Wyniki wyszukiwania

1

Past and recent lake eutrophication evidenced by microfossil (over 160 years) diatom succession in sediments, Lake Xingyun (Southwest China)

100%

Ji M., Li Y., Shen J.

Polish Journal of Ecology

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2013

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tom 61

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nr 4

Eutrophication, disappearance of aquatic vegetation and fish introduction are important disturbances of aquatic ecosystems, especially in plateau lakes, which are generally considered to be very vulnerable. This study investigated the effects of eutrophication, aquatic vegetation and fish introduction on the diatom community of Lake Xingyun by examining the changes of microfossil diatom assemblage. Results showed that diatom assemblages changed with increasing trophic level, decreasing aquatic vegetation and fish introduction. A mesotrophic, alkaliphilous species, Aulacoseira ambigua, was dominant in Lake Xingyun before 1950, which indicated the lake was mesotrophic in the period. Epiphytic diatom species (Achnanthes minutissima, Denticula sp., Gomphonema pumilum) presented high relative concentration between 1950–1980, which indicated aquatic vegetation had a higher cover in this period. The number of diatom species varied from 20 to 66, and to 52 with the change of aquatic vegetation from the past to present. Epiphytic diatoms except Achnanthes minutissima disappeared with the decrease of aquatic vegetation after 1980. Since 1980, with the sharply rising of TP and TN concentration, mesotrophic species (Aulacoseira ambigua) disappeared and eutrophic species (Cyclostephanos dubius, Fragilaria crotonensis, Aulacoseira granulata, Nitzschia palea) were dominant. It indicates the lake has evolved towards eutrophication after 1980. Our study indicated that change of trophic status and aquatic vegetation are important driving factors affecting diatom community composition in Lake Xingyun, but that fish introductions have also been an additional factor.

2

Distribution of ephemeropteran nymphs associated with different stolon sections of Eichhornia azurea [Schwartz] in two floodplain lakes of the Upper Parana River [Brazil]

100%

De M. S. M., Takeda A. M., Grzybkowska M., Monkolski A.

Polish Journal of Ecology

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2004

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tom 52

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nr 3

Eichhornia azurea (Schwartz) Kunth is one of the most abundant species of aquatic macrophyte in the Upper Paraná River floodplain, and ephemeropteran nymphs frequently inhabit this plant. The objective of this study was to analyze the distribution of ephemeropteran nymphs associated with three sections (apical, intermediate, and basal) of E. azurea in two floodplain lakes of the Upper Paraná River as well as to establish the relation of this distribution to biotic and abiotic factors. The samplings of apical, intermediate and basal sections of E. azurea were carried out monthly from October 1997 to October 1998. Higher concentration of dissolved oxygen may contribute to greater density of nymphs on the apical plant segments near the water surface. Callibaetes willineri was the most abundant taxon, occurring on the apical and intermediate plant sections whereas Campsu- rus spp. were recorded on the basal and intermediate sections of the plant, near the sediment and, mainly during high water. Lower dissolved oxygen concentrations near the lake bottom during the high water phase might suggest that during this phase the nymphs of Campsurus violaceus also migrate to E. azurea roots. It was found that changes in water level influenced the variation of the abundance of nymphs. Other genera, such as Tricorythodes and Leptohyphes, were recorded during the high water phase, when river water enters the lakes and their shores are flooded.

3

Production capacity of Scapania undulata [L.] Dum. with regard to its habitat

100%

Samecka-Cymerman A.

Acta Universitatis Wratislaviensis. Prace Botaniczne

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1994

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tom 59

4

Vegetation richness and nutrient loads in 16 lakes of Drawienski National Park [Northern Poland]

100%

Piotrowicz R., Kraska M., Klimaszyk P., Szyper H., Joniak T.

Polish Journal of Environmental Studies

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2006

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tom 15

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nr 3

The paper provides morphometric, physicochemical and vegetation structure of the 16 lakes in Drawieński National Park (DNP). These lakes showed considerable differentiation according to their morphometrical and physico-chemical variables. There are distinguished 4 groups of lakes: (1) throughflow lakes; (2) small, eutrophic non-throughflow lakes; (3) dystrophic lakes with humic water bodies; and (4) mesotrophic lakes. A dependence of the structure of the predominant vegetation types on morphometrical and physico-chemical variables was tested. Results of study of vegetation structure proves the initial classification of the lakes into several groups on the basis of environmental variables. The most important type of vegetation of throughflow lakes are helophytes and nymphaeids. The phytolitoral of eutrophic non-throughflow lakes is scanty. The vegetation of dystrophic lakes is dominated by species with floating leaves and mosses. The common vegetation of mesotrophic lakes is dominated by Chara species and elodeids.

5

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Mechanical strength of stems in aquatic macrophytes

84%

Bociag K., Galka A., Lazarewicz T., Szmeja J.

