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Dynamics of the daily course of water temperature in Polish lakes

Skowron R., Piasecki A.

Journal of Water and Land Development

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2016

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no. 31

149--156

EN

The study focuses on short-term changes in surface water temperature in Polish lakes, and is based upon the experimental measurements of water temperature conducted every 60 minutes during the years 1971–2015. 19 lakes were selected on the grounds of their morphometric properties. The examinations were carried out in the system of expeditionary measurements (up to 8 days) and stationary measurements (over 2 months), and included temperature of surface water and its vertical distribution. The analysis of the results showed that temperature differences of water (daily amplitudes) were observed in both time and spatial distribution. The biggest differences in water temperature occurred during spring warming, and often reached 4–5°C, while rarely exceed 2°C in the remaining periods of the yearly cycle. The mean day value occurs twice; in the morning between 8:00 (7:00 GMT) and 11:00 (10:00 GMT), and in the evening at 20:00 (19:00 GMT) and 22:00 (21:00 GMT). Daily changes in the vertical distribution of water temperature are clearly visible down to the depth of 2.5–3.5 m, whereas are just perceptible to the depth of 5.5–7.0 m.

PL

Praca dotyczy krótkotrwałych zmian temperatury wody powierzchniowej w jeziorach w Polsce. Została ona opracowana na podstawie eksperymentalnych pomiarów temperatury wody prowadzonych co 60 minut w latach 1971–2015 w 19 jeziorach wytypowanych na podstawie cech morfometrycznych. Badania prowadzono w systemie pomiarów ekspedycyjnych (do 8 dni) i stacjonarnych (ponad 2 miesiące) i obejmowały temperaturę powierzchniową wody oraz jej pionowy rozkład. Na podstawie analizy wyników stwierdzono różnice temperatury wody (amplitudy dobowe) zarówno w rozkładzie czasowym, jak i przestrzennym. Największe różnice temperatury wody występowały w okresie wiosennego nagrzewania i często osiągały 4–5°C, natomiast w pozostałych okresach cyklu rocznego rzadko przekraczały 2°C. Na podstawie cogodzinnych pomiarów temperatury wody można stwierdzić, że temperatura przed południem między godziną 8:00 a 11:00 (7:00 a 10:00 GMT) oraz późnym wieczorem w godzinach 20:00–22:00 (19:00–21:00 GMT) była najbardziej zbliżona do średniej dobowej. Zmiany dobowe w rozkładzie pionowym temperatury wody wyraźnie zaznaczają się do głębokości 2,5–3,5 m, natomiast dostrzegane są do głębokości 5,5–7,0 m.

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Rotifera communities associated with invasive Vallisneria spiralis L. (Hydrocharitaceae) versus native macrophytes in the lakes heated by power stations (Konin lakes, W. Poland)

Ejsmont-Karabin J., Hutorowicz A.

Polish Journal of Ecology

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2011

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Vol. 59, nr 3

569-576

EN

The role that invasive Vallisneria spiralis L. plays in determining the species richness of the rotifer community was examined in the littoral zone of two heated (by power stations) lakes near Konin (W. Poland) (Lake Licheńskie - area 153.6 ha, max. depth 13.3 m and Lake Ślesińskie - area 148.1 ha, max. depth 25.7 m). Vallisneria spiralis is a thermophilic and vegetative reproducing species which has been recorded in the lakes since the 1990s. It spreads very quickly in the lakes, forming monospecific, dense beds which, force out all other submerged vegetation. Samples were collected in August 2004 on 8 littoral stations of Lake Licheńskie and Ślesińskie. Five-liter samples of water (plankton species) and macrophytes (epiphytic species) were elaborated separately. An analysis of the taxonomic structure of rotifer communities inhabiting single-species Vallisneria beds and mixed-species (Vallisneria plus other macrophyte species) beds showed that both communities were relatively rich in species and similar in terms of species composition. A total of 100 species of Monogononta were identified. Single-species Vallisneria beds were inhabited by 77 species, whereas 82 species were found at stations with mixed vegetation. Species diversity was relatively high in both types of macrophyte assemblages. Numbers of rotifer species inhabiting the single-species Vallisneria beds are among the average values observed in a littoral zone rich in macrophyte species from lakes of different morphometry and trophic state. The above observations confirm part of the conclusions from literature that invasions by new plant species do not always lead to a decline in the habitat value for native animals. Otherwise, the invaded plant creates the habitat easily colonized by the native plankton and epiphytic invertebrates.

