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Harmful Algae

Chae-Hong Park, Myung-Hwan Park, Keun Hee Kim, Jung-Hwan Park, Dae-Ryul Kwon, Nan Young Kim, Byung-Jin Lim, Soon-Jin Hwang
Understanding how algal resting cells (e.g. akinetes) germinate and what factors influence their germination rate is crucial for elucidating the development of algal blooms and their succession. While laboratory studies have demonstrated algal germination rate and some key factors affecting the germination, the use of artificially induced akinetes and/or removal of the sediments are obviously limiting in simulating the natural environment when designing such controlled experiments. This study introduce a laboratory Akinete Germination Chamber (AGC) that facilitates research for cyanobacterial akinete germination and emergence in an environment similar to natural conditions while minimizing sediment disturbance...
February 2018: Harmful Algae
Falk Eigemann, Marc Schwartke, Heide Schulz-Vogt
Cyanobacterial blooms regularly occur in the Baltic Sea during the summer months, with filamentous, heterocystous Nodularia spumigena and Dolichospermum sp. and the coccoid picocyanobacterium Synechococcus spp. as important species. Under calm conditions, N. spumigena accumulate at the surface, whereas Dolichospermum sp. and Synechococcus sp. remain at the subsurface, in the upper water layer. This vertical separation allows co-occurring species to compete for the same resources. The factors that determine the vertical distribution within blooms, however, are mostly unknown...
February 2018: Harmful Algae
Inia M Soto, Mustafa Kemal Cambazoglu, Adam D Boyette, Kristina Broussard, Drew Sheehan, Stephan D Howden, Alan M Shiller, Brian Dzwonkowski, Laura Hode, Patrick J Fitzpatrick, Robert A Arnone, Paul F Mickle, Kimberly Cressman
Harmful Algal Blooms (HABs) of Karenia brevis have been documented along coastal waters of every state bordering the Gulf of Mexico (GoM). Some Gulf Coast locations, such as Florida and Texas, suffer from recurrent intense and spatially large blooms, while others such as Mississippi seem to rarely observe them. The main objective of this work is to understand the dynamics that led to the K. brevis bloom in Mississippi coastal waters in fall 2015. Blooms of K. brevis from the Florida Panhandle region are often advected westward towards the Mississippi-Alabama coast; however there is interannual variability in their presence and intensity in Mississippi coastal waters...
February 2018: Harmful Algae
Yue Zhang, Zhiming Yu, Xiuxian Song, Yongquan Yuan, Xihua Cao
Cyst formation plays an important role in the resistance of dinoflagellates to adverse environments, and cyst germination is considered one of the causes of harmful algal blooms (HABs). Among the methods for mitigating HABs, modified clay (MC) is considered a promising strategy because of its high efficiency and low environmental impacts. The typical HAB species Alexandrium pacificum was focused on in this study to clarify the effects of MC on cyst formation and germination. The results showed that more than 90% of the vegetative cells were removed under the 0...
February 2018: Harmful Algae
Dedmer B Van de Waal, Delphine Guillebault, Amparo Alfonso, Inés Rodríguez, Luis M Botana, Ronald Bijkerk, Linda K Medlin
Harmful cyanobacterial blooms are a major threat to water quality and human health. Adequate risk assessment is thus required, which relies strongly on comprehensive monitoring. Here, we tested novel multi-probe RNA chips developed in the European project, μAqua, to determine the abundance of harmful cyanobacterial species and expression of selected toxin genes in six Dutch lakes. All of the targeted cyanobacterial genera, except for Planktothrix, were detected using the microarray, with predominance of Dolichospermum and Microcystis signals, of which the former was found across all sites and detected by the probes for Anabaena where it was formerly placed...
February 2018: Harmful Algae
Zhipeng Duan, Xiao Tan, Keshab Parajuli, Sanjina Upadhyay, Danfeng Zhang, Xiaoqian Shu, Qianqian Liu
The ability of Microcystis to form large colonies is a key trait that contributes to competition ability over other phytoplankton and facilitates the formation of surface scums in many freshwater systems. The effect of temperature and nutrients on this trait, however, is far from clear and needs further investigation, especially under a warmer climate and nutrient overloading in aquatic systems globally. In this study, two colonial strains of Microcystis (M. wesenbergii and M. ichthyoblabe) originally isolated from Lake Taihu in China, were used to investigate cyanobacterial aggregation under a range of temperatures (15-30 °C), phosphorus availability (0...
February 2018: Harmful Algae
Stéphane Karasiewicz, Elsa Breton, Alain Lefebvre, Tania Hernández Fariñas, Sébastien Lefebvre
The link between harmful algal blooms, phytoplankton community dynamics and global environmental change is not well understood. To tackle this challenging question, a new method was used to reveal how phytoplankton communities responded to environmental change with the occurrence of an harmful algae, using the coastal waters of the eastern English Channel as a case study. The great interannual variability in the magnitude and intensity of Phaeocystis spp. blooms, along with diatoms, compared to the ongoing gradual decrease in anthropogenic nutrient concentration and rebalancing of nutrient ratios; suggests that other factors, such as competition for resources, may also play an important role...
