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1.
Periphyton biofilms are natural mixtures comprised of photoautotrophic and heterotrophic complex microorganisms. In this work, the inhibition effects of periphyton biofilms on cyanobacterial blooms were studied in pilot and field trials. Results show that the cyanobacterial species responsible for the blooms had an upper nutrient concentration threshold, below which it could not effectively compete with other organisms in the periphyton. The disappearance of the cyanobacterial blooms was due to the allelopathy between the cyanobacteria and periphyton biofilm. In particular, it was found that the periphyton biofilm could produce water-soluble allelochemicals such as indole and 3-oxo-α-ionone to significantly inhibit the growth of the cyanobacteria. These allelochemicals are able to damage the thylakoid membranes of the cyanobacteria, interrupt the electron transport in photosystem II, decrease effective quantum yields, and eventually lead to the failure of photosynthesis. A comprehensive discussion on the ecological consequences of these findings is also presented. This work demonstrates the potential of periphyton biofilm to be used as an environmentally friendly ecological engineering solution for (i) the control of cyanobacterial blooms and (ii) a transitional means for the construction of beneficial conditions for ecosystem restoration. In addition, this work provides significant insights into the competitive relationships between algae and biofilms. 相似文献
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A potable supply reservoir, with a long history of diatom blooms in spring and cyanobacterial blooms in summer, was treated with barley straw in March 1993 with subsequent additions in December 1993 and June 1994. Within two months of the initial treatment, algal numbers started to fall compared with previous years and have remained consistently lower throughout 1993 and 1994. Cyanobacteria have not bloomed and cell numbers remained low. Chemical analysis of the water showed locally elevated concentrations of geosmin close to the straw on one occasion but the overall concentration of this and a range of other organic molecules remained within acceptable limits and at concentrations similar to those found in other untreated reservoirs in the region. Observed and potential advantages to public health and potable supply management resulting from the use of barley straw are discussed. 相似文献
8.
Microcystin in cyanobacterial blooms in a Chilean lake. 总被引:4,自引:0,他引:4
V Campos S Cantarero H Urrutia R Heinze B Wirsing U Neumann J Weckesser 《Systematic and applied microbiology》1999,22(2):169-173
Cyanobacterial blooms dominated by Microcystis sp. occurred in lake Rocuant ("marisma", near Concepción/Chile) in February 1995 and 1996. In the bloom samples collected in both years the hepatotoxin microcystin was detected by RP-HPLC in both samples and in the sample of 1995 also by a toxicity assay using primary rat hepatocytes. In the bloom of 1995, the microcystin content of the dry bloom biomass was determined to be 130 micrograms/g on the basis of the RP-HPLC peak area and 800 micrograms/g on the basis of the rat hepatotoxicity assay, respectively. In the bloom of 1996, RP-HPLC analysis revealed a microcystin content of 8.13 micrograms/g bloom material dry weight. In this year no hepatotoxicity was measured using a concentration range up to 0.8 mg (d. w.) of bloom material per ml in the rat hepatotoxicity assay. This is the first report on the detection of microcystins in Chilean water bodies. 相似文献
9.
Anatoly Peretyatko Samuel Teissier Sylvia De Backer Ludwig Triest 《Hydrobiologia》2012,689(1):131-146
Nutrient enrichment of aquatic ecosystems caused dramatic increase in the frequency, magnitude and duration of cyanobacterial
blooms. Such blooms may cause fish kills, have adverse health effects on humans and contribute to the loss of biodiversity
in aquatic ecosystems. Some 50 eutrophic to hypereutrophic ponds from the Brussels Capital Region (Belgium) were studied between
2003 and 2009. A number of the ponds studied are prone to persistent cyanobacterial blooms. Because of the related health
concerns and adverse effects on ecological quality of the affected ponds, a tool for assessment of the risk of cyanobacterial
bloom occurrence was needed. The data acquired showed that cyanobacteria have threshold relationships with most of the environmental
factors that control them. This is negatively reflected on the predictive capacity of conventional statistical methods based
on linear relationships. Therefore, classification trees designed for the treatment of complex data and non-linear relationships
were used to assess the risk of cyanobacterial bloom occurrence. The main factors determining cyanobacterial bloom development
appeared to be phytoplankton biomass, pH and, to a lesser degree, nitrogen availability. These results suggest that to outcompete
eukaryotic phytoplankters cyanobacteria need the presence of environmental constraints: carbon limitation, light limitation
and nitrogen limitation, for which they developed a number of adaptations. In the absence of constraints, eukaryotic phytoplankters
appear to be more competitive. Therefore, prior build up of phytoplankton biomass seems to be essential for cyanobacterial
dominance. Classification trees proved to be an efficient tool for the bloom risk assessment and allowed the main factors
controlling bloom development to be identified as well as the risk of bloom occurrence corresponding to the conditions determined
by these factors to be quantified. The results produced by the classification trees are consistent with those obtained earlier
by probabilistic approach to bloom risk assessment. They can facilitate planning management interventions and setting restoration
priorities. 相似文献
10.
Marie-Elodie Perga Isabelle Domaizon Jean Guillard Valérie Hamelet Orlane Anneville 《Oecologia》2013,172(2):551-562
Cyanobacterial blooms induce significant costs that are expected to increase in the near future. Cyanobacterial resistance to zooplankton grazing is one factor thought to promote bloom events. Yet, numerous studies on zooplankton ability to graze upon cyanobacteria have been producing contradictory results and such a puzzle might arise from the lack of direct observations in situ. Our objective was to track, using fatty acid (FA) and fatty acid stable isotope analyses (FA-SIA), the fate of cyanobacterial organic matter in the food web of a lake subjected to summer blooms of Planktothrix rubescens. A metalimnetic bloom of P. rubescens occurred in Lake Bourget (France) during the study period (May–November 2009). The bloom was especially rich in α-linolenic acid, 18:3(n-3), but none of the considered zooplankton taxa exhibited spiking content in this particular FA. FA-SIA revealed, however, that over a quarter of 18:3(n-3) in small zooplankton (<500 μm) was provided by P. rubescens while large cladocerans (>500 μm) did not benefit from it. P. rubescens 18:3(n-3) could be tracked up to perch (Perca fluviatilis) young of the year (YOY) to which it contributed to ~15 % of total 18:3(n-3). Although transferred with a much lower efficiency than micro-algal organic matter, the P. rubescens bloom supported a significant share of the pelagic secondary production and did not constitute, sensu stricto, a ‘trophic dead end’. The cyanobacterial bloom also provided perch YOY with components of high nutritional values at a season when these are critical for their recruitment. This cyanobacterial bloom might thus be regarded as a significant dietary bonus for juvenile fish. 相似文献
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Effect of cyanobacterial blooms on thermal stratification 总被引:2,自引:0,他引:2
M. Kumagai S. Nakano C. Jiao K. Hayakawa S. Tsujimura T. Nakajima J.-J. Frenette A. Quesada 《Limnology》2000,1(3):191-195
Enclosure experiments were performed at Akanoi Bay, Lake Biwa, in 1995 to determine whether the blooms of cyanobacterial
algae changed thermal stratification in the lake. We used four rectangular enclosures, each 10 m × 10 m, with a volume of
200 m3, which were open to the sediments. Two enclosures, A and B, were mixed artificially by aquatic pumps from 1000 to 1400 every
day, and the other two enclosures, C and D, were controls with no mixing. The experiment was conducted during late summer
from August 3 to September 27. Chlorophyll a concentrations were highest in enclosure D, followed by enclosure C, both of which were controls without mixing. Enclosure A had lower concentrations than enclosures
C and D, and enclosure B had the lowest concentrations. No large cyanobacterial algae blooms of Anabaena sp. and Microcystis sp. were seen in the mixed enclosures A and B. In enclosures C and D, blooms of Anabaena sp. occurred in the middle of August, and Microcystis sp. later became dominant in enclosure D at the end of August. In enclosure D, the water temperature changed over the diel
cycle before August 17, with thermal stratification during the day and complete mixing at night. After August 17, as Anabaena sp. and Microcystis sp. became dominant, the temperature at the bottom of the enclosure did not change clearly over the 24-h cycle. The APE (available
potential energy) density (a measure of water column stability) in the enclosures increased by almost 100% when the biovolume
of Anabaena sp. + Microcystis sp. exceeded 20 mm3 l−1. These results indicate that blooms of Anabaena sp. and Microcystis sp. can increase the available potential energy in the water column and create more stable stratification for their growth.
