macrophyte
Dotaz
Zobrazit nápovědu
Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N) and carbon (δ13C) isotopic mixing models, perch (Perca fluviatilis L.) and rudd (Scardinius erythrophthalmus (L.)) showed larger individual variation (i.e., variance) in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.)). Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence the overall food-web structures in lake ecosystems.
- MeSH
- biodiverzita MeSH
- ekosystém * MeSH
- izotopy dusíku analýza MeSH
- potravní řetězec MeSH
- rostliny * MeSH
- ryby * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Two basic ecological relationships, herbivory and competition, distinctively influence terrestrial ecosystem characteristics, such as plant cover, species richness and species composition. We conducted a cage experiment under natural conditions in an aquatic ecosystem to test the impacts of two treatments combined in a factorial manner: (i) a pulse treatment - removal of dominant competitors among primary producers (macroalgae Chara sp. and Vaucheria sp.), and (ii) a press treatment - preventing herbivore (fish, crayfish) access to caged plots. The plots were sampled once before the treatments were established and four more times within two years. Both treatments had a significantly positive impact on macrophyte cover and species richness and changed the macrophyte species composition. The effect of the macroalgae removal was immediate with the highest species richness occurrence during the first post-treatment monitoring, but the positive effect vanished with time. In contrast, preventing herbivore access had a gradual but long-lasting effect and reached a more steady-state over time. Two of the most common species showed contrasting responses, the palatable Potamogeton pectinatus was most supported by caging, while the distasteful Myriophyllum spicatum preferred open plots. Our findings may be applicable during the revitalisation of aquatic ecosystems that aims to increase macrophyte biodiversity.
- MeSH
- biodiverzita * MeSH
- býložravci fyziologie MeSH
- Chara fyziologie MeSH
- distribuce rostlin * MeSH
- jezera MeSH
- rdestovité fyziologie MeSH
- regenerace a remediace životního prostředí MeSH
- ryby fyziologie MeSH
- severní raci fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Higher biomass especially of some aquatic macrophyte species offered a higher density of phytophilous zoobenthos, but did not increase the proportion of non-planktonic to planktonic prey in young-of-the-year perch Perca fluviatilis. Both abundance and biomass of non-planktonic prey dominated over planktonic prey in the pond with lower biomass of aquatic macrophytes and lower food. Survival of P. fluviatilis was lower (20%) in the pond with lower food than in the other pond (34%), however, specific growth rate (1.3% day(-1) ) and final Fulton's condition factor of P. fluviatilis were similar in both ponds.
- MeSH
- biomasa MeSH
- okounovití růst a vývoj MeSH
- plankton * MeSH
- potravní řetězec * MeSH
- rybníky MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cryptic pigmentation of prey is often thought to evolve in response to predator-mediated selection, but pigmentation traits can also be plastic, and change with respect to both abiotic and biotic environmental conditions. In such cases, identifying the presence of, and drivers of trait plasticity is useful for understanding the evolution of crypsis. Previous work suggests that cryptic pigmentation of freshwater isopods (Asellus aquaticus) has evolved in response to predation pressure by fish in habitats with varying macrophyte cover and coloration. However, macrophytes can potentially influence the distribution of pigmentation by altering not only habitat-specific predation susceptibility, but also dietary resources and abiotic conditions. The goals of this study were to experimentally test how two putative agents of selection, namely macrophytes and fish, affect the pigmentation of A. aquaticus, and to assess whether pigmentation is plastic, using a diet manipulation in a common garden. We performed two experiments: (a) in an outdoor mesocosm experiment, we investigated how different densities of predatory fish (0/30/60 three-spined stickleback [Gasterosteus aculeatus] per mesocosm) and macrophytes (presence/absence) affected the abundance, pigmentation and body size structure of isopod populations. (b) In a subsequent laboratory experiment, we reared isopods in a common garden experiment on two different food sources (high/low protein content) to test whether variation in pigmentation of isopods can be explained by diet-based developmental plasticity. We found that fish presence strongly reduced isopod densities, particularly in the absence of macrophytes, but had no effect on pigmentation or size structure of the populations. However, we found that isopods showed consistently higher pigmentation in the presence of macrophytes, regardless of fish presence or absence. Our laboratory experiment, in which we manipulated the protein content of the isopods' diet, revealed strong plasticity of pigmentation and weak plasticity of growth rate. The combined results of both experiments suggest that pigmentation of A. aquaticus is a developmentally plastic trait and that multiple environmental factors (e.g. macrophytes, diet and predation) might jointly influence the evolution of cryptic pigmentation of A. aquaticus in nature on relatively short time-scales.
