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Harmful Algae

Se Hyeon Jang, Hae Jin Jeong, Ji Eun Kwon, Kyung Ha Lee
To investigate tropical roles of the newly described Yihiella yeosuensis (ca. 8μm in cell size), one of the smallest phototrophic dinoflagellates in marine ecosystems, its trophic mode and the types of prey species that Y. yeosuensis can feed upon were explored. Growth and ingestion rates of Y. yeosuensis on its optimal prey, Pyramimonas sp. (Prasinophyceae), as a function of prey concentration were measured. Additionally, growth and ingestion rates of Y. yeosuensis on the other edible prey, Teleaulax sp. (Cryptophyceae), were also determined for a single prey concentration at which both these rates of Y...
February 2017: Harmful Algae
Man Xiao, Anusuya Willis, Michele A Burford
Microcystis aeruginosa and Cylindrospermopsis raciborskii are two cyanobacterial species that dominate freshwaters globally. Multiple strains of each species with different physiology occur, however, many studies have focused only on one or two strains, limiting our understanding of both strain variation and characterisation of the species. Therefore, in this study we examined the variation in growth and morphology of multiple isolates of both species, isolated from two adjacent Australian reservoirs. Four M...
February 2017: Harmful Algae
Gabriela Martínez de la Escalera, Carla Kruk, Angel M Segura, Lucía Nogueira, Ignacio Alcántara, Claudia Piccini
Bloom-forming species belonging to Microcystis aeruginosa complex (MAC) are the most commonly reported worldwide. MAC blooms are composed by toxic and non-toxic genotypes and the environmental conditions favouring the dominance of toxic genotypes are still a matter of debate among the scientific community. In this study, we evaluated the distribution of toxic MAC genotypes along a seasonal cycle and over an environmental gradient spanning 800km, from a eutrophic freshwater reservoir in Río Uruguay to marine water in the outer limit of Río de la Plata...
February 2017: Harmful Algae
Zheng-Xi Zhou, Ren-Cheng Yu, Ming-Jiang Zhou
The sea area adjacent to the Changjiang River estuary is the most notable region for harmful algal blooms (HABs(1)) in China as both diatom and dinoflagellate blooms have been recorded in this region. Affected by the Changjiang diluted water (CDW(2)) and currents from the open ocean (i.e., Taiwan warm current, TWC(3)), the environmental conditions in the coastal waters adjacent to the Changjiang River estuary are quite complex. To obtain a better understanding of the mechanisms of HABs in this region, analyses based on field investigation data collected by the National Basic Research Priority Program (CEOHAB I(4)) were performed using principle component analysis (PCA(5)), multiple regression analysis (MRA(6)) and path analysis (PA(7))...
February 2017: Harmful Algae
Masafumi Natsuike, Katsuhide Yokoyama, Goh Nishitani, Yuichiro Yamada, Ikuo Yoshinaga, Akira Ishikawa
While cyst germination may be an important factor for the initiation of harmful/toxic blooms, assessments of the fluctuation in phytoplankton cyst germination, from bottom sediments to water columns, are rare in situ due to lack of technology that can detect germinated cells in natural bottom sediments. This study introduces a simple mesocosm method, modeled after previous in situ methods, to measure the germination of plankton resting stage cells. Using this method, seasonal changes in germination fluxes of toxic dinoflagellates resting cysts, specifically Alexandrium fundyense (A...
February 2017: Harmful Algae
Hae Jin Jeong, Jae Seong Kim, Kyung Ha Lee, Kyeong Ah Seong, Yeong Du Yoo, Nam Seon Kang, Tae Hoon Kim, Jae Yoon Song, Ji Eun Kwon
To investigate interactions between the nematocyst-bearing mixotrophic dinoflagellate Paragymnodinium shiwhaense and different heterotrophic protist and copepod species, feeding by common heterotrophic dinoflagellates (Oxyrrhis marina and Gyrodinium dominans), naked ciliates (Strobilidium sp. approximately 35μm in cell length and Strombidinopsis sp. approximately 100μm in cell length), and calanoid copepods Acartia spp. (A. hongi and A. omorii) on P. shiwhaense was explored. In addition, the feeding activities of P...
February 2017: Harmful Algae
Caiwen Li, Tiantian Chen
The parasitic dinoflagellate Amoebophrya infects broad range of marine organisms. Particularly, Amoebophrya infections in planktonic dinoflagellates can prevent or delay the formation of algal blooms, and recycle undergrazed planktonic dinoflagellates back to the microbial loop by disrupting host cells. Its ecological significance was gradually recognized along with the discovery of its enormous molecular diversity in oceanic and coastal ecosystems. Thus, we developed a reliable, easily accessible and less time-consuming assay, to detect and assess Amoebophrya infections in planktonic dinoflagellates...
