scholarly journals Seasonal Dynamics Are the Major Driver of Microbial Diversity and Composition in Intensive Freshwater Aquaculture

2021 ◽  
Vol 12 ◽  
Author(s):  
Sophi Marmen ◽  
Eduard Fadeev ◽  
Ashraf Al Ashhab ◽  
Ayana Benet-Perelberg ◽  
Alon Naor ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Explanatory Power ◽  
Water Reservoir ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Nutrient Ratios ◽  
Seasonal Cycles ◽  
Fish Feed ◽  
Related Factors ◽  
Freshwater Aquaculture

Aquaculture facilities such as fishponds are one of the most anthropogenically impacted freshwater ecosystems. The high fish biomass reared in aquaculture is associated with an intensive input into the water of fish-feed and fish excrements. This nutrients load may affect the microbial community in the water, which in turn can impact the fish health. To determine to what extent aquaculture practices and natural seasonal cycles affect the microbial populations, we characterized the microbiome of an inter-connected aquaculture system at monthly resolution, over 3 years. The system comprised two fishponds, where fish are grown, and an operational water reservoir in which fish are not actively stocked. Clear natural seasonal cycles of temperature and inorganic nutrients concentration, as well as recurring cyanobacterial blooms during summer, were observed in both the fishponds and the reservoir. The structure of the aquatic bacterial communities in the system, characterized using 16S rRNA sequencing, was explained primarily by the natural seasonality, whereas aquaculture-related parameters had only a minor explanatory power. However, the cyanobacterial blooms were characterized by different cyanobacterial clades dominating at each fishpond, possibly in response to distinct nitrogen and phosphate ratios. In turn, nutrient ratios may have been affected by the magnitude of fish feed input. Taken together, our results show that, even in strongly anthropogenically impacted aquatic ecosystems, the structure of bacterial communities is mainly driven by the natural seasonality, with more subtle effects of aquaculture-related factors.

scholarly journals Seasonal dynamics are the major driver of microbial diversity and composition in intensive freshwater aquaculture

2021 ◽  
Author(s):  
Sophi Marmen ◽  
Eduard Fadeev ◽  
Ashraf Al Ashhab ◽  
Ayana Benet-Perelberg ◽  
Alon Naor ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Explanatory Power ◽  
Water Reservoir ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Nutrient Ratios ◽  
Seasonal Cycles ◽  
Fish Feed ◽  
Related Factors ◽  
Freshwater Aquaculture

Aquaculture facilities such as fishponds are one of the most anthropogenically impacted freshwater ecosystems. The high fish biomass reared in aquaculture is associated with an intensive input into the water of fish-feed and fish excrements. This nutrients load may affect the microbial community in the water, which in turn can impact the fish health. To determine to what extent aquaculture practices and natural seasonal cycles affect the microbial populations, we characterized the microbiome of an inter-connected aquaculture system at monthly resolution, over three years. The system comprised two fishponds, where fish are grown, and a "control" operational water reservoir in which fish are not actively stocked. Clear natural seasonal cycles of temperature and inorganic nutrients concentration, as well as recurring cyanobacterial blooms during summer, were observed in both the fishponds and the reservoir. The structure of the aquatic bacterial communities in the system, characterized using 16S rRNA sequencing, was explained primarily by the natural seasonality, whereas aquaculture-related parameters had only a minor explanatory power. However, the cyanobacterial blooms were characterized by different cyanobacterial clades dominating at each fishpond, possibly in response to distinct nitrogen and phosphate ratios. In turn, nutrient ratios may have been by the magnitude of fish feed input. Taken together, our results show that, even in strongly anthropogenically impacted aquatic ecosystems, the structure of bacterial communities is mainly driven by the natural seasonality, with more subtle effects if aquaculture-related factors.

Bacterial presence in polar regions associated with environment modification by chemical compounds including contaminants

2017 ◽  
Vol 25 (4) ◽  
pp. 481-491 ◽  
Author(s):  
Klaudia Kosek ◽  
Katarzyna Jankowska ◽  
Żaneta Polkowska
Keyword(s):  
Bacterial Communities ◽  
Chemical Compounds ◽  
Freshwater Ecosystems ◽  
Trophic Levels ◽  
Polar Regions ◽  
Bacterial Cells ◽  
Chemical Contamination ◽  
Climate Conditions ◽  
Biological Communities ◽  
Long Time

Microbes are omnipresent and diverse members of all biological communities. In marine and freshwater ecosystems, microorganisms form the base of the food chain supporting higher trophic levels. Even though microbes are generally thought to live in warm regions of Earth, many of them develop in cold climates. Polar regions remain relatively protected from widespread anthropogenic disturbances, which is a consequence of thier remoteness and extreme climate conditions. For a long time these regions were considered to be free from chemical contamination until scientists discovered a presence of pollutants there. Chemical contamination may induce serious disorders in the integrity of polar ecosystems influencing the growth of bacterial communities. Xenobiotics including persistent organic pollutants are transported thousands of kilometers by the air and ocean currents, and they are deposed in high-latitude regions and accumulate in all elements of the environment including bacterial communities. It is important to determine their concentration levels in bacterial cells to assess the possibility of contaminants becoming transferred to higher trophic levels; however, some species of bacteria are capable of metabolizing xenobiotics, which makes them less toxic or even removes them from the environment.

scholarly journals Mobile Genetic Elements Drive the Antibiotic Resistome Alteration in Freshwater Shrimp Aquaculture

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1461
Author(s):  
Hao Fang ◽  
Nan Ye ◽  
Kailong Huang ◽  
Junnan Yu ◽  
Shuai Zhang
Keyword(s):  
Bacterial Communities ◽  
High Throughput Sequencing ◽  
Procambarus Clarkii ◽  
Variation Partitioning ◽  
Antibiotic Resistance Genes ◽  
Mobile Genetic Elements ◽  
Shrimp Aquaculture ◽  
Sediment Samples ◽  
Genetic Elements ◽  
Freshwater Aquaculture

Shrimp aquaculture environments are a natural reservoir of multiple antibiotic resistance genes (ARGs) due to the overuse of antibiotics. Nowadays, the prevalence of these kinds of emerging contaminants in shrimp aquaculture environments is still unclear. In this study, high-throughput sequencing techniques were used to analyze the distribution of ARGs and mobile genetic elements (MGEs), bacterial communities, and their correlations in water and sediment samples in two types of typical shrimp (Procambarus clarkii and Macrobrachium rosenbergii) freshwater aquaculture environments. A total of 318 ARG subtypes within 19 ARG types were detected in all the samples. The biodiversity and relative abundance of ARGs in sediment samples showed much higher levels compared to water samples from all ponds in the study area. Bacitracin (17.44–82.82%) and multidrug (8.57–49.70%) were dominant ARG types in P. clarkii ponds, while sulfonamide (26.33–39.59%) and bacitracin (12.75–37.11%) were dominant ARG types in M. rosenbergii ponds. Network analysis underlined the complex co-occurrence patterns between bacterial communities and ARGs. Proteobacteria, Cyanobacteria, and Actinobacteria exhibited a high abundance in all samples, in which C39 (OTU25355) and Hydrogenophaga (OTU162961) played important roles in the dissemination of and variation in ARGs based on their strong connections between ARGs and bacterial communities. Furthermore, pathogens (e.g., Aeromonadaceae (OTU195200) and Microbacteriaceae (OTU16033)), which were potential hosts for various ARGs, may accelerate the propagation of ARGs and be harmful to human health via horizontal gene transfer mediated by MGEs. Variation partitioning analysis further confirmed that MGEs were the most crucial contributor (74.76%) driving the resistome alteration. This study may help us to understand the non-ignorable correlations among ARGs, bacterial diversity, and MGEs in the shrimp freshwater aquaculture environments.

scholarly journals Harmful phytoplankton blooms and fish mortality in a eutrophicated reservoir of northeast Brazil

2008 ◽  
Vol 51 (4) ◽  
pp. 633-641 ◽  
Author(s):  
Naithirithi Tiruvenkatachary Chellappa ◽  
Sarah Laxhmi Chellappa ◽  
Sathyabama Chellappa
Keyword(s):  
Cyanobacterial Bloom ◽  
Hplc Method ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Fish Mortality ◽  
Cylindrospermopsis Raciborskii ◽  
Northeast Brazil ◽  
Cyanobacterial Toxin ◽  
Bloom Formation ◽  
Harmful Effects

