Defining limits to multiple and simultaneous anthropogenic stressors in a lake ecosystem – Lake Kinneret as a case study

2014 ◽  
Vol 61 ◽  
pp. 424-432 ◽  
Author(s):  
Yael Gilboa ◽  
Gideon Gal ◽  
Eran Friedler
Keyword(s):  
Lake Kinneret ◽  
Lake Ecosystem ◽  
Anthropogenic Stressors

scholarly journals Evaluation of community respiratory mechanisms with oxygen isotopes: A case study in Lake Kinneret

2002 ◽  
Vol 47 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Boaz Luz ◽  
Eugeni Barkan ◽  
Yftach Sagi ◽  
Yosef Z. Yacobi
Keyword(s):  
Oxygen Isotopes ◽  
Lake Kinneret

The Main Factor Determining the Dynamics of the Lake Ecosystem under Excessive Nutrient Loading (A Case Study of the Naroch Lakes)

2019 ◽  
Vol 12 (6) ◽  
pp. 544-561
Author(s):  
T. I. Kazantseva ◽  
B. V. Adamovich ◽  
A. F. Alimov ◽  
T. M. Mikheyeva ◽  
T. V. Zhukova ◽  
...  
Keyword(s):  
Nutrient Loading ◽  
Lake Ecosystem ◽  
Main Factor

scholarly journals Is nitrate a driver for pigments of phytoplankton (a case study from a small shallow European lake)?

2018 ◽  
Vol 54 ◽  
pp. 38
Author(s):  
Alexandra L. Rizhinashvili ◽  
Olga B. Maksimova
Keyword(s):  
Nitrogen Limitation ◽  
Nitrate Nitrogen ◽  
Close Correlation ◽  
Freshwater Ecosystems ◽  
Lake Ecosystem ◽  
Nitrate Anion ◽  
Production Potential ◽  
The Relationship ◽  
Drainage Ratio

The traditional view of biogenic limitation in freshwater ecosystems considers phosphorus as the primary limiting element, but this concept has recently been challenged. There are a number of studies that suggest that photosynthetic indices may depend on the levels of nitrogen (especially, nitrate-nitrogen). To test the hypothesis about the possibility of nitrogen limitation in the lake ecosystem, the present study analysed the water in the littoral zone of a shallow model lake for the relationship between the content of phytoplankton pigments (chlorophyll a and carotenoids) and nitrate. The nitrate-nitrogen was selected because it is the most chemically stable nitrogen species. The study was conducted in a small lake with a pronounced autochthonous regime (as indicated by its small drainage ratio) during a vegetation season with contrasting hydrological conditions. The relationship with the nitrate concentration was not confirmed for chlorophyll a, but the levels of nitrate anion and carotenoids were shown to be related. Chlorophyll a, which is regarded as a metabolically active component of phytoplankton cells, shows a close correlation with air temperature. The corresponding prognostic regression models were created. The data on nominal availability of nitrate-nitrogen for primary production show possible nitrogen limitation on some of the observation dates. If the production potential represented by certain levels of nitrate is not realised by phytoplankton, it can be used by filamentous algae. The results of the study provide first steps toward prediction of one of the indicators of phytoplankton growth, the content of two main types of pigment (chlorophyll a and carotenoids).

scholarly journals An application of a water assessment and simulation model in the remediation of the eutrophication capacity of a tropical water system: Case study the Lake Obili in Yaounde (Cameroon)

2017 ◽  
Vol 33 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Gideon A. Ajeagah ◽  
W. Victorien B. Abanda ◽  
George E. Nkeng
Keyword(s):  
Environmental Protection Agency ◽  
Treatment Plant ◽  
Water System ◽  
Quality Analysis ◽  
Lake Ecosystem ◽  
Biological Engineering ◽  
Tropical Water ◽  
Incentive Policies ◽  
The City

Abstract Lake Obili is one of the most famous lakes in the city of Yaounde, Cameroon. Studies carried out in this lake showed that it was hyper eutrophic and therefore it represents a great danger because it is used for aquaculture, tourism and a suitable laboratory for hydro-biological engineering. It is thus very vital to restore this lake ecosystem that singles itself in the heart of the city of Yaounde. This can be greatly facilitated through the use of Water Quality Analysis Simulation Program (WASP) of the United State Environmental protection Agency (USEPA). The outcomes of the previous results obtained from EUTRO, a Subroutine of the WASP model specialised in determining eutrophication level have proven that the remediation of this lake can be achievable through the implementation of a wet dredging, the construction and restoration of a wastewater treatment plant, the implementation of environmental incentive policies and the arrangement of the access to the lake. The application of the model is a contribution to the scientific mastery of nutrient flow, lake functioning and possibilities of restauration of highly polluted tropical water bodies subjected to domestic and industrial pollution.

