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911.
Timothy Ingleton Tsuyoshi Kobayashi Brian Sanderson Ronald Patra Catriona M. O. Macinnis-Ng Bruce Hindmarsh Lee Clifford Bowling 《Hydrobiologia》2008,603(1):221-240
The survival and subsequent growth potential of Anabaena spp. and other filamentous cyanobacteria and the cells of Aulacoseira spp. (diatom) and Ceratium
hirundinella (dinoflagellate) following passage through the Multi Level Inlet Tower (MLIT) and offtake works at Chaffey Reservoir in New
South Wales, Australia was investigated in late summer. The study aimed to test whether the phytoplankton cells were destroyed
or otherwise rendered less viable during passage through the outlet works. The reservoir was strongly thermally stratified
with a shallow surface mixed layer, which contributed to considerable temporal variability in the numbers of phytoplankton
cells present immediately opposite the intake portal of the outlet works. To compensate, considerable replicate sampling was
undertaken both upstream and downstream of the MLIT. Results indicate limited destruction of cyanobacteria, with fewer cells
present immediately downstream compared to upstream. Greater destruction of cells was indicated at lower mean daily discharge
rates compared to higher discharge rates. Filament lengths of both cyanobacteria and Aulacoseira were also reduced during passage. There was no apparent reduction in Ceratium cell number. Laboratory incubation studies on surviving cells collected downstream indicated no impairment on the viability
of any taxa. Calculations of rates-of-strain likely to be experienced by the phytoplankton as they transited through the offtake
revealed very high stress being applied to the filaments and cells at the valve, and within the spillway sections of the works.
These were several orders of magnitude greater than published values shown to disrupt cells and filaments, and to impair viability
for subsequent growth in laboratory studies. However, exposure times to the high rates-of-strain at Chaffey Reservoir were
brief, which may reduce the impacts of the high turbulence. The conclusions were that unless cyanobacterial cell destruction
during passage through an outlet works can be shown to be more effective at larger reservoirs, the withdrawal of warm, cyanobacterial
infested waters from close to the surface is unlikely to provide an acceptable management action for the prevention of cold
water pollution downstream.
Handling editor: D. Ryder 相似文献
912.
In this study we compared the biodiversity of five waterbody types (ditches, lakes, ponds, rivers and streams) within an agricultural
study area in lowland England to assess their relative contribution to the plant and macroinvertebrate species richness and
rarity of the region. We used a Geographical Information System (GIS) to compare the catchment areas and landuse composition
for each of these waterbody types to assess the feasibility of deintensifying land to levels identified in the literature
as acceptable for aquatic biota. Ponds supported the highest number of species and had the highest index of species rarity
across the study area. Catchment areas associated with the different waterbody types differed significantly, with rivers having
the largest average catchment sizes and ponds the smallest. The important contribution made to regional aquatic biodiversity
by small waterbodies and in particular ponds, combined with their characteristically small catchment areas, means that they
are amongst the most valuable, and potentially amongst the easiest, of waterbody types to protect. Given the limited area
of land that may be available for the protection of aquatic biodiversity in agricultural landscapes, the deintensification
of such small catchments (which can be termed microcatchments) could be an important addition to the measures used to protect
aquatic biodiversity, enabling ‘pockets’ of high aquatic biodiversity to occur within working agricultural landscapes.
Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck
The ecology of European ponds: defining the characteristics of a neglected freshwater habitat 相似文献
913.
Zinc distribution and zinc-binding forms in Phragmites australis under zinc pollution 总被引:2,自引:0,他引:2
The influence of zinc (Zn) on physiological and biochemical parameters was studied to elucidate the mechanism of Zn resistance in Phragmites australis. Zn concentrations in roots, stems and leaves increased with exogenous Zn concentration, while Zn content in roots was much higher than in shoots. X-ray microanalysis was used to reveal compartments in which Zn accumulated in root cortex. Zinc concentrations followed a gradient with the sequence: intercellular space>cell wall >vacuole >cytoplasm, indicating that most Zn was immobilized in the apoplast or sequestered into the vacuolar lumen. Sequential extraction of various Zn chelates revealed that the ratio of Zn extracted with different extraction media was markedly different. Ethanol, HAc (acetic acid) and NaCl-extractable Zn were dominant in both roots and leaves of P. australis. Zn-binding protein fractions were found in the roots and leaves after gel filtration chromatography, among which a polypeptide with an apparent molecular mass of 14kDa bound Zn most effectively. Two newly synthesized polypeptides of 58 and 45kDa appeared under Zn pollution, whereas a prominent fraction of 72kDa disappeared. The involvement of Zn distribution in plant tissues, subcellular compartments and chelates and Zn-inducing proteins in the acclimation mechanism of P. australis to Zn pollution is discussed. 相似文献
914.
