scholarly journals Identification and Monitoring of Microalgal Genera Potentially Capable of Forming Harmful Algal Blooms in Punta Galeta, Panama

2019 ◽  
Vol 12 ◽  
pp. 117862211987276 ◽  
Author(s):  
Alexander González ◽  
Kathia Broce ◽  
José Fábrega-Duque ◽  
Nathalia Tejedor-Flores ◽  
Karen Young

Coastal areas are attractive for human settlements because they allow easy access to benefits like food, security, and fishing. These aquatic ecosystems are supported by photosynthetic organisms that constitute the base of the food web. The term “Harmful Algal Bloom” (HAB) refers to the excessive proliferation of some taxa of these microorganisms reaching harmful levels to humans and other organisms. Biotoxins produced by these HABs could be transferred to the food chain and are the best-documented impact that HABs have on humans. The location and abundance of the HAB species producing the toxin is a good indicator of a possible human health hazard. The aim of this study was to monitor potentially harmful benthic/epibenthic microalgae in Punta Galeta, Panama over a 15-month period. The 3 main microalgae found were 2 dinoflagellates from the genera Prorocentrum and Ostreopsis and 1 diatom from the genus Coscinodiscus. Sampling made with both natural and artificial substrates yielded similar overall abundance patterns; however, for the macroalgae samples, there appeared to be significant host preferences for Ostreopsis and Coscinodiscus. Physicochemical measures taken at the site were found to fall within previously reported growth parameters for the microalgae found in the study.

Author(s):  
Xiaoying Zhu ◽  
Shuangshuang Chen ◽  
Guiying Luo ◽  
Wei Zheng ◽  
Yun Tian ◽  
...  

P. globosa is one of the most notorious harmful algal bloom (HAB)-causing species, which can secrete hemolytic toxins, frequently cause serious ecological pollution, and pose a health hazard to animals and humans. Hence, screening for bacteria with high algicidal activity against P. globosa and studies on the algicidal characteristics and mechanism will contribute to providing an ecofriendly microorganism-controlling agent for preventing the occurrence of algal blooms and reducing the harm of algal blooms to the environment.


2008 ◽  
Vol 42 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Casey Moore

Over the past ten years, efforts to characterize the optical properties of Earth's natural waters have largely merged with the need to better understand underlying biological and chemical processes. Fundamental optical properties such as light level, absorption, scattering and fluorescence are now being utilized with increasing effectiveness to specify particulate and dissolved in-water components in a wide range of applications, including detection of harmful algal blooms, studying ecosystem dynamics, monitoring the effect of industrial and agricultural pollutants, and understanding carbon sequestration processes in the oceans. A diverse offering of commercial optical sensing products capable for research, routine measurements, and in some cases, operational monitoring are now available. These technologies have provided the scientific community with a set of tools for developing, testing, and placing into practice analytical and semi-analytical methods to infer specific biogeochemical parameters and processes. As a result, new, more specialized sensors are now emerging. New sensors couple basic optical property measurements with processing algorithms to provide specific indicators for Harmful Algal Bloom (HAB) identification, carbon products, nutrients, and particle size distributions. The basic measurement methods are described and examples of devices incorporating them are provided to illustrate their use in modern oceanographic research and monitoring.


Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 407 ◽  
Author(s):  
John R. Harley ◽  
Kari Lanphier ◽  
Esther G. Kennedy ◽  
Tod A. Leighfield ◽  
Allison Bidlack ◽  
...  

