scholarly journals Phytoplankton Communities and Cyanotoxin Production in Some Bulgarian Lowland Lakes and Reservoirs

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Detelina Belkinova ◽  
Ivanka Teneva ◽  
Stefan Kazakov ◽  
Silvia Stamenova
Keyword(s):  
Threshold Value ◽  
Toxin Production ◽  
Water Bodies ◽  
Cyanobacterial Blooms ◽  
Summer Period ◽  
Recreational Waters ◽  
Guideline Values ◽  
Phytoplankton Communities ◽  
Lakes And Reservoirs ◽  
Lowland Lakes

One of the most evident consequences of eutrophication of waters is the progressive spreading of persistent cyanobacterial blooms. They are often accompanied by the production of cyanotoxins in concentrations, which are hazardous for human health. In this research, we analysed phytoplankton communities in four lowland water bodies, for the presence of cyanobacterial blooms and toxin production. The cyanobacterial biovolumes we found, determine three of the lowland water bodies: Onogur Reservoir (OR), Asparuhov Val Reservoir (AVR), and Srebarna Lake (SL) as “Alert Level 1” of potentially hazardous levels of cyanotoxins. Cyanobacterial biovolume exceeds the threshold value of 8 mm3 L-1 (recreational waters) in AVR and SL at the end of the summer period. In OR, we registered sustainable bloom of Microcystis spp. during the whole summer season, and extremely high average seasonal value of the total biovolume (146.5 mm3 L-1). Micro-cystins were reported in all four analysed water bodies, with the highest concentration in OR (6 µg L-1). Cylindrospermopsin was detected in AVR and OR, while saxitoxins were in AVR and SL. The concentrations of cyanotoxins do not exceed the guideline values in recreational waters. However, the increased biovolumes of cyanobacteria are a signal that in three of the analysed water bodies, monitoring is recommended at the levels of cyanotoxins during the summer period.

scholarly journals Cyanobacterial Toxin Degrading Bacteria: Who Are They?

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Konstantinos Ar. Kormas ◽  
Despoina S. Lymperopoulou
Keyword(s):  
Meta Analysis ◽  
Toxin Production ◽  
Cyanobacterial Blooms ◽  
Ecological Knowledge ◽  
Cyanobacterial Toxin ◽  
Molecular Approaches ◽  
Degrading Bacteria ◽  
Ecological Problems ◽  
Ecosystem Level ◽  
Toxin Degradation

Cyanobacteria are ubiquitous in nature and are both beneficial and detrimental to humans. Benefits include being food supplements and producing bioactive compounds, like antimicrobial and anticancer substances, while their detrimental effects are evident by toxin production, causing major ecological problems at the ecosystem level. To date, there are several ways to degrade or transform these toxins by chemical methods, while the biodegradation of these compounds is understudied. In this paper, we present a meta-analysis of the currently available 16S rRNA andmlrA(microcystinase) genes diversity of isolates known to degrade cyanobacterial toxins. The available data revealed that these bacteria belong primarily to the Proteobacteria, with several strains from the sphingomonads, and one from each of theMethylobacillusandPaucibactergenera. Other strains belonged to the generaArthrobacter, Bacillus, andLactobacillus. By combining the ecological knowledge on the distribution, abundance, and ecophysiology of the bacteria that cooccur with toxic cyanobacterial blooms and newly developed molecular approaches, it is possible not only to discover more strains with cyanobacterial toxin degradation abilities, but also to reveal the genes associated with the degradation of these toxins.

