Julita Dunalska

Julita Dunalska
University of Gdansk | UG · Institute of Geography

About

70
Publications
20,800
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964
Citations
Citations since 2016
23 Research Items
790 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (70)
Article
Full-text available
The concentration of dissolved oxygen in aquatic systems helps to regulate biodiversity1,2, nutrient biogeochemistry3, greenhouse gas emissions4, and the quality of drinking water5. The long-term declines in dissolved oxygen concentrations in coastal and ocean waters have been linked to climate warming and human activity6,7, but little is known abo...
Article
Full-text available
The study aimed to assess the usefulness of mineral aggregates in orthophosphate (OP) removal from hypolimnetic water withdrawn from eutrophic lakes. Two low-cost and easily available reactive materials were tested: lightweight expanded clay aggregate (LECA) and crushed limestone (LS). Their performance regarding OP removal and the effect on the pH...
Article
A method of the simultaneous reduction of external and internal load of phosphorus as a new solution for lake restoration is presented. A flow-through, stratified lake, with diverse morphometry was selected for the study. In all three parts of the lake, an oxygen deficit was noted at the lake bottom at peak summer stagnation, with a simultaneous in...
Article
The aim of the study was to assess the efficiency of mineral aggregates in orthophosphate (OP) removal from hypolimentic water (HW) withdrawn from eutrophic lakes. Four P reactive materials were tested in sorption experiments: light weight expanded aggregate (LECA), zeolite (ZL), dolomite (DM) and limestone (LS). The two materials proved to be most...
Article
In this study, pressure driven ceramic membranes for microfiltration (MF) and ultrafiltration (UF) were used to improve the quality of waters in lakes. Four urban lakes located in the city of Olsztyn and belong to the Masurian Lake District: Track (53°47′21″N; 20°32′24″E), Podkówka (53°47′2″N; 20°27′1″E), Tyrsko (53°48′18″N; 20°25′21″E), and Redyka...
Article
Full-text available
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 probl...
Article
The article presents a novel, practical, sustainable and multi-purpose conceptual method for urban lakes water treatment. It is based on the separation of the inflowing water from the lake's main body with an impermeable barrier and a construction of enhanced littoral zone. The impermeable barrier alongside the shoreline creates a new littoral zone...
Article
The attempts to restore Lake Wolsztyńskie, by direct dosing to the water iron sulphate (PIX 113) and chloride polyaluminium (PAX 18) in 2005–2006, and then iron chloride to the lake's bottom sediments in 2012–2013, resulted in only short-lasting improvement of water quality. In 2016, the physicochemical and biological parameters have shown that the...
Article
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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.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to thei...
Article
Full-text available
Insight into how environmental change determines the production and distribution ofcyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus onhepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g.,anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their p...
Article
Phytoplankton (including plant-like, animal-like algae and Cyanobacteria) blooms have recently become a serious global threat to the sustenance of ecosystems, to human and animal health and to economy. This study focused on the composition and stability of blooms as well as their taxa-specific ecological sensitivity to the main causal factors (espe...
Article
Our analysis deals with the land development and management for tourist and recreational purposes around Drwȩckie Lake, a water body lying in the limits of the town Ostróda. A lot of tourists and residents in summer season can be attributed to the spatial management, a wide range of hospitality facilities and many opportunities to practice water sp...
Article
We studied an urban, flow-through lake with a large total catchment area, in the context of implementing complex protection and restoration methods in the shoreline zone and within the lake’s basin. The study was found that the annual total load of nutrients was 4 688 kg P and 50 652 kg N, which – when converted to the lake’s unit area – correspond...
Article
Full-text available
Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of pro...
Article
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We evaluated the influence of habitat connectivity and local environmental factors on the distribution and abundance of functional fish groups in 10 floodplain lakes in the Biebrza River, northeastern Poland. Fish were sampled by electrofishing, and 15 physico-chemical parameters were recorded at three sampling sites at each lake in the period of 2...
Article
The aim of this study was to determine seasonal changes in the occurrence of carbon forms in water and bottom sediment in lakes with a different type of mixing. The study was conducted in five urban lakes located in Olsztyn: Track, Sukiel, Podkówka, Redykajny and Tyrsko. The research was carried out in March, April, August and November. We analyzed...