Received: September 25, 1999 / Accepted: January 6, 2000 相似文献
12.
Martin Saker Cristiana Moreira Joana Martins Brett Neilan Vitor Manuel Vasconcelos 《Applied microbiology and biotechnology》2009,85(2):237-252
Cyanobacteria are prokaryotic photosynthetic living organisms that inhabit our planet for over three billion years. With a
worldwide distribution, they can be found in all types of environments: fresh, brackish and saltwater as well as terrestrial.
Though beneficial in the development of life on earth, they also constitute a serious risk to our ecosystems since they can
biologically produce harmful secondary metabolites named cyanotoxins. When studying cyanobacteria and their cyanotoxins, several
methodologies have been applied with an increasing relevance to molecular methods. Therefore, the aim of this review is to
describe alternative molecular methods that can be used as alternative methods for the identification of cyanobacteria. More
traditional chemotaxonomic methods are discussed briefly as are the standard and somewhat dated techniques for assessing genome
content for taxonomic classification schemes. The use of DNA amplification technology has been applied to the systematics
and phylogeny of many bacterial groups, and the optimisation of methods for rapid identification and classification of cyanobacteria
are presented. Together with novel methods developed for these photosynthetic microorganisms, the generated DNA profiles have
been utilised to study cyanobacterial bloom population diversity and prediction of strain toxigenicity. Finally, the genotypes
found were applied to a variety of phylogenetic analyses; trees were reconstructed and compared to the current morphological
system of classification. The ecology and diversity of the cyanobacteria is discussed with respect to the derived molecular
phylogenies and systematics. 相似文献
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Interannual variability of cyanobacterial blooms in lake erie 总被引:3,自引:0,他引:3
After a 20-year absence, severe cyanobacterial blooms have returned to Lake Erie in the last decade, in spite of negligible change in the annual load of total phosphorus (TP). Medium-spectral Resolution Imaging Spectrometer (MERIS) imagery was used to quantify intensity of the cyanobacterial bloom for each year from 2002 to 2011. The blooms peaked in August or later, yet correlate to discharge (Q) and TP loads only for March through June. The influence of the spring TP load appears to have started in the late 1990 s, after Dreissenid mussels colonized the lake, as hindcasts prior to 1998 are inconsistent with the observed blooms. The total spring Q or TP load appears sufficient to predict bloom magnitude, permitting a seasonal forecast prior to the start of the bloom. 相似文献
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Rainfall, phycocyanin, and N:P ratios related to cyanobacterial blooms in a Korean large reservoir 总被引:6,自引:0,他引:6
Nutrient concentrations and other environmental factors were measured in the Daechung Reservoir for 25 weeks from spring until autumn in 1999. The high irradiance after heavy rainfall provided optimal meteorological conditions for bloom formation during summer, therefore, rain would also appear to forecast imminent bloom. The bloom formation was largely governed by cyanobacteria, in particular, Microcystis spp. and Anabaenaspp. Phycocyanin showed higher correlation with cyanobacteria (r = 0.744, P < 0.001) compared to chlorophyll-a(r = 0.599, P < 0.01). Therefore, phycocyanin was more accurate and useful than chlorophyll-a in quantitatively measuring cyanobacterial blooms. The atomic N:P ratio of the particulate form also showed a high correlation with cyanobacteria (r = 0.541, P < 0.01), increasing from 4.3 to 14.6 during bloom formation, while that of the dissolved form decreased from 25.5 to 8.7. These results indicated that the algae assimilated N significantly without comparable P uptake during the blooming season, which was in sharp contrast to the excessive storage of P during the spring. 相似文献
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Microcystin synthetase-gene-specific primers were used to identify hepatotoxic microcystin producing genotypes in six Microcystis spp.-dominant water blooms. Four blooms gave positive PCR reaction. They produced microcystin-RR and -LR amounting to 0.037 to 0.095% of the dry mass. 相似文献
18.
Artificial mixing prevents nuisance blooms of the cyanobacterium Microcystis in Lake Nieuwe Meer, the Netherlands 总被引:5,自引:0,他引:5
PETRA VISSER BAS IBELINGS BART VAN DER VEER JAN KOEDOOD & R. MUR 《Freshwater Biology》1996,36(2):435-450
1. Artificial mixing in the hypertrophic Lake Nieuwe Meer was successful in preventing blooms of the cyanobacterium Microcystis. During the 2 years of artificial, deep mixing the number of colonies of Microcystis per litre and also per m2 was lower than in the two preceding control years. Hardly any nuisance scums of Microcystis occurred in the lake.
2. The phytoplankton shifted from a cyanobacteria-dominated community in summer to a mixed community of flagellates, green algae and diatoms. Reduced sedimentation losses in the mixed lake, probably in combination with a lower pH, favoured non-buoyant algae, while the entrainment of cyanobacteria in the turbulent flow nullified their advantage of buoyancy.
3. The chlorophyll concentrations were much lower in the mixed lake, but the euphotic depth did not show clear differences between the years. The chlorophyll content integrated through depth (m–2 ) increased in the artificially mixed lake.
4. The deep lake normally stratified in summer, but artificial mixing of the lake in 1993 resulted in a homogeneous temperature and oxygen distribution with depth. In spring 1994, the mixing was applied intermittently with a reduction of 75% of the energy costs, while the mixing was still sufficient to prevent stratification.
5. Determination of the buoyancy state of the colonies on a sunny and calm day showed that the buoyancy loss was low close to the bubble plumes, and high at some distance from these plumes. This suggests that Microcystis could escape the mixing at some distance from the plumes, and could synthesize more carbohydrates during its stay in the upper illuminated layer of the lake than the deep mixed colonies close to the bubble plumes. Determination of the buoyancy state appeared to be a good and simple method to investigate the extent of entrainment of colonies in the turbulent flow. 相似文献
2. The phytoplankton shifted from a cyanobacteria-dominated community in summer to a mixed community of flagellates, green algae and diatoms. Reduced sedimentation losses in the mixed lake, probably in combination with a lower pH, favoured non-buoyant algae, while the entrainment of cyanobacteria in the turbulent flow nullified their advantage of buoyancy.
3. The chlorophyll concentrations were much lower in the mixed lake, but the euphotic depth did not show clear differences between the years. The chlorophyll content integrated through depth (m
4. The deep lake normally stratified in summer, but artificial mixing of the lake in 1993 resulted in a homogeneous temperature and oxygen distribution with depth. In spring 1994, the mixing was applied intermittently with a reduction of 75% of the energy costs, while the mixing was still sufficient to prevent stratification.
5. Determination of the buoyancy state of the colonies on a sunny and calm day showed that the buoyancy loss was low close to the bubble plumes, and high at some distance from these plumes. This suggests that Microcystis could escape the mixing at some distance from the plumes, and could synthesize more carbohydrates during its stay in the upper illuminated layer of the lake than the deep mixed colonies close to the bubble plumes. Determination of the buoyancy state appeared to be a good and simple method to investigate the extent of entrainment of colonies in the turbulent flow. 相似文献
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PETRA VISSER BAS IBELINGS BART VAN DER VEER JAN KOEDOOD & R. MUR 《The Plant journal : for cell and molecular biology》2003,36(2):435-450
1. Artificial mixing in the hypertrophic Lake Nieuwe Meer was successful in preventing blooms of the cyanobacterium Microcystis. During the 2 years of artificial, deep mixing the number of colonies of Microcystis per litre and also per m2 was lower than in the two preceding control years. Hardly any nuisance scums of Microcystis occurred in the lake.
