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Wyszukujesz frazę "oxbow" wg kryterium: Wszystkie pola


Tytuł:
Impact of Jute Retting on Phytoplankton Diversity and Aquatic Health: Biomonitoring in a Tropical Oxbow Lake
Autorzy:
Ghosh, D.
Biswas, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/123191.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
biomonitoring
oxbow lake health
jute retting
phytoplankton
diversity index
Opis:
Phytoplankton acts as a primary producer and biological filter of aquatic ecosystem. Jute retting during monsoon is a common anthropological activity in the rural Bengal. Quantitative seasonal bio-monitoring of phytoplankton community composition with relative abundance and its diversity indices was carried out in this study from April 2013 to March 2014 to assess water quality and the impact of jute retting on phytoplankton diversity of a tropical fresh water oxbow lake in Nadia district of India. We recorded a total of 34 genera of 5 distinct classes, Chlorophyceae (15), Bacillariophyceae (13), Cyanophyceae (4), Dinophyceae (1) and Euglenophyceae (1). Members of Chlorophyceae dominated throughout the year. Unlike Cyanophyceae, Bacillariophyceae was found to be significantly increased during monsoon when compared to the rest of the year. Average phytoplankton density was highest in post-monsoon (8760/L) followed by monsoon (4680/L) and pre-monsoon (3650/L). Owing to the dominance of class Chlorophyceae and Bacillariophyceae we found this lake to be oligotrophic to mesotrophic. Indices values of genera richness, Shannon-Wiener, evenness and Simpson’s diversity reached their lowest 14, 1.61, 0.61 and 0.68 in monsoon and highest 23, 2.42, 0.77 and 0.86 in post monsoon respectively. The lowest diversity values during monsoon clearly suggested that the selected lake has highest anthropogenic pollution due to jute retting which impacted significantly on phytoplankton diversity. Therefore, the lake is not conducive for fish growth especially during monsoon and we opine that there is a need to regulate jute retting process, intensity and its density in the lake during the monsoon to ensure enhanced biodiversity for sustainable management and conservation of aquatic environment of this Oxbow lake.
Źródło:
Journal of Ecological Engineering; 2015, 16, 5; 15-25
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Pleistocene and Holocene environmental evolution of the Wkra River Valley near Bielawy Gołuskie (central Poland) recorded in palaeo-oxbow lake deposits
Autorzy:
Niska, M.
Jonczak, J.
Gadziszewska, J.
Powiązania:
https://bibliotekanauki.pl/articles/2060392.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
oxbow lake
Wkra River
Polska
Multi-proxy analysis
Early Holocene
Opis:
This study aimed to reconstruct environmental changes in the Wkra River Valley near Bielawy Gołuskie (central Poland) based on geochemical, palynological and subfossil Cladocera analysis of deposits filling a palaeo-oxbow lake. Two sediment boreholes collected from the palaeochannel bend (BG-1) and neck (BG-2) include full sequences of organic deposits lying on clastic deposits. The lower part of the BG-1 borehole contains gyttja that accumulated during the Younger Dryas and the Preboreal, which is covered by reed peat of Preboreal and Boreal age. On top of this is alder peat that accumulated during the Atlantic. The ages of the gyttja and peat were confirmed by both radiocarbon dating and palynological analysis. The peats are characterized by a significant content of organic matter, which is relatively stable over time. This indicates a low intensity of mechanical denudation in the catchment, which is supported by low concentrations of aluminum and potassium. Calcium values greatly exceed these elements, suggesting that the lake was mainly fed by groundwater. Variation in trophic conditions over time is indicated by a vertical variability in the content of nitrogen, as well as by the Cladocera population. The strong decomposition of peat in the top layer of the mire, and increased concentrations of phosphorus and heavy metals, testify to increasing human activity during the most recent time periods.
Źródło:
Geological Quarterly; 2017, 61, 2; 305--318
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mollusc communities of lowland rivers and oxbow lakes in agricultural areas with anthropogenically elevated nutrient concentration
Autorzy:
Lewin, I.
