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Copetti D, Valsecchi L, Tartari G, Mingazzini M, Palumbo MT. Phosphate adsorption by riverborne clay sediments in a southern-Italy Mediterranean reservoir: Insights from a "natural geo-engineering" experiment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:159225. [PMID: 36206898 DOI: 10.1016/j.scitotenv.2022.159225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
This paper reports data from a southern-Italy reservoir (Lake Occhito) characterized by a strong riverborne sediment transport. Main hydrochemical, trophic, and nutrient variables were measured (over a twelve-month period) in both lake and tributaries. Lacustrine sediments were subjected to mineralogical characterization and to phosphorus fractioning, while a 6-day long batch experiment was carried out to evaluate the lake sediment orthophosphate adsorption capacity. A set of algal growth potential tests was also undertaken on the lake and its tributaries. Results highlight the presence of a strong gradient in nutrient availability among the inflows. Most of the nutrient loads were from the main tributary (20.3 t P a-1, ~83 %), that showed the highest trophic potential (average: 56.8 mg L-1) and was nitrogen/phosphorus co-limited. The other inflows were phosphorus limited and characterized by a higher sediment transport. The lake showed the lowest nutrient concentrations (average total phosphorus: 21 μg P L-1) and was strongly phosphorus limited. Clays were the principal minerals in the lake sediments (~51 %), while the main phosphorus fraction was apatite (~78 %). The batch experiment demonstrated the capability of the lake sediments to reduce orthophosphate concentrations in phosphorus-rich waters (initial orthophosphate: 320 μg P L-1; ~80 % reduction). The lake sediment orthophosphate kinetics of abatement was similar to that of a commercially available phosphorus sorbent (lanthanum modified bentonite), although the stability of phosphorus binding was higher for the commercial product. Theoretical average in-lake total phosphorus, chlorophyll-a, and transparency values, estimated through Vollenweider models, were approximately double of the average values measured in the lake. Therefore, the massive presence of riverborne clay sediments seems to markedly reduce the in-lake orthophosphate concentrations (and light penetration), inducing an overall lowering of the lake trophic state, as if the lake ecosystem were permanently subjected to a geo-engineering phosphorus sorbent treatment.
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Affiliation(s)
- Diego Copetti
- Water Research Institute, National Research Council, Via del Mulino, 19, 20861 Brugherio, Italy.
| | - Lucia Valsecchi
- Water Research Institute, National Research Council, Via del Mulino, 19, 20861 Brugherio, Italy
| | - Gianni Tartari
- Water Research Institute, National Research Council, Via del Mulino, 19, 20861 Brugherio, Italy
| | - Marina Mingazzini
- Water Research Institute, National Research Council, Via del Mulino, 19, 20861 Brugherio, Italy
| | - Maria Teresa Palumbo
- Water Research Institute, National Research Council, Via del Mulino, 19, 20861 Brugherio, Italy
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2
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Erratt K, Creed IF, Freeman EC, Trick CG, Westrick J, Birbeck JA, Watson LC, Zastepa A. Deep Cyanobacteria Layers: An Overlooked Aspect of Managing Risks of Cyanobacteria. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17902-17912. [PMID: 36414474 PMCID: PMC9775209 DOI: 10.1021/acs.est.2c06928] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 06/16/2023]
Abstract
The risk of human exposure to cyanotoxins is partially influenced by the location of toxin-producing cyanobacteria in waterbodies. Cyanotoxin production can occur throughout the water column, with deep water production representing a potential public health concern, specifically for drinking water supplies. Deep cyanobacteria layers are often unreported, and it remains to be seen if lower incident rates reflect an uncommon phenomenon or a monitoring bias. Here, we examine Sunfish Lake, Ontario, Canada as a case study lake with a known deep cyanobacteria layer. Cyanotoxin and other bioactive metabolite screening revealed that the deep cyanobacteria layer was toxigenic [0.03 μg L-1 microcystins (max) and 2.5 μg L-1 anabaenopeptins (max)]. The deep layer was predominantly composed of Planktothrix isothrix (exhibiting a lower cyanotoxin cell quota), with Planktothrix rubescens (exhibiting a higher cyanotoxin cell quota) found at background levels. The co-occurrence of multiple toxigenic Planktothrix species underscores the importance of routine surveillance for prompt identification leading to early intervention. For instance, microcystin concentrations in Sunfish Lake are currently below national drinking water thresholds, but shifting environmental conditions (e.g., in response to climate change or nutrient modification) could fashion an environment favoring P. rubescens, creating a scenario of greater cyanotoxin production. Future work should monitor the entire water column to help build predictive capacities for identifying waterbodies at elevated risk of developing deep cyanobacteria layers to safeguard drinking water supplies.