Heavy metal pollution of the soils around an abandoned Pb-Zn mine site located in the Alcudia Valley (South Central Spain) have been characterized by analysis of extractable and total metal concentrations in 60 samples of arable, pasture, and mine lands. The samples showed a broad range of size-particle distribution, cation exchange capacity, and pH values as well as high levels of total metal concentrations (up to 98510 mg kg?1 of Pb, up to 20912 mg kg?1 of Zn, and up to 61 mg kg?1 of Cd). In order to assess the potential availability of metals the metal partitioning in two different soil size fractions (<2 mm and <63 μm) was determined using EDTA and CaCl2 as sequestering reagents. The average contents of Pb, Zn, and Cd in the <63 μm particle size fraction for both extractions were higher than those of the <2 mm fraction due to the high metal adsorption capacity of the fine soil particles. Concentrations of heavy metals extracted by CaCl2 were up to three orders of magnitude lower than those extracted by EDTA, because CaCl2 only extracts the easily mobile fraction. Metal concentrations extracted by both procedures in the two granulometric fractions increased with total metal concentrations, thus increasing the potential environmental risk associated to heavy metal pollution. 相似文献
915.
Saeed Khalil Mater H. Mahnashi Manzoor Hussain Naheed Zafar Waqar-Un-Nisa Falak Sher Khan Umara Afzal Ghulam Mujtaba Shah Usama Muhammad Niazi Muhammad Awais Muhammad Irfan 《Saudi Journal of Biological Sciences》2021,28(10):5728
ObjectivesTo explore the algal floral diversity and its role to determine water quality.MethodsThe regular monthly collection of algal and water samples was made during 2018. Unicellular algae were preserved in 2 to 3% formalin while macroalgae in 4% formalin. Microphotographs of algae were taken at the biotechnological Lab of PCSIR Lahore, Pakistan. Palmer pollution index was used to determine water quality.ResultsThe study identified 201 algal species distributed among 57 genera, 42 families, 25 orders, 10 classes and 7 divisions. The total score of Algal Genus Pollution Index of Banjosa Lake, Ali Sojal Dam, Dothan Dam, Drake Dam and Rawalakot Nullah (city) were 14, 9, 10, 18 and 25 respectively. It was revealed that Banjosa Lake has probable organic pollution, Ali Sojal Dam and Dothan Dam showed lack of organic pollution, Drake Dam indicated moderate pollution while Rawalakot Nullah (City) indicated confirm high organic pollution.ConclusionWe strongly recommend the conservation and managed status of algal species for sustainable resource of algal- derived products in future. It was revealed that the water quality of Banjosa Lake, Drak Dam and Rawalakot Nullah was affected from anthropogenic activities and needs to be managed. 相似文献
916.
917.
918.
Field and laboratory research has repeatedly shown that free-living soil nematodes differ in their sensitivity to soil pollution. In this paper, we analyze whether nematode genera proved sensitive or tolerant toward heavy metals and organic pollutants in six long-term field experiments. We discuss overlaps between nematode physiological responses to heavy metals and to organic pollutants, which may explain why nematodes can exhibit co-tolerance toward several contaminants. We propose a simple method for separating direct effects of soil contamination on nematode populations from indirect effects mediated through the food chain. Finally, we analyze the extent to which nematodes exhibited consistent responses across the experiments analyzed. Our results show that (a) indirect effects of pollution were generally strong; (b) fewer nematode genera were tolerant than sensitive; (c) many genera, including practically all Adenophorea, exhibited a common response pattern to contaminants; and (d) several genera of the Secernentea exhibited differential tolerance toward particular pollutants. We conclude that bioindication of soil contamination should preferentially be based on tolerant, and less on sensitive, nematodes. We provide a list of nematode genera that may potentially serve as differential bioindicators for specific soil contaminants. 相似文献
919.
O3 impacts on plant development: a meta-analysis of root/shoot allocation and growth 总被引:1,自引:0,他引:1
The mechanism of O3 action on plants remains poorly characterized. Symptoms include visible lesions on the leaf surface, reduced growth and a hypothesized reduction in allocation of carbohydrate to roots. The generality of this latter phenomenon has not been demonstrated. Here, a meta-analysis is performed of all available experimental data, to test the hypotheses that O3 exposure of the shoot inhibits biomass allocation below ground (the root/shoot allometric coefficient, k) and inhibits whole-plant growth rate [relative growth rate (RGR)]. Both k and RGR were significantly reduced by O3 (5.6 and 8.2%, respectively). Variability in k was greater than in RGR, and both exhibited some positive as well as mostly negative responses. The effects on k were distinct from the effects on RGR. In some cases, k was reduced while RGR was unaffected. Slow-growing plants (small RGR) exhibited the largest declines in k. These observations may have mechanistic implications regarding O3 phytotoxicity. There were no effects of type of exposure chamber on sensitivity to O3. The analyses indicate that the O3 inhibition of allocation to roots is real and general, but variable. Further experiments are needed for under-represented plant groups, to characterize exceptions to this generalization and to evaluate O3--environment interactions. 相似文献
920.