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1.
《Harmful algae》2017
The effects of cyanobacteria on zooplankton abundance, structure and diversity were investigated, based on a systematic study on spatial and temporal variations of cyanobacteria and zooplankton in Lake Taihu from 1998 to 2007. It was found that similar increasing trends of cyanobacteria/phytoplankton ratios were accompanied by different trends in biomass, composition and biodiversity of zooplankton in different regions of the lake; the cladocerans benefitted from the increase in cyanobacteria; however, rotifers and protozoans were negatively affected by cyanobacteria. The biomass-based biodiversity of phytoplankton and zooplankton was negatively affected by cyanobacteria as well, and the adverse effects were in proportion to the cyanobacteria/phytoplankton ratio. These results indicated interestingly that higher amounts of cyanobacteria do not necessarily reduce zooplankton biomass, as the biomass of larger zooplankton such as cladocerans was positively related to cyanobacteria. The findings are essential to understand the complex ecological effects of cyanobacteria blooms in lakes. 相似文献
2.
Due to the intensive mixing polymictic lakes should be homogenous. However, morphometric diversity and high water dynamics contribute to the differentiation of many parameters in various areas of the lakes. This study analyzes both phytoplankton and zooplankton to assess differences in water quality along the north–south axis of the longest lake in Poland. New phytoplankton indicators were applied for determining the lake's ecological status: the Q index based on functional groups and the PMPL (Phytoplankton Metric for Polish Lakes) index based on phytoplankton biomass. TSIROT index (Rotifer Trophic State Index), which comprises the percentage of species indicating a high trophic state in the indicatory group and the percentage of bacteriovorus in the Rotifera population, was used for zooplankton analysis.TP content was different at different sites – we observed its gradual increase from the south to the north. Spatial variation of phosphorus did not considerably affect plankton diversity. The phytoplankton was dominated by Oscillatoriales, typical of shallow, well-mixed eutrophic lakes. The ecological status of the lake based on the EQR (Ecological Quality Ratio) was poor or moderate. The zooplankton was dominated by rotifers (at almost all sites), which indicates a eutrophic state of the lake. The values of phytoplankton indices at the studied sites did not differ considerably; the differences resulted more from local conditions such as the contaminant inflow and the macrophyte development than water dynamics.We have demonstrated that in the lake dominated by filamentous Cyanobacteria the ecological status should be determined according to the PMPL index or other indices dependent on the dominant Cyanobacteria species. Since the Q index does not include the functional group S1, the results can lead to the false conclusion that water quality improves with an increased amount of phytoplankton. The high abundance of Cyanobacteria in the lake may have contributed to the poor growth of rotifers. 相似文献
3.
The viable propagule banks of a temporary stream were studied from sections with different agricultural history. Hatching
of zooplankton (copepods, rotifers and cladocerans) was recorded in the laboratory under controlled temperature and light
conditions from an agriculturally modified area with average hydroperiods of about a week per year and two semi-natural reference
areas with average hydroperiods of more than 3 weeks per year. We found significant differences in both taxon richness and
abundance of zooplankton hatching between areas, which were lower in the agriculturally modified section, compared to the
reference sections. Another factor likely to have influenced hatching in our experiment was conductivity, which differed between
the two reference sections and might have affected hatching at high conductivities. For restoration purposes, hydrological
reconnection of stream segments is important to facilitate dispersal from the high diversity upstream segments to the depleted
sites downstream. 相似文献
4.
5.
Jonathan T. Hovius Beatrix E. Beisner Kevin S. McCann Norman D. Yan 《Biological invasions》2007,9(3):233-243
As a recent invader of North American lakes, Bythotrephes longimanus has induced large changes in crustacean zooplankton communities through direct predation effects. Here we demonstrate that
Bythotrephes can also have indirect food web effects, specifically on rotifer fauna. In historical time series data, the densities of
the colonial rotifer Conochilus unicornis significantly increased after Bythotrephes invasion in Harp Lake, Ontario. No such changes were observed in a non-invaded reference lake, the nearby Red Chalk Lake.
Evidence for two mechanisms explaining the Conochilus increase was examined based on changes to the crustacean zooplankton community over time. Rapid and severe declines in several
herbivorous species of cladoceran zooplankton after Bythotrephes detection indicated a decrease in exploitative competition pressure on Conochilus. Secondly, a later and significant decline to virtual extinction of native invertebrate predators (Mesocyclops and Leptodora) could account for the observed Conochilus increase which also began 1–2 years after invasion by Bythotrephes. Ultimately, it appears that both reduced competition followed by a loss of native invertebrate predators were necessary
to lead to the large Conochilus densities observed following invader establishment. From this analysis of long-term community data, it appears that Bythotrephes has important indirect, as well as direct, food web effects in newly invaded North American lakes with implications for trophic
relationships. 相似文献
6.