The aim of this work was to study the eutrophication in the tropical freshwater ecosystems and the consequent cyanobacterial bloom formation and economical damage to fisheries and harmful effects to public health. Mass fish mortality due to toxin producing cyanobacterial blooms was registered during December 2003 in Marechal Dutra Reservoir, Acari/RN, Northeast Brazil. Phytoplankton and fish samplings were carried out on alternate days during the episode of fish mortality and monthly during January to June 2004. The cyanobacterial toxin was identified and quantified from the seston samples and liver of the dead fishes using the standard HPLC method. The results indicated that the toxic blooms of Cylindrospermopsis raciborskii and Microcystis aeruginosa were persistent for two weeks and represented 90% of the phytoplankton species assemblages. The lethally affected fishes were Oreochromis niloticus, Plagioscion squamosissimus, Cichla monoculus, Prochilodus brevis, Hoplias malabaricus and Leporinus friderici. The microcystin levels varied from 0.07 to 8.73µg L-1 the seston samples and from 0.01 to 2.59µg g-1in the liver samples of the fishes during the bloom period.

scholarly journals Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

2016 ◽  
Author(s):  
Guotao Peng ◽  
Zhengqiu Fan ◽  
Xiangrong Wang ◽  
Chen Chen
Keyword(s):  
Chlorophyll Fluorescence ◽  
Algal Blooms ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Photosynthetic Response ◽  
Nitrogen And Phosphorus ◽  
Ammonium Toxicity ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
N Assimilation

<p>The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N) and phosphorus (P). In this study, the effect of inorganic (nitrate and ammonium) and organic (urea) nitrogen at varied N/P ratios on the <em>Microcystis</em> <em>aeruginosa</em> FACHB-905 accumulation and photosynthesis was investigated.  The optimal NO<sub>3</sub>/P in this study were 30~50 indicated by the cell abundance (4.1×10<sup>6</sup>/mL), pigment concentration (chlorophyll a 3.1 mg/L,  phycocyanin 8.3mg/L), and chlorophyll fluorescence parameters (<em>rETR</em>, <em>E<sub>k</sub>, α, φPSII</em> and <em>F<sub>v</sub>/F<sub>m</sub> </em>values), while too high NO<sub>3</sub>-N (N/P=100:1) would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH<sub>4</sub>-N (N/P=4:1) would favor the <em>M. aeruginosa </em>growth and photosynthesis, and high NH<sub>4</sub>/P ratio (&gt;16) would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, <em>M. aeruginosa </em>responded similarly to the NH<sub>4</sub>-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on <em>Microcystis</em> abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by <em>Microcystis</em> and  the photosynthetic response to nutrient stress at the molecular level.</p>

Toxic cyanobacterial blooms in a drinking water reservoir - causes, consequences and management strategy

2001 ◽  
Vol 1 (2) ◽  
pp. 237-246 ◽  
Author(s):  
M. Tarczyńska ◽  
Z. Romanowska-Duda ◽  
T. Jurczak ◽  
M. Zalewski
Keyword(s):  
Drinking Water ◽  
Management Strategies ◽  
Cyanobacterial Bloom ◽  
Water Reservoir ◽  
Dry Weight ◽  
Cyanobacterial Blooms ◽  
Potential Health ◽  
North East ◽  
Drinking Water Reservoir ◽  
Lowland Reservoirs

Eutrophication of reservoirs used for drinking water supplies is a very common problem, particularly in lowland reservoirs. Long water retention time (60-120 days) favours cyanobacterial bloom occurrence in Sulejów Reservoir, Poland. The localisation of the water intake in a bay exposed to north-east winds favoured the Microcystis bloom accumulation, which formed a 0.5 m thick dense scum for the first time in September 1999. Cyanobacterial hepatotoxins can pose a potential health problem because the presence of about 0.8 μg/l microcystins was detected in drinking water during three series of analysis. An investigation of the efficiency of each stage of water treatment processes in the elimination of microcystins showed that pre-chlorination, coagulation, and rapid sand filtration were ineffective in removing microcystins from water. Significant elimination was observed after ozonation and chlorination. The concentration of microcystins in bloom material was between 12 to 860 μg/g dry weight of phytoplankton biomass. Management strategies for reservoirs should consider the important role of ecohydrological processes, which are often very easy to regulate, and which can be useful for bio-manipulation of the water ecosystem.

