摘要:

AbstractStudies on the zooplankton community of the Bothnian Bay (BB), the northernmost basin of the Baltic Sea, were carried out in 1976–78. Only 8–14 taxa dominated in the zooplankton community. The highest abundances and biomasses occurred during the warmest period or immediately afterwards, in July–September. The production of zooplankton was estimated to be 3.1–7.8 g C · m−2. a−1in the coastal area and 2.5–3.6 g C · m−2· a−1in the open sea. During the short growing season (June–September) the biomass turnover took place in about 11 days. The productivity of zooplankton is discussed in relation to available food of both autochthonous and allochthonous origin and compared with the other p

ISSN:0020-9309    

DOI:10.1002/iroh.19870720202

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

摘要:

AbstractRelationships between number of eggs (Ng), brood weight (Wg), and body length (L) and weight (W) of females were studied for 16 orders and suborders of Crustacea. The study was based on the authors' observations in the inland waters of the European USSR, in the coastal regions of the fareastern and northern seas and data from V. V. KUZNETSOV (preserved in archives). An extensive literature was also used. The equations describing the relationships (Ng=f(L) andWg=f(W) are calculated for some species and high taxons. On the average for the superclass (excluding the order Notostraca) theWg/Wratio appeared to be 0.16. This ratio is markedly different for species of Notostraca. It is supposed that this difference is due to the high metabolic rate of Notostraca.

ISSN:0020-9309    

DOI:10.1002/iroh.19870720203

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19870720204

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

摘要:

AbstractLimnological characteristics of six subtropical lakes were monitored to determine the factors which regulate chlorophyll α concentrations and phytoplankton standing crops. Most physical chemical variables showed non‐significant differences with depth but differences between lakes often were large. Phytoplankton blooms occurred throughout the year and there were marked differences between the hypereutrophic and mesotrophic lakes in chlorophyll α concentrations, standing stocks, and dominant species. Densities of total zooplankton and rotifers in the hypereutrophic lakes were 3‐ to 6‐fold greater than in the mesotrophic lakes. Regression models for chlorophyll α and total phytoplankton cell volume were calculated for each lake and for all lakes combined, butR2values and numbers of shared variables tended to be low indicating the need for additional variables and more frequent

ISSN:0020-9309    

DOI:10.1002/iroh.19870720205

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19870720206

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

摘要:

The Comparative Productivity of Two Ponds in the Vicinity of Lake St‐John, QuébecIn 1980 and 1981, the productivity of two ponds near Lake St. John were evaluated. One, the pond of Desbiens, did not communicate with Lake St. John and the other, the pond of St‐Gédéon, was connected to the lake. The aim of this study was to evaluate the contribution that a pond could make to the increase in productivity of Lake St. John which is a reservoir. The pond of Desbiens is more productive than Lake St. John but two to three times less than the pond of St‐Gédéon. The pond of Desbiens shows an advanced degree of eutrophication whereas the pond of St‐Gédéon is similar to the northern lakes by its physico‐chemistry, zooplankton, sediments and benthic fauna. If we want to create artificial ponds, for a better productivity of reservoirs, it is important that they be connect

ISSN:0020-9309    

DOI:10.1002/iroh.19870720207

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19870720208

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

摘要:

AbstractThere are two sewage outfalls along the Jordanian coastline in the Gulf of Aqaba. During 1982 and 1983 a total of 328 core samples (0.01 m2to a depth of 15 cm) were collected from the two outfalls, two control stations which resemble the outfalls in depth and sediment texture, and from two stations 100 m on both sides of each outfall. Faunal analysis revealed that the total number of individuals, number of species, species richness, and faunal similarities of macrobenthic invertebrates were lower at the sewage outfall near the phosphate loading port than the control station during both collections. At the 100 m stations, the numbers of individuals were generally higher than the sewage and control stations. The number of species, however, was highest at the control station and lowest at the sewage outfall.At the other sewage outfall, where the sewage effluent is discharged sporadically, no measurable effects on macrobenthic invertebrates were found.

ISSN:0020-9309    

DOI:10.1002/iroh.19870720209

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

摘要:

AbstractThe taxonEurycercus glacialisof Western Europe has been discovered living in the turloughs (tuar loch = dry lake) of Western Ireland. Only four populations were found during three field excursions, but because of the multitude of these waterbodies in the region, there must be many populations present. Turloughs are mainly periodic waterbodies occupying depressions in the drift overlying limestone. Most of them dry every year, and the bottoms are then used for grazing cattle. This periodicity prevents the establishment of fish populations, which would rapidly eliminate the cladoceran by size‐selective predation. Only one of the many populations known from Western Europe survives in the presence of fishes. A species of theglacialisgroup in Newfoundland (not yet described), which is the southernmost known location ofE. glacialissens. lat. in the world, occurs commonly with salmonid or gasterosteid fishes, but this is a completely different species. Scanning electron micrographs ofE. glacialisandE. lamellatusin Western Europe will aid in understanding their morphological difference

ISSN:0020-9309    

DOI:10.1002/iroh.19870720210

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19870720211

出版商:Akademie Verlag, Berlin    

年代:1987

数据来源: WILEY