Cyanobacteria and algae blooms: Review of health and environmental data from the Harmful Algal Bloom-Related Illness Surveillance System (HABISS) 2007-2011

Logistics Network Management of Livestock Waste for Spatiotemporal Control of Nutrient Pollution in Water Bodies

Nutrient pollution is a widespread water quality problem, which originates from excess nutrient runoff from agricultural land, improperly managed farming operations, and point sources such as wastewater treatment plants. Some nutrient pollution impacts include harmful algal blooms (HABs), hypoxia, and eutrophication. HABs are major environmental events that cause severe health threats and economic losses (e.g., tourism, real estate, commercial fishing). A dimension of the nutrient pollution problem that has not received much attention is that this interacts with organic waste management practices. As a result, it is important to connect the time and location of point and nonpoint nutrient source releases, nutrient soil content, spatial layout, and hydrology of agricultural lands with the transport of nutrients to water bodies and their impacts on aquatic ecosystems. In this work, we show how nutrient concentration in water bodies and other spatiotemporal factors are related to HAB development and how logistics management of livestock waste can be used to conduct space-time management of nutrient pollution. A case study for the Upper Yahara Watershed in the State of Wisconsin (U.S.) is employed to demonstrate the practicability of the modeling framework. Our framework reveals that logistics network management for waste and nutrients can reduce the incidence rates of HABs, but reducing it to nonharmful levels would require long-term efforts such as installing nutrient recovery technologies, coordinating manure storage and application, and deploying management incentive plans.

The importance of cyanobacteria and microalgae present in aerosols to human health and the environment - Review study

Airborne microalgae and cyanobacteria are among the least studied organisms in aerobiology. While those of them living in freshwater and seawater are well recognized, those constituting the components of aerosols are rarely the focus of research. However, their presence has been noted by scientists from all over the world. The presence of these organisms is not indifferent to the environment as they participate in the formation of clouds and influence both the hydrological cycle and Earth's climate. Recent studies have concentrated mostly on the negative impact of airborne cyanobacteria and microalgae, as well as the toxic compounds they produce, on human health. This review focuses on measurement results published on those bioaerosols, combining the achievements of scientists from the last century with the latest reports and trends. Within it gaps in current knowledge are discussed, including the role of airborne organisms in the transport of harmful chemicals like PAHs and heavy metals. The current studies on which it is based emphasize the advantages and disadvantages of the measurement methods used in sampling and analysing. It also visualizes, in the form of maps, where research on bioaerosols has so far been conducted, while at the same time determining the share of organisms potentially dangerous to human health. In addition, we have also tried to recommend future research directions for both environmental and laboratory-based studies.

Cloning and Expression of Genes for Biodegrading Nodularin by Sphingopyxis sp. USTB-05

Biodegradation is efficient for removing cyanobacterial toxins, such as microcystins (MCs) and nodularin (NOD). However, not all the microbial strains with the microcystin-biodegrading enzymes MlrA and MlrC could biodegrade NOD. Studies on genes and enzymes for biodegrading NOD can reveal the function and the biodegradation pathway of NOD. Based on successful cloning and expression of the USTB-05-A and USTB-05-C genes from Sphingopyxis sp. USTB-05, which are responsible for the biodegradation of MCs, the pathway for biodegrading NOD by these two enzymes was investigated in this study. The findings showed that the enzyme USTB-05-A converted cyclic NOD (m/z 825.4516) into its linear type as the first product by hydrolyzing the arginine and Adda peptide bond, and that USTB-05-C cut off the Adda and glutamic acid peptide bond of linearized NOD (m/z 843.4616) and produced dimeric Adda (m/z 663.4377) as the second product. Further, based on the homology modeling of enzyme USTB-05-A, site-directed mutants of USTB-05-A were constructed and seven crucial sites for enzyme USTB-05-A activity were found. A complete enzymatic mechanism for NOD biodegradation by USTB-05-A in the first step was proposed: glutamic acid 172 and histidine 205 activate a water molecule facilitating a nucleophilic attack on the arginine and Adda peptide bond of NOD; tryptophan 176 and tryptophan 201 contact the carboxylate side chain of glutamic acid 172 and accelerate the reaction rates; and histidine 260 and asparagine 264 function as an oxyanion hole to stabilize the transition states.

An automated 3D-printed smartphone platform integrated with optoelectrowetting (OEW) microfluidic chip for on-site monitoring of viable algae in water

A sudden increase of algae and their associated toxins in aquatic ecosystems can detrimentally affect the quality of the water, causing serious socio-economic and public health problems. To prevent the spread of harmful algae in aquatic ecosystems, it is essential to track the water's quality through rapid and in-situ monitoring systems. Conventional methods of algae quantification such as microscopy, hemocytometry, and UV-vis spectroscopy, however, are often unsuitable or inconvenient for in-situ assessment as they require skilled labor and expensive equipment. In this study, we developed a three-dimensional (3D)-printed smartphone platform integrated with a light-driven microfluidic chip operated by optoelectrowetting (OEW). This OEW-driven microfluidic chip not only allows multiplexed drop-wise functions such as droplet transportation, merging, mixing, immobilization on a detection zone, for on-chip water sample preparation but also fluorescent detection and counting of target algae cells using a commercially-available smartphone. Two freshwater algae (C. reinhardtii and M. aeruginosa) and two marine water algae (Amphiprora sp and C. closterium) were employed to validate the 3D-printed smartphone platform in this study. The fluorescence images of viable algae and the cell counting from the microfluidic chip were comparable to the results from a hemocytometer (P > 0.05). We have further conducted tests with spiked samples using freshwater and marine water that were directly collected from environmental samples, showing the same order of magnitude of cell numbers in the spiked and control cultures of algae cells (10⁶ cell/mL, P > 0.05). Unlike traditional quantification methods, the 3D-printed smartphone platform integrated with the OEW offers a highly portable, user-friendly, low-cost tool that enables simple on-chip sample preparation and detection of viable algae. Thus, this stand-alone technology has the potential for rapid and in-situ monitoring of water quality, while using the smartphone's wireless communication capabilities to report the quality of the water in real-time.