scholarly journals Effects of Cyanobacteria on Phosphorus Cycling and Other Aquatic Organisms in Simulated Eutrophic Ecosystems

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2265
Author(s):  
Peng Gu ◽  
Qi Li ◽  
Hao Zhang ◽  
Xin Luo ◽  
Weizhen Zhang ◽  
...  
Keyword(s):  
Nutrient Management ◽  
Lake Taihu ◽  
Cyanobacterial Bloom ◽  
Aquatic Organisms ◽  
Pilot Scale ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Eutrophic Lakes ◽  
P Concentration ◽  
Bloom Formation

Cyanobacterial blooms caused by eutrophication in Lake Taihu have led to ecological threats to freshwater ecosystems. A pilot scale experiment was implemented to investigate the relationship between cyanobacteria and other aquatic plants and animals in simulated eutrophic ecosystems under different phosphorus (P) regimes. The results of this study showed that cyanobacteria had two characteristics favorable for bloom formation in eutrophic ecosystems. One is the nutrient absorption. The presence of alkaline phosphatase was beneficial for algal cells in nutrition absorption under low P concentration. Cyanobacteria exhibited a stronger ability to absorb and store P compared to Vallisneria natans, which contributed to the fast growth of algal cells between 0.2 and 0.5 mg·L−1 of P (p < 0.05). However, P loads affected only the maximum biomass, but not the growth phases. The growth cycle of cyanobacteria remained unchanged and was not related to P concentration. P cycling indicated that 43.05–69.90% of the total P existed in the form of sediment, and P content of cyanobacteria showed the highest increase among the organisms. The other is the release of microcystin. Toxic microcystin-LR was released into the water, causing indirectly the growth inhibition of Carassius auratus and Bellamya quadrata and the reduction of microbial diversity. These findings are of importance in exploring the mechanism of cyanobacterial bloom formation and the nutrient management of eutrophic lakes.

scholarly journals Inhibition of Extracellular Enzymes Exposed to Cyanopeptides

2020 ◽  
Vol 74 (3) ◽  
pp. 122-128
Author(s):  
Christine M. Egli ◽  
Regiane S. Natumi ◽  
Martin R. Jones ◽  
Elisabeth M.-L. Janssen
Keyword(s):  
Extracellular Enzymes ◽  
Heterotrophic Bacteria ◽  
Hydrolytic Enzymes ◽  
Aquatic Organisms ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Biologically Relevant ◽  
Metabolic Functions ◽  
Harmful Cyanobacterial Blooms ◽  
Quality Assessments

Harmful cyanobacterial blooms in freshwater ecosystems produce bioactive secondary metabolites including cyanopeptides that pose ecological and human health risks. Only adverse effects of one class of cyanopeptides, microcystins, have been studied extensively and have consequently been included in water quality assessments. Inhibition is a commonly observed effect for enzymes exposed to cyanopeptides and has mostly been investigated for human biologically relevant model enzymes. Here, we investigated the inhibition of ubiquitous aquatic enzymes by cyanobacterial metabolites. Hydrolytic enzymes are utilized in the metabolism of aquatic organisms and extracellularly by heterotrophic bacteria to obtain assimilable substrates. The ubiquitous occurrence of hydrolytic enzymes leads to the co-occurrence with cyanopeptides especially during cyanobacterial blooms. Bacterial leucine aminopeptidase and alkaline phosphatase were exposed to cyanopeptide extracts of different cyanobacterial strains ( Microcystis aeruginosa wild type and microcystin-free mutant, Planktothrix rubescens) and purified cyanopeptides. We observed inhibition of aminopeptidase and phosphatase upon exposure, especially to the apolar fractions of the cyanobacterial extracts. Exposure to the dominant cyanopeptides in these extracts confirmed that purified microcystins, aerucyclamide A and cyanopeptolin A inhibit the aminopeptidase in the low mg L–1 range while the phosphatase was less affected. Inhibition of aquatic enzymes can reduce the turnover of nutrients and carbon substrates and may also impair metabolic functions of grazing organisms.