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Affiliation(s)
- Kevin
J. Erratt
- School
of Environment & Sustainability, University
of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SaskatchewanS7N 5E2, Canada
| | - Irena F. Creed
- School
of Environment & Sustainability, University
of Saskatchewan, Collaborative Science Research Building, 112 Science Place, Saskatoon, SaskatchewanS7N 5E2, Canada
- Department
of Physical & Environmental Sciences, University of Toronto, 1265 Military Trail, Toronto, OntarioM1C 1A4, Canada
| | - Erika C. Freeman
- Ecosystems
and Global Change Group, Department of Plant Sciences, University of Cambridge, CambridgeCB2 1TN, U.K.
| | - Charles G. Trick
- Department
of Health & Society, University of Toronto, 1265 Military Trail, Toronto, OntarioM1C 1A4, Canada
| | - Judy Westrick
- Lumigen
Instrument Center, Wayne State University, 5101 Cass Avenue, Detroit, Michigan48202, United States
| | - Johnna A. Birbeck
- Lumigen
Instrument Center, Wayne State University, 5101 Cass Avenue, Detroit, Michigan48202, United States
| | - L. Cynthia Watson
- Environment
and Climate Change Canada, Canada Centre
for Inland Waters, 867
Lakeshore Road, Burlington, OntarioL7S1A1, Canada
| | - Arthur Zastepa
- Environment
and Climate Change Canada, Canada Centre
for Inland Waters, 867
Lakeshore Road, Burlington, OntarioL7S1A1, Canada
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Wood SA, Puddick J, Hawes I, Steiner K, Dietrich DR, Hamilton DP. Variability in microcystin quotas during a Microcystis bloom in a eutrophic lake. PLoS One 2021; 16:e0254967. [PMID: 34288957 PMCID: PMC8294494 DOI: 10.1371/journal.pone.0254967] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 07/08/2021] [Indexed: 11/18/2022] Open
Abstract
Microcystis is a bloom-forming genus of cyanobacteria with some genotypes that produce highly toxic microcystin hepatotoxins. In waterbodies where biological and physical factors are relatively homogenous, toxin quotas (the average amount of toxin per cell), at a single point in time, are expected to be relatively constant. In this study we challenged this assumption by investigating the spatial distribution of microcystin quotas at a single point in time on two separate occasions in a lake with a major Microcystis bloom. Microcystis cell concentrations varied widely across the lake on both sampling occasions (730- and 137-fold) together with microcystin quotas (148- and 362-fold). Cell concentrations and microcystin quotas were strongly positively correlated (R2 = 0.89, P < 0.001, n = 28; R2 = 0.67, P < 0.001, n = 25). Analysis of Microcystis strains using high-throughput sequencing of the 16S-23S rRNA intergenic spacer region showed no relationship between microcystin quota and the relative abundance of specific sequences. Collectively, the results of this study indicate an association between microcystin production and cell density that magnifies the potential for bloom toxicity at elevated cell concentrations.
