摘要:

AbstractParticulate organic matter in a downriver riffle of the Grand River, the largest Canadian Great Lakes tributary, was studied between June 1970 and April 1972. In winter and spring, concentrations of particulate organic matter (1.0–26.2 mg/l) varied with river flow. High summer levels (3.4–12.7 mg/l) were attributable to high autochthonous primary production. Mean chlorophyllaconcentration in summer (29.8 mg/m3) was nearly 15 times higher than in winter, and 8 times the spring mean level. High algal cell counts (15,000–19,000 cells/l) also occurred in summer. Autochthonous and allochthonous contributions to the total particulate organic carbon input to the river in summer were estimated by daily organic input and river flow relationships, carbon to chlorophyllaand to pheopigments ratios. The allochthonous source accounted for 21.5% of the total organic carbon while the autochthonous contributed the remaining 78.5%. The latter included living algae (23.0%), senescent plant material (30.3%) and detritus (25.2% — including microbes). The study establishes a new approach whereby the various components of particulate organic matter in river water can be indirectly partitioned and their biomass estimated by using quantitative relationships among readily obtainable parameters of river flow, standing biomass, chlorophyllaand pheop

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620401

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe composition and abundance of the macroscopic biota of a sandy‐bottomZostera marinacommunity at a depth of 3–5 m were studied in Tvärminne, S Finland, in 1968–1971.Zosteraoccurred contagiously and very sparsely, 6 ± 2 shoots · m−2, ash‐free dry weight (AFDW) 2 ± 1 g · m−2(95% confidence interval).Totals of 45 plant and 70 animal taxa were found.Fucus vesiculosus(80%) andZostera marina(11%) dominated the plant biomass, 16.5 ± 17.8 g · m−2in June 1971. At this time animal density was 8540 ± 830 ind. · m−2(0.6‐mm mesh) and AFDW 17.3 ± 5.0 g · m−2, 80–90% of the latter consisting ofMacoma baltica, Mya arenaria, Corophium volutator, Nereis diversicolorandHydrobiaspp. The same percentage of animal density was made up byHydrobiaspp.,M. baltica, C. volutatorandPygospio elegans.Normal analysis by classification of the samples suggested that the community was spatially rather homogeneous in 1971. Inverse analysis, based on interspecific correlations, revealed three distributional groups of species. These groups corresponded to the compositional subdivisions suggested by normal analysis. The community was subdivided into strata characterized by (D) deposit feeders, (Z)Zostera marinaand (F)Fucus vesiculosus.The periodicity of the biota in theZostera‐characterized stratum was investigated. The principal dominants, especiallyFucus, ZosteraandMacoma, showed no distinct seasonal or interannual differences in 1968–1971, which made the community seem very stable. Yet, the species diversity of plants varied with the abundance of filamentous algae. Animal species diversity and mean animal density reached their seasonal minima in late summer, when the parental stocks of many invertebrates were dying and the summer's offspring were often still too small to be obtained by our methods. The recruitment of many important animal species failed in 1

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620402

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractA computer simulated model is presented which predicts changes in phytoplankton populations from six‐week mining operations conducted at different times of the year. Barely perceptable changes are predicted from the six‐week May mining operation, while similar operations at other times of the year were predicted to have variable and sometimes long term impacts on the phytoplankton dynam

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620403

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe small‐scale distributions of the rotifersPolyarthra vulgaris, Synchaeta stylata, Conochilus unicornis, Hexarthra mira, andAsplanchna priodontawere investigated in Lancaster Lake, Cheboygan County, Michigan, July 21, 1974. Measurements were taken for 13 depths (at 1‐m intervals) and at 4 times of the day (1:00 AM, 7:00 AM, 1:00 PM, and 7:00 PM). In addition, the abundances of 6 crustacean, 2 planktonic dipteran, and 10 algal species, as well as temperature, light, oxygen, chlorophylla, alkalinity, pH and free carbon dioxide were measured. Whereas abiotic factors appeared to control large scale occupation of the lake, and excluded most species from the deeper portions of the hypolimnion, small‐scale distributional variation of the rotifers depended upon biotic interactions, particularly with the crustacean zoopla

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620404

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe authors found quite a close relationship between hydrological regime and fish yield in the Czechoslovakian Danube stretch. This relationship is not only true with the corresponding years but also for water level of the preceding year and the yield of the year to come. The equations characterizing the latter may, to quite a reliable extent, be applied to the prediction of fish yield in the next year. Biological mechanisms of the relationships investigated are discussed and examples of their utilization are given.

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620405

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractBacteria isolated from surface sea waters, brackish waters and from algal cultures were classified in nutritional clusters. Results obtained with an hierarchical method were improved by using the correspondence analysis. The former main statements appear confirmed and new informations are pointed out, mainly concerning the organic compounds which are the best indexes of the nutritional characteristics;e. g. a few organic acids and amino‐acids can be used to estimate the versatility of bacteria; it also appears that strains which preferentially assimilate substrates of one chemical group, do not easily attack substances of other group

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620406

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractAbsorption spectra of intact phytoplankton cells collected from a stratified eutrophic lake in Japan were studied.Vertical and seasonal changes in the content of phycoerythrin of blue‐green algae were indicated on the basis of the absorbance at 560 nm in those spectra. The possibility of an application of the technique to estimate the standing crop of blue‐green algae in the phytoplankton community was discus

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620407

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620409

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620411

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620413

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY