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Quantitative real-time PCR for determination of microcystin synthetase e copy numbers for microcystis and anabaena in lakes 总被引:3,自引:0,他引:3
Vaitomaa J Rantala A Halinen K Rouhiainen L Tallberg P Mokelke L Sivonen K 《Applied and environmental microbiology》2003,69(12):7289-7297
Cyanobacterial mass occurrences in freshwater lakes are generally formed by Anabaena, Microcystis, and Planktothrix, which may produce cyclic heptapeptide hepatotoxins, microcystins. Thus far, identification of the most potent microcystin producer in a lake has not been possible due to a lack of quantitative methods. The aim of this study was to identify the microcystin-producing genera and to determine the copy numbers of microcystin synthetase gene E (mcyE) in Lake Tuusulanj?rvi and Lake Hiidenvesi in Finland by quantitative real-time PCR. The microcystin concentrations and cyanobacterial cell densities of these lakes were also determined. The microcystin concentrations correlated positively with the sum of Microcystis and Anabaena mcyE copy numbers from both Lake Tuusulanj?rvi and Lake Hiidenvesi, indicating that mcyE gene copy numbers can be used as surrogates for hepatotoxic Microcystis and ANABAENA: The main microcystin producer in Lake Tuusulanj?rvi was Microcystis spp., since average Microcystis mcyE copy numbers were >30 times more abundant than those of ANABAENA: Lake Hiidenvesi seemed to contain both nontoxic and toxic Anabaena as well as toxic Microcystis strains. Identifying the most potent microcystin producer in a lake could be valuable for designing lake restoration strategies, among other uses. 相似文献
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Species-specific phytoplankton sedimentation in relation to primary production along an inshore--offshore gradient in the Baltic Sea 总被引:2,自引:0,他引:2
The temporal and spatial variability in the quality and quantityof settling phytoplankton material in relation to concurrentprimary production was studied using sediment traps at threecoastal stations from a semi-enclosed bay (Pojo Bay) throughthe outer archipelago to the open Gulf of Finland. The fluxof settling phytoplankton was high (9.3 g C m2period1)in Pojo Bay, especially in spring, and lower in the archipelago(8.1 g C m2 period1) and open-sea area (5.2 gC m"2 period"1), although the primary production followed theopposite pattern. A large influx of allochthonous material intoPojo Bay in spring brought allochthonous phytoplankton cellsinto the traps, but limited primary production. Diatoms werethe most abundant settled phytoplankton at all stations, butthe species composition varied between Pojo Bay (Aulacoseiraspp., Rhizosolenia minima) and the outer stations (Skeletonemacostatum, Chaetoceros spp.)At the outer stations, migratingdinoflagellates (Peridiniella catenate) comprised part of thesettling material in spring. The high settling flux of the cyanophyteAphanizomenon flos-aquae is discussed. The species compositionof the phytoplankton assemblage influenced the proportion ofthe total organic carbon sedimentation that consisted of phytoplanktoncarbon. 相似文献
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Effects of Biomanipulation on Fish and Plankton Communities in Ten Eutrophic Lakes of Southern Finland 总被引:5,自引:0,他引:5
M. Olin M. Rask J. Ruuhijärvi J. Keskitalo J. Horppila P. Tallberg T. Taponen A. Lehtovaara I. Sammalkorpi 《Hydrobiologia》2006,553(1):67-88
The effects of biomanipulation were studied in ten Finnish lakes to determine responses in fish and plankton communities and
water quality after mass removal of cyprinids. From 1997 to 2001, the fish communities shifted from the dominance of large
cyprinids to an explosion of small cyprinids and a higher proportion of piscivores in effectively biomanipulated lakes (>200 kg ha−1 3 yr−1). The biomass of cyanobacteria decreased, and the duration of the blooms shortened and shifted towards the autumn. Decreased
concentrations and slower cycling of nutrients and increased grazing by cladocerans probably affected the declined biomass
of cyanobacteria. Less intensive sediment disturbance and increased phosphorus-retention in fast growing fish biomass may
have turned the role of the fish assemblage from ‘nutrient recycler’ to ‘nutrient storage’. Increased potential grazing pressure,
higher proportion of edible algae, and lower chlorophyll a:total phosphorus ratio indicated strengthened herbivore control. A high mass removal catch in relation to trophic state,
low background turbidity, and bearable external loading favoured the successful biomanipulation, whereas intensive cyprinid
reproduction, high nutrient loading and non-algal turbidity hindered the recovery. Three important issues should be noticed
before biomanipulation in Finland: (1) careful selection of target lake, (2) well-planned, effective and long-lasting biomanipulation
and (3) sustainable management of piscivores.
An erratum to this article is available at . 相似文献
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Quantitative Real-Time PCR for Determination of Microcystin Synthetase E Copy Numbers for Microcystis and Anabaena in Lakes 总被引:3,自引:0,他引:3
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Jaana Vaitomaa Anne Rantala Katrianna Halinen Leo Rouhiainen Petra Tallberg Lena Mokelke Kaarina Sivonen 《Applied microbiology》2003,69(12):7289-7297
Cyanobacterial mass occurrences in freshwater lakes are generally formed by Anabaena, Microcystis, and Planktothrix, which may produce cyclic heptapeptide hepatotoxins, microcystins. Thus far, identification of the most potent microcystin producer in a lake has not been possible due to a lack of quantitative methods. The aim of this study was to identify the microcystin-producing genera and to determine the copy numbers of microcystin synthetase gene E (mcyE) in Lake Tuusulanjärvi and Lake Hiidenvesi in Finland by quantitative real-time PCR. The microcystin concentrations and cyanobacterial cell densities of these lakes were also determined. The microcystin concentrations correlated positively with the sum of Microcystis and Anabaena mcyE copy numbers from both Lake Tuusulanjärvi and Lake Hiidenvesi, indicating that mcyE gene copy numbers can be used as surrogates for hepatotoxic Microcystis and Anabaena. The main microcystin producer in Lake Tuusulanjärvi was Microcystis spp., since average Microcystis mcyE copy numbers were >30 times more abundant than those of Anabaena. Lake Hiidenvesi seemed to contain both nontoxic and toxic Anabaena as well as toxic Microcystis strains. Identifying the most potent microcystin producer in a lake could be valuable for designing lake restoration strategies, among other uses. 相似文献
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The chemical and microbiological responses of profundal surface sediment were monitored in sediment enriched with natural
settled material collected in May, July or August, and with diatom or cyanobacteria cultures. The activation of the sediment
microbial community was clearest after the addition of settled seston collected in May which was richer in organic matter
than those collected later in the summer. N was released when the sediment was enriched with settled seston which had been
collected in July and August and had C:N ratios lower than 10:1. The diatom-rich May-material enhanced the release of P to
the interstitial water, obviously because of chemical competition between P and diatom-derived Si at the sediment surface.
The July- and August-materials did not release P, nor did the diatom and cyanobacteria cultures. The results thus indicate
that the seasonal variations in the quality and quantity of the settling phytoplankton affect the P dynamics at the sediment
surface, both chemically and biologically. 相似文献
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Jukka Horppila Tommi Malinen Leena Nurminen Petra Tallberg Mika Vinni 《Hydrobiologia》2000,436(1-3):81-90
The diurnal vertical migrations of smelt (Osmerus eperlanus), larvae of phantom midge (Chaoborus flavicans) and cladoceran zooplankton in eutrophic Lake Hiidenvesi were studied in order to clarify the factors behind the low zooplankton biomass. In the study area, an oxygen minimum occurred in the metalimnion in the 10–15 m depth. No diurnal fluctuations in the position of the minimum were observed. Cladocerans inhabited the epilimnion throughout the study period and their vertical movements were restricted to above the thermocline and above the oxygen minimum. C. flavicansconducted a diurnal migration. During the day, the majority of the population inhabited the 12 – 15 m depth just in the oxygen minimum, while during darkness they were found in the uppermost 8 m. Smelts started ascending towards the water surface before sunset and reached the uppermost 3 m around 23:00. During daytime, the majority of smelts inhabited the depth of 7–9 m, where the water temperature was unfavourably high for them (18 °C). Smelts thus probably avoided the steep oxygen gradient in the metalimnion, whereas Chaoborusused the oxygen minimum as a refuge against predation. Those smelts that were found in the same water layers as Chaoborusused the larvae as their main prey. The metalimnetic oxygen minimum thus seemed to favour the coexistence of vertebrate and invertebrate predators, leading to a depression of cladoceran zooplankton. 相似文献
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