Powiązania:
https://bibliotekanauki.pl/articles/84406.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Mikołaja Kopernika. Wydział Biologii i Ochrony Środowiska. Stowarzyszenie Malakologów Polskich
Opis:
Anthropogenically elevated nutrient concentration occurs in both ground and surface waters and cause grave environmental problems which are responsible for the degradation of water quality on a worldwide scale. The progressive anthropogenic pressure caused by prolonged agricultural activity has a negative effect on most water ecosystems including rivers and reservoirs. Freshwater molluscs, which are hololimnic organisms, have a limited mobility; therefore, they are good bioindicators of changes in their habitats. They reflect the abiotic or biotic state of water habitats, which represents the impact of environmental change on the habitat, community as well as on the ecosystem. A long-term survey of mollusc communities revealed the occurrence of 44 species including some rare, vulnerable, threatened or legally protected species, e.g. Borysthenia naticina , Unio crassus , Anodonta cygnea , Pseudanodonta complanata or Sphaerium rivicola , in the Wkra River, its tributaries and selected oxbow lakes. In the Wkra River catchment area, the mollusc communities, including U. crassus (Habitats Directive Natura 2000), are under a combined effect of several environmental factors. Conductivity, hardness, current velocity, river width, temperature, nutrient concentration and the size of sediment particles were the parameters most associated (statistically significant according to the forward selection results) with the distribution of mollusc species. The forward selection results showed that the concentration of dissolved oxygen and the occurrence of macrophytes also exerted a significant influence on the distribution of Mollusca. Among environmental factors, anthropogenically elevated concentrations of nitrites and nitrates in the water were the most predictive parameters that negatively influenced (stressors) the structure of mollusc communities. The novel findings of this survey showed that some mollusc species could tolerate wider ranges of some environmental factors and higher concentrations of nutrients than had been expected. U. crassus is more tolerant of a relatively high concentration of nitrates in the water than was previously expected, as well as of nitrites and phosphates, and it can survive in rivers with relatively high nutrient concentration. The present results confirm both the field and the toxicological research on the negative effect of nitrites and nitrates, which is caused by their toxicity to freshwater molluscs. The number of individuals, number of mollusc species and density decreased dramatically within the last year of the survey in the Wkra River and its tributaries. This phenomenon seems to be a direct result of the nutrient enrichment in the Wkra River catchment area, the regulation of riverbeds or an indirect result, e.g. lack of primary or appropriate host fishes for unionid species. The declining trend in the global mollusc population has probably begun to occur in the Wkra River catchment area.
Źródło:
Folia Malacologica; 2014, 22, 2
1506-7629
Pojawia się w:
Folia Malacologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The significance of oxbow lakes for the ecosystem of afforested river valleys
Znaczenie starorzeczy dla ekosystemu zalesionych dolin rzecznych
Autorzy:
Koc, J.
Kobus, S.
Glińska-Lewczuk, K.
Powiązania:
https://bibliotekanauki.pl/articles/292833.pdf
Data publikacji:
2009
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
azot
fosfor
ochrona wód
osady denne
retencja leśna
retencja wód
starorzecza
bottom sediments
forest retention
nitrogen
oxbow lakes
phosphorus
water protection
water retention
Opis:
The interest in significance of forest areas in water quality improvement has been increasing since creation of biogeochemical barriers became effective tools against the input of pollutants to surface water from diffuse sources. Along meandering river valleys, numerous floodplain lakes often appear as valuable water ecosystems but of advanced eutrophy. Their trophic status depends not only on the hydrological connectivity with the river but also land use in the direct vicinity of the reservoir. Research on water ecosystems in the postglacial river valleys in northern Poland contributed to identification of the role of woodland area in pollutants migration in the valley of the Łyna River. The study on the ecosystem concerned seasonal variation in nutrient concentrations (N and P) and bottom sediments properties in relation to hydrological conditions (water level fluctuations). Based on the collected data we attempted prediction of the reservoir lifetime. Depending on hydrological, geological and topographic conditions the origin of water supply of the basin is changing. Annual water level fluctuations in the range of 200 cm cause the basin capacity variation as much as 5 times. Nevertheless, water quality in the lake was conditioned by the riverine supply, the significant share in the lake feeding has groundwater supply from hillslope aquifer and seepage through alluvial aquifer. Contribution of every origin supply depends on river flow rate and valley water level, it depends on alluvial ground formations permeability and relief. Hillslope erosion of the concave bank was responsible for high nitrogen and phosphorus outflows. The research showed that primary and secondary production and freshets contributed to intensive deposition of bottom sediments in oxbow lake. The increase rate of sediment determined on the base of matter balance was 10 times higher than deposition rate of bottom sediments in glacial lakes. The accelerated processes of silting-up and shallowing and terrestialization of the valuable ecosystems indicate the necessity of floodpain lakes protection due to ecological functions they play in forestry landscape.