scholarly journals An UAV and Satellite Multispectral Data Approach to Monitor Water Quality in Small Reservoirs

2020 ◽  
Vol 12 (9) ◽  
pp. 1514 ◽  
Author(s):  
Carmen Cillero Castro ◽  
Jose Antonio Domínguez Gómez ◽  
Jordi Delgado Martín ◽  
Boris Alejandro Hinojo Sánchez ◽  
Jose Luis Cereijo Arango ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spectral Band ◽  
Water Reservoir ◽  
Cyanobacterial Blooms ◽  
Landsat 8 ◽  
Chl A ◽  
Multispectral Data ◽  
Small Reservoirs ◽  
In Situ Data ◽  
Drinking Water Reservoir

A multi-sensor and multi-scale monitoring tool for the spatially explicit and periodic monitoring of eutrophication in a small drinking water reservoir is presented. The tool was built with freely available satellite and in situ data combined with Unmanned Aerial Vehicle (UAV)-based technology. The goal is to evaluate the performance of a multi-platform approach for the trophic state monitoring with images obtained with MultiSpectral Sensors on board satellites Sentinel 2 (S2A and S2B), Landsat 8 (L8) and UAV. We assessed the performance of three different sensors (MultiSpectral Instrument (MSI), Operational Land Imager (OLI) and Rededge Micasense) for retrieving the pigment chlorophyll-a (chl-a), as a quantitative descriptor of phytoplankton biomass and trophic level. The study was conducted in a waterbody affected by cyanobacterial blooms, one of the most important eutrophication-derived risks for human health. Different empirical models and band indices were evaluated. Spectral band combinations using red and near-infrared (NIR) bands were the most suitable for retrieving chl-a concentration (especially 2 band algorithm (2BDA), the Surface Algal Bloom Index (SABI) and 3 band algorithm (3BDA)) even though blue and green bands were useful to classify UAV images into two chl-a ranges. The results show a moderately good agreement among the three sensors at different spatial resolutions (10 m., 30 m. and 8 cm.), indicating a high potential for the development of a multi-platform and multi-sensor approach for the eutrophication monitoring of small reservoirs.

scholarly journals Spatiotemporal Variations in Microcystin Concentrations and in the Proportions of Microcystin-Producing Cells in Several Microcystis aeruginosa Populations

2010 ◽  
Vol 76 (14) ◽  
pp. 4750-4759 ◽  
Author(s):  
M. Sabart ◽  
D. Pobel ◽  
E. Briand ◽  
B. Combourieu ◽  
M. J. Salençon ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Environmental Conditions ◽  
Real Time Pcr ◽  
Geographical Area ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Spatiotemporal Variations ◽  
Potential Toxicity ◽  
Genotype Composition ◽  
Over Time

ABSTRACT With the aim of explaining the variations in microcystin (MC) concentrations during cyanobacterial blooms, we studied several Microcystis aeruginosa populations blooming in different freshwater ecosystems located in the same geographical area. As assessed by real-time PCR, it appeared that the potentially MC-producing cells (mcyB +) were predominant (70 to 100%) in all of these M. aeruginosa populations, with the exception of one population in which non-MC-producing cells always dominated. Apart from the population in the Grangent Reservoir, we found that the proportions of potentially MC-producing and non-MC-producing cells varied little over time, which was consistent with the fact that according to a previous study of the same populations, the intergenic transcribed spacer (ITS) genotype composition did not change (38). In the Grangent Reservoir, the MC-RR variant was the dominant microcystin variant throughout the bloom season, despite changes in the ITS composition and in the proportions of mcyB + cells. Finally, the variations in total MC concentrations (0.3 to 15 μg liter−1) and in the MC cellular quotas (0.01 to 3.4 pg cell−1) were high both between and within sites, and no correlation was found between the MC concentrations and the proportion of mcyB + cells. All of these findings demonstrate that very different results can be found for the proportions of potentially MC-producing and non-MC-producing cells and MC concentrations, even in M. aeruginosa populations living in more or less connected ecosystems, demonstrating the importance of the effect of very local environmental conditions on these parameters and also the difficulty of predicting the potential toxicity of Microcystis blooms.

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