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Affiliation(s)
| | | | - Ian Hawes
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
| | | | | | - David P. Hamilton
- Australian Rivers Institute, Griffith University, Brisbane, Australia
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4
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Yuan LL, Pollard AI. Combining national and state data improves predictions of microcystin concentration. HARMFUL ALGAE 2019; 84:75-83. [PMID: 31128815 PMCID: PMC7147962 DOI: 10.1016/j.hal.2019.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/31/2019] [Accepted: 02/28/2019] [Indexed: 05/31/2023]
Abstract
Data collected from lakes at national (regional) scales and state (local) scales can provide different insights regarding relationships between environmental factors and biological responses, and combining these two types of data can potentially yield more precise and accurate understanding of ecological phenomena. National data can include many measures, cover large spatial areas, and span broad environmental gradients. Because of these characteristics, analyses of these data can yield accurate estimates of relationships among different lake characteristics. However, the number of samples in a national data set that is available for estimating a relationship specific to waterbodies within a smaller region, like a single state, is limited. Conversely, state monitoring data provide intensive sampling of lakes within a smaller area, but these data span a narrower range of conditions and may only include a subset of relevant measurements. Here, a Bayesian network model is described that represents the causal linkages between observations of chlorophyll a concentration, cyanobacterial biovolume, and microcystin concentration. This network model was fit to national data and provided a context for modeling observations of chlorophyll a and microcystin collected from lakes in Iowa. Using the knowledge inherent in the national network model improved the accuracy of predictions of microcystin concentrations in Iowa compared to a model based only on Iowa data.
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Affiliation(s)
- Lester L Yuan
- Office of Water, U.S. Environmental Protection Agency, Washington DC, 20460, USA.
| | - Amina I Pollard
- Office of Water, U.S. Environmental Protection Agency, Washington DC, 20460, USA
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5
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Tao Y, Hou D, Zhou T, Cao H, Zhang W, Wang X. UV-C suppression on hazardous metabolites in Microcystis aeruginosa: Unsynchronized production of microcystins and odorous compounds at population and single-cell level. JOURNAL OF HAZARDOUS MATERIALS 2018; 359:281-289. [PMID: 30041121 DOI: 10.1016/j.jhazmat.2018.07.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 06/28/2018] [Accepted: 07/11/2018] [Indexed: 06/08/2023]
Abstract
The effectiveness of UV-C towards the toxin and odor of M. aeruginosa at population and single cell levels were investigated in three ways. In the absence of UV-C, MC-LR and β-cyclocitral production show similar pattern of incremental rate with growth rate on population level shown as intracellular concentrations of MC-LR (CMC) and β-cyclocitral (CBCC), but the cellular quota of MC-LR (QMC) and β-cyclocitral (QBCC) at single-cell level reached the maximum values, 37.5 ± 1.2 fg cell-1 and 4.3 ± 0.1 fg cell-1, just after the early exponential phase. Second, upon UV-C irradiation, the CMC consistently decreased by 10-41% with increase of UV-C dosage (50-200 mJ cm-2) while CBCC increased by 2-14%. Third, during the 14 days' post-UV incubation, UV-C at 75-200 mJ cm-2 induced remarkable suppressing effects on both CMC and CBCC for 3-14 days. The suppressing effects on QMC and QBCC were induced by UV-C at 100 mJ cm-2 and above, with shorter suppressing periods by 1-4 days and lower decremental rates by 21%-30% than that of CMC and CBCC, indicating interruptions on biosynthesis processes partially contribute to suppression effects of CMC and CBCC. The suppression effect on either CBCC or QBCC, with higher decrement rates while lower recovery rates, was more severe than CMC and QMC.
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Affiliation(s)
- Yi Tao
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, 518055, China.