A survey of toxicity of cyanobacterial blooms in Lake Ladoga and adjacent water bodies

Hydrobiologia ◽  
1996 ◽  
Vol 322 (1-3) ◽  
pp. 149-151 ◽  
Author(s):  
Boris V. Gromov ◽  
Alexey A. Vepritsky ◽  
Kira A. Mamkaeva ◽  
Lyudmila N. Voloshko
Keyword(s):  
Water Bodies ◽  
Cyanobacterial Blooms ◽  
Lake Ladoga ◽  
Adjacent Water

scholarly journals Advancing Knowledge on Cyanobacterial Blooms in Freshwaters

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2583
Author(s):  
Elisabeth Vardaka ◽  
Konstantinos Ar. Kormas
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Mathematical Modelling ◽  
Ecological Status ◽  
Toxin Production ◽  
Cyanobacterial Blooms ◽  
Special Issue ◽  
Research Papers ◽  
Cyanobacterial Species ◽  
Water Quality Deterioration

Cyanobacterial blooms have become a frequent phenomenon in freshwaters worldwide; they are a widely known indicator of eutrophication and water quality deterioration. Information and knowledge contributing towards the evaluation of the ecological status of freshwaters, particularly since many are used for recreation, drinking water, and aquaculture, is valuable. This Special Issue, entitled “Advancing Knowledge on Cyanobacterial Blooms in Freshwaters”, includes 11 research papers that will focus on the use of complementary approaches, from the most recently developed molecular-based methods to more classical approaches and experimental and mathematical modelling regarding the factors (abiotic and/or biotic) that control the diversity of not only the key bloom-forming cyanobacterial species, but also their interactions with other biota, either in freshwater systems or their adjacent habitats, and their role in preventing and/or promoting cyanobacterial growth and toxin production.

Global scanning of anatoxins in aquatic systems: environment and health hazards, and research needs

2020 ◽  
Vol 71 (5) ◽  
pp. 689 ◽  
Author(s):  
Lea M. Lovin ◽  
Bryan W. Brooks
Keyword(s):  
Surface Water ◽  
Aquatic Toxicity ◽  
Aquatic Systems ◽  
Cyanobacterial Blooms ◽  
Asia Pacific ◽  
Quality Data ◽  
Published Data ◽  
Research Needs ◽  
Global Public Health ◽  
Guideline Values

Surface water contamination from the neurotoxic cyanotoxin anatoxin-a and its analogues present risks to global public health and the environment. Understanding aquatic hazards is critical for cyanobacterial blooms increasing in magnitude, frequency and duration. We examined published data to identify exceedances of guideline values (GVs) globally in various aquatic systems to understand hazards when exposure occurs. Environmental exposure distributions of surface water data (intra- and extracellular toxins) from recreational and potable source waters exceeded common GVs of 0.1, 1 and 300µgL–1 when blooms occur 79.62, 48.37 and 1.42% of the time respectively. In total, 66% of occurrences were from lacustrine ecosystems compared with reservoir, river, coastal and other systems, with almost all data from Asia–Pacific, Europe and North America, highlighting the need for more monitoring efforts in diverse systems and in developing regions. Reservoirs had greatest exceedances of the highest GV compared with other systems, especially in Europe, where an exceedance of 19.92% was observed. Aquatic toxicity and bioaccumulation data were examined and compared to these environmentally relevant concentrations, though a lack of high-quality data highlights major research needs. This study further identifies the utility of probabilistic cyanotoxins assessments to support identification of where environmental monitoring and research may be more effectively focused.

scholarly journals Exploring How Cyanobacterial Traits Affect Nutrient Loading Thresholds in Shallow Lakes: A Modelling Approach

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2467 ◽  
Author(s):  
Manqi Chang ◽  
Sven Teurlincx ◽  
Jan Janse ◽  
Hans Paerl ◽  
Wolf Mooij ◽  
...  
Keyword(s):  
Water Quality ◽  
Nitrogen Fixation ◽  
Shallow Lakes ◽  
Lake Restoration ◽  
Nutrient Loading ◽  
Ecosystem Model ◽  
Water Bodies ◽  
Cyanobacterial Blooms ◽  
Eutrophic Water ◽  
Modelling Approach

