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Harmful Algae

Connor B Driscoll, Kevin A Meyer, Sigitas Šulčius, Nathan M Brown, Gregory J Dick, Huansheng Cao, Giedrius Gasiūnas, Albertas Timinskas, Yanbin Yin, Zachary C Landry, Timothy G Otten, Timothy W Davis, Susan B Watson, Theo W Dreher
In order to better understand the relationships among current Nostocales cyanobacterial blooms, eight genomes were sequenced from cultured isolates or from environmental metagenomes of recent planktonic Nostocales blooms. Phylogenomic analysis of publicly available sequences placed the new genomes among a group of 15 genomes from four continents in a distinct ADA clade (Anabaena/Dolichospermum/Aphanizomenon) within the Nostocales. This clade contains four species-level groups, two of which include members with both Anabaena-like and Aphanizomenon flos-aquae-like morphology...
July 2018: Harmful Algae
Mark W Vandersea, Steven R Kibler, Patricia A Tester, Kristine Holderied, Dominic E Hondolero, Kim Powell, Steve Baird, Angela Doroff, Darcy Dugan, R Wayne Litaker
Despite the long history of paralytic shellfish poisoning (PSP) events in Alaska, little is known about the seasonal distribution and abundance of the causative organism, Alexandrium, or the environmental factors that govern toxic bloom development. To address this issue, a five year study (2012-2017) was undertaken in Kachemak Bay and lower Cook Inlet Alaska to determine how the occurrence of Alexandrium catenella, the dominant PSP-causing Alexandrium species, was influenced by temperature, salinity, nutrient concentrations, and other environmental factors...
July 2018: Harmful Algae
Monika Dhanji-Rapkova, Alison O'Neill, Benjamin H Maskrey, Lewis Coates, Mickael Teixeira Alves, Rebecca J Kelly, Robert G Hatfield, Stephanie J Rowland-Pilgrim, Adam M Lewis, Myriam Algoet, Andrew D Turner
Official control biotoxin testing of bivalve molluscs from Great Britain has been conducted by Cefas for over a decade. Reflecting the changes in legislation, bioassays were gradually replaced by analytical methods, firstly for analysis of Paralytic shellfish toxins, followed by introduction of liquid chromatography tandem mass spectrometric (LCMS/MS) method for lipophilic toxins (LTs) in 2011. Twelve compounds, representing three main groups of regulated lipophilic toxins, as well as two non-regulated cyclic imines were examined in over 20,500 samples collected between July 2011 and December 2016...
July 2018: Harmful Algae
Rodrigo M Montes, Ximena Rojas, Paulina Artacho, Alfredo Tello, Renato A Quiñones
Harmful algal blooms (HABs) have affected salmon farms in Chile since the early 1970's, causing massive losses in fish. Two large HABs occurred in 2002 and 2009, during which Alexandrium catenella blooms killed tons of salmon over an extended geographic area in southern Chile. At the beginning of 2016, high and persistent densities of Pseudochattonella cf. verruculosa and A. catenella were detected in the estuarine and marine ecosystems of southern Chile. Mortality for this latter event reached 27 million salmon and trout (i...
July 2018: Harmful Algae
Houshuo Jiang, David M Kulis, Michael L Brosnahan, Donald M Anderson
Predator-prey interactions of planktonic protists are fundamental to plankton dynamics and include prey selection, detection, and capture as well as predator detection and avoidance. Propulsive, morphology-specific behaviors modulate these interactions and therefore bloom dynamics. Here, interactions between the mixotrophic, harmful algal bloom (HAB) dinoflagellate Dinophysis acuminata and its ciliate prey Mesodinium rubrum were investigated through quantitative microvideography using a high-speed microscale imaging system (HSMIS)...
July 2018: Harmful Algae
Mohamed Amine Hachani, Amel Dhib, Afef Fathalli, Boutheina Ziadi, Souad Turki, Lotfi Aleya
The spatio-temporal distribution of epiphytic and planktonic microalgae coupled with environmental factors was investigated for a one-year period in the Gulf of Tunis (northeastern Tunisia). Harmful microalgae assemblages were dominated by three toxic epiphytic dinoflagellates: Ostreopsis sp., Prorocentrum lima and Coolia monotis. They were observed, both on macrophytes (1.03 × 105 cells g-1 FW ; 1.3 × 104 cells g-1 FW and 865 cells g-1 FW, respectively) and in the water column (2.35 × 104 cells L-1 ; 3...
