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Harmful Algae

Yeong Du Yoo, Kyeong Ah Seong, Hyung Seop Kim, Hae Jin Jeong, Eun Young Yoon, Jaeyeon Park, Jong Im Kim, Woongghi Shin, Brian Palenik
The phototrophic euglenophyte Eutreptiella eupharyngea often causes blooms in the coastal waters of many countries, but its mode of nutrition has not been assessed. This species has previously been considered as exclusively auxotrophic. To explore whether E. eupharyngea is a mixotrophic species, the protoplasm of E. eupharyngea cells were examined using light, epifluorescence, and transmission electron microscopy after eubacteria, the cyanobacterium Synechococcus sp., and diverse algal species were provided as potential prey...
March 2018: Harmful Algae
Justin D Chaffin, Timothy W Davis, Derek J Smith, Mikayla M Baer, Gregory J Dick
The toxin-producing, bloom-forming cyanobacterial genera Microcystis and Planktothrix require fixed nitrogen (N), such as nitrate, ammonium, or organic N (e.g., urea) for growth and production of microcystins (MC). Bioavailable N can enter lakes in pulses via tributary discharge and through in-lake recycling, which can maintain low N concentrations. Additionally, light intensity has been suggested to play a role in MC production. This study examined how three forms of N (nitrate, ammonium, and urea) interacted with N loading rate (one large pulse vs...
March 2018: Harmful Algae
Jin Ho Kim, Pengbin Wang, Bum Soo Park, Joo-Hwan Kim, Shailesh Kumar Patidar, Myung-Soo Han
Genetic sub-populations (clades) of cosmopolitan marine diatom Pseudo-nitzschia pungens might have distinct habitats, and their hybrid zone is suspected in higher latitude area of the West Pacific area, however, it is still unrevealed because of technical difficulties and lack of evidences in natural environments. The aim of this study is to investigate the habitat characteristics of each clade of P. pungens on geographical distribution with the habitat temperature ranges of each clade and to reveal their hybrid zone in the West Pacific area...
March 2018: Harmful Algae
Charlotte Duval, Solène Thomazeau, Yannick Drelin, Claude Yéprémian, Marc Bouvy, Arnaud Couloux, Marc Troussellier, Florence Rousseau, Cécile Bernard
Phylogenetic relationships among heterocytous genera (the Nostocales order) have been profoundly modified since the use of polyphasic approaches that include molecular data. There is nonetheless still ample scope for improving phylogenetic delineations of genera with broad ecological distributions, particularly by integrating specimens from specific or up-to-now poorly sampled habitats. In this context, we studied 36 new isolates belonging to Chrysosporum, Dolichospermum, Anabaena, Anabaenopsis, and Cylindrospermopsis from freshwater ecosystems of Burkina-Faso, Senegal, and Mayotte Island...
March 2018: Harmful Algae
Rosa Isabel Figueroa, Marta Estrada, Esther Garcés
In coastal and offshore waters, Harmful Algal Blooms (HABs) currently threaten the well-being of coastal countries. These events, which can be localized or involve wide-ranging areas, pose risks to human health, marine ecosystems, and economic resources, such as tourism, fisheries, and aquaculture. Dynamics of HABs vary from one site to another, depending on the hydrographic and ecological conditions. The challenge in investigating HABs is that they are caused by organisms from multiple algal classes, each with its own unique features, including different life histories...
March 2018: Harmful Algae
Nathan S Hall, R Wayne Litaker, W Judson Kenworthy, Mark W Vandersea, William G Sunda, James P Reid, Daniel H Slone, Susan Butler
A brown tide bloom of Aureoumbra lagunensis developed in Guantánamo Bay, Cuba during a period of drought in 2013 that followed heavy winds and rainfall from Hurricane Sandy in late October 2012. Based on satellite images and water turbidity measurements, the bloom appeared to initiate in January 2013. The causative species (A. lagunensis) was confirmed by microscopic observation, and pigment and genetic analyses of bloom samples collected on May 28 of that year. During that time, A. lagunensis reached concentrations of 900,000 cells ml-1 (28 ppm by biovolume) in the middle portion of the Bay...
March 2018: Harmful Algae
Anusuya Willis, Jason N Woodhouse, Sarah E Ongley, Aaron R Jex, Michele A Burford, Brett A Neilan
Cyanobacteria form harmful algal blooms and are highly adapted to a range of habitats, in part due to their phenotype plasticity. This plasticity is partially the result of co-existence of multiple strains within a single population. The toxic cyanobacterium Cylindrospermopsis raciborskii has remarkable phenotypic plasticity, strain variation and environmental adaptation resulting in an expansion of its global range. To understand the genetic basis of the high level of plasticity within a C. raciborskii population, the genomes of nine co-occurring strains were compared...