2. The phytoplankton shifted from a cyanobacteria-dominated community in summer to a mixed community of flagellates, green algae and diatoms. Reduced sedimentation losses in the mixed lake, probably in combination with a lower pH, favoured non-buoyant algae, while the entrainment of cyanobacteria in the turbulent flow nullified their advantage of buoyancy.
3. The chlorophyll concentrations were much lower in the mixed lake, but the euphotic depth did not show clear differences between the years. The chlorophyll content integrated through depth (m–2 ) increased in the artificially mixed lake.
4. The deep lake normally stratified in summer, but artificial mixing of the lake in 1993 resulted in a homogeneous temperature and oxygen distribution with depth. In spring 1994, the mixing was applied intermittently with a reduction of 75% of the energy costs, while the mixing was still sufficient to prevent stratification.
5. Determination of the buoyancy state of the colonies on a sunny and calm day showed that the buoyancy loss was low close to the bubble plumes, and high at some distance from these plumes. This suggests that Microcystis could escape the mixing at some distance from the plumes, and could synthesize more carbohydrates during its stay in the upper illuminated layer of the lake than the deep mixed colonies close to the bubble plumes. Determination of the buoyancy state appeared to be a good and simple method to investigate the extent of entrainment of colonies in the turbulent flow. 相似文献
2. The phytoplankton shifted from a cyanobacteria-dominated community in summer to a mixed community of flagellates, green algae and diatoms. Reduced sedimentation losses in the mixed lake, probably in combination with a lower pH, favoured non-buoyant algae, while the entrainment of cyanobacteria in the turbulent flow nullified their advantage of buoyancy.
3. The chlorophyll concentrations were much lower in the mixed lake, but the euphotic depth did not show clear differences between the years. The chlorophyll content integrated through depth (m
4. The deep lake normally stratified in summer, but artificial mixing of the lake in 1993 resulted in a homogeneous temperature and oxygen distribution with depth. In spring 1994, the mixing was applied intermittently with a reduction of 75% of the energy costs, while the mixing was still sufficient to prevent stratification.
5. Determination of the buoyancy state of the colonies on a sunny and calm day showed that the buoyancy loss was low close to the bubble plumes, and high at some distance from these plumes. This suggests that Microcystis could escape the mixing at some distance from the plumes, and could synthesize more carbohydrates during its stay in the upper illuminated layer of the lake than the deep mixed colonies close to the bubble plumes. Determination of the buoyancy state appeared to be a good and simple method to investigate the extent of entrainment of colonies in the turbulent flow. 相似文献
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《Harmful algae》2019
Lake Taihu, the third largest freshwater lake in China, suffers from harmful cyanobacteria blooms caused by Microcystis spp., which do not fix nitrogen (N). Reduced N (i.e., NH4+, urea and other labile organic N compounds) is an important factor affecting the growth of Microcystis. As the world use of urea as fertilizer has escalated during the past decades, an understanding of how urea cycling relates to blooms of Microcystis is critical to predicting, controlling and alleviating the problem. In this study, the cycling rates of urea-N in Lake Taihu ranged from non-detectable to 1.37 μmol N L−1 h−1 for regeneration, and from 0.042 μmol N L−1 h−1 to 2.27 μmol N L−1 h−1 for potential urea-N removal. The fate of urea-N differed between light and dark incubations. Increased 15NH4+ accumulated and higher quantities of the removed urea-15N remained in the 15NH4+ form were detected in the dark than in the light. A follow-up incubation experiment with 15N-urea confirmed that Microcystis can grow on urea but its effects on urea dynamics were minor, indicating that Microcystis was not the major factor causing the observed fates of urea under different light conditions in Lake Taihu. Bacterial community composition and predicted functional gene data suggested that heterotrophic bacteria metabolized urea, even though Microcystis spp. was the dominant bloom organism. 相似文献