Zainteresowanie funkcją, jaką pełnią obszary leśne w poprawie jakości wody, wzrastało od kiedy bariery biogeochemiczne stały się efektywnym narzędziem przeciwko zanieczyszczeniom obszarowym, wprowadzanym do wód powierzchniowych. Wzdłuż dolin rzek meandrujących pojawiają się liczne jeziora równin zalewowych jako cenne ekosystemy wodne, lecz o zaawansowanym stopniu eutrofizacji. Ich poziom troficzny zależy nie tylko od stopnia połączenia z rzeką, ale również od użytkowania przyległego obszaru. Badania prowadzone nad ekosystemami wodnymi rzek północnej części kraju przyczyniły się do poznania roli, jaką odgrywają obszary zalesione w migracji zanieczyszczeń w dolinie Łyny. Badania dotyczyły sezonowej zmienności koncentracji azotu i fosforu oraz właściwości osadów dennych w odniesieniu do zmiennych warunków hydrologicznych. W kontekście lokalnych warunków hydrologicznych, geologicznych i topograficznych zasilanie starorzecza ma różny charakter. Oscylacje poziomu wody w zbiorniku w cyklu rocznym w zakresie dochodzącym do ponad 200 cm determinowała ponad 5-krotną zmienność jego objętości i zdolności retencyjnej. Jednakże jakość wody w zbiorniku była uwarunkowana zasilaniem przez wody rzeki, istotny udział w zasilaniu zbiornika miały wody gruntowe zbocza doliny i wody aluwialne przesiąkające z koryta rzecznego. Ich udział jest zmienny w czasie i zależy bezpośrednio od wielkości przepływu w rzece i poziomu wód w dolinie, przepuszczalności utworów aluwialnych oraz rzeźby terenu. Erozja stromej skarpy brzegu wklęsłego zbiornika odpowiadała za duży spływ azotu i fosforu do jego wód. Procesami generującymi depozycję osadów dennych w starorzeczach były produkcja pierwotna i wtórna oraz wezbrania rzeczne. Bilans materii w zbiorniku odpowiadał za przynajmniej 10-krotnie szybszy przyrost osadów niż w jeziorach glacjalnych. Przyśpieszony proces odcinania, wypłycania i zalądowienia cennych ekosystemów wymusza konieczność ochrony w odniesieniu do funkcji, jakie pełnią one w krajobrazie leśnym.
Źródło:
Journal of Water and Land Development; 2009, no. 13a; 115-131
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mollusc assemblages from Subatlantic oxbow lake deposits in the Szreniawa River valley near Słomniki (Miechow Upland, southern Poland)
Autorzy:
Alexandrowicz, W.P.
Powiązania:
https://bibliotekanauki.pl/articles/84275.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Mikołaja Kopernika. Wydział Biologii i Ochrony Środowiska. Stowarzyszenie Malakologów Polskich
Źródło:
Folia Malacologica; 2018, 26, 4
1506-7629
Pojawia się w:
Folia Malacologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Younger Dryas climatic reconstructions in central Poland
Autorzy:
Pawłowski, D.
Powiązania:
https://bibliotekanauki.pl/articles/139212.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Younger Dryas
cladocera
temperature
oxbow lake
climate
młodszy dryas
Cladocera
temperatura
starorzecze
klimat
Opis:
Cladoceran-based paleotemperature estimates for the Younger Dryas for ten sections of paleo-oxbow lakes, valley mires, and lacustrine sediments from central Poland are presented, and their potential usefulness to climatostratigraphy is described. Most of the changes observed in the cladoceran assemblages are responses to climate changes. The cladoceran-based temperature reconstructions reflect cold conditions during the Younger Dryas (YD) and allow a division of this period into two phases: an older colder phase, between 12,800 and 12,000 cal yrs BP, and a younger, warmer phase, between ca. 12,000 and 11,500 cal yrs BP. The geomorphological features of the study sites and local environmental forces are also taken into consideration. The cladoceran-inferred summer temperature estimates from all of the study sites correspond closely with the available climate reconstruction for the YD in central Europe.
Źródło:
Acta Geologica Polonica; 2017, 67, 4; 567-584
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Yistulian deposits at Świnna Poręba, western Outer Carpathians (Southern Poland)
Autorzy:
Bińka, Krzysztof
Grzybowski, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/2026787.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Carpathians
Early Vistulian
pollen
alluvia
oxbow deposits
Opis:
Alluvial and oxbow deposits preserved 18 m above the Skawa River valley floor are related to the Early Vistulian. Pollen analysis of the two mainly terrestrial profiles revealed a boreal forest succession. The age of the deposits is discussed.