February 2017: Harmful Algae
Hai-Long Huang, Peng Zhu, Cheng-Xu Zhou, Shan He, Xiao-Jun Yan
The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) combined with a chromatographic lateral flow dipstick (LFD) assay to rapidly and specifically detect the Karlodinium veneficum ITS gene. Four groups of LAMP primers were specially designed to target the K. veneficum ITS gene. The LAMP-LFD detection limit was 7.4pg/μL (approximately 6.5cells/mL) of K. veneficum genomic DNA and was 10 times more sensitive than standard PCR. The LAMP-LFD method exhibited high specificity and accurately identified K...
February 2017: Harmful Algae
Nobuharu Inaba, Vera L Trainer, Yuka Onishi, Ken-Ichiro Ishii, Sandy Wyllie-Echeverria, Ichiro Imai
The algicidal and growth-inhibiting bacteria associated with seagrasses and macroalgae were characterized during the summer of 2012 and 2013 throughout Puget Sound, WA, USA. In 2012, Heterosigma akashiwo-killing bacteria were observed in concentrations of 2.8×10(6)CFUg(-1) wet in the outer organic layer (biofilm) on the common eelgrass (Zostera marina) in north Padilla Bay. Bacteria that inhibited the growth of Alexandrium tamarense were detected within the biofilm formed on the eelgrass canopy at Dumas Bay and North Bay at densities of ∼10(8)CFUg(-1) wet weight...
February 2017: Harmful Algae
Kaytee L Pokrzywinski, Charles L Tilney, Shannon Modla, Jeffery L Caplan, Jean Ross, Mark E Warner, Kathryn J Coyne
The algicide, IRI-160AA, induces mortality in dinoflagellates but not other species of algae, suggesting that a shared characteristic or feature renders this class of phytoplankton vulnerable to the algicide. In contrast to other eukaryotic species, the genome of dinoflagellates is stabilized by high concentrations of divalent cations and transition metals and contains large amounts of DNA with unusual base modifications. These distinctions set dinoflagellates apart from other phytoplankton and suggest that the nucleus may be a dinoflagellate-specific target for IRI-160AA...
February 2017: Harmful Algae
Urban Tillmann, David Jaén, Lourdes Fernández, Marc Gottschling, Matthias Witt, Juan Blanco, Bernd Krock
Azaspiracids (AZA) are a group of food poisoning phycotoxins that are known to accumulate in shellfish. They are produced by some species of the planktonic dinophycean taxon Amphidomataceae. Azaspiracids have been first discovered in Ireland but are now reported in shellfish from numerous global sites thus showing a wide distribution. In shellfish samples collected in 2009 near Huelva (Spain), AZA was also found along the Andalusian Atlantic coast for the first time. Analysis using LC-MS/MS revealed the presence of two different AZA analogues in different bivalve shellfish species (Chamelea gallina, Cerastoderma edule, Donax trunculus, and Solen vagina)...
February 2017: Harmful Algae
Kathryn Tiling, C Edward Proffitt
Cyanobacterial blooms have been increasing worldwide due to increased nutrients associated with urban, industrial, and agricultural development. Blooms that occur in the Indian River Lagoon (IRL), Florida may be increased by nutrient-laden runoff from storm water and non-point sewage pollution due to alterations to the watershed. In the IRL, during the summer of 2006, extensive blooms of the marine cyanobacterium, Lyngbya majuscula, were observed forming mats throughout beds of the seagrass Halodule wrightii in Fort Pierce, Florida...
February 2017: Harmful Algae
Glenn B McGregor, Barbara C Sendall
A new nodularin producing benthic cyanobacterium Iningainema pulvinus gen nov., sp nov. was isolated from a freshwater ambient spring wetland in tropical, north-eastern Australia and characterised using combined morphological and phylogenetic attributes. It formed conspicuous irregularly spherical to discoid, blue-green to olive-green cyanobacterial colonies across the substratum of shallow pools. Morphologically Iningainema is most similar to Scytonematopsis Kiseleva and Scytonema Agardh ex Bornet & Flahault...