Diagnosing Microcystin Intoxication of Canines: Clinicopathological Indications, Pathological Characteristics, and Analytical Detection in Postmortem and Antemortem Samples

In the summer of 2018, six dogs exposed to a harmful algal bloom (HAB) of Microcystis in Martin County Florida (USA) developed clinicopathological signs of microcystin (MC) intoxication (i.e., acute vomiting, diarrhea, severe thrombocytopenia, elevated alanine aminotransferase, hemorrhage). Successful supportive veterinary care was provided and led to survival of all but one patient. Confirmation of MC intoxication was made through interpretation of clinicopathological abnormalities, pathological examination of tissues, microscopy (vomitus), and analytical MC testing of antemortem/postmortem samples (vomitus, blood, urine, bile, liver, kidney, hair). Gross and microscopic examination of the deceased patient confirmed massive hepatic necrosis, mild multifocal renal tubular necrosis, and hemorrhage within multiple organ systems. Microscopy of a vomitus sample confirmed the presence of Microcystis. Three analytical MC testing approaches were used, including the MMPB (2-methyl-3-methoxy-4-phenylbutyric acid) technique, targeted congener analysis (e.g., liquid chromatography tandem-mass spectrometry of MC-LR), and enzyme-linked immunosorbent assay (ELISA). Total Adda MCs (as MMPB) were confirmed in the liver, bile, kidney, urine, and blood of the deceased dog. Urinalysis (MMPB) of one surviving dog showed a high level of MCs (32,000 ng mL⁻¹) 1-day post exposure, with MCs detectable >2 months post exposure. Furthermore, hair from a surviving dog was positive for MMPB, illustrating another testable route of MC elimination in canines. The described cases represent the first use of urine as an antemortem, non-invasive specimen to diagnose microcystin toxicosis. Antemortem diagnostic testing to confirm MC intoxication cases, whether acute or chronic, is crucial for providing optimal supportive care and mitigating MC exposure.

Monitoring cyanobacterial toxins in a large reservoir: relationships with water quality parameters

Cyanobacteria are widely distributed in fresh, brackish, and ocean water environments, as well as in soil and on moist surfaces. Changes in the population of cyanobacteria can be an important indicator of alterations in water quality. Metabolites produced by blooms of cyanobacteria can be harmful, so cell counts are frequently monitored to assess the potential risk from cyanobacterial toxins. A frequent uncertainty in these types of assessments is the lack of strong relationships between cell count numbers and algal toxin concentrations. In an effort to use ion concentrations and other water quality parameters to determine the existence of any relationships with cyanobacterial toxin concentrations, we monitored four cyanobacterial toxins and inorganic ions in monthly water samples from a large reservoir over a 2-year period. Toxin concentrations during the study period never exceeded safety limits. In addition, toxin concentrations at levels above the limit of quantitation were infrequent during the 2-year sampling period; non-detects were common. Microcystin-LA was the least frequently detected analyte (86 of 89 samples were ND), followed by the other microcystins (microcystin-RR, microcystin-LR). Cylindrospermopsin and saxitoxin were the most frequently detected analytes. Microcystin and anatoxin concentrations were inversely correlated with Cl-, SO4 - 2 , Na+, and NH4 + , and directly correlated with turbidity and total P. Cylindrospermopsin and saxitoxin concentrations in water samples were inversely correlated with Mg+2 and directly correlated with water temperature. Results of our study are expected to increase the understanding of potential relationships between human activities and water quality.

Diversity and Coding Potential of the Microbiota in the Photic and Aphotic Zones of Tropical Man-Made Lake with Intensive Aquaculture Activities: a Case Study on Temengor Lake, Malaysia

Although freshwater biomes cover less than 1% of the Earth's surface, they have disproportionate ecological significances. Attempts to study the taxonomy and function of freshwater microbiota are currently limited to samples collected from temperate lakes. In this study, we investigated samples from the photic and aphotic of an aquaculture site (disturbed) of Temengor Lake, a tropical lake in comparison with the undisturbed site of the lake using 16S rRNA amplicon and shotgun metagenomic approaches. Vertical changes in bacterial community composition and function of the Temengor Lake metagenomes were observed. The photic water layer of Temengor Lake was dominated by typical freshwater assemblages consisting of Proteobacteria, Actinobacteria, Bacteroidetes, Verrucomicrobia, and Cyanobacteria lineages. On the other hand, the aphotic water featured in addition to Proteobacteria, Bacteroidetes, Verrucomicrobia, and two more abundant bacterial phyla that are typically ubiquitous in anoxic habitats (Chloroflexi and Firmicutes). The aphotic zone of Temengor Lake exhibited genetic potential for nitrogen and sulfur metabolisms for which terminal electron acceptors other than oxygen are used in the reactions. The aphotic water of the disturbed site also showed an overrepresentation of genes associated with the metabolism of carbohydrates, likely driven by the enrichment of nutrient resulting from aquaculture activities at the site. The results presented in this study can serve as a basis for understanding the structure and functional capacity of the microbial communities in the photic and aphotic zones/water layers of tropical man-made lakes.