| | - Delin Hou
- Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Tingru Zhou
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
| | - Huansheng Cao
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, 85287, USA
| | - Wen Zhang
- Department of Civil and Environmental Engineering, New Jersey Institute of Technology, Newark, New Jersey, USA
| | - Xuejian Wang
- Key Laboratory of Microorganism Application and Risk Control (MARC) of Shenzhen, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China
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6
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Zhang L, Liu J, Zhang D, Luo L, Liao Q, Yuan L, Wu N. Seasonal and spatial variations of microcystins in Poyang Lake, the largest freshwater lake in China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:6300-6307. [PMID: 29247414 DOI: 10.1007/s11356-017-0967-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 12/06/2017] [Indexed: 06/07/2023]
Abstract
Poyang Lake is the largest freshwater lake in China and an important drinking water source. Since the year 2000, toxic cyanobacteria have been observed frequently in Poyang Lake. In the present study, spatial and seasonal variations of microcystins (MCs; MC-RR, MC-YR, and MC-LR) in water column were examined monthly from January to December (except the months of March, May, and November) in 2013, by using ultra-high-performance liquid chromatography-electrospray ionization tandem triple quadrupole/mass spectrometry (UPLC-MS/MS). MC-RR was the most dominant variant, followed by MC-LR, while MC-YR was detected in low concentration. Total MC concentrations (intracellular + extracellular MCs) ranged from 1.26 to 9916.05 ng/L, with an average of 469.99 ng/L, and only 3.14% (6 out of 192 samples) of the water samples contained MC concentrations that exceeded the drinking water guideline level of 1 μg/L for MC-LR proposed by the World Health Organization (WHO). MC concentrations in water column showed obvious seasonal variations in Poyang Lake. Intracellular and extracellular MCs were both at a low level from January to April but increased quickly from June to August and decreased dramatically thereafter. Intracellular MCs exhibited similar spatial distribution pattern with extracellular MCs. Both intracellular and extracellular MC concentrations in eastern bays and around Songmen Mountain of Poyang Lake were higher than other regions. Intracellular MC concentrations were positively correlated with Chl a (r = 046, P < 0.01), pH (r = 0.25, P < 0.01), cyanobacterial biomass (r = 0.40, P < 0.01), and temperature (r = 0.36, P < 0.01) but negatively correlated with TN (r = - 0.28, P < 0.01), suggesting that TN, cyanobacteria biomass, pH, and temperature might be regulating factors for MC production in Poyang Lake.
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Affiliation(s)
- Li Zhang
- Institute for Quality and Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanlian Road 602, Nanchang, 330200, Jiangxi, People's Republic of China
| | - Jutao Liu
- Jiangxi Provincial Institute of Water Sciences, Nanchang, Jiangxi, 330200, China
| | - Dawen Zhang
- Institute for Quality and Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanlian Road 602, Nanchang, 330200, Jiangxi, People's Republic of China.
| | - Linguang Luo
- Institute for Quality and Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanlian Road 602, Nanchang, 330200, Jiangxi, People's Republic of China
| | - Qiegen Liao
- Institute for Quality and Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanlian Road 602, Nanchang, 330200, Jiangxi, People's Republic of China
| | - Lijuan Yuan
- Institute for Quality and Safety and Standards of Agricultural Products Research, Jiangxi Academy of Agricultural Sciences, Nanlian Road 602, Nanchang, 330200, Jiangxi, People's Republic of China
| | - Naicheng Wu
- Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000, Aarhus C, Denmark
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7
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Zimba PV, Huang IS, Gutierrez D, Shin W, Bennett MS, Triemer RE. Euglenophycin is produced in at least six species of euglenoid algae and six of seven strains of Euglena sanguinea. HARMFUL ALGAE 2017; 63:79-84. [PMID: 28366403 PMCID: PMC5380236 DOI: 10.1016/j.hal.2017.01.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 06/07/2023]
Abstract
Euglena sanguinea is known to produce the alkaloid toxin euglenophycin and is known to cause fish kills and inhibit mammalian tissue and microalgal culture growth. An analysis of over 30 species of euglenoids for accumulation of euglenophycin identified six additional species producing the toxin; and six of the seven E. sanguinea strains produced the toxin. A phylogenetic assessment of these species confirmed most taxa were in the Euglenaceae, whereas synthesis capability apparently has been lost in the Phacus, Eutreptiella, and Discoplastis branches.
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Affiliation(s)
- Paul V Zimba
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA.
| | - I-Shuo Huang
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA
| | - Danielle Gutierrez
- Center for Coastal Studies, Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA; Mass Spectrometry Research Center, and Department of Biochemistry, Vanderbilt University, 9160 Medical Research Building III, 465 21st Avenue South, Nashville, TN 37240-7916, USA.
| | - Woongghi Shin
- Department of Biology, Chungnam National University, Daejeon 305-764, South Korea.
| | - Matthew S Bennett
- Plant Biology, Michigan State University, 612 Wilson Rd., S-138 Plant Biology Laboratories, East Lansing, MI 48824, USA.