February 2017: Harmful Algae
Jiayi Xu, Per Juel Hansen, Lasse Tor Nielsen, Bernd Krock, Urban Tillmann, Thomas Kiørboe
Zooplankton responses to toxic algae are highly variable, even towards taxonomically closely related species or different strains of the same species. Here, the individual level feeding behavior of a copepod, Temora longicornis, was examined which offered 4 similarly sized strains of toxic dinoflagellate Alexandrium spp. and a non-toxic control strain of the dinoflagellate Protoceratium reticulatum. The strains varied in their cellular toxin concentration and composition and in lytic activity. High-speed video observations revealed four distinctly different strain-specific feeding responses of the copepod during 4h incubations: (i) the 'normal' feeding behavior, in which the feeding appendages were beating almost constantly to produce a feeding current and most (90%) of the captured algae were ingested; (ii) the beating activity of the feeding appendages was reduced by ca...
February 2017: Harmful Algae
Hae Jin Jeong, Jin Hee Ok, An Suk Lim, Ji Eun Kwon, So Jin Kim, Sung Yeon Lee
Takayama spp. are phototrophic dinoflagellates belonging to the family Kareniaceae and have caused fish kills in several countries. Understanding their trophic mode and interactions with co-occurring phytoplankton species are critical steps in comprehending their ecological roles in marine ecosystems, bloom dynamics, and dinoflagellate evolution. To investigate the trophic mode and interactions of Takayama spp., the ability of Takayama helix to feed on diverse algal species was examined, and the mechanisms of prey ingestion were determined...
December 2016: Harmful Algae
Z K Klouch, F Caradec, M Plus, T Hernández-Fariñas, L Pineau-Guillou, A Chapelle, S Schmitt, J Quéré, L Guillou, R Siano
Within the framework of research aimed at using genetic methods to evaluate harmful species distribution and their impact on coastal ecosystems, a portion of the ITS1rDNA of Alexandrium minutum was amplified by real-time PCR from DNA extracts of superficial (1-3cm) sediments of 30 subtidal and intertidal stations of the Bay of Brest (Brittany, France), during the winters of 2013 and 2015. Cell germinations and rDNA amplifications of A. minutum were obtained for sediments of all sampled stations, demonstrating that the whole bay is currently contaminated by this toxic species...
December 2016: Harmful Algae
F Joan Hardy, Debra Bouchard, Marisa Burghdoff, Ray Hanowell, Beth LeDoux, Ellen Preece, Lindsay Tuttle, Gene Williams
While numerous strategies have been used to educate and notify the public about potential hazards from exposure to Harmful Algal Blooms (HABs), at present there are no national guidelines or suggested outreach approaches. To raise public awareness and determine effective HAB outreach methods, two Washington State agencies and three counties in the Puget Sound region implemented several education and notification strategies. These approaches were rated for effectiveness by state and county public health and water quality professionals...
December 2016: Harmful Algae
María García-Portela, Pilar Riobó, José Mariano Franco, Rosa Mª Bañuelos, Francisco Rodríguez
The genus Ostreopsis includes several toxic species that can develop blooms in benthic ecosystems, with potential harmful consequences for human health and marine invertebrates. Despite of this, little is known about the allelopathic interactions between these organisms and other co-occurring microalgae that exploit similar spatial and nutrient resources in benthic ecosystems. The aim of this study was to follow these interactions in cultures of two Ostreopsis ribotypes with different toxin profiles (O. cf...
December 2016: Harmful Algae
Kirsty F Smith, Lesley Rhodes, Arjun Verma, Belinda G Curley, D Tim Harwood, Gurjeet S Kohli, Dorothy Solomona, Teina Rongo, Rex Munday, Shauna A Murray
Ciguatera fish poisoning (CFP) has been reported for many years in Rarotonga, Cook Islands, and has had the world's highest reported incidence of this illness for the last 20 years. Following intensive sampling to understand the distribution of the causative organisms of CFP, an undescribed Gambierdiscus species was isolated from the Rarotongan lagoon. Gambierdiscus cheloniae sp. nov. has the common Gambierdiscus Kofoidian plate formula (except for a variability in the number of precingular plates in aberrant cells): Po, 3', 6″ (7″), 6C?, 6 or 7S, 5'″, 1p and 2″″...
December 2016: Harmful Algae
Tae Gyu Park, Jin Joo Kim, Won Jin Kim, Kyoung Mi Won
Morphological observations have confirmed that cysts are produced by dinoflagellates. However, finding a seed bed or unknown cysts in field samples by microscopy is extremely time consuming. Real-time PCR has been used to facilitate the detection of dinoflagellate cysts in sediment. However, DNA from dead vegetative cells remaining on the surface sediment may persist for a long period of time, which can cause false positive DNA detection. In this study, a non-quantitative RNA targeted probe using real-time RT-PCR was developed for detection of viable cysts in sediment...
December 2016: Harmful Algae
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