The data on metagenomic profile of bacterial diversity changes in the different concentration of fermented romaine lettuce brine

This article describes the data on metagenomic profile of the bacterial community and diversity in the brine of fermented romaine lettuce in two experimental brine salinity (5 and 10%) obtained by Illumina MiSeq sequencing of V3-V4 region of 16S rRNA gene. A total of 98,660 reads (10%) and 95,968 (5%) consisted 38 and 47 consensus lineages (OTUs), respectively. Predominating phyla in 10% were 55.89% Proteobacteria and 41.97% Firmicutes, while predominating phyla in 5% brine were 63.47% Proteobacteria and 34.60% Firmicutes. The predominating lower taxa in 10% brine were Haererehalobacter salaria (54.19%) and Bacillaceae (33.2%), while in 5% brine were Enterobacteriaceae (46.67%) and Bacillus (21.53%). Leuconostoc (6.97%) and Lactococcus (3.97%) only appeared in 5% brine. The data presented here is the first metagenomic profile of romaine lettuce fermentation in different brine concentration and will serve as a baseline to understand the shifting of bacterial diversity associated with the change in brine concentration.

Evaluating the treatment effectiveness of copper-based algaecides on toxic algae Microcystis aeruginosa using single cell-inductively coupled plasma-mass spectrometry

Single cell-inductively coupled plasma-mass spectrometry (SC-ICP-MS) is an emerging technology. In this work, we have developed a novel SC-ICP-MS method to quantify metal ions in individual cells of a toxic cyanobacterial species, Microcystis aeruginosa (M. aeruginosa), without complicated post-dosing sample preparation, and applied this method to study the treatment effectiveness of copper-based algaecides (cupric sulfate and EarthTec®) on the toxic algae M. aeruginosa. The developed SC-ICP-MS method uses new intrinsic metal element magnesium to determine real transport efficiency and cell concentration. The cell viability and microcystin-LR release by algaecide treatment were studied by flow cytometry and ultra-fast liquid chromatography-tandem mass spectrometry, respectively. The results showed that this novel method was very rapid, highly sensitive (detection limits of intracellular copper and magnesium were 65 ag/cell and 98 ag/cell, respectively), and reproducible (relative standard deviation within 12%). The algaecide effectiveness study further demonstrated that copper in the forms of cupric sulfate and copper-based algaecide EarthTec® successfully diminished M. aeruginosa populations. The higher the copper concentration used to treat the cells, the faster the speeds of copper uptake and cell lysis in the copper concentrations ranged from 0 to 200 μg/L of copper-based algaecide. The cells exhibit obvious heterogeneity in copper uptake. The result suggests that M. aeruginosa cells uptake and cumulate copper followed by cellular lysis and microcystin-LR release. These novel results indicated that though the copper-based algaecides could control this type of harmful algal bloom, further treatment to remove the released algal toxin from the treated water would be needed.

Perspectives on Harmful Algal Blooms (HABs) and the Cyberbiosecurity of Freshwater Systems

Harmful Algal Blooms (HABs) have been observed in all 50 states in the U.S., ranging from large freshwater lakes, such as the Great Lakes, to smaller inland lakes, rivers, and reservoirs, as well as marine coastal areas and estuaries. In 2014, a HAB on Lake Erie containing microcystin (a liver toxin) contaminated the municipal water supply in Toledo, Ohio, providing non-potable water to 400,000 people. Studying HABs is complicated as different cyanobacteria produce a range of toxins that impact human health, such as microcystins, saxitoxin, anatoxin-a, and cylindrospermopsin. HABs may be increasing in prevalence with rising temperatures and higher nutrient runoff. Consequently, new tools and technology are needed to rapidly detect, characterize, and respond to HABs that threaten our water security. A framework is needed to understand cyber threats to new and existing technologies that monitor and forecast our water quality. To properly detect, assess, and mitigate security threats on water infrastructure, it is necessary to envision water security from the perspective of a cyber-physical system (CPS). In doing so, we can evaluate risks and research needs for cyber-attacks on HAB-monitoring networks including data injection attacks, automated system hijacking attacks, node forgery attacks, and attacks on learning algorithms. Herein, we provide perspectives on the research needed to understand both the threats posed by HABs and the coupled cyber threats to water security in the context of HABs.

Review of Two Popular Eating Plans within the Multiple Sclerosis Community: Low Saturated Fat and Modified Paleolithic

The precise etiology of multiple sclerosis (MS) is unknown but epidemiologic evidence suggests this immune-mediated, neurodegenerative condition is the result of a complex interaction between genes and lifetime environmental exposures. Diet choices are modifiable environmental factors that may influence MS disease activity. Two diets promoted for MS, low saturated fat Swank and modified Paleolithic Wahls Elimination (WahlsElim), are currently being investigated for their effect on MS-related fatigue and quality of life (NCT02914964). Dr. Swank theorized restriction of saturated fat would reduce vascular dysfunction in the central nervous system (CNS). Dr. Wahls initially theorized that detailed guidance to increase intake of specific foodstuffs would facilitate increased intake of nutrients key to neuronal health (Wahls™ diet). Dr. Wahls further theorized restriction of lectins would reduce intestinal permeability and CNS inflammation (WahlsElim version). The purpose of this paper is to review the published research of the low saturated fat (Swank) and the modified Paleolithic (Wahls™) diets and the rationale for the structure of the Swank diet and low lectin version of the Wahls™ diet (WahlsElim) being investigated in the clinical trial.

Anabaena/Dolichospermum as the source of lethal microcystin levels responsible for a large cattle toxicosis event

Thirty-two 14-month old steers died during a period of four days (19-23 June 2017) after drinking from Junipers Reservoir (southeastern Oregon, USA) during a cyanobacterial bloom. Clinical and histopathological findings were consistent with acute liver disease, and microcystin-LR was present at 3000 μg/L in a reservoir water sample and at 7100 μg/L in the rumen contents of one of the mortalities. Serum biochemistry and histological examination indicated severe liver damage consistent with microcystin toxicosis. Microscopic observation of reservoir water samples, limited to frozen or poorly stored and partially degraded samples, indicated the presence of abundant Anabaena/Dolichospermum, but the presence of other toxic cyanobacteria such as Microcystis could not be excluded. Metagenomic analysis showed the presence in these samples of a single cyanobacterium whose cpcBA, rpoB and rbcL genes indicated membership in the Anabaena/Dolichospermum genus. The sequence of a complete mcy gene cluster with homology to previously identified Anabaena mcy genes was recovered. These results emphasize the capacity for Anabaena/Dolichospermum blooms to produce lethal levels of microcystin, posing a danger to public health and livestock. Further, our findings indicate that such occurrences can occur outside the far-northern latitudes in which microcystin-producing Anabaena have typically been found.