Globally, many shallow lakes have shifted from a clear macrophyte-dominated state to a turbid phytoplankton-dominated state due to eutrophication. Such shifts are often accompanied by toxic cyanobacterial blooms, with specialized traits including buoyancy regulation and nitrogen fixation. Previous work has focused on how these traits contribute to cyanobacterial competitiveness. Yet, little is known on how these traits affect the value of nutrient loading thresholds of shallow lakes. These thresholds are defined as the nutrient loading at which lakes shift water quality state. Here, we used a modelling approach to estimate the effects of traits on nutrient loading thresholds. We incorporated cyanobacterial traits in the process-based ecosystem model PCLake+, known for its ability to determine nutrient loading thresholds. Four scenarios were simulated, including cyanobacteria without traits, with buoyancy regulation, with nitrogen fixation, and with both traits. Nutrient loading thresholds were obtained under N-limited, P-limited, and colimited conditions. Results show that cyanobacterial traits can impede lake restoration actions aimed at removing cyanobacterial blooms via nutrient loading reduction. However, these traits hardly affect the nutrient loading thresholds for clear lakes experiencing eutrophication. Our results provide references for nutrient loading thresholds and draw attention to cyanobacterial traits during the remediation of eutrophic water bodies.

scholarly journals Seasonal Succession of Phytoplankton Functional Groups and Driving Factors of Cyanobacterial Blooms in a Subtropical Reservoir in South China

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1167 ◽  
Author(s):  
Lingai Yao ◽  
Xuemin Zhao ◽  
Guang-Jie Zhou ◽  
Rongchang Liang ◽  
Ting Gou ◽  
...  
Keyword(s):  
Functional Groups ◽  
South China ◽  
Algal Cell ◽  
Seasonal Succession ◽  
Geographic Location ◽  
Water Source ◽  
Cyanobacterial Blooms ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Communities ◽  
Phytoplankton Functional Groups

Freshwater phytoplankton communities can be classified into a variety of functional groups that are based on physiological, morphological, and ecological characteristics. This classification method was used to study the temporal and spatial changes in the phytoplankton communities of Gaozhou Reservoir, which is a large municipal water source in South China. Between January 2015 and December 2017, a total of 155 taxa of phytoplankton that belong to seven phyla were identified. The phytoplankton communities were classified into 28 functional groups, nine of which were considered to be representative functional groups (relative biomass > 10%). Phytoplankton species richness was greater in the summer and autumn than in the winter and spring; cyanobacterial blooms occurred in the spring. The seasonal succession of phytoplankton functional groups was characterized by the occurrence of functional groups P (Staurastrum sp. and Closterium acerosum) and Y (Cryptomonas ovata and Cryptomonas erosa) in the winter and spring, and functional groups NA (Cosmarium sp. and Staurodesmus sp.) and P (Staurastrum sp. and Closterium acerosum) in the summer and autumn. The temperature, nitrogen, and phosphorus levels were the main factors driving seasonal changes in the phytoplankton communities of Gaozhou Reservoir. The functional group M (Microcystis aeruginosa) dominated the community during the cyanobacterial blooms in spring 2016, with the maximum algal cell density of 3.12 × 108 cells L−1. Relatively low temperature (20.8 °C), high concentrations of phosphorus (0.080–0.110 mg L−1), suitable hydrological and hydrodynamic conditions (e.g., relatively long retention time), and relatively closed geographic location in the reservoir were the key factors that stimulated the cyanobacterial blooms during the early stages.

