Search Results

1 - 10 of 53 items :

  • "Trophic level" x
  • Life Sciences, other x
Clear All

Travaux de l’Institut de Pêches Maritime, 41, 3, 271-281. Stagioni, M., Montanini, S., Vallisneri, M. (2011): Feeding Habits of European Hake, Merluccius merluccius (Actinopterygii: Gadiformes: Merlucciidae), from the Northeastern Mediterranean Sea. Acta Ichthyologica et Piscatoria, 41, 4, 277-284. Stergiou, K. I., Karpouzi, V. S. (2002): Feeding habits and trophic levels of Mediterranean fish. Review in Fish Biology and Fisheries, 11, 217-254. Sutton, T. M., Cyterski, M. J., Ney, J. J., Duval, M. C. (2004): Determination of factors influencing stomach content

Abstract

: Between the years 1970-2010, using the Carlson model criteria, the rate of eutrophication and trophic level of the largest dimictic lakes of Western Pomerania were studied. It was found that during the testing period, Lake Ińsko Duże was a mesotrophic reservoir, and Lakes Wądół, Będzin and Ińsko Małe were characterized by a highly advanced eutrophy. Lakes Woświn, Morzycko, Krzemień, Chłop Duży and Jelenin had borderline characteristics between being mesotrophic and eutrophic, while Lakes Narost, Chłop Mały and Wisala were typically eutrophic reservoirs. During the study, changes in the trophic level of Lakes Ińsko Duże and Morzycko and Woświn were noted. The first of the reservoirs listed had the best water quality in the second half of the 1990s, during which time the other two lakes had the worst water quality, taking into account the whole study period. Such changes were not observed in the other reservoirs examined.

Cyanobacterial blooms in shallow lakes of the Iławskie Lake District

The dominance of blue-green algae observed in many lakes is related to a high trophic level. Shallow eutrophic lakes are particularly often abundant in blue-green algae. The research on phytoplankton, the results of which are presented in this paper, was carried out between 2002 and 2005 in six lakes. These lakes differed considerably in their size and management methods applied in the catchment (drainage) area. A few types of water blooms were distinguished, which is related to the catchment area management, the intensity of mixing and the trophic level. Algal blooms of the Planktothrix type appeared in lakes situated in an open area of agricultural catchment basins. Algal blooms of the Limnothrix type were characteristic of lakes with a forest-agricultural catchment area but surrounded by high shores, which reduced the wind influence on the mixing. Sporadic mixed algal blooms were typical of lakes situated in forest catchment areas.

Eutrophication parameters and Carlson-type trophic state indices in selected Pomeranian lakes

The objective of the study (2007-09) was to determine the current trophic state of eight selected lakes - Rybiec, Niezabyszewskie, Czarne, Chotkowskie, Obłęże, Jasień Południowy, Jasień Północny, Jeleń - based on Carlson-type indices (TSIs) and, to examine the relationship between the four calculated trophic state indices: TSI(SD), TSI(Chl), TSI(TP) and TSI(TN). Based on these values, it can be claimed that the trophy level of the lakes are within the mesotrophic and eutrophic states. It was observed that the values of the TSI(TP) in the analysed lakes are higher than the values of the indices calculated on the basis of the other variables. Moreover, the differences between the indices for particular lakes, suggest that in none of the analysed lakes is phosphorus a factor which limits algal productivity.

Toxicity Tests for Ensuring Succesful Industrial Wastewater Treatment Plant Operation

Industrial wastewaters are complex and can be polluted by non-biodegradable end toxic organic compounds and are a serious threat to the environment. Chemical procedure alone cannot provide sufficient information. A complete evaluation of wastewaters should include ecotoxicological tests too, especially concerning the complex wastewaters. In the literature review the authors attempted to establish which is the more promising and suitable aquatic toxicology test for sewage treatment plant influent toxicity monitoring.

A variety of types of organisms representing different trophic levels and many different species are used for aquatic toxicity testing. Toxicity characterization would be needed both for influents and effluents of wastewater treatment plant. For the purpose of screening biological wastewater treatment influent, toxicity to activated sludge microorganisms is important and toxicology tests here used are respirometry and bioluminescence toxicology tests. Respirometry toxicity tests are easy, fast and inexpensive compared to other approaches. Bioluminescence has been widely used, the most thoroughly investigated test system is the Microtox. The toxicity tests have also been compared by different authors. International, national and regional authorities use these tools to meet various regulatory and legislative requirements. Importance of biotesting has been emphasized also in EU legislation.