Nitrate loads in sub-tropical headwater streams driven by intensive horticulture

Nitrogen runoff from fertiliser intensive land uses has become an issue worldwide, contributing to algal blooms, hypoxic waters and aquatic biodiversity losses. This study assessed potential nutrient pollution from blueberry farms in subtropical Australia and examines whether nutrient loads were driven by groundwater discharge and/or surface water runoff. Streams downstream of eight blueberry farms were compared to eight nearby control sites without any blueberry activity. In the 90 day sample period, there were three rain events >90 mm day^-1 that produced runoff sufficient to create flooding. Overall, the results revealed a clear link between blueberry farming and nitrogen runoff in headwater streams. While NO_X (nitrate + nitrite) was the dominant nitrogen species downstream of blueberry farms, dissolved organic nitrogen (DON) was the dominant species in control sites. The concentrations and loads of NO_x were one order of magnitude lower in the eight non-blueberry (6.3 ± 2.0 μmol L^-1; 1.6 ± 1.2 kg N-NO_X ha^-1 yr^-1) than the eight blueberry (56.9 ± 14.2 μmol L^-1; 21.8 ± 8.0 kg N-NO_X ha^-1 yr^-1) sites. NO_X concentrations and loads were highest following rain events. Radon (²²²Rn, a natural groundwater tracer) observations and low nitrogen concentration in groundwater samples further suggest that surface runoff dominates the delivery of nitrogen to the creeks investigated. NO_X concentrations and loads in creeks correlated with blueberry farm density. At >15% of blueberry land use in a catchment, there was a detectable influence in NO_X concentrations and loads in the headwater streams. Assuming that our load estimates can be up-scaled to annual nitrogen creek exports, and that local farmers use the recommended amount of fertiliser (121 kg N ha^-1 yr^-1), between 18 and 25% of the used fertiliser was lost to the creeks. This implies that there are opportunities for decreasing the use of fertilisers in this catchment and managing any nitrogen that escapes to the creeks.

The stresses of allelochemicals isolated from culture solution of diatom Phaeodactylum tricornutum Bohlin on growth and physiology of two marine algae

The allelopathic effects of extracts isolated from the culture filtrate of diatom Phaeodactylum triconutum Bohlin on typical marine microalgae Prorocentrum donghaiense Lu and Dunaliella salina Teodoresco were investigated by determining different physiological and biochemical parameters, such as growth rate, membrane systems and esterase activity under controlled laboratory conditions. The growth of P. donghaiense was significantly inhibited immediately after exposure to the allelochemicals, while the algae density of D. salina was less sensitive. Chlorophyll-a content, membrane systems, as well as esterase activity were simultaneously investigated by flow cytometry with particular fluorescent markers and exhibited changeable sensitivities. The results demonstrated that the membrane systems of P. donghaiense were suppressed by the allelochemicals directly, causing loss of integrity and membrane penetration. Esterase activity was the most sensitive indicator as that of P. donghaiense cells significantly increased in short time and was inhibited subsequently. However, the membrane of D. salina remained intact still after exposure to the extracts and the esterase activity was only inhibited on last day during experiment period. Membrane potential and chlorophyll-a content of the two marine algae also showed somewhat different changes, as that of P. donghaiense cells were impaired after 5 day exposure to all volume conditions while these two characteristics of D. salina was only suppressed by exposure to high volume of the allelochemicals on day 6. The present results indicated that the inhibition of culture filtrate of P. triconutum on P. donghaiense was algicidal whereas the effect on D. salina appeared to be algistatic.

Emerging threats and persistent conservation challenges for freshwater biodiversity

In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world's lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth's surface, these ecosystems host at least 9.5% of the Earth's described animal species. Furthermore, using the World Wide Fund for Nature's Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies, managed relocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.

Cyanobacterial Blooms and Microcystins in Southern Vietnam

Studies on cyanobacteria in Vietnam are limited and mainly restricted to large reservoirs. Cyanobacterial blooms in small water bodies may pose a health risk to local people. We sampled 17 water bodies in the vicinity of urban settlements throughout the Mekong basin and in southeast Vietnam. From these, 40 water samples were taken, 24 cyanobacterial strains were isolated and 129 fish, 68 snail, 7 shrimp, 4 clam, and 4 duck samples were analyzed for microcystins (MCs). MCs were detected up to 11,039 µg/L or to 4033 µg/g DW in water samples. MCs were detected in the viscera of the animals. MC-LR and MC-RR were most frequently detected, while MC-dmLR, MC-LW, and MC-LF were first recorded in Vietnam. Microcystis was the main potential toxin producer and the most common bloom-forming species. A potential health hazard was found in a duck⁻fish pond located in the catchment of DauTieng reservoir and in the DongNai river where raw water was collected for DongNai waterwork. The whole viscera of fish and snails must be completely removed during food processing. Cyanobacterial monitoring programs should be established to assess and minimize potential public health risks.

