ISSN:0020-9309    

DOI:10.1002/iroh.19930780202

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractCalcite precipitation in model solutions and natural waters depends on the magnitude of saturation (saturation index ≫ 1). Continuous lye addition should simulate the CO2decrease through assimilation by algae and the experiments can be applied to the autochthonic calcite precipitation in lakes. It seems possible to restore lakes with artificial calcite precipitation. Basic data for this experiment are given in this pape

ISSN:0020-9309    

DOI:10.1002/iroh.19930780203

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19930780204

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractThe composition of the protist communities of three coastal areas of the Sea of Cantabria were studied, and the seasonal variation of the larger groups of these organisms described, with respect to the productivity. Also, the annual dynamics of consumption and degradation of organic matter achieved by the ciliate species were analyzed.

ISSN:0020-9309    

DOI:10.1002/iroh.19930780205

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractSamples were taken in fine‐sand community of the North Latium coast in February and September for two years.Eigthy‐eight species of Polychaetes were identified. The most abundant wasOwenia fusiformiswhich was highly correlated to the clay fraction in the sediments. Species richness and abundance of other polychaete species were related to the abundance of this tubicolous species which provides a spatial refuge from predators and implements sediment stability. There was a persistency in the community structure in spite of seasonal fluctuations in the abundance of dominant spec

ISSN:0020-9309    

DOI:10.1002/iroh.19930780206

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19930780207

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractThe seasonal and spatial distribution of vitamin B12was investigated in Eastern Mediterranean (Saronicos Gulf, Aegean Sea). Vitamin B12concentration had an annual range 0.12–7.93 ng. 1−1and an annual mean 1.88 ng. 1−1. The statistical analysis of data indicated significant seasonal and regional variations of vitamin B12in this area and an inverse relationship of this vitamin with chla.The results showed that the Eastern Mediterranean Sea contains less vitamin B12than the Western Mediterranea

ISSN:0020-9309    

DOI:10.1002/iroh.19930780208

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19930780209

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractThe ranges of 10 tropical Pacific phytoplankton species are shown in the maps. Five types of these ranges are discussed. Except for broadly tropical species some species with much narrower ranges are characterized. The bases of ranges and the expatriation areas are given. The bases of ranges of all the species studied fall into similar temperature and salinity limits. Most of the species inhabit a wide range of nutrients concentration, butClimacodium frauenfeldianumandHemiaulus hauckiiare only found at low phosphate and silicate concentrations. These peculiarities determine the geography of ranges of these two species. Among the species investigated onlyCeratium gravidumbelongs to the shade flora.

ISSN:0020-9309    

DOI:10.1002/iroh.19930780210

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY

摘要:

AbstractA study on the decomposition process ofPistia stratiotesL. was carried out in Cisne Reservoir, Uruguay. For this purpose, leaves and roots were considered separately, and the process was studied in the littoral and the pelagic zone. The litter bag technique was used to estimate dry weight losses at different times. Leaves decomposed faster than roots in both zones.Pistiadecomposed faster in the pelagic zone due to better oxygen conditions and a more intensive water movement that removes material from within the bags. Phosphorus, potassium, sodium and magnesium were leached rapidly during the first week. Nitrogen content in the leaves initially increased, reaching its maximum in the littoral zone that coincided with that of bacterial numbers colonizing the litter. The number of macroinvertebrates, dominated by Chironomidae, was low. A rough estimation of the phosphorus impact on the littoral zone associated to the decomposition process shows that after 24 h between 13.9 and 16.8 μg‐at.1−1have been released to the w

ISSN:0020-9309    

DOI:10.1002/iroh.19930780211

出版商:Akademie Verlag, Berlin    

年代:1993

数据来源: WILEY