Francis O. Arimoro Henry E. Olisa Unique N. Keke Adesola V. Ayanwale Victoria I. Chukwuemeka 《农业工程》2018,38(3):216-223
Ecology of plankton in the downstream reaches of Kaduna River, Zungeru, Niger state, Nigeria was investigated between April and August 2015. Plankton and surface water samples were collected monthly from three stations for analysis of plankton diversity and physico-chemical parameters respectively. Station 1 is relatively unperturbed station located at the outskirts of Zungeru town, station 2 with moderate human activity located in Zungeru town while station 3 with minimal level of anthropogenic activities was located in Wushishi town about 7 km from station 2. The result revealed that the minimum and maximum values for pH water temperature, air temperature, conductivity, dissolved oxygen (DO) biochemical oxygen demand (BOD), phosphate, Nitrate, and secchi disc transparency were 5.38–6.79, 25–31 °C, 26–31 °C, 32–72 μs/cm, 3.50–8.20 mg/l, 1.00–5.00 mg/l, 0.06–1.13 mg/l 0.44–1.31 mg/l, 39.140 cm respectively. A total of 26 species of zooplankton and 24 species of phytoplankton were encountered in the study. The highest number of plankton (20 taxa) was recorded at station 2 while station 1 with 18 taxa and station 3 with 13 representative taxa. For zooplankton, the highest number of taxa was recorded at station 1 (20 taxa), followed by station 3 (14 taxa) and 10 taxa in station 2 were identified. Copepoda of the order cyclopidae dominated all the three stations while Bacillariophyta dominated the three stations for phytoplankton diversity. Canonical correspondence analysis (CCA) ordination was used to determine phytoplankton and zooplankton abundance in relation to the physico-chemical parameters. Nitrate, phosphate and dissolved oxygen had over riding influence on the distribution of the plankton in the water body which indicate that the river is still very productive in terms of providing starter food organisms for higher aquatic life. However, care should be taken to protect the river from further deterioration due to various degrees of human activities. 相似文献
7.
Natalia Kuczyńska-Kippen 《Hydrobiologia》2007,593(1):27-37
The distribution of rotifer communities between emergent (Typha angustifolia) and submerged (Chara tomentosa) vegetation and a comparatively open water zone were compared during the spring, summer and autumn seasons at three macrophyte-dominated
lakes. This survey identified 107 rotifera species of which 58% of the taxonomical structure was common for the three examined
lakes. Stoneworts with a more complicated spatial and morphological structure (having a much longer stem length than the narrow
leaf cattail), supported higher rotifer densities. The stem length appeared to be the best predictor of all the macrophyte
parameters and pH and chlorophyll a for the chemical variables, for explaining the variation of rotifer densities using the stepwise multiple forward regressions.
The distribution of pelagic species did not differ between particular sites, which may have reflected the behavioural requirements
of those rotifers. Some of them remained in the open water zone while others seeking an anti-predator refuge, gathered within
macrophyte stands during the daytime. Moreover, there were nine Chara-associated species recorded and only one Typha-associated species was noted. The similarity of rotifer communities was most strongly influenced by particular habitat and
season.
Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont & R. Rico-Martínez
Advances in Rotifer Research 相似文献
8.
Preliminary data on rotifers in the interstitial of the Ninnescah river, Kansas, USA 总被引:1,自引:1,他引:0
Paul N. Turner 《Hydrobiologia》1996,319(3):179-184
One-hundred five rotifer species were identified from a sandy, plains river in Kansas, USA (the Ninnescah river). Of those
rotifers identified, eighty occurred only in the interstitial sand, fifty-six in only the flow as plankton, and thirty-one
from both habitats. Most species can be characterized as being more commonly found in littoral habitats, and not the interstitial
or plankton. Lecane inermis (Bryce, 1892) had the highest density in the hygropsammon interstitial with an average 401 ind. 10 cm−3 at 1–3 cm depth in September 1993.
New records for the US include Encentrum wiszniewski Wulfert (1939), E. longidens Donner (1943) ant E. (Parencentrum) longipes Wulfert (1960). A small form of Lecane levistyla Olofsson (1917) is further examined and discussed. 相似文献
9.
Molecular evidence for Acanthocephala as a subtaxon of Rotifera 总被引:7,自引:0,他引:7
James R. Garey Thomas J. Near Michael R. Nonnemacher Steven A. Nadler 《Journal of molecular evolution》1996,43(3):287-292
Rotifers are free-living animals usually smaller than 1 mm that possess a characteristic wheel organ. Acanthocephalans (thorny-headed
worms) are larger endoparasitic animals that use vertebrates and arthropods to complete their life cycle. The taxa Acanthocephala
and Rotifera are considered separate phyla, often within the taxon Aschelminthes. We have reexamined the relationship between
Rotifera and Acanthocephala using 18S rRNA gene sequences. Our results conclusively show that Acanthocephala is the sister
group of the rotifer class Bdelloidea. Rotifera was nonmonophyletic in all molecular analyses, which supports the hypothesis
that the Acanthocephala represent a taxon within the phylum Rotifera and not a separate phylum. These results agree with a
previous cladistic study of morphological characters.
Correspondence to: J.R. Garey 相似文献
10.
The rotifer fauna of the River Loire (France), at the level of the nuclear power plants 总被引:7,自引:7,他引:0
N. Lair 《Hydrobiologia》1980,73(1-3):153-160
In the heated affluents of nuclear power plants of the river Loire, rotifers are abundant. Cosmopolitan species are numerically dominant, but a tropical fauna is also present, among which the genus Brachionus, representing 20% of the total species, is best represented. From a comparison between water upstream and downstream of the power plants, it further appears that in downstream warmed-up waters, some species show an important development, but not in colder upstream waters. 相似文献