- MeSH
- ekosystém MeSH
- Isopoda * MeSH
- pigmentace MeSH
- predátorské chování MeSH
- sladká voda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Essential trace elements (Cu(2+), Zn(2+), etc) lead to toxic effects above a certain threshold, which is a major environmental problem in many areas of the world. Here, environmentally relevant sub-micromolar concentrations of Cu(2+) and simulations of natural light and temperature cycles were applied to the aquatic macrophyte Ceratophyllum demersum a s a model for plant shoots. In this low irradiance study resembling non-summer conditions, growth was optimal in the range 7.5-35nM Cu, while PSII activity (Fv/Fm) was maximal around 7.5nM Cu. Damage to the light harvesting complex of photosystem II (LHCII) was the first target of Cu toxicity (>50nM Cu) where Cu replaced Mg in the LHCII-trimers. This was associated with a subsequent decrease of Chl a as well as heat dissipation (NPQ). The growth rate was decreased from the first week of Cu deficiency. Plastocyanin malfunction due to the lack of Cu that is needed for its active centre was the likely cause of diminished electron flow through PSII (ΦPSII). The pigment decrease added to the damage in the photosynthetic light reactions. These mechanisms ultimately resulted in decrease of starch and oxygen production.
- MeSH
- biologické markery metabolismus MeSH
- chemické látky znečišťující vodu chemie toxicita MeSH
- fotosyntéza účinky léků fyziologie MeSH
- Magnoliopsida účinky léků růst a vývoj metabolismus MeSH
- měď chemie nedostatek toxicita MeSH
- proteom účinky léků metabolismus MeSH
- proteomika MeSH
- světlo MeSH
- testy toxicity MeSH
- vodní organismy účinky léků metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Constructed wetlands (CWs) are decentralized wastewater treatment systems considered to be green and low cost. They have the potential to effectively remove pollutants and recycle nutrients with plant composting. However, they need large areas to implement them due to the usual high Hydraulic Retention Times (HRT), reaching up to 50 days. The main objective of the present study was to evaluate the influence of HRT (HRT = 3, 7, and 10 days), and seasonality on Total Phosphorus (TP) removal, and standing stock in a pilot scale free water surface CW (FWS CW). Unplanted and planted (Eichhornia crassipes) tanks were evaluated in wet and dry seasons. The FWS CW was set up as a complementary treatment to a secondary level wastewater treatment plant. The system was monitored weekly for ten months, totalizing 29 replicate samplings (n = 58). Planted tanks were harvested every week to keep free space for plant reproduction (∼40%). The mean removal efficiency of TP ranged between 82% and 95% without a significant difference between HRT (pvalue > 0.05). However, when the effects of the sedimentation of the unplanted tanks were disregarded, the lowest HRT (3 days) tank presented the highest standing stock of TP. The wet season presented a significant difference in TP removal results (pvalue < 0.05), associated with higher macrophyte growth rate due to more intense solar irradiation and incorporation of TP by E. crassipes. The results point out advances in P removal and recycling by a low-cost ecological engineering system.
OBJECTIVES: An enhanced worldwide application of platinum group elements (PGE), in particular platinum, has been observed during recent decades. An increased concentration of PGE was determined in collected samples of great amount of aqueous ecosystems.The aim was to compare phytotoxic effect of platinum (PtCl4) by performing two different bioassays on green algae Pseudokirchneriella subcapitata and macrophyte duckweed, Lemna minor. MEDTHODS: The algal experiment (Pseudokichneriella subcapitata) followed OECD 201, the concentration row for PtCl4 was: 0.05; 0.01; 0.25; 0.5; 1 μM. The duckweed (Lemna minor) experiment was conducted according to OECD 221, employed PtCl4 concentrations were: 5; 10; 25; 50; 100 μM. Plants were cultivated as a microbiotest, using micro-volumes. RESULTS: The results of the algal test showed significant growth inhibition of the final biomass. The values of 72hEC5(μ), 72hEC10(μ), 72hEC20(μ) counted on a basis of average specific growth rate (μ) were 0.31 μM, 0.58 μM and 1.12 μM of PtCl4, respectively. The values, obtained on a basis of the area under the growth curves (A), were 0.04 μM (72hEC5(A)), 0.24 μM (72hEC10(A)) and 0.64 μM (72hEC20(A)). The experiment with duckweed showed 50% of growth inhibition and the values of 168hEC50(μ) were 19.55 μM and 168hEC50(A) 13.63 μM of PtCl4. CONCLUSION: The fronds of duckweed showed strong adverse effect of platinum influence (chlorosis, necrosis). The algal test and the estimation of 72hEC5(A) appears to be the most sensitive.