| | - Richard E Triemer
- Plant Biology, Michigan State University, 612 Wilson Rd., S-138 Plant Biology Laboratories, East Lansing, MI 48824, USA
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8
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Salmaso N, Cerasino L, Boscaini A, Capelli C. PlankticTychonema(Cyanobacteria) in the large lakes south of the Alps: phylogenetic assessment and toxigenic potential. FEMS Microbiol Ecol 2016; 92:fiw155. [DOI: 10.1093/femsec/fiw155] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2016] [Indexed: 12/24/2022] Open
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9
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Kurmayer R, Deng L, Entfellner E. Role of toxic and bioactive secondary metabolites in colonization and bloom formation by filamentous cyanobacteria Planktothrix. HARMFUL ALGAE 2016; 54:69-86. [PMID: 27307781 PMCID: PMC4892429 DOI: 10.1016/j.hal.2016.01.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 01/15/2016] [Accepted: 01/15/2016] [Indexed: 05/22/2023]
Abstract
Bloom-forming cyanobacteria Planktothrix agardhii and P. rubescens are regularly involved in the occurrence of cyanotoxin in lakes and reservoirs. Besides microcystins (MCs), which inhibit eukaryotic protein phosphatase 1 and 2A, several families of bioactive peptides are produced, thereby resulting in impressive secondary metabolite structural diversity. This review will focus on the current knowledge of the phylogeny, morphology, and ecophysiological adaptations of Planktothrix as well as the toxins and bioactive peptides produced. The relatively well studied ecophysiological adaptations (buoyancy, shade tolerance, nutrient storage capacity) can partly explain the invasiveness of this group of cyanobacteria that bloom within short periods (weeks to months). The more recent elucidation of the genetic basis of toxin and bioactive peptide synthesis paved the way for investigating its regulation both in the laboratory using cell cultures as well as under field conditions. The high frequency of several toxin and bioactive peptide synthesis genes observed within P. agardhii and P. rubescens, but not for other Planktothrix species (e.g. P. pseudagardhii), suggests a potential functional linkage between bioactive peptide production and the colonization potential and possible dominance in habitats. It is hypothesized that, through toxin and bioactive peptide production, Planktothrix act as a niche constructor at the ecosystem scale, possibly resulting in an even higher ability to monopolize resources, positive feedback loops, and resilience under stable environmental conditions. Thus, refocusing harmful algal bloom management by integrating ecological and phylogenetic factors acting on toxin and bioactive peptide synthesis gene distribution and concentrations could increase the predictability of the risks originating from Planktothrix blooms.
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Affiliation(s)
- Rainer Kurmayer
- University of Innsbruck, Research Institute for Limnology, Mondseestrasse 9, 5310 Mondsee, Austria.
| | - Li Deng
- Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Elisabeth Entfellner
- University of Innsbruck, Research Institute for Limnology, Mondseestrasse 9, 5310 Mondsee, Austria
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Manganelli M, Stefanelli M, Vichi S, Andreani P, Nascetti G, Scialanca F, Scardala S, Testai E, Funari E. Cyanobacteria biennal dynamic in a volcanic mesotrophic lake in central Italy: Strategies to prevent dangerous human exposures to cyanotoxins. Toxicon 2016; 115:28-40. [PMID: 26948426 DOI: 10.1016/j.toxicon.2016.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/29/2016] [Accepted: 03/03/2016] [Indexed: 10/22/2022]
Abstract
Vico Lake, a volcanic meso-eutrophic lake in Central Italy, whose water is used for drinking and recreational activities, experienced the presence of the microcystins (MC) producing cyanobacterium Planktothrix rubescens. In order to assess the human health risks and to provide the local health authorities with a scientific basis for planning tailored monitoring activities, we studied P. rubescens ecology and toxicity for two years. P. rubescens generally dominated the phytoplankton community, alternating with Limnothrix redekei, potentially toxic. P. rubescens was distributed throughout the water column during winter; in summer it produced intense blooms where drinking water is collected (-20 m); here MC were detected all year round (0.5-5 μg/L), with implications for drinking water quality. In surface waters, MC posed no risk for recreational activities in summer, while in winter surface blooms and foams (containing up to 56 μg MC/L) can represent a risk for people and children practicing water sports and for animals consuming raw water. Total phosphorus, phosphate and inorganic nitrogen were not relevant to predict densities nor toxicity; however, a strong correlation between P. rubescens density and aminopeptidase ectoenzymatic activity, an enzyme involved in protein degradation, suggested a role of organic nitrogen for this species. The fraction of potentially toxic population, determined both as mcyB(+)/16SrDNA (10-100%) and as the MC/mcyB(+) cells (0.03-0.79 pg MC/cell), was much more variable than usually observed for P. rubescens. Differently from other Italian and European lakes, the correlation between cell density or the mcyB(+) cells and MC explained only ∼50 and 30% of MC variability, respectively: for Vico Lake, monitoring only cell or the mcyB(+) cell density is not sufficient to predict MC concentrations, and consequently to protect population health. Finally, during a winter bloom one site has been sampled weekly, showing that monthly sampling during such a phase could greatly underestimate the 'hazard'. Our results highlight the need to adopt a stepwise monitoring activity, considering the lake and the cyanobacteria specific features. This activity should be complemented with communication to the public and involvement of stakeholders.