scholarly journals The Effects of Artemia Cyst Harvesting on the Salt Lake Ecosystem

2020 ◽  
pp. 348-357
Author(s):  
Liudmila I. Litvinenko ◽  
Aleksander I. Litvinenko ◽  
Elena G. Boyko ◽  
Kirill V. Kutsanov ◽  
Marina A. Korentovich
Keyword(s):  
Salt Lake ◽  
Lake Ecosystem ◽  
Hypersaline Lake ◽  
Daily Production ◽  
Artemia Cyst ◽  
Main Components ◽  
Artemia Cysts ◽  
Artemia Population ◽  
B Coefficients

In Russia, the main stocks of Artemia cysts and cyst harvesting activities are concentrated in Western Siberia. About 1,100 tons of cysts are harvested annually, including 180 tons in the Kurgan Region and 140 tons from Medvezhye Lake (about 2 % of their world harvest). The purpose of this study was to determine the degree of influence of Artemia cyst harvesting on the ecosystem of a salt lake in a case study of Medvezhye Lake. The main trophic components of the ecosystem – phytoplankton, zooplankton, and zoobenthos – were analyzed. The salinity of the brine of Medvezhye Lake varied between 110 and 320 g/dm3 in different years. Phytoplankton in the lake function throughout the year. They are characterized by small cell sizes, low biomass (0.76±0.24 mg/L) and daily production (1.03±0.18 mgO2/L or 0.3±0.05 gC/m2), and high levels of A/B and P/B coefficients. Zooplankton and zoobenthos are represented mainly by Artemia. The biomass of Artemia shrimp reached 21.9±3.2 mg/L (219 kg/ha) on average during 1995-2018. During this period, the stock of cysts formed annually in the lake was 114.5±14.3 kg/ha; the harvest was 23.7±3.0 kg/ha (21 % of the stock). The main components of the ecosystem – phytoplankton – Artemia shrimp – Artemia cysts – were produced annually in the following proportions: 8390:2678:115 kg/ha·year (75:24:1 %). The removal of 23.7 kg/ha of the cysts (0.22 % of the production of all components) from the lake is negligible compared to the other components of the ecosystem. The residual density of cysts after harvesting, which is necessary for the reproduction of the Artemia population for the next season during the 1st generation, is 10 kg/ha. Averaged data indicate that the amount of Artemia cysts left in the ecosystem of Medvezhye Lake after cyst harvesting is 91 kg/ha, i.e. 9 times greater than the minimum required density. The results reported in the present study indicate that the current level of cyst harvesting cannot have any significant impact on the ecosystem of the hypersaline lake

scholarly journals Anthropogenic Stressors in Upland Rivers: Aquatic Macrophyte Responses. A Case Study from Bulgaria

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2708
Author(s):  
Gana Gecheva ◽  
Karin Pall ◽  
Milcho Todorov ◽  
Ivan Traykov ◽  
Nikolina Gribacheva ◽  
...  
Keyword(s):  
Plant Communities ◽  
Vascular Plants ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Base Flow ◽  
Urban Structures ◽  
Anthropogenic Stressors ◽  
Biological Responses ◽  
Riparian Habitats

Upland rivers across Europe still exhibit undisturbed conditions and represent a treasure that we cannot afford to lose. We hypothesize that the combination of pristine and modified conditions could demonstrate biological responses along the stressor gradients. Thus, the response of aquatic macrophyte communities to anthropogenic stressors along upland rivers in Bulgaria was studied. Six stressors were selected out of 36 parameters grouped into hydromorphological, chemical variables and combined drivers (catchment land use). The stressors strongly affected species richness on the basis of biological type (bryophytes vs. vascular plants) and ecomorphological type (hydrophytes vs. helophytes). Hydrological alteration expressed by the change of the river’s base flow and altered riparian habitats has led to a suppression of bryophytes and a dominance of riverbank plant communities. Seventy-five percent of mountain sites were lacking bryophytes, and the vegetation at semi-mountainous sites was dominated by vascular plants. It can be concluded that hydropeaking, organic and inorganic pollution, and discontinuous urban structures caused important modifications in the aquatic macrophyte assemblages. Macrophyte abundance and the biological and ecomorphological type of aquatic macrophytes reflect multi-stressor effects in upland rivers.

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