Environmental factors associated with a toxic bloom of Microcystis aeruginosa

2000 ◽  
Vol 57 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Jean M Jacoby ◽  
Diane C Collier ◽  
Eugene B Welch ◽  
F Joan Hardy ◽  
Michele Crayton
Keyword(s):  
Environmental Factors ◽  
Microcystis Aeruginosa ◽  
Toxin Production ◽  
Water Transparency ◽  
Cyanobacterial Blooms ◽  
Zooplankton Abundance ◽  
Factors Associated ◽  
Water Column Stability ◽  
Microcystin Concentration ◽  
Toxic Bloom

Environmental factors associated with the occurrence of toxic cyanobacterial blooms and toxin production were investigated during the summers of 1994 and 1995 in Steilacoom Lake, Washington. A pronounced and prolonged toxic bloom of Microcystis aeruginosa occurred during summer 1994 but not during 1995. Lake characteristics that were associated with the toxic bloom in 1994 were higher total phosphorus, decreased water transparency, high water column stability, high surface water temperature and pH, and decreased lake flushing. Decreased water transparency during 1994 may have been due to significantly lower zooplankton abundance. We hypothesize that this decreased transparency was caused by increased planktivory by higher numbers of coho salmon (Oncorhynchus kisutch) fingerlings during 1994 and (or) inhibition of zooplankton grazing by Microcystis. The success of Microcystis over other cyanobacteria was associated with low nitrogen to phosphorus ratios and low nitrate-nitrogen with sufficient ammonium-nitrogen concentrations. Toxin production (i.e., micrograms of microcystin per gram of plankton biomass) was not constant over the duration of detectable toxicity; hence, no relationship was found between Microcystis abundance and microcystin concentration. However, microcystin concentration was positively correlated with increasing soluble reactive phosphorus concentrations between 1 and 10 µg·L-1, indicating that toxin production may have been limited by phosphorus.

Stepwise strategy for monitoring toxic cyanobacterial blooms in lentic water bodies

2017 ◽  
Vol 189 (12) ◽  
Author(s):  
Inês P. E. Macário ◽  
Bruno B. Castro ◽  
Isabel M. S. Nunes ◽  
Cristina Pizarro ◽  
Carla Coelho ◽  
...  
Keyword(s):  
Water Bodies ◽  
Cyanobacterial Blooms ◽  
Lentic Water

scholarly journals Rapid adaptation of harmful cyanobacteria to rising CO2

2016 ◽  
Vol 113 (33) ◽  
pp. 9315-9320 ◽  
Author(s):  
Giovanni Sandrini ◽  
Xing Ji ◽  
Jolanda M. H. Verspagen ◽  
Robert P. Tann ◽  
Pieter C. Slot ◽  
...  
Keyword(s):  
Cyanobacterial Bloom ◽  
Eutrophic Lake ◽  
Cyanobacterial Blooms ◽  
High Flux ◽  
Flux Rate ◽  
Eutrophic Lakes ◽  
Field Evidence ◽  
Evolutionary Changes ◽  
Lakes And Reservoirs ◽  
Harmful Cyanobacterial Blooms

Rising atmospheric CO2 concentrations are likely to affect many ecosystems worldwide. However, to what extent elevated CO2 will induce evolutionary changes in photosynthetic organisms is still a major open question. Here, we show rapid microevolutionary adaptation of a harmful cyanobacterium to changes in inorganic carbon (Ci) availability. We studied the cyanobacterium Microcystis, a notorious genus that can develop toxic cyanobacterial blooms in many eutrophic lakes and reservoirs worldwide. Microcystis displays genetic variation in the Ci uptake systems BicA and SbtA, where BicA has a low affinity for bicarbonate but high flux rate, and SbtA has a high affinity but low flux rate. Our laboratory competition experiments show that bicA + sbtA genotypes were favored by natural selection at low CO2 levels, but were partially replaced by the bicA genotype at elevated CO2. Similarly, in a eutrophic lake, bicA + sbtA strains were dominant when Ci concentrations were depleted during a dense cyanobacterial bloom, but were replaced by strains with only the high-flux bicA gene when Ci concentrations increased later in the season. Hence, our results provide both laboratory and field evidence that increasing carbon concentrations induce rapid adaptive changes in the genotype composition of harmful cyanobacterial blooms.

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