Article
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Lakes along with their surroundings are an attractive landscape component that play an important role in recreation and relaxation. In Poland, the Great Masurian Lakeland, visited by a million tourists every year, is considered to be the most attractive lake area. However, tourist pressure has several negative effects which cause degradation of the...
Article
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We analysed total bacterial number and mean volume of cells at three sites in each of ten floodplain lakes in the Middle Basin of the Biebrza River, North-Eastern Poland to test bacterioplankton communities change according to the distance to the river. The composition of the bacterial communities was determined by fluorescent in situ hybridization...
Article
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This study compared selected methods of assessing the pollution in the littoral sediments by heavy metals (Zn, Cu, Pb, Ni and Cd) in 13 lakes of the Borecka Forest. For this purpose, the ecotoxicological criteria (PEL TEL), the geoaccumulation index (Igeo), the contamination factor (CF) and the contamination degree (Cd) were applied. Characteristic...
Article
Lake Domowe Duze (surface area 54 ha, maximum depth 7.2 m) is one of the two lakes lying in the town limits of Szczytno. For years, despite its large recreational potential, the lake had been rarely exploited by town residents or visitors due to its classless water quality. The restoration project initiated in 2010 has raised interest in spending l...
Article
Full-text available
The factors affecting prokaryotic and virus structure dynamics and bacterial community composition (BCC) in aquatic habitats along a ca. 1500 m of the Brattegg Valley lake-stream system (SW Spitsbergen) composed of three postglacial lakes created by Brattegg Glacier meltwater were examined. A high number of small-volume prokaryotic cells were found...
Article
The experiment was established in a set of containers. Every container held a 10 cm thick layer of profundal sediments and water from a badly polluted lake. The following five preparations were tested (brand names): AQUAKALGON+, BIOGEN REMEDIANT, BIODENN K, ECOTABS 1(TABLETS), ECOTABS 2(POWDER). The biological preparations were applied twice: phase...
Article
We investigated the effect of long-term inflow of untreated municipal sewage on the trophic status of the four urban lakes (Mielenko, Karczemne, Klasztorne Małe, Klasztorne Duże) connected by the river into one system. We delineated the catchments and sub-catchments of the individual lakes, to determine their hydrological parameters as well as the...
Article
Full-text available
An excess of nitrogen and phosphorus causes an increase in productivity, leading to degradation of a water reservoir. In order to reduce the eutrophication, protective and restoration methods are used. The objective of the paper was to determine the hourly and daily variability in nitrogen and phosphorus compounds in a lake restored by the hypolimn...
Article
Cyanobacterial blooms are broadly recognized as a global problem for aquatic ecosystems, health and economics. This study focused on determining the intensity and main contributors of cyanobacteria blooms, and identifying the cyanobacteria-environment based recovery potential of impaired urban lakes. Based on physicochemical parameters, nutrient-ri...
Article
The study was conducted on Lake Długie, located in the city of Olsztyn, which for 20 years received raw domestic sewage (400 m3 per day). After preliminary conservation operations, the lake was restored by artificial circulation and phosphorus inactivation methods. During artificial circulation, water temperature in the whole lake volume was equali...
Article
Full-text available
This study focused on the determination of the phytoplankton-based recovery requirement, including bloom intensity thresholds in human-affected lakes, helpful in the restoration. The phytoplankton and physicochemical analyses were carried out on seven urban lakes in Kartuzy and Skępe. The Phytoplankton Metric for Polish Lakes was used to assess the...
Article
Full-text available
The Gulf of Gdańsk is influenced by freshwater inflow from the River Vistula and by a wind-driven current along the coast. Bacterial communities from five stations along a salinity gradient were sampled during one day and analysed by terminal restriction fragment length polymorphism (T-RFLP), catalysed reporter deposition-fluorescence in situ hybri...
Article
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The fate of phytoplankton communities in different hydrological and hydrochemical conditions was studied in the middle basin of the Biebrza River (NE Poland). Our results showed that hydrological connec-tivity significantly influenced phytoplankton abundance in floodplain lakes: minimal abundance was stated in lotic and maximal in lentic waterbodie...