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The dynamics of phosphorus in lacustrine sediments : contents and fractions in relation to lake trophic state and chemical composition of bottom deposits

Rzepecki M.

Polish Journal of Ecology

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2010

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Vol. 58, nr 3

409-427

EN

Phosphorus is still recognized as the element driving the matter cycling in freshwater ecosystems. It is the key nutrient in productivity and eutrophication process of lakes and reservoirs. The bottom sediments cumulatively formed inside and in-shore of lakes play a crucial role in accumulation/sorption of phosphorus organic compounds, as well as in release/desorption of the compounds available for uptake by producers and microbial heterotrophs. These two opposite processes are dependent on the chemical composition of sediments and on the site conditions (like oxygen, pH) in over-bottom layers. About three hundred of the sediment surface layer samples were taken from the lacustrine habitats in a variety of lakes typical for postglacial landscape (Masurian Lakeland, Poland): profundal and littoral zones in lakes forming a trophic gradient including a humic lake, river/lake ecotone zone and wetland sites adjacent to lake shoreline. The contents of Ca, Fe, Mg, Mn and Al were analysed as well as the amount of total P (TP) and its three basic groups i.e. easily exchangeable, hardly exchangeable and non-exchangeable fractions. It was found that the sediments of humic lake had the most different, distinct chemical composition and contained very small amounts of Fe, Mn, Mg and Ca - nearly 30 times less than sediments of other, non-humic lakes. These sediments contained the most of organic matter and similar (as in non-humic lakes) amounts of TP whose dominant part (80%) consists of hardly exchangeable organic fraction. Sediments of lakes forming the trophic gradient along the small (15 km long) river (Jorka River) showed consistent changes in the chemical composition. Sediments of lakes situated up the river system (meso- and meso-eutrophic lakes) had higher content of organic matter and Ca but lower content of TP, Fe and Mg than sediments of lakes in the lower part of the river system (eutrophic and hypertrophic lakes). The content of these elements was also higherin profundal than in littoral sediments. Significantly higher content (40-70%) of non-exchangeable P was found in sediments of eutrophic and hypertrophic lakes than in sediments of meso- and meso-eutrophic lakes (30-60%) in both the littoral and profundal zones. Sediments of the river-lake-river ecotones (Krutynia River) showed also the consistent changes of element content along the river flow through the lake. The amount of TP was lower in riverine sediments down and upstream the lake than in lake sediments. Organic matter and Fe contents were lower and Ca, Mg, Mn and Al contents were higher in river-lake-river ecotones or similar to those in sediments of the lakes from the trophic gradient. Easily exchangeable phosphorus prevailed in lake sediments; TP in riverine sediments was dominated by hardly exchangeable and non-exchangeable forms and was similar to that found in littoral sediments of lakes from the trophic gradient. Inshore wetland sediments were characterized by a highcontent of organic matter - higher than in littoral and profundal sediments of lakes forming the trophic gradient. The content of Ca, Mg, Mn and Fe was two to five times lower than in sediments of lakes from the trophic gradient but similar to sediments of humic lake. They also contained less TP than profundal sediments from the trophic gradient and humic lakes but had similar content to littoral and riverine sediments. As in the case of profundal and riverine sediments, non-exchangeable and hardly exchangeable P fractions dominated TP content in wetland inshore sediments. Almost all phosphorus a ccumulated in these sediments is associated with a high organic matter deposition. The study results concern the basic types of lake and lacustrine habitats representative for the postglacial landscape of north and north-east Europe. A significant diversity of sediment origin, chemical composition and phosphorus amount and its potential mobility was found among the sediment types. The wetland and humic sediments appeared to be active in cumulation and stabilisation of P resources while sediment of nonhumic, trophic lakes (especially in profundal zoners) are the active sites for P release and sorption processes.