- MeSH
- biomasa MeSH
- biotest MeSH
- chemické látky znečišťující vodu toxicita MeSH
- Chlorophyta účinky léků růst a vývoj MeSH
- ekosystém MeSH
- platina toxicita MeSH
- sloučeniny platiny toxicita MeSH
- testy toxicity MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Understanding how an invasive plant can colonize a large range of environments is still a great challenge in freshwater ecology. For the first time, we assessed the relative importance of four factors on the phosphorus uptake and growth of an invasive macrophyte Elodea nuttallii (Planch.) St. John. This study provided data on its phenotypic plasticity, which is frequently suggested as an important mechanism but remains poorly investigated. The phosphorus uptake of two Elodea nuttallii subpopulations was experimentally studied under contrasting environmental conditions. Plants were sampled in the Rhine floodplain and in the Northern Vosges mountains, and then maintained in aquaria in hard (Rhine) or soft (Vosges) water. Under these conditions, we tested the influence of two trophic states (eutrophic state, 100 μg x l(-1) P-PO4(3-) and hypertrophic state, 300 μg x l(-1) P-PO4(3-)) on the P metabolism of plant subpopulations collected at three seasons (winter, spring and summer). Elodea nuttallii was able to absorb high levels of phosphorus through its shoots and enhance its phosphorus uptake, continually, after an increase of the resource availability (hypertrophic > eutrophic). The lowest efficiency in nutrient use was observed in winter, whereas the highest was recorded in spring, what revealed thus a storage strategy which can be beneficial to new shoots. This experiment provided evidence that generally, the water trophic state is the main factor governing P uptake, and the mineral status (softwater > hardwater) of the stream water is the second main factor. The phenological stage appeared to be a confounding factor to P level in water. Nonetheless, phenology played a role in P turnover in the plant. Finally, phenotypic plasticity allows both subpopulations to adapt to a changing environment.
- MeSH
- biologický transport MeSH
- fenotyp MeSH
- fosfor metabolismus MeSH
- Hydrocharitaceae růst a vývoj metabolismus MeSH
- kinetika MeSH
- kvalita vody * MeSH
- vápník analýza MeSH
- voda chemie MeSH
- výhonky rostlin růst a vývoj metabolismus MeSH
- zavlečené druhy * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Four emergent plants (helophytes, synonyms emersion macrophytes, marsh plants, etc.) Phragmites australis, Juncus glaucus, Carex gracillis and Typha latifolia were successfully used for degradation of TNT (2,4,6-trinitrotoluene) under in vitro conditions. The plants took up and transformed more than 90% of TNT from the medium within ten days of cultivation. The most efficient species was Ph. australis which took up 98% of TNT within ten days. The first stable degradation products 4-amino-2,6-dinitrotoluene (4-ADNT) and 2-amino-4,6-dinitrotoluene (2-ADNT) were identified and analysed during the cultivation period. [14C] TNT was used for the detection of TNT degradation products and their compartmentalization in plant tissues after two weeks of cultivation. Forty one percent of 14C was detected as insoluble or bound in cell structures: 34% in roots and 8% in the aerial parts. These results open the perspective of using the above-mentioned plants for the remediation of TNT contaminated waters.
- MeSH
- biodegradace MeSH
- chemické látky znečišťující vodu analýza metabolismus toxicita MeSH
- financování organizované MeSH
- kořeny rostlin chemie metabolismus MeSH
- Magnoliopsida chemie metabolismus růst a vývoj MeSH
- nadzemní části rostlin chemie metabolismus MeSH
- radioizotopy uhlíku MeSH
- trinitrotoluen analýza metabolismus toxicita MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- srovnávací studie MeSH