Article
We investigated changes in the spatial distribution of phosphorus (P) and nitrogen (N) in the deep, mesotrophic Lake Hańcza. The raw data collection, supported by global navigation satellite system (GNSS) positioning, was conducted on 79 sampling points. A geostatistical method (kriging) was applied in spatial interpolation. Despite the relatively...
Article
Full-text available
Phytoplankton dominance structure and abundance as indicators of the trophic state and ecological status of Lake Kortowskie (northeast Poland) restored with selective hypolimnetic withdrawal – Arch. Pol. Fish. Abstract. The objective of the study was to identify seasonal changes in phytoplankton taxonomic structure and development rates to characte...
Article
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Water eutrophication is associated with an increase in the organic carbon content (both particulate and dissolved forms), which may affect the functioning of the zooplankton community. Mesotrophic and eutrophic lakes in the Masurian Lake District (Poland) were selected to evaluate the relationship between the organic carbon level and the zooplankto...
Article
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The aim of this study was to compare the concentration of nitrogen and trace the dynamics of its changes in two lakes with different intensity of anthropogenic pressure. The dominant land use of Lake Paskierz catchment is built-up areas, while in Lake Sajmino, wasteland is the dominant land use. The total amount of nitrogen in Lake Paskierz ranged...
Article
Coagulation behaviour of polyaluminium chloride (PACl) was comparatively investigated in terms of the removal of turbidity and colour with surface water. The growth of flocs was also compared. The results show that the decrease in saturation and values of dissolved oxygen was ca. 20% for ALCAT and PAX 18 at both dosages and 15% for PAX XL 19H, resp...
Article
Full-text available
Littoral zone is the first zone of the lake, which directly borders the land and is a barrier to substances flowing from the catchment. It can play an important role in the productivity of the entire ecosystem, with both production and degradation of organic carbon. The aim of this study was to determine the role of phytoplankton in primary product...
Article
Full-text available
Effect of increased hypolimnion water temperature on stability of thermal profiles in startified lakes. Abstract The results demonstrated a distinct increase in temperature during the summer stagnation in the water layer below 7 meters of depth in the experimental part of the lake. There, the temperature of near-bottom water increased by 5.6⁰C from...
Article
The object of present study was Sukiel Lake (area 20.8 ha, max. depth 25 m), localised in north-eastern Poland (Mazurian Lake District), in Olsztyn city. The aim of this study was to analyse the phosphorus fractions in the sediments of two lake bottom zones - profundal (25 m) and sublittoral (7 m). Observed high P concentrations in the deposits of...
Article
We experimentally manipulated the thermal environment in laboratory mesocosms to evaluate the effect of temperature on organic matter transformation in two systems of lower and higher ambient nutrient availability. We used a system of 6 mesocosms, equipped with heating and cooling systems; 3 were filled with water from a mesotrophic lake and 3 with...
Conference Paper
Hypolimnetic withdrawal as a restoration method of lakes comprises the withdrawal of the nutrient-rich hypolimnion by a pipe directly to the outlet, thus replacing the surface outflow. One of the main factors determining the effectiveness of this method is water balance of a lake. The uneven distribution of precipitation in a year, as one of the ef...
Article
Full-text available
Sediments from hypereutrophic Lake Łajskie localized in northeastern Poland were examined on the basis of P-fraction. The sediments were collected at five sampling sites. In the investigated lake, the rank order of P-fractions was HCl-P > BD-P > NH4Cl-P > NaOH - nrP. The loosely sorbed phosphorus NH4Cl-P represented < 3% of the sedimentary inorgani...
Article
Full-text available
The aim of this study was to determine the chemical composition of Lake Widryńskie bottom sediments (max. depth. 27.0 m, area 123.9 ha). The sampling of bottom sediments was conducted once, on 16 August 2010. Sampling was made in 10 specific areas. Among the 10 samples, 4 samples were taken from the littoral and sublittoral zones, while the rest we...
Article
The study lakes are located in north-eastern Poland, in the same physiographic system. These lakes were formed during the last glacial period. The lakes differed in morphometry, catchment size and environmental conditions. The study included deep, clear water lakes that stratify in summer. The results from multiple linear regression equations indic...