Algicidal Activity of Novel Marine Bacterium Paracoccus sp. Strain Y42 against a Harmful Algal-Bloom-Causing Dinoflagellate, Prorocentrum donghaiense

Prorocentrum donghaiense blooms occur frequently in the Yangtze River estuary and the adjacent East China Sea. These blooms have damaged marine ecosystems and caused enormous economic losses over the past 2 decades. Thus, highly efficient, low-cost, ecofriendly approaches must be developed to control P. donghaiense blooms. In this study, a bacterial strain (strain Y42) was identified as Paracoccus sp. and was used to lyse P. donghaiense The supernatant of the strain Y42 culture was able to lyse P. donghaiense, and the algicidal activity of this Y42 supernatant was stable with different temperatures and durations of light exposure and over a wide pH range. In addition to P. donghaiense, Y42 showed high algicidal activity against Alexandrium minutum, Scrippsiella trochoidea, and Skeletonema costatum, suggesting that it targets primarily Pyrrophyta. To clarify the algicidal effects of Y42, we assessed algal lysis and determined the chlorophyll a contents, photosynthetic activity, and malondialdehyde contents of P. donghaiense after exposure to the Y42 supernatant. Scanning electron microscopy and transmission electron microscopy analyses showed that the Y42 supernatant disrupted membrane integrity and caused algal cell breakage at the megacytic zone. Photosynthetic pigment loss and significant declines in both photosynthetic efficiency and the electron transport rate indicated that the Y42 supernatant damaged the photosynthetic system of P. donghaiense Malondialdehyde overproduction indicated that the Y42 supernatant caused lipid peroxidation and oxidative damage to membrane systems in the algal cell, ultimately leading to death. The findings of this study reveal the potential of Y42 to remove algal cells from P. donghaiense blooms.IMPORTANCEP. donghaiense is one of the most common dinoflagellate species that form harmful algal blooms, which frequently cause serious ecological pollution and pose health hazards to humans and other animals. Screening for bacteria with high algicidal activity against P. donghaiense and studying their algicidal processes and characteristics will contribute to an understanding of their algicidal effects and provide a theoretical basis for preventing algal blooms and reducing their harm to the environment. This study reports the algicidal activity and characteristics of Paracoccus against P. donghaiense The stability of the algicidal activity of Paracoccus in different environments (including different temperature, pH, and sunlight conditions) indicates its potential for use in the control of P. donghaiense blooms.

Multi-Toxin Occurrences in Ten French Water Resource Reservoirs

Cyanobacteria are known to produce a wide array of metabolites, including various classes of toxins. Among these, hepatotoxins (Microcystins), neurotoxins (Anatoxin-A and PSP toxins) or cytotoxins (Cylindrospermopsins) have been subjected to numerous, individual studies during the past twenty years. Reports of toxins co-occurrences, however, remain scarce in the literature. The present work is an inventory of cyanobacteria with a particular focus on Nostocales and their associated toxin classes from 2007 to 2010 in ten lakes used for drinking water production in France. The results show that potential multiple toxin producing species are commonly encountered in cyanobacteria populations. Individual toxin classes were detected in 75% of all samples. Toxin co-occurrences appeared in 40% of samples as two- or three-toxin combinations (with 35% for the microcystins–anatoxin combination), whereas four-toxin class combinations only appeared in 1% of samples. Toxin co-occurrences could be partially correlated to species composition and water temperature. Peak concentrations however could never be observed simultaneously and followed distinct, asymmetrical distribution patterns. As observations are the key for preventive management and risk assessment, these results indicate that water monitoring should search for all four toxin classes simultaneously instead of focusing on the most frequent toxins, i.e., microcystins.

Nanobiotechnology for the Environment: Innovative Solutions for the Management of Harmful Algal Blooms

Nanobiotechnology has played important roles in solving contemporary health problems, including cancer and diabetes, but has not yet been widely exploited for problems in food security and environmental protection. Water scarcity is an emerging worldwide problem as a result of climate change and population increase. Current methods of managing water resources are not efficient or sustainable. In this perspective, we focus on harmful algal blooms to demonstrate how nanobiotechnology can be explored to understand microbe-environment interactions and allow for toxin/pollutant detection with significantly improved sensitivity. These capabilities hold potential for future development of sustainable solutions for drinking water management.

Four Major South Korea's Rivers Using Deep Learning Models

Harmful algal blooms are an annual phenomenon that cause environmental damage, economic losses, and disease outbreaks. A fundamental solution to this problem is still lacking, thus, the best option for counteracting the effects of algal blooms is to improve advance warnings (predictions). However, existing physical prediction models have difficulties setting a clear coefficient indicating the relationship between each factor when predicting algal blooms, and many variable data sources are required for the analysis. These limitations are accompanied by high time and economic costs. Meanwhile, artificial intelligence and deep learning methods have become increasingly common in scientific research; attempts to apply the long short-term memory (LSTM) model to environmental research problems are increasing because the LSTM model exhibits good performance for time-series data prediction. However, few studies have applied deep learning models or LSTM to algal bloom prediction, especially in South Korea, where algal blooms occur annually. Therefore, we employed the LSTM model for algal bloom prediction in four major rivers of South Korea. We conducted short-term (one week) predictions by employing regression analysis and deep learning techniques on a newly constructed water quality and quantity dataset drawn from 16 dammed pools on the rivers. Three deep learning models (multilayer perceptron, MLP; recurrent neural network, RNN; and long short-term memory, LSTM) were used to predict chlorophyll-a, a recognized proxy for algal activity. The results were compared to those from OLS (ordinary least square) regression analysis and actual data based on the root mean square error (RSME). The LSTM model showed the highest prediction rate for harmful algal blooms and all deep learning models out-performed the OLS regression analysis. Our results reveal the potential for predicting algal blooms using LSTM and deep learning.

