Effects of continuous nitrate treatment of hypolimnion in a small, hypereutrophic lake.

Continuous nitrate treatment is an innovative, nature-based and cost-effective restoration method that has been implemented in a small, hypereutrophic lake by redirecting the nitrate-rich waters of the lake's natural tributaries into its hypolimnion. The aim of this treatment is to increase the redox potential at the sediment-water interface in order to provide conditions for efficient phosphorus binding. To assess the effects of this treatment, studies of the physico-chemical and biological parameters of the lake waters were carried out before its application (PreNT - years 2005-2007), during its application (FullNT - 2008-July 2019), and in the period when installation was partly clogged (LimNT- August 2019-2021).

Spatio-temporal variations in water quality of a river-lake system during restoration treatments.

To fill the knowledge gap about the functioning of the lake-river system subjected to restoration treatments, two tributaries, a shallow, restored lake and its outflow, were examined. The quality of water inflows, lake and outflow was compared before (BR), during sustainable (SR, deep water aeration, phosphorus inactivation and biomanipulation for 3 years) and limited lake restoration (LR, only aeration for 2 years). Physico-chemical parameters were analysed monthly at five stations.

The influence of land use in the catchment area of small waterbodies on the quality of water and plant species composition.

Land use significantly affects the function of waterbodies in landscape. Although there have been numerous studies on the influence of the catchment area on the trophic and ecological status of waterbodies, still is not reached an agreement on the width of the buffer zone that is necessary for effective protection of waterbodies. The aim of the study was to show whether small waterbodies are predominantly influenced by land use in the entire catchment area or only in the zone extending 100 or 200 m away from the shoreline.

Verifying the usefulness of macrophytes as an indicator of the status of small waterbodies.

Small waterbodies are characterised by a high variability of physicochemical parameters. This has an impact on aquatic macrophytes, which are functional components of aquatic ecosystems that also exert a strong influence on other components of these ecosystems. Therefore, their importance in the classification of reservoirs is unquestionable.

Zooplankton changes during bottom-up and top-down control due to sustainable restoration in a shallow urban lake.

Long-term cyanobacterial blooms and hypereutrophic state have been typical for the shallow, urban Swarzędzkie Lake for many years. Diversion of sewage did not change its trophic status, so restoration began in autumn 2011 using the sustainable approach based on three methods. The aim of the study was to analyse how sustainable restoration affects zooplankton.

Water quality and phytoplankton structure changes under the influence of effective microorganisms (EM) and barley straw - Lake restoration case study.

Many lakes worldwide, especially shallow, experience great changes due to eutrophication, manifested in severe, usually toxic water blooms, disqualifying them from recreation. In order to improve water quality, restoration programs are implemented, including numerous methods. Intense nutrient cycling resulting from detrimental role of sediments impede obtaining of clear water state.

A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins.

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification.

Internal Phosphorus Loading from the Bottom Sediments of a Dimictic Lake During Its Sustainable Restoration.

The ribbon type Lake Durowskie (Western Poland) is currently undergoing a sustainable restoration process due to water quality deterioration, manifested in water blooms, low transparency, and oxygen deficits near the bottom sediments. Three restoration methods were applied: (i) hypolimnion aeration using two wind-driven pulverizing aerators installed at the deepest places, (ii) phosphorus inactivation using small doses of iron sulfate and magnesium chloride several times a year, and (iii) biomanipulation using pike fry stocking. Research on the exchange of phosphorus in the sediment-water interphase was conducted in the years 2009-2016 to determine the multiannual changes of internal phosphorus loading from bottom sediments during the restoration process.

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins.

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.

Influence of stormwater runoff on macroinvertebrates in a small urban river and a reservoir.

The impact of stormwater on benthic macroinvertebrates was studied in two annual cycles. Five small catchments drained by stormwater sewers to a small urban river and a small and shallow reservoir situated in its course were selected. These catchments were located in residential areas with single-family houses or blocks of flats as well as industrial areas, i.

Cyanobacteria blooms before and during the restoration process of a shallow urban lake.