Article
Full-text available
Total organic carbon (TOC) can be one of the parameters used to determine trophic state in lakes, as shown by the statistically significant correlation between TOC and chlorophyll, total phosphorus and Secchi disk transparency. Calculation of the TSI index based on TOC according to the formula TSI(TOC) = 20.59 + 15.71 ln(TOC) and its introduction a...
Article
Full-text available
Hypolimnetic withdrawal as a restoration method comprises the withdrawal of the nutrient-rich hypolimnion by a pipe directly to the outlet, thus replacing the surface outflow. The method was first applied to Lake Kortowskie in 1956 and continues today. The direct effects of hypolimnetic withdrawal can be observed in the near-bottom waters during th...
Article
Full-text available
This study demonstrates the significant effect of the thermal regime of the Konin lasek on the structure of bacterioplanktonand the concentration of heteromorphic organic master. Seasonal differentiation in the maximum concentrations of POC and DOC should be considered the most typical trait of the lakes examined. Trhe dynbamics of POC were charac...
Article
Full-text available
Nine reservoirs were examined, with the surface area ranging from 0.2 to 2.7 ha and the depth from 1.0 to 2.2 m, situated on the eastern peripheries of the Olsztyn City. The drainage basins of these reservoirs have been transformed by man. Concentrations of the individual chemical parameters in the water of the hollows depended on the direct draina...
Article
Full-text available
This study investigated concentration changes of dissolved and particulate organic carbon in a meromictic lake to determine the lake’s productivity. It was revealed that the dominant form of organic carbon was the dissolved form (DOC). Maximum production activity was observed in summer (with the peak in June). At the same time, the factors restrict...
Article
Full-text available
Lake Kortowskie was studied during water stagnation, when it is subjected to bottom water withdrawal to outflow through a pipeline. The examinations were carried out after flow reduction from 0.25 m 3 ⋅ s -1 to about 0.05 m 3 ⋅ s -1 . It has been revealed that hypolimnion withdrawal has much more effect on the temperature and oxygen content in the...
Article
Full-text available
The study object was Lake Kortowo, restored since 1956 by withdrawing nutrient-rich hypolimnion water directly to the outflow by means of a pipeline. The studies were carried out after limiting the water flow in the pipeline from 0.25 m3·s-1 to 0.05 m3·s-1. The nutrients budget analysed in detail for the period of the pipeline operation was later c...
Article
Full-text available
Lake Kortowskie is restored by the hypolimnetic withdrawal method: rich in nutrients near-bottom waters are removed by a pipeline directly to the outflow instead of the natural outflow of surface waters. It has been found out that the amount of water discharged through the pipeline and therefore the amount of removed phosphorus depends on the surfa...
Article
Physical and chemical water studies were conducted in the period May 1991-April 1994 in four distinctly different parts of the Ukiel lake located in the city of Olsztyn. The results obtained revealed eutrophic characteristics of the lake. The Gutkowska and Przejma lake parts appeared to be less eutrophied than the Lupsztychska and Olsztynska parts....
Article
Full-text available
e results of the study revealed a clear variability in the concentrations of organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP). e maximum mean values were observed in the spring and determined mainly by the organic forms. e source of organic matter in the spring is the primary production in the lake, as confirmed by the low valu...
Article
Full-text available
The study revealed that the surficial sediments of Lake Licheñskie were mineral with a low organic matter content. The main components of the chemical composition were calcium carbonate and silica. Phosphorus in the surficial sediments occurred in small amounts not exceeding 2 mg Pg -1 d.w. Higher values (maximum to 6.232 mg P g-1 d.w.) were observ...
Article
Full-text available
The aim of the study was to examine the spatial and seasonal variability, and the dynamics of organic carbon compared to the hydrochemical parameters, and subsequently, to determine the productivity of the waters included in the cooling system of two power plants. The results of the study revealed obvious differences in the content of dissolved (DO...
Article
Full-text available
This study focused on the environmental conditions in four mesotrophic lakes, Mielno, Maróz, Œwiête, and £añskie, located in the catchment basin of the Marózka and upper £yna rivers. Changes in the thermal and oxygen conditions and the trophic status of the water of these lakes were evaluated based on the results of measurements conducted in 2004-2...