A novel portable filtration system for sampling and concentration of microorganisms: Demonstration on marine microalgae with subsequent quantification using IC-NASBA

This paper presents a novel portable sample filtration/concentration system, designed for use on samples of microorganisms with very low cell concentrations and large volumes, such as water-borne parasites, pathogens associated with faecal matter, or toxic phytoplankton. The example application used for demonstration was the in-field collection and concentration of microalgae from seawater samples. This type of organism is responsible for Harmful Algal Blooms (HABs), an example of which is commonly referred to as "red tides", which are typically the result of rapid proliferation and high biomass accumulation of harmful microalgal species in the water column or at the sea surface. For instance, Karenia brevis red tides are the cause of aquatic organism mortality and persistent blooms may cause widespread die-offs of populations of other organisms including vertebrates. In order to respond to, and adequately manage HABs, monitoring of toxic microalgae is required and large-volume sample concentrators would be a useful tool for in situ monitoring of HABs. The filtering system presented in this work enables consistent sample collection and concentration from 1 L to 1 mL in five minutes, allowing for subsequent benchtop sample extraction and analysis using molecular methods such as NASBA and IC-NASBA. The microalga Tetraselmis suecica was successfully detected at concentrations ranging from 2 × 10⁵ cells/L to 20 cells/L. Karenia brevis was also detected and quantified at concentrations between 10 cells/L and 10⁶ cells/L. Further analysis showed that the filter system, which concentrates cells from very large volumes with consequently more reliable sampling, produced samples that were more consistent than the independent non-filtered samples (benchtop controls), with a logarithmic dependency on increasing cell numbers. This filtering system provides simple, rapid, and consistent sample collection and concentration for further analysis, and could be applied to a wide range of different samples and target organisms in situations lacking laboratories.

Warming Affects Growth Rates and Microcystin Production in Tropical Bloom-Forming Microcystis Strains

Warming climate is predicted to promote cyanobacterial blooms but the toxicity of cyanobacteria under global warming is less well studied. We tested the hypothesis that raising temperature may lead to increased growth rates but to decreased microcystin (MC) production in tropical Microcystis strains. To this end, six Microcystis strains were isolated from different water bodies in Southern Vietnam. They were grown in triplicate at 27 °C (low), 31 °C (medium), 35 °C (high) and 37 °C (extreme). Chlorophyll-a-, particle- and MC concentrations as well as dry-weights were determined. All strains yielded higher biomass in terms of chlorophyll-a concentration and dry-weight at 31 °C compared to 27 °C and then either stabilised, slightly increased or declined with higher temperature. Five strains easily grew at 37 °C but one could not survive at 37 °C. When temperature was increased from 27 °C to 37 °C total MC concentration decreased by 35% in strains with MC-LR as the dominant variant and by 94% in strains with MC-RR. MC quota expressed per particle, per unit chlorophyll-a and per unit dry-weight significantly declined with higher temperatures. This study shows that warming can prompt the growth of some tropical Microcystis strains but that these strains become less toxic.

Microorganisms-based methods for harmful algal blooms control: A review

Harmful algal blooms (HABs) are a worldwide problem with numerous negative effects on water systems, which have prompted researchers to study applicable measures to inhibit and control them. This review summarized the current microorganisms-based methods or technologies aimed at controlling HABs. Based on their characteristics, these methods can be divided into two categories: methods based on single-species microorganisms and methods based on microbial aggregates, and four types: methods for rapid decrease of algal cells density (e.g., alga-bacterium and alga-fungus bioflocculation), inhibition of harmful algal growth, lysis of harmful algae (e.g. algicidal bacteria, fungi, and actinomycete), and methods based on microbial aggregates (periphytons and biofilms). An integrative process of "flocculation-lysis-degradation-nutrients regulation" is proposed to control HABs. This review not only offers a systematic understanding of HABs control technologies based on microorganisms but also elicits a re-thinking of HABs control based on microbial aggregates.

Detection of a Planktothrix agardhii Bloom in Portuguese Marine Coastal Waters

Cyanobacteria blooms are frequent in freshwaters and are responsible for water quality deterioration and human intoxication. Although, not a new phenomenon, concern exists on the increasing persistence, scale, and toxicity of these blooms. There is evidence, in recent years, of the transfer of these toxins from inland to marine waters through freshwater outflow. However, the true impact of these blooms in marine habitats has been overlooked. In the present work, we describe the detection of Planktothrix agardhii, which is a common microcystin producer, in the Portuguese marine coastal waters nearby a river outfall in an area used for shellfish harvesting and recreational activities. P. agardhii was first observed in November of 2016 in seawater samples that are in the scope of the national shellfish monitoring system. This occurrence was followed closely between November and December of 2016 by a weekly sampling of mussels and water from the sea pier and adjacent river mouth with salinity ranging from 35 to 3. High cell densities were found in the water from both sea pier and river outfall, reaching concentrations of 4,960,608 cells·L⁻¹ and 6810.3 × 10⁶ cells·L⁻¹ respectively. Cultures were also established with success from the environment and microplate salinity growth assays showed that the isolates grew at salinity 10. HPLC-PDA analysis of total microcystin content in mussel tissue, water biomass, and P. agardhii cultures did not retrieve a positive result. In addition, microcystin related genes were not detected in the water nor cultures. So, the P. agardhii present in the environment was probably a non-toxic strain. This is, to our knowledge, the first report on a P. agardhii bloom reaching the sea and points to the relevance to also monitoring freshwater harmful phytoplankton and related toxins in seafood harvesting and recreational coastal areas, particularly under the influence of river plumes.