Źródło:
Studia Quaternaria; 2001, 18; 11-16
1641-5558
2300-0384
Pojawia się w:
Studia Quaternaria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The reactivation of Warsaw oxbow lakes as a leitmotiv of urban design
Autorzy:
Solarek, Krystyna
Powiązania:
https://bibliotekanauki.pl/articles/292354.pdf
Data publikacji:
2020
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
extreme daily precipitation
GEV distribution
homogeneous regions
L-moments
regional frequency analysis
Opis:
Oxbow lakes occurring in floodplains are those natural elements that are subject to rapid changes, which may lead to their disappearance. These are extremely valuable ecosystems and landscape components, as well as water management units. However, they quickly disappear if they are not periodically fed with river water, which takes place especially when rivers are embanked. Such a situation occurs, among others in Warsaw, in the Vistula valley. There are many opportunities for the reactivation of oxbow lakes, including through technical activities. It is not always possible to restore the natural values of the valley in urbanized areas, however, oxbow lakes can then also play a recreational role and they can fulfill an important task in improving the quality of life, being also an important element of the public space system. The author has carried out research related to land development projects of the new district located in the Vistula River valley in Warsaw (the Siekierkowski Arc). Many different design solutions have been proposed, taking as a leitmotiv the restoration of oxbow lakes, for example: (1) reconstruction of the water channel in the former watercourse with the boulevard along its fragment and with the public park in another part, (2) water supplying of the existing oxbow lake through the green and blue infrastructure system. The author presents few urban designs carried out under her direction for this area and shows that creative reactivation of oxbow lakes can improve water conditions, and be beneficial for the introduction of a new, attractive development.
Źródło:
Journal of Water and Land Development; 2020, 45; 165-170
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Results of floodplain forests protection in the Uroczysko Warta, the Wielkopolska Region, Poland
Autorzy:
Miler, Antoni T.
Dobraczyński, Marek
Powiązania:
https://bibliotekanauki.pl/articles/100899.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
floodplain forest
deadwood
small water retention
oxbow lake
Uroczysko Warta
Opis:
The Uroczysko Warta is one of the most important riparian forest areas in Poland. The construction of the Jeziorsko reservoir resulted in changes in the Warta river hydrological regimes. This in turn led to a reduction in the floodplain area and flooding frequency, which as a consequence has had a dramatically detrimental effect on the floodplain forests in that wilderness. Riparian forests are among the richest and most beautiful forest ecosystems. Unfortunately, river regulation and flood control measures result in their degradation. In Poland only 0.2% total area is covered by riparian forests. The Uroczysko Warta is one of the most important groups of these habitats not only in Poland, but also on the European scale. It was assumed that the implementation of simple land and water system restoration systems - gates, barrages, culverts with backwater valve gates - may promote recreation of advantageous hydrological relations. This study presents results of water monitoring in the Uroczysko Warta Wilderness and the volume of deadwood formed as a consequence of hydrometeorological conditions. The paper provides a detailed description of climate characteristics (air temperature and precipitation) in the 30-year period of 1988-2017, i.e. after the commissioning of the Jeziorsko reservoir along with the hydrological characteristic of the wilderness area in the years 2009-2017 (water stages in the Warta river and in the Lutynia river, water stages in oxbow lakes and groundwater tables) and the volume of deadwood formed in the years 2006-2014. Water stages in the Warta and the Lutynia as well as water levels in oxbow lakes and groundwater tables show considerable mutual correlations. This indicates efficient operation of constructed land reclamation systems. The volume of formed deadwood shows no evident trends, only a close relationship with climatic conditions. Thus it may be hypothesised that the concept for the protection of floodplain forests in the Uroczysko Warta, consisting in the buffer supply of oxbow lakes at high water stages in the Warta and the Lutynia is appropriate, particularly since waters supplying the wilderness area do not stagnate, but they move within the ground.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2019, II/1; 7-24
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New and rare species of Volvocaceae (Chlorophyta) in the Polish phycoflora
Autorzy:
Dembowska, E.A.
Powiązania:
https://bibliotekanauki.pl/articles/57700.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
new species
rare species
Volvocaceae
Chlorophyta
Polska
phycoflora
Pleodorina
Pandorina
Eudorina
biodiversity
phytoplankton
oxbow lake
Vistula River
Opis:
Seven species of Volvocaceae were recorded in the lower Vistula River and its oxbow lakes, including Pleodorina californica for the first time in Poland. Three species – Eudorina cylindrica, E. illinoisensis and E. unicocca – were found in the Polish Vistula River in the 1960s and 1970s, as well as at present. They are rare species in the Polish aquatic ecosystems. Three species are common both in the oxbow lakes and in the Vistula River: Eudorina elegans, Pandorina morum and Volvox aureus. New and rare Volvocaceae species were described in terms of morphology and ecology; also photographic documentation (light microscope microphotographs) was completed.
Źródło:
Acta Societatis Botanicorum Poloniae; 2013, 82, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł

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