drought years resulted in an average fluvial organic carbon load of only 7.3 g Cm−2y−1or 4% of median phytoplankton net photosynthesis. Tumbleweeds were the most common terrestrial plant material observed in Pyramid Lake comprising a maximum projected importance of 6% of total annual carbon input. Windborne dust represented<.1% of annual carbon input.Phytoplankton primary production is the predominant energy source to Pyramid Lake, accounting for over 80% of annual carbon influx. The relative magnitude of autochthonous and allochthonous vectors to the annual carbon budget of this desert salt lake are comparable to those of the few other large lakes for which detailed energy input budgets have been

ISSN:0020-9309    

DOI:10.1002/iroh.19860710504

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractThe distribution of merolimnic benthic insects was studied in Lake Cromwell, a small (9 ha) and shallow (max. depth 9 m) dimictic lake with a summer hypolimnetic warming on the Laurentian highlands of Québec. Communities were described from 22 sets of emergence data. Two hundred and twelve species were recognized of which 153 were Chironomidae (Diptera). Through clustering and ordination techniques, five communities were recognized: one in the flooded shrub zone along the shore, two littoral, one sublittoral and one profundal. Differences between the communities were more quantitative than qualitative. The majority of species inhabited the shore and littoral stations, and only the hardiest reached the deepest zone. There were few species characteristic of the profundal, none of them abundant. Discriminating, dominant, and characteristic species were determined for each community, as were the ubiquitous species. There is a general decrease in species richness, species diversity and population density, and a change in community structure along the depth gradient. A discontinuity at 1–2 m is related to a sharp increase in Chaoboridae in the deeper wate

ISSN:0020-9309    

DOI:10.1002/iroh.19860710505

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19860710507

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractAdontorhina cycliaBERRY, 1947 is widely distributed on the continental borderland of southern California. It is a faunal element in every major habitat type including two of the outer deep basins, Santa Cruz Basin and San Nicolas Basin. On the mainland shelf it is discontinuously distributed from Point Conception to the US/Mexican Border. The depth distribution ofAdontorhinareflects the fact that it inhabits both topographic highs and some of the deep basins of the borderland. Its depth range is from 11.6 to 1,886.0 meters. WhileAdontorhinais able to inhabit a wide range of sediment types, from 1.5 to 8.1 mean phi, it was primarily collected from locations where sediments ranged from 3 to 5 mean phi. A diverse array of macrofaunal taxa is associated withAdontorhina. The numerically dominant taxa varied from habitat to habitat.

ISSN:0020-9309    

DOI:10.1002/iroh.19860710508

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractValues of length growth ofBranchiostoma lanceolatumoff Heligoland were gained in 1962–63 by COURTNEY(1975a, b) over six age groups comprising about 800 individuals. Growth, generally was found to stop when sea water temperatures fell below 10 °C. Stagnation for at least six months could be observed as a result. COURTNEYgave a graph for length development in consecutive age groups by connecting clusters of points by straight lines, for lack of more adequate methods not available at that time.In a review, tests are recalled for the mathematical representation of growth with seasonal variations. Initial work was done by URSIN(1963), followed by CLOERNand NICHOLS(1978). These authors tried to introduce temperature to the PÜTTER/BERTALANFFYfunction of length growth, in a direct or indirect way. SAGER(1982) extended this idea regardless of the growth function proper. In a first step, the modification holds for seasonally restricted growth just down to momentary stagnation (SAGER, 1983a, b). The second step (SAGER, 1984a) allows for stagnation over several months and is suitable for approximation of the COURTNEYvalues, which is performed by nonlinear regression.Results show fully satisfying coincidence, as manifested in numerical and graphical displays. Moreover, the growth rate or growth velocity has been calculated and is plotted graphically. Complete description of growth development, according to the COURTNEYsamples, has been achieved by a function with only five paramet

ISSN:0020-9309    

DOI:10.1002/iroh.19860710509

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19860710511

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

摘要:

AbstractIngestion time, digestion time, and assimilation efficiency by the sea anemoneAiptasia pallidawere studied in the laboratory by feeding individual anemones preweighed pellets of freeze‐driedArtemia salinanauplii. There was no significant correlation between anemone size, measured as dry weight, and either ingestion time, digestion time or assimilation efficiency. Similarly, there was no significant correlation between meal size (i.e., dry weight of ingested brine shrimp pellet) and either ingestion time, digestion time or assimilation efficiency. These results suggest that, under these conditions, assimilation efficiency is unaffected by either “meal” size or anemone

ISSN:0020-9309    

DOI:10.1002/iroh.19860710512

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19860710513

出版商:Akademie Verlag, Berlin    

年代:1986

数据来源: WILEY