Swarzędzkie Lake (near Poznań) has been heavily polluted. To improve the water quality, the restoration of lake by three methods: aeration, phosphorus inactivation using small doses of iron sulphate and magnesium chloride (FeSO and MgCl) and biomanipulation was initiated at the end of 2011. The aim of the present study was to determine whether sustainable restoration has a significant impact on phytoplankton, especially cyanobacterial blooms in a shallow, urban, degraded lake.

The influence of restoration measures on phosphorus internal loading from the sediments of a hypereutrophic lake.

Uzarzewskie Lake was a hypereutrophic, dimictic lake characterized by low water transparency, high chlorophyll-a concentration and intense phytoplankton blooms; thus, restoration treatment was started. A chemical treatment, based on phosphorus inactivation with small doses of iron sulphate, was undertaken in 2006-2007. Nitrate-rich groundwater flowing from seepage springs was directed into the lake hypolimnion to increase redox potential since 2008.

Chemometric approach to evaluate element distribution in muscle, liver and fish bone of roach (Rutilus rutilus), silver bream (Blicca bjoerkna) and crucian carp (Carassius carassius) from Swarzędzkie Lake (Poland) using ICP-MS and FIAS-CVAAS techniques.

The content of elements in fish tissues and organs from Swarzędzkie Lake was investigated in order to evaluate the possible risk associated with their consumption by animals as well as humans. Samples of muscle, liver and fish bone of three fish species; roach (Rutilus rutilus), silver bream (Blicca bjoerkna) and crucian carp (Carassius carassius) were collected from seine catches undertaken as part of the biomanipulation of Swarzędzkie Lake. Element concentration (Al, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) was determined by inductively coupled plasma mass spectrometry (ICP-MS), with the exception of Hg where the flow injection analysis system cold vapour atomic absorption spectrometry (FIAS-CVAAS) was applied.

Phytoplankton Composition and Abundance in Restored Maltański Reservoir under the Influence of Physico-Chemical Variables and Zooplankton Grazing Pressure.

In this paper we present the effects of environmental factors and zooplankton food pressure on phytoplankton in the restored man-made Maltański Reservoir (MR). Two methods of restoration: biomanipulation and phosphorus inactivation have been applied in the reservoir. Nine taxonomical groups of phytoplankton represented in total by 183 taxa were stated there.

Storm water contamination and its effect on the quality of urban surface waters.

We studied the effect of storm water drained by the sewerage system and discharged into a river and a small reservoir, on the example of five catchments located within the boundaries of the city of Poznań (Poland). These catchments differed both in terms of their surface area and land use (single- and multi-family housing, industrial areas). The aim of the analyses was to explain to what extent pollutants found in storm water runoff from the studied catchments affected the quality of surface waters and whether it threatened the aquatic organisms.

Spatial and seasonal variability of pore water phosphorus concentration in shallow Lake Swarzędzkie, Poland.

Pore waters play an important role in phosphorus dynamics in aquatic ecosystems. Phosphorus concentrations in pore waters are much higher than above the bottom. This is confirmed by the results of this study concerning the hypereutrophic lake.

Environmental applications of ICP-MS for simultaneous determination of trace elements and statistical data analysis.

Water samples collected from two lakes separated from each other by the cascade of four small lowland reservoirs were subjected to analyses in order to compare contamination levels in these ecosystems. Inductively coupled plasma mass spectrometry was used to determine eight elements: Al, As, Cd, Cr, Li, Mn, Sb, and Zn. Statistical methods were applied in order to assess the degree of self-purification of water, during its flow from Swarzedzkie Lake to Malta Lake.

Spatial distribution of major and trace elements in the water of Swarzedzkie Lake (Poland).

In order to characterize the contamination of the Swarzedzkie Lake and generate elemental distribution patterns 18 elements have been determined in samples of water, taken just above the bottom sediments. Analyses were carried out using two instrumental techniques - ICP-OES and ICP-MS. Two main sources of contamination were identified - diffuse pollution from agriculture and stormwater from the town.