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Affiliation(s)
- Maura Manganelli
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Mara Stefanelli
- Research, Certification and Control Division - INAIL, via Fontana candida 1, Monteporzio Catone, Rome, Italy.
| | - Susanna Vichi
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Paolo Andreani
- Tutela acque - Concessioni e Risorse idriche, Provincia di Viterbo, Via del Collegio, Viterbo, Italy.
| | - Giuseppe Nascetti
- Department of Ecology and Biology - University La Tuscia, via S. Giovanni decollato 1, Viterbo, Italy.
| | - Fabrizio Scialanca
- Department of Ecology and Biology - University La Tuscia, via S. Giovanni decollato 1, Viterbo, Italy.
| | - Simona Scardala
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Emanuela Testai
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
| | - Enzo Funari
- Department of the Environment and Primary Prevention - Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
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Mariani MA, Padedda BM, Kaštovský J, Buscarinu P, Sechi N, Virdis T, Lugliè A. Effects of trophic status on microcystin production and the dominance of cyanobacteria in the phytoplankton assemblage of Mediterranean reservoirs. Sci Rep 2015; 5:17964. [PMID: 26648532 PMCID: PMC4673696 DOI: 10.1038/srep17964] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/09/2015] [Indexed: 11/09/2022] Open
Abstract
The aim of our study was to evaluate the abundance of cyanobacteria and microcystins in four Sardinian reservoirs (Italy) characterised by different trophic status to define a reference picture for future changes. Increasing levels of eutrophication and the abundance of cyanobacteria are expected to occur due to climate change, especially in the southern Mediterranean. Consequently, an in-depth study of the occurrence of harmful cyanobacteria is important to develop appropriate management strategies for water resources at a local scale. Monthly samples were collected at one station in each reservoir over an 18-month period. The Analysis of similarity indicated that cyanobacterial abundance and species composition differed significantly among the reservoirs. The Redundancy analysis highlighted their relationship to trophic, hydrological and seasonal patterns. Spearman’s analysis indicated that there were significant correlations among the most important species (Planktothrix agardhii–rubescens group, Aphanizomenon flos-aquae and Dolichospermum planctonicum), nutrients and microcystins. We highlighted that the species composition during periods of maximum microcystin concentrations differed from those typically reported for other Mediterranean sites. We found new potential microcystin producers (Aphanizomenon klebahnii, Dolichospermum macrosporum and Dolichospermum viguieri), which emphasised the high diversity of cyanobacteria in the Mediterranean area and the need for detailed research at the local scale.
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Affiliation(s)
- Maria Antonietta Mariani
- University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy
| | - Bachisio Mario Padedda
- University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy
| | - Jan Kaštovský
- University of South Bohemia, Faculty of Science, Department of Botany, České Budějovice, Czech Republic
| | - Paola Buscarinu
- Ente acque della Sardegna, Settore della limnologia degli invasi, Viale Elmas 116, 09122 Cagliari, Italy
| | - Nicola Sechi
- University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy
| | - Tomasa Virdis
- Ente acque della Sardegna, Settore della limnologia degli invasi, Viale Elmas 116, 09122 Cagliari, Italy
| | - Antonella Lugliè
- University of Sassari, Dipartimento di Architettura, Design e Urbanistica, Via Piandanna 4, 07100 Sassari, Italy
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