摘要:

AbstractThe development of the connotations attached to the terms pleuston, neuston, and some of their derivatives is outlined. In the marine literature, the term hyponeuston has presently two principal. quite different meanings: organisms attached from below to the surface film and largely supported by it, and organisms frequenting the upper decimeter of the sea. To reduce the ensuing confusion in the marine realm and to maintain uniformity of aquatic terminology, the term endopleuston is proposed as a replacement for the second, recently acquired meaning of hyponeuston. Another new term, exopleuston, refers to positively buoyant organisms with dry upper surfaces which, however, live principally underwater, in the habitat of the endopleuston. The pleustal is recognized as the habitat of these organisms. It may be useful to regard it as a category. of equal rank the epipelagial or bathypelagial.

ISSN:0020-9309    

DOI:10.1002/iroh.19750600401

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

摘要:

AbstractThe dominance structure of a shallow water (17 m), soft‐bottom community at St. Margaret's Bay, Nova Scotia was studied using multivariate statistical methods over the period January 1970 to January 1971. Seventy‐four species were encountered in the samples, and the majority were crustaceans and polychaetes. Ordination was the best method, compared to classification and measures of species diversity, for determining the changes in dominance from the mass of complex data. An ostracod (Normanicythere leioderma), two polychaetes (Micronephytis minutaandPrionospio steenstrupi), and an amphipod (Photis reinhardi) were identified as the species that determined change in the assemblages resulting from the multivariate analyses. The changes in these species' population structure were related to seasonal fluctuations in temperat

ISSN:0020-9309    

DOI:10.1002/iroh.19750600402

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

摘要:

AbstractThe predatory feeding ofMesocyclops edaxandCyclops vicinuswas studied using the14C‐labelledCeriodaphniaand some other kinds of the crustacean zooplankters. When given a choice, both species exhibited clear selection of smaller specimens of prey. The feeding rates depend on the kind of prey. The daily ration for the prey readily accepted byMesocyclopswas roughly equal to the predator's biomass, while it was only one half or one third of the body biomass inCyclops vicinus. Only about one third of the killed biomass was actually ingested and 21–32% was assimilated when the copepods preyed upon the cladocerans or the copepodid larvae. When fed with naupliar larvae the cyclopoid copepods assimilated over 70% of the killed biomass. Almost one half of the freshly assimilated carbon passes through the short term cycle and is quickly respired and excre

ISSN:0020-9309    

DOI:10.1002/iroh.19750600403

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

摘要:

AbstractIn May 1965 and June 1966 an ecological study of the Arrecife Blanquilla, Arrecife Pajaros, Bajo Verde and Anegada de Adentro coral reefs off Veracruz, Mexico was made using aqualungs. The present work summarizes and discusses the existing knowledge about these reefs which is still incomplete. Similarly structured reef portions and similar features found in a number of reefs in ecologically comparable locations led the author to conclude that the reefs as a whole are similar to each other. In their position on the shelf, their round‐oval shape, their elevated ridges, their shallow lagoon‐type centres and their tendency to form islands they are basically comparable to the platform reefs of the Australian Great Barrier Reef. The coral associations have been produced by the environmental factors prevailing in the three recognizable habitats, the surf zone, the shallow body of calm water, and the steep slopes with moderate water movement. The coral fauna was found to be poorer than that of other reef areas in the West Ind

ISSN:0020-9309    

DOI:10.1002/iroh.19750600404

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

摘要:

AbstractOn the basis of investigations of the diatom flora and the Plecoptera, Ephemeroptera and Trichoptera fauna in two mountain brooks with different chemisms the different effects of the regional factors of the water chemism and the extraregional factors, current and temperature, on the biocoenosis is discussed. The zoocoenotic division of mountain streams is affected by the extraregional factors; the structure of the diatom associations and the distribution of individual species of the insect fauna are dependent on the regional effect of the water chemism. The correlation of the halobic indices as ecological characteristics of the diatom flora with the factors of the water chemism, pH and alkalinity, and their relationship with the distribution of some species of the insect fauna suggest that the halobic index is a useful criterion for the ecological classification of waters. Also for the judgement of the trophic conditions and the self‐purification of waters the halobic index can be regarded as an additional criterio

ISSN:0020-9309    

DOI:10.1002/iroh.19750600405

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

摘要:

AbstractFrom 1972 to 1974 the invertebrates of a woodland‐brooklet of the “Naturpark Kottenforst‐Ville” (Rhineland) were investigated concerning abundance and standing crop at selected sampling stations of the “epirhithron”. In the shaded brooklet the allochthonous autumn‐shed leaves proved to be the most important food for the aquatic invertebrates. Carbon‐14 radioisotope tags were used to get data on the primary productivity of the periphyton community, which is less important for the energy balance of the macrobenthic organisms. The most frequent macroconsumers areGammarus fossarumKOCH,Leptophlebia marginataL. and some caddis larvae which feed directly on detritus and dec

ISSN:0020-9309    

DOI:10.1002/iroh.19750600406

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19750600407

出版商:Akademie Verlag, Berlin    

年代:1975

数据来源: WILEY