Harmful Algal Bloom-Associated Illnesses in Humans and Dogs Identified Through a Pilot Surveillance System - New York, 2015

Cyanobacteria, also known as blue-green algae, are photosynthetic, aquatic organisms found in fresh, brackish, and marine water around the world (1). Rapid proliferation and accumulation of potentially toxin-producing cyanobacteria characterize one type of harmful algal bloom (HAB). HABs have the potential to cause illness in humans and animals (2,3); however, the epidemiology of these illnesses has not been well characterized. Statewide in 2015, a total of 139 HABs were identified in New York, 97 (70%) of which were confirmed through laboratory analysis; 77 independent beach closures were ordered at 37 beaches on 20 different bodies of water. To better characterize HAB-associated illnesses, during June-September 2015, the New York State Department of Health (NYSDOH) implemented a pilot surveillance system in 16 New York counties. Activities included the collection of data from environmental HAB reports, illness reports, poison control centers, and syndromic surveillance, and increased outreach to the public, health care providers, and veterinarians. During June-September, 51 HAB-associated illnesses were reported, including 35 that met the CDC case definitions*; 32 of the cases occurred in humans and three in dogs. In previous years, New York never had more than 10 HAB-associated illnesses reported statewide. The pilot surveillance results from 16 counties during a 4-month period suggest that HAB-associated illnesses might be more common than previously reported.

Satellite monitoring of cyanobacterial harmful algal bloom frequency in recreational waters and drinking source waters

Cyanobacterial harmful algal blooms (cyanoHAB) cause extensive problems in lakes worldwide, including human and ecological health risks, anoxia and fish kills, and taste and odor problems. CyanoHABs are a particular concern in both recreational waters and drinking source waters because of their dense biomass and the risk of exposure to toxins. Successful cyanoHAB assessment using satellites may provide an indicator for human and ecological health protection, In this study, methods were developed to assess the utility of satellite technology for detecting cyanoHAB frequency of occurrence at locations of potential management interest. The European Space Agency's MEdium Resolution Imaging Spectrometer (MERIS) was evaluated to prepare for the equivalent series of Sentine1-3 Ocean and Land Colour Imagers (OLCI) launched in 2016 as part of the Copernicus program. Based on the 2012 National Lakes Assessment site evaluation guidelines and National Hydrography Dataset, the continental United States contains 275,897 lakes and reservoirs >1 hectare in area. Results from this study show that 5.6 % of waterbodies were resolvable by satellites with 300 m single-pixel resolution and 0.7 % of waterbodies were resolvable when a three by three pixel (3×3-pixel) array was applied based on minimum Euclidian distance from shore. Satellite data were spatially joined to U.S. public water surface intake (PWSI) locations, where single-pixel resolution resolved 57% of the PWSI locations and a 3×3-pixel array resolved 33% of the PWSI locations. Recreational and drinking water sources in Florida and Ohio were ranked from 2008 through 2011 by cyanoHAB frequency above the World Health Organization's (WHO) high threshold for risk of 100,000 cells mL-1. The ranking identified waterbodies with values above the WHO high threshold, where Lake Apopka, FL (99.1 %) and Grand Lake St. Marys, OH (83 %) had the highest observed bloom frequencies per region. The method presented here may indicate locations with high exposure to cyanoHABs and therefore can be used to assist in prioritizing management resources and actions for recreational and drinking water sources.

Early transcriptional response pathways in Daphnia magna are coordinated in networks of crustacean-specific genes

Natural habitats are exposed to an increasing number of environmental stressors that cause important ecological consequences. However, the multifarious nature of environmental change, the strength and the relative timing of each stressor largely limit our understanding of biological responses to environmental change. In particular, early response to unpredictable environmental change, critical to survival and fitness in later life stages, is largely uncharacterized. Here, we characterize the early transcriptional response of the keystone species Daphnia magna to twelve environmental perturbations, including biotic and abiotic stressors. We first perform a differential expression analysis aimed at identifying differential regulation of individual genes in response to stress. This preliminary analysis revealed that a few individual genes were responsive to environmental perturbations and they were modulated in a stressor and genotype-specific manner. Given the limited number of differentially regulated genes, we were unable to identify pathways involved in stress response. Hence, to gain a better understanding of the genetic and functional foundation of tolerance to multiple environmental stressors, we leveraged the correlative nature of networks and performed a weighted gene co-expression network analysis. We discovered that approximately one-third of the Daphnia genes, enriched for metabolism, cell signalling and general stress response, drives transcriptional early response to environmental stress and it is shared among genetic backgrounds. This initial response is followed by a genotype- and/or condition-specific transcriptional response with a strong genotype-by-environment interaction. Intriguingly, genotype- and condition-specific transcriptional response is found in genes not conserved beyond crustaceans, suggesting niche-specific adaptation.

Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment

Cyanobacterial harmful algal blooms (CyanoHABs) have serious adverse effects on human and environmental health. Herein, we developed a modeling framework that predicts the effect of climate change on cyanobacteria concentrations in large reservoirs in the contiguous U.S. The framework, which uses climate change projections from five global circulation models, two greenhouse gas emission scenarios, and two cyanobacterial growth scenarios, is unique in coupling climate projections with a hydrologic/water quality network model of the contiguous United States. Thus, it generates both regional and nationwide projections useful as a screening-level assessment of climate impacts on CyanoHAB prevalence as well as potential lost recreation days and associated economic value. Our projections indicate that CyanoHAB concentrations are likely to increase primarily due to water temperature increases tempered by increased nutrient levels resulting from changing demographics and climatic impacts on hydrology that drive nutrient transport. The combination of these factors results in the mean number of days of CyanoHAB occurrence ranging from about 7 days per year per waterbody under current conditions, to 16-23 days in 2050 and 18-39 days in 2090. From a regional perspective, we find the largest increases in CyanoHAB occurrence in the Northeast U.S., while the greatest impacts to recreation, in terms of costs, are in the Southeast.