July 2018: Harmful Algae
Wansheng Zou, Zhi Wang, Qisheng Song, Shaoxian Tang, Yuande Peng
The frequent occurrence of Microcystis aeruginosa blooms benefit from the dormant Microcystis cells, which will be recruited from sediment into overlying water to form a dominant population and algal blooms when external environmental conditions are suitable. Previous studies have unveiled factors involved in M. aeruginosa recruitment and bloom initiation, including nutrition, illumination, temperature, and hydrodynamic force. In this study, three dominant benthic bacterial species isolated from Lake Chongtian with frequent blooms-forming were identified through next generation sequencing (NGS) techniques, and laboratory experiments were conducted on the recruitment of dormant M...
July 2018: Harmful Algae
Jin Zhao, Peng Jiang, Ri Qiu, Yingying Ma, Chunhui Wu, Huihui Fu, Huaxin Chen, Fuchao Li
Large scale green tides have bloomed successively in the Yellow Sea since 2007. The floating ecotype of Ulva prolifera, which is responsible for the environmental disaster, drifted a long distance during the blooming time and was exotic to the coastal area. The Yellow Sea green tide can be a potential source to incur bio-invasion. In this study, the distribution pattern and propagule pressure of the floating ecotype was investigated along the Qingdao coastline, which was seriously impacted by the green tide...
July 2018: Harmful Algae
Jiangbing Qiu, Cheryl Rafuse, Nancy I Lewis, Aifeng Li, Fanping Meng, Daniel G Beach, Pearse McCarron
The dinoflagellate genus Alexandrium Halim has frequently been associated with harmful algal blooms. Although a number of species from this genus are known to produce paralytic shellfish toxins (PST) and/or cyclic imines (CI), studies on comprehensive toxin profiling using techniques capable of detecting the full range of PST and CI analogues are limited. Isolates of Alexandrium spp. from Atlantic Canada were analyzed by targeted and untargeted liquid chromatography-tandem mass spectrometry (LC-MS). Results showed a number of distinct profiles and wide ranging cell quotas of PST and spirolides (SPX) in both A...
July 2018: Harmful Algae
Chenlin Hu, Stuart A Ludsin, Jay F Martin, Elke Dittmann, Jiyoung Lee
Mycosporine-like amino acids (MAAs) are UV-absorbing metabolites found in cyanobacteria. While their protective role from UV in Microcystis has been studied in a laboratory setting, a full understanding of the ecology of MAA-producing versus non-MAA-producing Microcystis in natural environments is lacking. This study presents a new tool for quantifying MAA-producing Microcystis and applies it to obtain insight into the dynamics of MAA-producing and non-MAA-producing Microcystis in Lake Erie. This study first developed a sensitive, specific TaqMan real-time PCR assay that targets MAA synthetase gene C (mysC) of Microcystis (quantitative range: 1...
July 2018: Harmful Algae
Frederik Frøsig Gai, Cecilie Kirketerp Hedemand, Deon C Louw, Kolette Grobler, Bernd Krock, Øjvind Moestrup, Nina Lundholm
A field study was undertaken to investigate the occurrence and toxin production of species in the diatom genus Pseudo-nitzschia in Namibian waters, in the extremely productive Benguela upwelling system. From surveys conducted on the R/V Mirabilis and the R/V !Anichab, 52 strains were morphologically determined to species level, supported by nuclear ITS rDNA data. Seven species were identified; P. australis, P. decipiens, P. dolorosa, P. fraudulenta, P. plurisecta, P. pungens var. cingulata, and the new species P...
June 2018: Harmful Algae
Stacie L Flood, JoAnn M Burkholder
The potential for toxic contaminants and nutrient pollution to alter natural cycles of estuarine phytoplankton blooms is well known, yet few studies have examined how these combined stressors affect harmful algal species. Here, a robust testing protocol was developed to enable an ecotoxicological assessment of responses to commonly co-occurring estuarine contaminants by harmful algal bloom species. The population growth and toxicity (as cell density and hemolytic activity, respectively) of a cultured strain of the toxigenic raphidiophycean, Chattonella subsalsa, were assessed in two experiments (duration 10 days and 28 days) across a gradient of atrazine concentrations and N:P ratios simulating nutrient-rich versus nutrient-depleted regimes...
June 2018: Harmful Algae
Mitsutaka Nakada, Yuki Hatayama, Akira Ishikawa, Tetsuro Ajisaka, Shigeki Sawayama, Ichiro Imai
The occurrence of the ciguatera fish poisoning (CFP) causative Gambierdiscus spp. was confirmed in the Sea of Japan for the first time in 2009. This paper reports seasonal distribution of Gambierdiscus spp. and epiphytic diatoms in the Sea of Japan. Monitoring results suggested an antagonistic interaction in abundances between epiphytic diatoms and the dinoflagellate Gambierdiscus spp. Allelopathic effects of diatoms were considered to be involved in the competitive phenomenon. Therefore it is hypothesized that cell densities of epiphytic pennate diatoms on macroalgae are a novel determinant affecting the abundance of Gambierdiscus spp...