Acta Societatis Botanicorum Poloniae

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2009

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tom 78

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nr 3

181-187

In populations of submerged macrophytes, individuals are selected in terms of resistance to the effect of hydrodynamic forces. The aim of this study was to check whether individuals growing in river water are more tensile and bending resistant than plants occurring in places not exposed to flow stress. We determined the ultimate tensile strength of stems in four macrophyte species, Potamogeton natans, P. pectinatus, Batrachium fluitans and Chara fragilis, which occur in two environmental variants: in running (current velocity of 0.1-0.6 m/s-1) and stagnant water. In addition, flexure of P. natans stems from both environmental variants was examined. What is more, the type and arrangement of strengthening structures in stems of the plants under study were determined. Potamogeton natans stems are the most resistant to stretching (15.6±4.7 N), while stems of P. pectinatus (3.3±1.0 N) and Batrachium fluitans (2.6±0.8 N) are less resistant. Chara fragilis (0.6±0.3 N) has the least resistant stems. Batrachium, Chara and P. pectinatus are more resistant to stretching if they occur in a river current, whereas P. natans, in stagnant lake water. Ultimate bending moment of P. natans stems from lakes is also much greater than of stems from a river (9.75•10-3 – 4.25•10-3 Nm as compared to 2.12•10-3 – 1.00•10-3 Nm). The resistance of stems to breaking is directly proportional to the stem and thallus cross sectional areas. On the one hand, in all the studied Cormophyta species, the more resistant stems (in P. natans from stagnant water, in the others from running water) are thicker and characterised by a higher contribution of air spaces in the overall stem cross-section. On the other hand, the stems retain their species specific structure and have a similar proportion of strengthening elements.

6

Distribution and composition of aquatic macrophytes in Santhapettai Lake of Villupuram district in Tamil Nadu

84%

Dhanam S., Elayaraj B.

International Letters of Natural Sciences

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2015

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tom 47

Macrophytes are important component of the aquatic ecosystem and broad changes in the abundance of individual species and community composition provide valuable information on how and why an ecosystem might be changing. Santhapettai lake is one of the biggest fresh water lake in Villupuram district, Tamil Nadu. The physico-chemical parameters were analysed for one year (October 2012-September 2013). Quadrates were laid randomly and extending from shoreline towards the lake center. The macrophytes falling in each quadrate were sorted species wise, identified and data were recorded. The plants have been identified from fresh materials with the help of different floras. In this present investigation, a total of 33 species belonging to 23 families and 28 genera were identified under algae, pteridophytes, dicotyledons and monocotyledons. Further, the plants were classified in morphological group as floating (7), submerged (1), submerged anchored (13), floating leaved (1) and emergent anchored (11). The coverage/spread of macrophytes along the shorelines was higher compared to the centre of the lakes where the species composition was found reduced. Assessment of biota, continuous monitoring and conservation lake are the important components to safeguard the biological wealth of lentic and lotic freshwater ecosystem.

7

The response of two aquatic macrophytes and a.sponge to ultraviolet radiation in conjunction with cadmium and Hplus ion stress

84%

Zobel A. M., Cybulski K.

Ochrona Środowiska i Zasobów Naturalnych

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1999

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tom 18

8

Biochemical changes in an aquatic macrophyte Spirodela polyrhiza [L.] growing in different ecological conditions at Bhagalpur, Bihar [India]

84%

Nayak M. R., Choudhary S. K.

Polskie Archiwum Hydrobiologii

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1997

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tom 44

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nr 3

9

Microorganisms associated with charophytes under different salinity conditions

67%

Katarzyte M., Vaiciute D., Bucas M., Gyraite G., Petkuviene J.

Oceanologia

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2017

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tom 59

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nr 2

Microorganisms associated with aquatic macrophytes can in various ways interact with a plant and influence its activity and vice versa. A low-salinity intrusion into freshwater environment can affect plant-microorganism interactions. In this study, effects of different salinity conditions on the abundance and community composition of associated microorganisms with charophytes in the Curonian Lagoon were assessed. From the results, we found that short term salinity changes affected the abundance of bacteria and fungi associated with charophytes, whereas no response was reflected in the taxa composition of fungi, showing that other factors could be of more importance. The increased fungi abundances and different fungi composition in August in comparison to June was probably related to senescence process of aquatic vegetation. 8 fungi taxa were isolated and identified in association with charophytes, while higher diversity was revealed by DGGE technique.

10

Interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities in a small water body in Northern Nigeria

67%

Chia M. A., Adelanwa M. A., Ladan Z., Iortsuun D. N., Adanyi S. E., Stephen B. J.

Oceanological and Hydrobiological Studies

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2012

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tom 41

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nr 2

11

Adapting floodplain connectivity conditions - a prerequisite for sustaining aquatic macrophyte diversity in the UNESCO Biosphere Reserve Lobau (Austria)

67%

Barta V., Schmidt-Mumm U., Janauer G. A.