February 2018: Harmful Algae
Bum Soo Park, Jin Ho Kim, Joo-Hwan Kim, Seung Ho Baek, Myung-Soo Han
Although there have been extensive studies on dinoflagellate blooms in recent decades, the mechanism that allows the maintenance of blooms over long periods remains uncertain, and studies on genetically differentiated subpopulations may provide insights into this mechanism. In this study, the influence of two genetically distinct subpopulations of the dinoflagellate Cochlodinium polykrikoides, referred to as Group I and IV, on bloom duration in Korean coastal waters (KCW) was examined using a quantitative PCR (qPCR) assay...
January 2018: Harmful Algae
Kenneth Neil Mertens, M Consuelo Carbonell-Moore, Vera Pospelova, Martin J Head, Andrea Highfield, Declan Schroeder, Haifeng Gu, Karl B Andree, Margarita Fernandez, Aika Yamaguchi, Yoshihito Takano, Kazumi Matsuoka, Elisabeth Nézan, Gwenael Bilien, Yuri Okolodkov, Kazuhiko Koike, Mona Hoppenrath, Maya Pfaff, Grant Pitcher, Abdulrahman Al-Muftah, André Rochon, Po Teen Lim, Chui Pin Leaw, Zhen Fei Lim, Marianne Ellegaard
Strains of a dinoflagellate from the Salton Sea, previously identified as Protoceratium reticulatum and yessotoxin producing, have been reexamined morphologically and genetically and Pentaplacodinium saltonense n. gen. et sp. is erected to accommodate this species. Pentaplacodinium saltonense differs from Protoceratium reticulatum (Claparède et Lachmann 1859) Bütschli 1885 in the number of precingular plates (five vs. six), cingular displacement (two widths vs. one), and distinct cyst morphology. Incubation experiments (excystment and encystment) show that the resting cyst of Pentaplacodinium saltonense is morphologically most similar to the cyst-defined species Operculodinium israelianum (Rossignol, 1962) Wall (1967) and O...
January 2018: Harmful Algae
Remington X Poulin, Kelsey L Poulson-Ellestad, Jessie S Roy, Julia Kubanek
Harmful algae are known to utilize allelopathy, the release of compounds that inhibit competitors, as a form of interference competition. Competitor responses to allelopathy are species-specific and allelopathic potency of producing algae is variable. In the current study, the biological variability in allelopathic potency was mapped to the underlying chemical variation in the exuded metabolomes of five genetic strains of the red tide dinoflagellate Karenia brevis using 1H nuclear magnetic resonance (NMR) spectroscopy...
January 2018: Harmful Algae
Mélanie Roué, Hélène Taiana Darius, Jérôme Viallon, André Ung, Clémence Gatti, D Tim Harwood, Mireille Chinain
Ciguatera fish poisoning is a food-borne illness caused by the consumption of seafood contaminated with ciguatoxins (CTXs) produced by dinoflagellates in the Gambierdiscus genus. Since most surveillance programs currently rely on the survey of Gambierdiscus cell densities and species composition, supplementary toxin-based methods allowing the time- and spatially integrated sampling of toxins in ciguateric environments are needed for a more reliable assessment and management of the risks associated with Gambierdiscus proliferation...
January 2018: Harmful Algae
Wei Chen, Ricardo Colon, J William Louda, Freddy Rodriguez Del Rey, Michaella Durham, Kathleen S Rein
The Florida red tide dinoflagellate, Karenia brevis, is the major harmful algal bloom dinoflagellate of the Gulf of Mexico and plays a destructive role in the region. Blooms of K. brevis can produce brevetoxins: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, such as reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The endogenous role of the brevetoxins remains uncertain. Recent work has shown that some forms of NADPH dependent thioredoxin reductase (NTR) are inhibited by brevetoxin-2 (PbTx-2)...
January 2018: Harmful Algae
María Ángeles Lezcano, Antonio Quesada, Rehab El-Shehawy
Massive proliferations of cyanobacteria coexist and have different interactions with other microorganisms, including microcystin (MC)-degrading bacteria. Despite their relevance in the environment for the removal of MCs, this bacterial community has been scarcely studied. The influence of physicochemical factors and the seasonal dynamics of toxic cyanobacteria on the relative abundance and seasonal dynamics of the MC-degrading bacterial community with mlr genes (mlr+) were investigated during a two-year study at a water reservoir in central Spain...