June 2018: Harmful Algae
Manjunath Manubolu, Jiyoung Lee, Kenneth M Riedl, Zi Xun Kua, Lindsay P Collart, Stuart A Ludsin
Human-driven environmental change has increased the occurrence of harmful cyanobacteria blooms in aquatic ecosystems. Concomitantly, exposure to microcystin (MC), a cyanobacterial toxin that can accumulate in animals, edible plants, and agricultural soils, has become a growing public health concern. For accurate estimation of health risks and timely monitoring, availability of reliable detection methods is imperative. Nonetheless, quantitative analysis of MCs in many types of biological and environmental samples has proven challenging because matrix interferences can hinder sample preparation and extraction procedures, leading to poor MC recovery...
June 2018: Harmful Algae
Richard Johansen, Richard Beck, Jakub Nowosad, Christopher Nietch, Min Xu, Song Shu, Bo Yang, Hongxing Liu, Erich Emery, Molly Reif, Joseph Harwood, Jade Young, Dana Macke, Mark Martin, Garrett Stillings, Richard Stumpf, Haibin Su
This study evaluated the performances of twenty-nine algorithms that use satellite-based spectral imager data to derive estimates of chlorophyll-a concentrations that, in turn, can be used as an indicator of the general status of algal cell densities and the potential for a harmful algal bloom (HAB). The performance assessment was based on making relative comparisons between two temperate inland lakes: Harsha Lake (7.99 km2 ) in Southwest Ohio and Taylorsville Lake (11.88 km2 ) in central Kentucky. Of interest was identifying algorithm-imager combinations that had high correlation with coincident chlorophyll-a surface observations for both lakes, as this suggests portability for regional HAB monitoring...
June 2018: Harmful Algae
Amber Brown, Amanda Foss, Melissa A Miller, Quincy Gibson
Microcystins/Nodularins (MCs/NODs) are potent hepatotoxic cyanotoxins produced by harmful algal blooms (HABs) that occur frequently in the upper basin of the St. Johns River (SJR), Jacksonville, FL, USA. Areas downstream of bloom locations provide critical habitat for an estuarine population of bottlenose dolphins (Tursiops truncatus). Since 2010, approximately 30 of these dolphins have stranded and died within this impaired watershed; the cause of death was inconclusive for a majority of these individuals...
June 2018: Harmful Algae
Paul A Bukaveckas, Rima Franklin, Spencer Tassone, Brendan Trache, Todd Egerton
We examined seasonal and longitudinal patterns in the occurrence of toxic cyanobacteria in the James River Estuary (Virginia). Highest chlorophyll and cyanobacteria levels were observed in the tidal freshwater segment, particularly during dry summers when freshwater replacement time was long. Cyanobacteria accounted for a small proportion of phytoplankton biomass (7-15%), and Microcystis comprised a small proportion of the cyanobacteria (<1%). Despite this, measureable levels of microcystin were commonly observed in water (>85% of samples in July, August and September), fish tissues (87% of planktivorous fishes) and shellfish (83% of individuals)...
June 2018: Harmful Algae
Adam K Rose, Larelle Fabbro, Susan Kinnear
Mitigation of cyanobacterial or "blue-green algal" blooms is a challenging task for water managers across Australia. In the present study, a regional drinking water source (located in Central Queensland) was studied to identify the potential risks posed by cyanobacteria. Data were collected from the drinking water source (a lagoon) as well as the drinking water supply infrastructure, at monthly intervals between September 2012 and December 2014. In March 2013 there was an extreme rainfall event where floodwaters infiltrated the water supply without passing through bank filtration...
June 2018: Harmful Algae
Christos-Moritz Loukas, Matthew C Mowlem, Maria-Nefeli Tsaloglou, Nicolas G Green
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...
May 2018: Harmful Algae
Liang Zhao, Yulong Song, Lin Li, Nanqin Gan, Jerry J Brand, Lirong Song
The occurrence of harmful Microcystis blooms is increasing in frequency in a myriad of freshwater ecosystems. Despite considerable research pertaining to the cause and nature of these blooms, the molecular mechanisms behind the cosmopolitan distribution and phenotypic diversity in Microcystis are still unclear. We compared the patterns and extent of DNA methylation in three strains of Microcystis, PCC 7806SL, NIES-2549 and FACHB-1757, using Single Molecule Real-Time (SMRT) sequencing technology. Intact restriction-modification (R-M) systems were identified from the genomes of these strains, and from two previously sequenced strains of Microcystis, NIES-843 and TAIHU98...
May 2018: Harmful Algae
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