scholarly journals Using Microcystin Gene Copies to Determine Potentially-Toxic Blooms, Example from a Shallow Eutrophic Lake Peipsi

Toxins ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 211 ◽  
Author(s):  
Kristel Panksep ◽  
Marju Tamm ◽  
Evanthia Mantzouki ◽  
Anne Rantala-Ylinen ◽  
Reet Laugaste ◽  
...  

Global warming, paired with eutrophication processes, is shifting phytoplankton communities towards the dominance of bloom-forming and potentially toxic cyanobacteria. The ecosystems of shallow lakes are especially vulnerable to these changes. Traditional monitoring via microscopy is not able to quantify the dynamics of toxin-producing cyanobacteria on a proper spatio-temporal scale. Molecular tools are highly sensitive and can be useful as an early warning tool for lake managers. We quantified the potential microcystin (MC) producers in Lake Peipsi using microscopy and quantitative polymerase chain reaction (qPCR) and analysed the relationship between the abundance of the mcyE genes, MC concentration, MC variants and toxin quota per mcyE gene. We also linked environmental factors to the cyanobacteria community composition. In Lake Peipsi, we found rather moderate MC concentrations, but microcystins and microcystin-producing cyanobacteria were widespread across the lake. Nitrate (NO3−) was a main driver behind the cyanobacterial community at the beginning of the growing season, while in late summer it was primarily associated with the soluble reactive phosphorus (SRP) concentration. A positive relationship was found between the MC quota per mcyE gene and water temperature. The most abundant variant—MC-RR—was associated with MC quota per mcyE gene, while other MC variants did not show any significant impact.

2014 ◽  
Vol 26 (4) ◽  
pp. 442-456 ◽  
Author(s):  
Rodrigo da Rocha Andrade ◽  
Danilo Giroldo

AIM: to provide a long-term limnological characterisation of a subtropical shallow lake in addition to verifying seasonal differences, including phytoplankton variation. METHODS: monthly sampling at sites IP, SJ and MD from 2000 to 2009 to analyse temperature - T; depth - Z; the depth of the euphotic zone - Zeu; Zeu/Z (%); total suspended solids - TSS; dissolved oxygen - DO; pH; electrical conductivity - EC; N-NH3, N-NO2, N-NO3; soluble reactive phosphorus - SRP; chlorophyll a - Chl-a and phytoplankton. RESULTS: low values of Z and Zeu characterised the shallow and turbid conditions of lake and corresponded to the contribution of nano-microflagellates (Chlamydomonas sp., Spermatozopsis sp., Cryptomonas sp. and Rhodomonas sp ) and diatoms (Aulacoseira granulata). Zeu/Z (%), SRP and Chl-a were significantly different at site IP (meso-eutrophic) compared to sites SJ and MD (eutrophic). Phytoplankton density was also significantly higher at sites SJ and MD, and the largest relative contribution of Actinastrum sp., Dictyosphaerium sp., Micractinium sp., Monoraphidium sp., Scenedesmus/Desmodesmus sp. and Euglena sp. corresponded to the most polluted waters at site SJ. The significantly higher T (ºC) in summer corresponded to significantly higher Chl-a as well as a greater richness and density of phytoplankton. Cocconeis sp., Gomphonema sp. and Pinnularia sp. (pennated diatoms) were negatively correlated with temperature and were therefore more representative at the three sites in winter. Asterionella formosa was correlated with SRP and vernal blooms were recorded (2000-2001). Planktothrix isothrix and Planktothricoides raciborskii were expressive in the summer/late summer (2004-2005), and were significantly correlated with Chl-a and low SRP in water column. CONCLUSIONS: The study corroborated the sensitivity of phytoplankton in characterising different stages of eutrophication at different sites and corresponding watersheds as well as in characterising different seasons in a shallow lake in the subtropical zone of Brazil.


2015 ◽  
Vol 27 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Raiane Santos Costa ◽  
Joseline Molozzi ◽  
Luiz Ubiratan Hepp ◽  
Diógenes Félix da Silva Costa ◽  
Paulo Roberto Nunes da Silva ◽  
...  