January 2018: Harmful Algae
Juliana Dos Santos Severiano, Viviane Lúcia Dos Santos Almeida-Melo, Maria do Carmo Bittencourt-Oliveira, Mathias Ahii Chia, Ariadne do Nascimento Moura
Zooplankton are important biocontrol agents for algal blooms in temperate lakes, while their potential in tropical and subtropical environments is not well understood. The aim of the present study was to evaluate the influence of increased zooplankton biomass on phytoplankton community and cyanotoxins (microcystins and saxitoxin) content of a tropical reservoir (Ipojuca reservoir, Brazil) using in situ mesocosms. Mesocosms consisted of 50L transparent polyethylene bags suspended in the reservoir for twelve days...
January 2018: Harmful Algae
Reynaldo Patiño, Rakib H Rashel, Amede Rubio, Scott Longing
This study examined the ability of acidic and neutral/alkaline fractions of a methanolic extract from giant reed (Arundo donax) and of two of its constituents, gramine and skatole, to inhibit growth of the ichthyotoxic golden alga (Prymnesium parvum) in batch culture. For this study, growth suppression was defined as inhibition of maximum cell density, algicidal activity as early occurrence of negative growth, and algistatic activity as lack of net growth. The acidic fraction did not affect algal growth. The neutral/alkaline fraction showed growth-suppressing and algicidal activities but no signs of algistatic activity - namely, cells in cultures surviving a partial-algicidal exposure concentration (causing transient negative growth) were later able to initiate positive growth but at higher concentrations, algicidal activity was full and irreversible...
January 2018: Harmful Algae
Alexander K Leynse, Michael L Parsons, Serge E Thomas
In culture, Gambierdiscus spp. have been shown to prefer irradiances that are relatively low (≤250μmol photonsm(-2)s(-1)) versus those to which they are frequently exposed to in their natural environment (>500μmol photonsm(-2)s(-1)). Although several behavioral strategies for coping with such irradiances have been suggested, it is unclear as to how these dinoflagellates do so on a physiological level. More specifically, how do long term exposures (30days) affect cell size and cellular chlorophyll content, and what is the photosynthetic response to short term, high irradiance exposures (up to 1464μmol photonsm(-2)s(-1))? The results of this study reveal that cell size and chlorophyll content exhibited by G...
December 2017: Harmful Algae
Silvia M Nascimento, M Cristina Q Mendes, Mariângela Menezes, Francisco Rodríguez, Catharina Alves-de-Souza, Suema Branco, Pilar Riobó, José Franco, José Marcos C Nunes, Mariusz Huk, Steven Morris, Santiago Fraga
A new species of toxic benthic dinoflagellate is described based on laboratory cultures isolated from two locations from Brazil, Rio de Janeiro and Bahia. The morphology was studied with SEM and LM. Cells are elliptical in right thecal view and flat. They are 37-44μm long and 29-36μm wide. The right thecal plate has a V shaped indentation where six platelets can be identified. The thecal surface of both thecal plates is smooth and has round or kidney shaped and uniformly distributed pores except in the central area of the cell, and a line of marginal pores...
December 2017: Harmful Algae
Shuya Liu, Zhiming Yu, Xiuxian Song, Xihua Cao
Among the strategies for treating harmful algal blooms, flocculation using modified clay (MC) has been widely applied in the field. This paper studied the mitigation of MC on Amphidinium carterae Hulburt, finding that MC could not only effectively remove A. carterae, but also affect the physiological activities of the residual algae and inhibit their normal growth. The superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content of the residual algae significantly increased compared with the control, indicating that MC stimulated the accumulation of reactive oxygen species (ROS) in algal cells...
December 2017: Harmful Algae
Winnie Lik Sing Lau, Ing Kuo Law, Guat Ru Liow, Kieng Soon Hii, Gires Usup, Po Teen Lim, Chui Pin Leaw
In 2015, a remarkably high density bloom of Alexandrium minutum occurred in Sungai Geting, a semi-enclosed lagoon situated in the northeast of Peninsular Malaysia, causing severe discoloration and contaminated the benthic clams (Polymesoda). Plankton and water samples were collected to investigate the mechanisms of bloom development of this toxic species. Analysis of bloom samples using flow cytometry indicated that the bloom was initiated by the process of active excystment, as planomycetes (>4C cells) were observed in the early stage of the bloom...
December 2017: Harmful Algae
Holly A Bowers, Roman Marin, James M Birch, Christopher A Scholin
New sandwich hybridization assay (SHA) probes for detecting Pseudo-nitzschia species (P. arenysensis, P. fraudulenta, P. hasleana, P. pungens) are presented, along with updated cross-reactivity information on historical probes (SHA and FISH; fluorescence in situ hybridization) targeting P. australis and P. multiseries. Pseudo-nitzschia species are a cosmopolitan group of diatoms that produce varying levels of domoic acid (DA), a neurotoxin that can accumulate in finfish and shellfish and transfer throughout the food web...
December 2017: Harmful Algae
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