International Journal of Ecohydrology and Hydrobiology

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2009

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tom 09

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nr 1

The UNESCO Biosphere Reserve Lobau (Austria), established in 1977 within the city limits of Vienna, is part of the Danube National Park and one of the ecologically richest parts of the Danube River Corridor. Hardly noticed by diverging stakeholder interests the smaller aquatic habitats in the floodplain area are acutely threatened by wetland ageing and terrestrialisation processes. In 2007 an aquatic plant survey was carried out in the water bodies of the active floodplain on the left bank of the Danube main river channel as well as in the semi-separated water bodies of the Lobau. Results clearly show the impact of through-flow on aquatic plant species composition and abundance, as these metrics are significantly higher in the semiseparated location. Suitable water regime for all sensitive aquatic plants is an essential prerequisite for sustaining aquatic macrophyte diversity in the Lobau Biosphere Reserve, and could provide an ecohydrological basis for rehabilitation activities in other regulated river floodplains located in cultivated landscapes.

12

Relationships between epipelic diatoms, aquatic macrophytes, and water quality in Akarcay Stream, Afyonkarahisar, Turkey

67%

Kargıoglu M., Serteser A., Kıvrak E., Icaga Y., Konuk M.

Oceanological and Hydrobiological Studies

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2012

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tom 41

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nr 1

13

Biomass allocation to anchoring structures in the aquatic macrophytes from the subcontinental and Atlantic climates in Europe

67%

Szmeja J., Clement B., Bociag K., Galka A., Skurzynski P.

Acta Societatis Botanicorum Poloniae

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2008

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tom 77

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nr 2

Biomass allocation to anchoring structures in 10 species of aquatic macrophytes in two types of the cool and humid temperate climate in Europe, subcontionental (NW Poland) and Atlantic (W France), was examined. The study focused on the weight of anchoring organs in Chara delicatula Ag., Ch. fragilis Desv., Juncus bulbosus L., Littorella uniflora (L.) Asch., Luronium natans (L.) Raf., Potamogeton pectinatus L., P. perfoliatus L., P. natans L. and Ranunculus fluitans (Lam.) Wimm., as well as submerged structures in Hydrocharis morsus-ranae L. The plants were collected from 10 geographically distant lakes and 2 rivers with a current velocity of 0.3-0.5 m s-1. It was assumed that biomass allocation to anchoring structures in rooting macrophytes depends on the time that mechanical forces, which can remove the plants from the occupied area, exert their effect. It was found that, in the Atlantic and subcontinental climates, the ratio between the biomass of underground (or submerged) and above-ground structures (U/A index), calculated for the ramets of Chara fragilis, Hydrocharis morsus-ranae and Ranunculus fluitans, has similar values (p>0.05). Nevertheless, among seven species of Cormophyta, which were anchored in the lake or pond littoral, six (Juncus bulbosus, Littorella uniflora, Luronium natans, Potamogeton pectinatus, P. perfoliatus and P. natans) had higher values of the U/A index in the Atlantic climate than in the subcontinental type (p < 0.05). This can be explained by the lack of ice cover and, consequently, a longer time of wave action than in the subcontinental climate.

Ograniczanie wyników

Past and recent lake eutrophication evidenced by microfossil (over 160 years) diatom succession in sediments, Lake Xingyun (Southwest China)

Distribution of ephemeropteran nymphs associated with different stolon sections of Eichhornia azurea [Schwartz] in two floodplain lakes of the Upper Parana River [Brazil]

Production capacity of Scapania undulata [L.] Dum. with regard to its habitat

Vegetation richness and nutrient loads in 16 lakes of Drawienski National Park [Northern Poland]

Mechanical strength of stems in aquatic macrophytes

Distribution and composition of aquatic macrophytes in Santhapettai Lake of Villupuram district in Tamil Nadu

The response of two aquatic macrophytes and a.sponge to ultraviolet radiation in conjunction with cadmium and Hplus ion stress

Biochemical changes in an aquatic macrophyte Spirodela polyrhiza [L.] growing in different ecological conditions at Bhagalpur, Bihar [India]

Microorganisms associated with charophytes under different salinity conditions

Interactions of Ipomoea aquatica and Utricularia reflexa with phytoplankton densities in a small water body in Northern Nigeria

Adapting floodplain connectivity conditions - a prerequisite for sustaining aquatic macrophyte diversity in the UNESCO Biosphere Reserve Lobau (Austria)

Relationships between epipelic diatoms, aquatic macrophytes, and water quality in Akarcay Stream, Afyonkarahisar, Turkey

Biomass allocation to anchoring structures in the aquatic macrophytes from the subcontinental and Atlantic climates in Europe