ObjectiveThis study analyzed the influence of ecological filters (abiotic variables) on the phytoplankton community in hypersaline ecosystems.MethodsThe abiotic variables measured herein were: pH, water temperature, salinity, ammonium ion, total nitrogen, nitrite, nitrate, total phosphorus, and soluble reactive phosphorus. The phytoplankton community was studied for density, richness and Shannon-Wiener diversity index. Data were analyzed using analysis of variance, linear regression and Canonical correspondence analysis (CCA).ResultsIn total, 110 taxa were identified in 3 solar salterns, distributed into 9 taxonomic classes, with the predominance of Cyanobacteria (41.8%) and Bacillariophyceae (22.7%). The species Pseudanabaena galeata was the only species sampled in all saline environments. Salinity significantly influenced the richness in the three salterns, Augusto Severo (F(1,22) = 23.2, p <0.001), Francisco Menescal (F(1,22) = 50.02, p <0.001) and Santa Clara (F(1,22) = 66.33, p <0.001). The first two CCA axes explained 41.6% of total data variability, with a negative relationship with soluble reactive phosphorus for axis 2.ConclusionThe study showed the influence of the dynamics of salterns ecosystems on the phytoplankton community structure. This is associated with filters developed by the environment, where the increasing salinity, temperature and precipitation of salts influence the composition of these organisms in the ecosystem.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1947
Author(s):  
Ling Su ◽  
Chen Zhong ◽  
Lei Gan ◽  
Xiaolin He ◽  
Jinlei Yu ◽  
...  

The application of lanthanum modified bentonite (Phoslock®) and polyaluminium chloride (PAC) is popular in the restoration of European temperate lakes; however, the effects of the application on the concentrations of phosphorus (P) in both the water and the sediments have been poorly evaluated to date. We studied the effects of the application of Phoslock® + PAC on the concentrations of total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), total suspended solids (TSS) and chlorophyll a (Chla) in the water, and different P forms in the sediments, in an isolated part of Lake Yanglan. The results showed that the concentrations of TP, PP, SRP, TSS and Chla decreased significantly after the addition of Phoslock® + PAC. Moreover, the concentrations of labile-P, reductant-soluble-P and organic-P in the sediments were also significantly decreased after the Phoslock® + PAC application. However, the concentrations of both the stable apatite-P and residual-P in the sediments after application of Phoslock® + PAC were much higher than the pre-addition values, while the concentrations of metal-oxide-P did not differ significantly between the pre- and post- application conditions. Our findings imply that the combined application of Phoslock® and PAC can be used in the restoration of subtropical shallow lakes, to reduce the concentrations of P in the water and suppress the release of P from the sediments.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Qing Xu ◽  
Xiaoping Yu ◽  
Yafei Guo ◽  
Tianlong Deng ◽  
Yu-Wei Chen ◽  
...  

Overlying sediment and pore waters were collected in summer and winter at upstream (Jintang) and downstream (Neijiang) sites of the Tuohe River, which is one of the five largest tributaries of the Yangtze River in China. Phosphorus species, including soluble reactive phosphorus (SRP), soluble unreactive phosphorus (SUP), and total dissolved phosphorus (TDP), and some diagenetic constituents including dissolved Fe(II), Mn(II), and sulfide in overlying and pore waters, were measured systematically. The seasonal variations and vertical distributions of phosphorus species in overlying and pore waters at both sampling sites were obtained to elucidate some aspects of the transport and transformations of phosphorus. Based on the profiles of pore and overlying waters as well as the TDN/TDP data during an algal bloom in 2007, it was clearly demonstrated that phosphorus was the main factor limiting the phytoplankton growth in the Tuohe River.


2014 ◽  
Vol 122 (2-3) ◽  
pp. 229-251 ◽  
Author(s):  
Lauriane Vilmin ◽  
Najla Aissa-Grouz ◽  
Josette Garnier ◽  
Gilles Billen ◽  
Jean-Marie Mouchel ◽  
...  

Hydrobiologia ◽  
1994 ◽  
Vol 294 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Hassan Taleb ◽  
Patricia Reyes-Marchant ◽  
Nicole Lair

1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.


2016 ◽  
Vol 77 (3) ◽  
pp. 495-505 ◽  
Author(s):  
R. S. Cordeiro ◽  
J. E. L. Barbosa ◽  
G. Q. Lima Filho ◽  
L. G. Barbosa

Abstract The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates.


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