Epiphytic metazoans on emergent macrophytes in oxbow lakes of the Krapina River, Croatia: differences related to plant species and limnological conditions

This study investigated the structure of the epiphytic metazoans on emerged macrophytes in the littoral zone of two oxbow lakes with different trophic levels. Differences in the diversity and density of the epiphytic metazoans were analyzed in relation to plant architecture (simple or complex stems), food resources (algae and detritus) and water characteristics (transparency and derived trophic state index). A significant negative correlation was found between detritus on plants as food resource, and diversity and density of epiphytic metazoans, indicating grazing of microphagous species. Rotifers dominated in diversity and density in the epiphyton on all habitats. Total density of metazoans, rotifers and copepods in epiphyton were significantly higher on Mentha in mesotrophic lake than on Iris in a eutrophic lake. We presume that macrophyte belt width and trophic state governed biotic interactions and consequently epiphytic assemblages more strongly than macrophyte architecture. However, a Mentha habitat showed a slightly higher density and diversity of epiphytic metazoans in relation to Iris at the same site, but these differences were not significant.

Abstract

The succession of ungulate fauna was studied under conditions of artificially high density and limited residential area on the Biryuchy Island of the Azov-Sivash National Nature Park. Forming of inter-specific relationships between populations of the moufflon, red-deer and fallow-deer were revealed. The social hierarchy of the mentioned species, which are at the same trophic level, is determined. For the population of each species the factors influencing the dynamics of its number are given. Competition of species in steppe habitat is based solely on trophic relationships because the protective properties of the land are minimized. The forage base creates equal conditions for different species, since there is no woody vegetation in the steppe, which makes the large size of the red deer not important for the food obtaining. Concerning the fallow-deer, there is activation in reproductive potential, which is the part of the strategy in competition for resources and indicates its wider ecological lability in comparison with the red-deer. Meanwhile, a high level of adaptation to the conditions of the open steppe is noted in the moufflon, which (together with high reproductive capacity) rationally uses pasture potentials while the fallow-deer and red-deer have a certain level of stenophagy.

Comparison of offshore macrozoobenthos of the eutrophic Lake Gardzień and the alloiotrophic Lake Stęgwica

The aim of the present paper was to compare offshore macrozoobenthos and selected abiotic parameters of water and bottom sediments of two shallow lakes: Lake Gardzień, a "typical" eutrophic lake, and the polyhumic, alloiotrophic Lake Stęgwica. As both lakes are located very close to each other and have a similar morphometry and trophy level, it is highly probable that the observed differences may be the effect of a different humic substance content.

It was found that the presence of humic substances did not significantly affect the taxonomic composition and the biodiversity of the bottom fauna. In contrast to the similar taxonomic composition, the density of zoobenthos in the polyhumic Lake Stęgwica was over 10 times greater than in Lake Gardzień, which was the consequence of the more numerous occurrence of all groups of bottom fauna, particularly Oligochaeta and Chaoborus larvae.

A distinct increase in the abundance of bottom fauna in the polyhumic lake may be the consequence of an improvement in the nutritional conditions in the sediments (an increase in the calorific value, development of microorganisms), as well as a decrease in the negative effect of any toxic substances.

-350. Grochowska, J., Gawrońska H., 2004, Restoration effectiveness of a degraded lake using multi-year artificial aeration, Pol. J. Environ. Stud. 13: 671-681. Jaeger D., 1994, Effects of hypolimnetic water aeration and iron-phosphate precipitation on the trophic level of Lake Krupunder, Hydrobiologia 275/276: 433-444. Jiang J.-G., Shen Y.-F., 2006, Estimation of the natural purification rate of a eutrophic lake after pollutant removal. Ecol. Engin. 28: 166-173. Kronvag B., Jeppesen E., Conley D.J., Sondergaard M., Larsen S.E., Ovesen N.B., Carstensen J., 2005, Nutrient

C., Moretti M., Rocklin R., Schaffner U. 2008. Exotic knotweeds ( Fallopia spp.) negatively affect native plant and invertebrate assemblages in European riparian habitats. Biol. Cons. 141: 646-654. Hartley M. K., DeWalt S., Rogers W. E., Siem ann E. 2004. Characterization of arthropod assemblage supported by the Chinese Tallow tree ( Sapium sebiferum ). Tex. J. Sci. 56: 369-82. Kappes H., Lay R., Topp W. 2007. Changes in different trophic levels of litter-dwelling macrofauna associated with giant knotweed invasion. Ecosystems 2: 734-744. doi:10.1007/s10021