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Wymiar fraktalny fragmentów zdjęć lotniczych strefy przybrzeżnej jeziora Mikołajskiego, Śniardw i Łuknajno

Miałdun J., Ostrowski M.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2010

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Vol. 21

267--279

PL

Opis, klasyfikacja i wizualizacja cech przestrzeni są podstawowymi czynnikami budującymi wielowymiarowy intelektualny model środowiska naturalnego. Jednym z kryteriów opisu środowiska jest wnioskowanie analityczne i ocena dynamiki zjawisk na podstawie cech strukturalnych, przy czym struktura przestrzeni i kształtujące ją zjawiska zależą w znacznym stopniu od przyjętych założeń i sposobu rejestracji, analizy oraz zastosowanych narzędzi. Jedną z metod oceny krajobrazu ekologicznego, która staje się coraz bardziej znacząca i doceniana, jest wymiar fraktalny satelitarnych i lotniczych zobrazowań powierzchni Ziemi. W pracy, i w opisie krajobrazu, wykorzystano wymiary fraktalne, których algorytmy obliczania zostały oparte na „metodzie graniastosłupów trójkątnych” w opcji zarówno globalnej, jak i lokalnej. Do testowania metody wykorzystano zeskanowane spektrostrefowe zdjęcia lotnicze pobrzeża i litoralu jezior charakterystycznych jezior mazurskich: Mikołajskiego, Śniardw i Łuknajno. Są to obszary o zróżnicowanym przestrzennie i strukturalnie litoralu obejmującego pasy: roślinności bagiennej, roślin wynurzonych (trzcinowiska), roślin pływających, jak i – również uwidocznioną na zdjęciach –strefę podwodną roślin zanurzonych, które porastają dno zbiornika. W celu porównania i klasyfikacji obliczonych wymiarów fraktalnych wybrano fragmenty wymienionych zbiorników obrazujące przykłady różnych stref roślinności przybrzeżnej, a także dodatkowo, jako obszary referencyjne, obszary lądowe w różnym stopniu użytkowane rolniczo, zalesione lub zurbanizowane, charakteryzujące się zróżnicowanymi formami tekstury. Wyniki badań wykazały, że przy odpowiedniej standaryzacji przygotowania danych teledetekcyjnych, wymiar fraktalny może być cennym wskaźnikiem różnorodności krajobrazu i jego klasyfikacji jakościowej.

EN

A description and classification of the characteristics of space are the fundamental factors in building a multidimensional model of the natural environment. One of the criteria of describing an environment is analytical inferring and evaluation of the dynamics of phenomena based on structural attributes. The structure of space depends on the point of view. In this study, also in landscape description, were used fractal dimensions whose calculation algorithms were based on the „triangular prism method” in both the global and local options. To test the method, scanned infrared spectrozonal aerial images of the shore zones of the Mazury lakes Mikołajskie, Śniardwy and Łuknajno were chosen. There are areas with variously developed littoral zone embracing belts of marsh vegetation, emerged plants (reeds), floating plants, as well as the – also visualized in the images – zone of submerged plants growing on the bottom of the water body. To compare the calculated fractal dimensions, fragments were chosen of the mentioned water bodies representing different zones of shoreline vegetation, as well as the surrounding land under agricultural use, forest cover and urbanized areas. The results of the investigation revealed that, with appropriate standardization of remote sensing data preparation, the fractal dimension can be a valuable indicator of quality of landscape diversity.