Many communities in Southeast Alaska harvest shellfish such as mussels and clams as an important part of a subsistence or traditional diet. Harmful algal blooms (HABs) of phytoplankton such as Alexandrium spp. produce toxins that can accumulate in shellfish tissues to concentrations that can pose a hazard for human health. Since 2013, several tribal governments and communities have pooled resources to form the Southeast Alaska Tribal Ocean Research (SEATOR) network, with the goal of minimizing risks to seafood harvest and enhancing food security. SEATOR monitors toxin concentrations in shellfish and collects and consolidates data on environmental variables that may be important predictors of toxin levels such as sea surface temperature and salinity. Data from SEATOR are publicly available and are encouraged to be used for the development and testing of predictive algorithms that could improve seafood risk assessment in Southeast Alaska. To date, more than 1700 shellfish samples have been analyzed for paralytic shellfish toxins (PSTs) in more than 20 locations, with potentially lethal concentrations observed in blue mussels (Mytilus trossulus) and butter clams (Saxidomus gigantea). Concentrations of PSTs exhibit seasonality in some species, and observations of Alexandrium are correlated to sea surface temperature and salinity; however, concentrations above the threshold of concern have been found in all months, and substantial variation in concentrations of PSTs remain unexplained.


2019 ◽  
Vol 7 (9) ◽  
pp. 288 ◽  
Author(s):  
Bi ◽  
Wang ◽  
Zhang

Dinoflagellates are important primary producers for marine ecosystems and are also responsible for certain essential components in human foods. However, they are also notorious for their ability to form harmful algal blooms, and cause shellfish poisoning. Although much work has been devoted to dinoflagellates in recent decades, our understanding of them at a molecular level is still limited owing to some of their challenging biological properties, such as large genome size, permanently condensed liquid-crystalline chromosomes, and the 10-fold lower ratio of protein to DNA than other eukaryotic species. In recent years, omics technologies, such as genomics, transcriptomics, proteomics, and metabolomics, have been applied to the study of marine dinoflagellates and have uncovered many new physiological and metabolic characteristics of dinoflagellates. In this article, we review recent application of omics technologies in revealing some of the unusual features of dinoflagellate genomes and molecular mechanisms relevant to their biology, including the mechanism of harmful algal bloom formations, toxin biosynthesis, symbiosis, lipid biosynthesis, as well as species identification and evolution. We also discuss the challenges and provide prospective further study directions and applications of dinoflagellates.


2020 ◽  
Author(s):  
Peter W. Schafran ◽  
Victor Cai ◽  
Hsiao-Pei Yang ◽  
Fay-Wei Li

ABSTRACTWater bodies around the world are increasingly threatened by harmful algal blooms (HABs) under current trends of rising water temperature and nutrient load. Metagenomic characterization of HABs can be combined with water quality and environmental data to better understand and predict the occurrence of toxic events. However, standard short-read sequencing typically yields highly fragmented metagenomes, preventing direct connection of genes to a single genome. Using Oxford Nanopore long-read sequencing, we were able to obtain high quality metagenome-assembled genomes, and show that dominant organisms in a HAB are readily identified, though different analyses disagreed on the identity of rare taxa. Genes from diverse functional categories were found not only in the most dominant genera, but also in several less common ones. Using simulated datasets, we show that the Flongle flowcell may provide an option for HAB monitoring with less data, at the expense of failing to detect rarer organisms and increasing fragmentation of the metagenome. Based on these results, we believe that Nanopore sequencing provides a fast, portable, and affordable method for studying HABs.


2021 ◽  
Author(s):  
Ning Ding ◽  
Wenjun Du ◽  
Yanlou Feng ◽  
Yuhao Song ◽  
Chao Wang ◽  
...  

Abstract Harmful algal blooms have deleterious effects on aquatic ecosystems and human health. The application of algicidal bacteria is a promising and environmentally friendly method of preventing and eradicating harmful algal blooms. In this study, a screen for algicidal agents against harmful algal blooms was used to identify an algicidal bacterial strain isolated from a Karenia mikimotoi culture. Strain O-1 exhibited a strong inhibitory effect on harmful K. mikimotoi and was identified as a Paracoccus species via 16S rRNA gene sequence analysis. This strain killed K. mikimotoi by secreting active algicidal compounds, which were stable at temperatures of -80–121 °C, but these substances were sensitive to strongly acidic conditions. The algicidal properties of strain O-1 against K. mikimotoi were cell density- and time-dependent. No significant changes or negative effects were noted for two other Chlorophyta species, which highlighted the specificity of the studied algicidal substance. Finally, single-factor experiments revealed the optimum growth conditions of strain O-1 under different pH and temperature conditions. Strain O-1 therefore has potential as a bio-agent for reducing the biomass of harmful K. mikimotoi blooms.