Effects of cyanobacteria Synechocystis spp. in the host-parasite model Crassostrea gasar-Perkinsus marinus

Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4h) and long (48h and 7days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of cyanobacteria; while neither the WCs nor the ECPs modified phagocytosis of the biological particles, zymosan and P. marinus. Our results suggest a negative effect of cyanobacteria from the Synechocystis genus on host immune cells, in contrast to a more beneficial effect on the parasite cell, which could together disrupt the balance of the host-parasite interaction and make oysters more susceptible to P. marinus as well as opportunistic infections.

Cyanotoxins in inland lakes of the United States: Occurrence and potential recreational health risks in the EPA National Lakes Assessment 2007

A large nation-wide survey of cyanotoxins (1161 lakes) in the United States (U.S.) was conducted during the EPA National Lakes Assessment 2007. Cyanotoxin data were compared with cyanobacteria abundance- and chlorophyll-based World Health Organization (WHO) thresholds and mouse toxicity data to evaluate potential recreational risks. Cylindrospermopsins, microcystins, and saxitoxins were detected (ELISA) in 4.0, 32, and 7.7% of samples with mean concentrations of 0.56, 3.0, and 0.061μg/L, respectively (detections only). Co-occurrence of the three cyanotoxin classes was rare (0.32%) when at least one toxin was detected. Cyanobacteria were present and dominant in 98 and 76% of samples, respectively. Potential anatoxin-, cylindrospermopsin-, microcystin-, and saxitoxin-producing cyanobacteria occurred in 81, 67, 95, and 79% of samples, respectively. Anatoxin-a and nodularin-R were detected (LC/MS/MS) in 15 and 3.7% samples (n=27). The WHO moderate and high risk thresholds for microcystins, cyanobacteria abundance, and total chlorophyll were exceeded in 1.1, 27, and 44% of samples, respectively. Complete agreement by all three WHO microcystin metrics occurred in 27% of samples. This suggests that WHO microcystin metrics based on total chlorophyll and cyanobacterial abundance can overestimate microcystin risk when compared to WHO microcystin thresholds. The lack of parity among the WHO thresholds was expected since chlorophyll is common amongst all phytoplankton and not all cyanobacteria produce microcystins.

Sentinel Animals in a One Health Approach to Harmful Cyanobacterial and Algal Blooms

People, domestic animals, and wildlife are all exposed to numerous environmental threats, including harmful algal blooms (HABs). However, because animals exhibit wide variations in diet, land use and biology, they are often more frequently or heavily exposed to HAB toxins than are people occupying the same habitat, making them sentinels for human exposures. Historically, we have taken advantage of unique physiological characteristics of animals, such as the sensitivity of canaries to carbon monoxide, to more quickly recognize threats and help protect human health. As HAB events become more severe and widespread worldwide, exposure and health outcome data for animals can be extremely helpful to predict, prevent, and evaluate human exposures and health outcomes. Applying a One Health approach to investigation of HABs means that lessons learned from animal sentinels can be applied to protect people, animals and our shared environment.

Health impacts from cyanobacteria harmful algae blooms: Implications for the North American Great Lakes

Harmful cyanobacterial blooms (cHABs) have significant socioeconomic and ecological costs, which impact drinking water, fisheries, agriculture, tourism, real estate, water quality, food web resilience and habitats, and contribute to anoxia and fish kills. Many of these costs are well described, but in fact are largely unmeasured. Worldwide cHABs can produce toxins (cyanotoxins), which cause acute or chronic health effects in mammals (including humans) and other organisms. There are few attempts to characterize the full health-related effects other than acute incidences, which may go unrecorded. At present these are difficult to access and evaluate and may be ascribed to other causes. Such information is fundamental to measure the full costs of cHABs and inform the need for often-costly management and remediation. This paper synthesizes information on cHABs occurrence, toxicology and health effects, and relates this to past and current conditions in the Great Lakes, a major global resource which supplies 84% of the surface water in North America. This geographic region has seen a significant resurgence of cHABs since the 1980s. In particular we focus on Lake Erie, where increased reporting of cHABs has occurred from the early 1990's. We evaluate available information and case reports of cHAB-related illness and death and show that cHABs occur throughout the basin, with reports of animal illness and death, especially dogs and livestock. Lake Erie has consistently experienced cHABs and cyanotoxins in the last decade with probable cases of human illness, while the other Great Lakes show intermittent cHABs and toxins, but no confirmed reports on illness or toxicity. The dominant toxigenic cyanobacterium is the genus Microcystis known to produce microcystins. The presence of other cyanotoxins (anatoxin-a, paralytic shellfish toxins) implicates other toxigenic cyanobacteria such as Anabaena (Dolichospermum) and Lyngbya.

ACQUA: Automated Cyanobacterial Quantification Algorithm for toxic filamentous genera using spline curves, pattern recognition and machine learning

Toxigenic cyanobacteria are one of the main health risks associated with water resources worldwide, as their toxins can affect humans and fauna exposed via drinking water, aquaculture and recreation. Microscopy monitoring of cyanobacteria in water bodies and massive growth systems is a routine operation for cell abundance and growth estimation. Here we present ACQUA (Automated Cyanobacterial Quantification Algorithm), a new fully automated image analysis method designed for filamentous genera in Bright field microscopy. A pre-processing algorithm has been developed to highlight filaments of interest from background signals due to other phytoplankton and dust. A spline-fitting algorithm has been designed to recombine interrupted and crossing filaments in order to perform accurate morphometric analysis and to extract the surface pattern information of highlighted objects. In addition, 17 specific pattern indicators have been developed and used as input data for a machine-learning algorithm dedicated to the recognition between five widespread toxic or potentially toxic filamentous genera in freshwater: Aphanizomenon, Cylindrospermopsis, Dolichospermum, Limnothrix and Planktothrix. The method was validated using freshwater samples from three Italian volcanic lakes comparing automated vs. manual results. ACQUA proved to be a fast and accurate tool to rapidly assess freshwater quality and to characterize cyanobacterial assemblages in aquatic environments.