Suchergebnisse

Ergebnisse 1 - 10 von 86 :

  • "Trophic level" x
Alle zurücksetzen
Diet Composition and Trophic Level of Greater Forkbeard Phycis blennoides (Gadiform: Phycidae) from the Algerian Coast

: 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 retention by striped bass captured using gillnets. Journal of Fish Biology, 64, 903-910. Treasurer, J. W. (1988): Measurement of regurgitation in feeding studies of predatory

Open access
Evaluation of trophic level of the largest dimictic lakes of western Pomerania based on the Carlson criteria

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.

Open access
Turkusowe Lake (Wolin Island, Poland) - Surface Waters Quality Changes in Years 1986-2010

Abstract

After presentation of the characteristics of a water reservoir in CaCO3 excavation pit, called the Turkusowe Lake, situated in the Wolin National Park on the Wolin Island, available results of the analyses referring to the quality of surface water of this water reservoir and being carried out since 1986 as well as those of own studies being carried out from 1999 to 2010 were gathered, collecting this way a research material covering the quarter-century 1986-2010. It was shown that the Turkusowe Lake is a water reservoir being resistant by nature to eutrophication (lake basin development and depth, surrounding by the heights adhering to it, and presence of CaCO3 building the lake basin), whereas an increase in the trophic level and development of eutrophication phenomena in the form of weak phytoplankton blooms being observed, particularly in 2005-2010, is connected with increased anthropogenic pressure in the form of direct discharge of municipal sewage to the lake and waste-water to the soil in the alimentation zone of underground waters feeding this lake. The extent of anthropogenic pressure was so big that it started to prevail over the natural processes limiting an increase in the trophic level in this lake.

Open access
Towards Methodological Problems of Trophic State Assessment of Running Waters

Abstract

Deep analysis of trophic state assessment methods has led to conclusion, that currently there is no universal methodology and existing methods are characterized by significant shortcomings. The approach proposed by the authors is different from generally used. Authors start from the assumption, that trophic state can be reflected by the state of biotic balance, which can be described by the values of Index of Trophic State. Researches were carried out in order to assess the trophic state of running waters and to estimate the limiting role of biogenic substances for eutrophication process development on the base of author's concept founded on above mentioned index.

Open access
Cyanobacterial blooms in shallow lakes of the Iławskie Lake District

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.

Open access
Can thiol compounds be used as biomarkers of aquatic ecosystem contamination by cadmium?

Can thiol compounds be used as biomarkers of aquatic ecosystem contamination by cadmium?

Due to anthropogenic activities, heavy metals still represent a threat for various trophic levels. If aquatic animals are exposed to heavy metals we can obviously observe considerable toxicity. It is well known that an organism affected by cadmium (Cd) synthesize low molecular mass thiol compounds rich in cysteine (Cys), such as metallothioneins (MT) and glutathione (GSH/GSSG). The aim of this study was to summarize the effect of Cd on level of thiol compounds in aquatic organisms, and evaluate that the concentrations of thiol compounds are effective indicators of Cd water pollution and explain their potential use in biomonitoring applications.

Open access
Trophic Status of Blidinje Lake (Bosnia and Herzegovina) Based on the Determination of the Trophic State Index (TSI)

Abstract

Blidinje lake is an integral part of the Nature Park Blidinje established in 1995. Blidinje lake is largest mountain lake in Bosnia and Herzegovina (B&H) according to the surface and water supplies. Considering the surface, it is surprising to its low depth and large surface changes.

Eutrophication is defined as the ‘biological effect of increasing concentrations of plant nutrients in aquatic ecosystems’. Eutrophication results in increased primary production or the production of aquatic plants. It can adversely affect the suitability of the use of water resources for other purposes. Metabolism of shallow lakes is extremely specific such as classical connections; algal biomass with a load of nutrients in shallow lakes can have catastrophic effects.

Nutrients that come directly or indirectly into water lead to increase in the amount of algae as well as changes in the composition of phytoplankton, where there is suppression of diatoms and green algae by cyanobacteria.

The values of parameters assessing trophic index (Trophic State Index [TSI]) are total phosphorus, chlorophyll a and transparency. This method that generalises numerous data using mathematical equations allows the expression of trophic level.

On the basis of earlier studies on physical and chemical parameters of water quality in Blidinje lake, Carlson trophic index was calculated, and based on that assessment, trophic level is given.

Open access
Optimization of The Hydraulic System of The Storage Reservoir Hydraulically Unloading The Sewage Network

Abstract

After presentation of the characteristics of a water reservoir in CaCO3 excavation pit, called the Turkusowe Lake, situated in the Wolin National Park on the Wolin Island, available results of the analyses referring to the quality of surface water of this water reservoir and being carried out since 1986 as well as those of own studies being carried out from 1999 to 2010 were gathered, collecting this way a research material covering the quarter-century 1986-2010. It was shown that the Turkusowe Lake is a water reservoir being resistant by nature to eutrophication (lake basin development and depth, surrounding by the heights adhering to it, and presence of CaCO3 building the lake basin), whereas an increase in the trophic level and development of eutrophication phenomena in the form of weak phytoplankton blooms being observed, particularly in 2005-2010, is connected with increased anthropogenic pressure in the form of direct discharge of municipal sewage to the lake and waste-water to the soil in the alimentation zone of underground waters feeding this lake. The extent of anthropogenic pressure was so big that it started to prevail over the natural processes limiting an increase in the trophic level in this lake.

Open access
Bioindication of Water Properties by Algal Communities in the Pamir High Mountain Mineral and Thermal Springs

Abstract

The bioindication methods have been implemented for the first time for the analyses of water properties in six mineral and thermal springs of Pamir. The studied environment was characterized as flow-alkaline, well oxygenated with low salinity, and low to middle organically polluted. Studied diatom communities preferred periphytonic and benthic habitats of temperate temperature waters. Bioindicator species preferred photosynthetic way of protein synthesis. In first time assessed the trophic level of each studied source show that all they have a state from oligotrophic to mesotrophic. Bioindication methods revealed the effectiveness of nature conservation system in Tajikistan and relevance of bioindication methods using in purpose of assessment and monitoring of water sources on the protected territories.

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

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.

Open access