2021 ◽  
Vol 49 (1) ◽  
pp. 110-124
Author(s):  
Victor A. Cervantes-Urieta ◽  
Ma. Nieves Trujillo-Tapia ◽  
Juan Violante-González ◽  
Giovanni Moreno-Díaz ◽  
Agustín A. Rojas-Herrera ◽  
...  

The phytoplankton community's temporal variability associated with environmental factors and harmful algal blooms in Acapulco Bay was analyzed. Phytoplankton samples were taken monthly at three sites (MSL: Morro de San Lorenzo, CDO: Casa Díaz Ordaz, and PP: Playa Palmitas) over 11 months in 2018. The physical and chemical variables of surface water were measured in situ, and the composition and community structure of phytoplankton were analyzed. The physical and chemical characteristics studied varied significantly. The highest temperatures were obtained in September and October (September: 29.6 ± 3.58°C, October: 34.61 ± 1.83°C), whereas the highest salinities and chlorophyll-a concentrations occurred from February to May (salinity: 34.06 ± 0.38, chlorophyll-a: 2.73 ± 0.15 μg L-1). The highest oxygen concentrations were recorded during the rainy season (June 91.8% and December 100%). A total of 201 phytoplankton species were identified: 94 diatoms, 101 dinoflagellates, 4 cyanobacteria, and 2 silicoflagellates. Diatoms dominated during the rainy season, whereas dinoflagellates dominated during the dry season (June to December). A total of 17 harmful species were identified; four toxin-producing species included a diatom genus (Pseudonitszchia sp.) and three dinoflagellate species (Gymnodinium catenatum, Dinophysis caudata, and Phalacroma rotundata). One species that produces oxygen reactive species and hemolysis (Margalefidinium polykrikoides) caused a harmful algal bloom at the CDO and PP stations. The temperature is one of the most critical factors for its bloom in October.


2022 ◽  
Author(s):  
Han Gao ◽  
Ze Zhao ◽  
Lu Zhang ◽  
Feng Ju

Cyanobacterial harmful algal blooms (CyanoHABs) are globally intensifying and exacerbated by climate change and eutrophication. However, microbiota assembly mechanisms underlying CyanoHABs remain scenario specific and elusive. Especially, cyanopeptides, as a group of bioactive secondary metabolites of cyanobacteria, could affect microbiota assembly and ecosystem function. Here, the trajectory of cyanopeptides were followed and linked to microbiota during Microcystis-dominated CyanoHABs in lake Taihu, China. The most abundant cyanopeptide classes detected included microginin, spumigin, microcystin, nodularin and cyanopeptolin with total MC-LR-equivalent concentrations between 0.23 and 2051.54 ppb, of which cyanotoxins beyond microcystins (e.g., cyanostatin B and nodularin_R etc.) far exceeded reported organismal IC50 and negatively correlated with microbiota diversity, exerting potential collective eco-toxicities stronger than microcystins alone. The microbial communities were differentiated by size fraction and sampling date throughout CyanoHABs, and surprisingly, their variances were better explained by cyanopeptides (19-38%) than nutrients (0-16%). Cyanopeptides restriction (e.g., inhibition) and degradation are first quantitatively verified as the deterministic drivers governing community assembly, with stochastic processes being mediated by interplay between cyanopeptide dynamics and lake microbiota. This study presents an emerging paradigm in which cyanopeptides restriction and degradation co-mediate lake water microbiota assembly, unveiling new insights about the ecotoxicological significance of CyanoHABs to freshwater ecosystems.


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