March 2018: Harmful Algae
Fabiano Alcísio E Silva, Alessandra Giani
Aquatic ecosystems have been severely altered by invasive species and a connection has been observed between bivalve invasions and an increase in frequency of cyanobacteria toxic blooms. In South America, the invasive golden mussel, Limnoperna fortunei, has caused serious environmental and economic impacts, because of its high filtration rates, high population densities and rapid dispersion. Changes in the plankton community have been detected at sites invaded by this species. The aim of the present study was to investigate the possible effects of this mussel on the growth of the bloom-forming cyanobacterium Microcystis aeruginosa, in laboratory experiments under controlled light and temperature conditions...
March 2018: Harmful Algae
Melissa B Peacock, Corinne M Gibble, David B Senn, James E Cloern, Raphael M Kudela
San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic organisms that are responsible for harmful algal blooms. While there are few commercial fishery harvests within SFB, recreational and subsistence harvesting for shellfish is common. Coastal shellfish are monitored for domoic acid and paralytic shellfish toxins (PSTs), but within SFB there is no routine monitoring for either toxin. Dinophysis shellfish toxins (DSTs) and freshwater microcystins are also present within SFB, but not routinely monitored...
March 2018: Harmful Algae
Jae Hoon Noh, Wonkook Kim, Seung Hyun Son, Jae-Hyun Ahn, Young-Je Park
Accurate and timely quantification of widespread harmful algal bloom (HAB) distribution is crucial to respond to the natural disaster, minimize the damage, and assess the environmental impact of the event. Although various remote sensing-based quantification approaches have been proposed for HAB since the advent of the ocean color satellite sensor, there have been no algorithms that were validated with in-situ quantitative measurements for the red tide occurring in the Korean seas. Furthermore, since the geostationary ocean color imager (GOCI) became available in June 2010, an algorithm that exploits its unprecedented observation frequency (every hour during the daytime) has been highly demanded to better track the changes in spatial distribution of red tide...
March 2018: Harmful Algae
Regina L Radan, William P Cochlan
The toxigenic diatom Pseudo-nitzschia multiseries Hasle, isolated from the U.S. Pacific Northwest, was examined in unialgal laboratory cultures and in natural assemblages during shipboard experiments, to examine cellular growth and domoic acid (DA) production as a function of nitrogen (N) substrate and availability expected during bloom development and decline. Laboratory experiments utilizing batch cultures conducted at saturating (120 μmol photons m-2  s-1 ) photosynthetic photon flux density (PPFD), demonstrated that P...
March 2018: Harmful Algae
Leila Basti, Toshiyuki Suzuki, Hajime Uchida, Takashi Kamiyama, Satoshi Nagai
Species of the harmful algal bloom (HAB) genera Dinophysis are causative of one of the most widespread and expanding HAB events associated with the human intoxication, diarrheic shellfish poisoning (DSP). The effects of warming temperature on the physiology and toxinology of these mixotrophic species remain intractable due to their low biomass in nature and difficulties in establishing and maintaining them in culture. Hence, the present study investigated the influence of warming temperature, encompassing present and predicted climate scenarios, on growth and toxin production in a strain of the most cosmopolitan DSP-causative species, Dinophysis acuminata...
March 2018: Harmful Algae
Chih-Hsien Michelle Lin, Vyacheslav Lyubchich, Patricia M Glibert
The harmful dinoflagellate, Karlodnium veneficum, has been implicated in fish-kill and other toxic, harmful algal bloom (HAB) events in waters worldwide. Blooms of K. veneficum are known to be related to coastal nutrient enrichment but the relationship is complex because this HAB taxon relies not only on dissolved nutrients but also particulate prey, both of which have also changed over time. Here, applying cross-correlations of climate-related physical factors, nutrients and prey, with abundance of K. veneficum over a 10-year (2002-2011) period, a synthesis of the interactive effects of multiple factors on this species was developed for Chesapeake Bay, where blooms of the HAB have been increasing...
March 2018: Harmful Algae
Chunyun Zhang, Yuanyuan Wang, Changlu Guo, Guofu Chen, Guangfeng Kan, Panpan Cai, Jin Zhou
The fish-killing alga Heterosigma akashiwo is a globally distributed, toxic, and bloom-forming raphidophyte that has caused great losses to the fishing industry in many coastal countries. Therefore, rapid and sensitive detection methods should be developed to present timely warning of harmful algal blooms. In this study, hyperbranched rolling circle amplification (HRCA) was established for the detection of H. akashiwo and compared with loop-mediated isothermal amplification (LAMP) in terms of specificity and sensitivity...
March 2018: 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
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