scholarly journals Promotion of harmful algal blooms by zooplankton predatory activity

2006 ◽  
Vol 2 (2) ◽  
pp. 194-197 ◽  
Author(s):  
Aditee Mitra ◽  
Kevin J Flynn
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Algal Species ◽  
Algal Growth ◽  
Nutrient Stress ◽  
Nutrient Ratios ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Hab Species

The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios.

Occurrence characteristics of harmful and non-harmful algal species related to coastal environments in the southern sea of Korea

2019 ◽  
Vol 70 (6) ◽  
pp. 794 ◽  
Author(s):  
Jin Ho Kim ◽  
Minji Lee ◽  
Young Kyun Lim ◽  
Yun Ji Kim ◽  
Seung Ho Baek
Keyword(s):  
South Korea ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phytoplankton Community ◽  
Algal Species ◽  
Coastal Environments ◽  
Survey Period ◽  
Offshore Area ◽  
Occurrence Characteristics ◽  
Hab Species

Because the phytoplankton community and blooms are regulated by various environmental factors, it is difficult to define the cause and occurrence of the phenomenon of harmful algal blooms (HABs). This study evaluated the phytoplankton community and occurrence characteristic of HAB species related to coastal environments in South Korea, 2016. In summer, because of strong upwelling event, the surface sweater temperature around Geoje Island was abnormally low (17°C), and an unusual high temperature (29°C) and low salinity (29psu) were measured in offshore area. Diatoms and dinoflagellates showed contrasting occurrences during the survey period. Diatoms were dominant in the inshore area, whereas dinoflagellates occurred in the offshore area. The phytoplankton-community structures were established depending on different hydro-oceanographic characteristics. In statistical analysis, HABs of dinoflagellate Karenia appeared in upwelling areas with a high nutritional content, whereas Gymnodinium, Gyrodinium and Prorocentrum appeared in areas of low nutrients in June, and HAB species showed an equivalent tendency to appear at high water temperature and low saline level in August. Our results indicated that hydro-oceanographic events such as river discharge, current and upwelling play important roles in determining the phytoplankton community and potential occurrence characteristics of HABs in the coastal environment of South Korea.

scholarly journals Spatiotemporal Distribution of Harmful Algal Flora in the Tropical Estuarine Complex of Goa, India

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Suraksha M. Pednekar ◽  
S. G. Prabhu Matondkar ◽  
Vijaya Kerkar
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Algal Species ◽  
Spatiotemporal Variability ◽  
Algal Flora ◽  
The Past ◽  
Tropical Estuarine ◽  
Mandovi And Zuari Estuaries ◽  
Hab Species

Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading.

scholarly journals Fiber-Optic Microarray for Simultaneous Detection of Multiple Harmful Algal Bloom Species

2006 ◽  
Vol 72 (9) ◽  
pp. 5742-5749 ◽  
Author(s):  
Soohyoun Ahn ◽  
David M. Kulis ◽  
Deana L. Erdner ◽  
Donald M. Anderson ◽  
David R. Walt
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Fiber Optic ◽  
Harmful Algal Bloom ◽  
Simultaneous Detection ◽  
Cross Reactivity ◽  
Detection Methods ◽  
Sandwich Hybridization ◽  
Field Samples ◽  
Hab Species

ABSTRACT Harmful algal blooms (HABs) are a serious threat to coastal resources, causing a variety of impacts on public health, regional economies, and ecosystems. Plankton analysis is a valuable component of many HAB monitoring and research programs, but the diversity of plankton poses a problem in discriminating toxic from nontoxic species using conventional detection methods. Here we describe a sensitive and specific sandwich hybridization assay that combines fiber-optic microarrays with oligonucleotide probes to detect and enumerate the HAB species Alexandrium fundyense, Alexandrium ostenfeldii, and Pseudo-nitzschia australis. Microarrays were prepared by loading oligonucleotide probe-coupled microspheres (diameter, 3 μm) onto the distal ends of chemically etched imaging fiber bundles. Hybridization of target rRNA from HAB cells to immobilized probes on the microspheres was visualized using Cy3-labeled secondary probes in a sandwich-type assay format. We applied these microarrays to the detection and enumeration of HAB cells in both cultured and field samples. Our study demonstrated a detection limit of approximately 5 cells for all three target organisms within 45 min, without a separate amplification step, in both sample types. We also developed a multiplexed microarray to detect the three HAB species simultaneously, which successfully detected the target organisms, alone and in combination, without cross-reactivity. Our study suggests that fiber-optic microarrays can be used for rapid and sensitive detection and potential enumeration of HAB species in the environment.

scholarly journals Bacilysin from Bacillus amyloliquefaciens FZB42 Has Specific Bactericidal Activity against Harmful Algal Bloom Species

2014 ◽  
Vol 80 (24) ◽  
pp. 7512-7520 ◽  
Author(s):  
Liming Wu ◽  
Huijun Wu ◽  
Lina Chen ◽  
Shanshan Xie ◽  
Haoyu Zang ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Bacillus Amyloliquefaciens ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Algal Cell ◽  
Algal Species ◽  
Inhibitory Effect ◽  
Cell Organelle ◽  
Content Type

ABSTRACTHarmful algal blooms, caused by massive and exceptional overgrowth of microalgae and cyanobacteria, are a serious environmental problem worldwide.In the present study, we looked forBacillusstrains with sufficiently strong anticyanobacterial activity to be used as biocontrol agents. Among 24 strains,Bacillus amyloliquefaciensFZB42 showed the strongest bactericidal activity againstMicrocystis aeruginosa, with a kill rate of 98.78%. The synthesis of the anticyanobacterial substance did not depend on Sfp, an enzyme that catalyzes a necessary processing step in the nonribosomal synthesis of lipopeptides and polyketides, but was associated with thearogene cluster that is involved in the synthesis of thesfp-independent antibiotic bacilysin. Disruption ofbacB, the gene in the cluster responsible for synthesizing bacilysin, or supplementation with the antagonistN-acetylglucosamine abolished the inhibitory effect, but this was restored when bacilysin synthesis was complemented. Bacilysin caused apparent changes in the algal cell wall and cell organelle membranes, and this resulted in cell lysis. Meanwhile, there was downregulated expression ofglmS,psbA1,mcyB, andftsZ—genes involved in peptidoglycan synthesis, photosynthesis, microcystin synthesis, and cell division, respectively. In addition, bacilysin suppressed the growth of other harmful algal species. In summary, bacilysin produced byB. amyloliquefaciensFZB42 has anticyanobacterial activity and thus could be developed as a biocontrol agent to mitigate the effects of harmful algal blooms.

scholarly journals Distribution of Harmful Algal Growth-Limiting Bacteria on Artificially Introduced Ulva and Natural Macroalgal Beds

2020 ◽  
Vol 10 (16) ◽  
pp. 5658
Author(s):  
Nobuharu Inaba ◽  
Isamu Kodama ◽  
Satoshi Nagai ◽  
Tomotaka Shiraishi ◽  
Kohei Matsuno ◽  
...  
Keyword(s):  
Biological Control ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Growth ◽  
Macroalgal Species ◽  
Chattonella Antiqua ◽  
Cultured Fish ◽  
Wet Weight ◽  
Artificial Introduction ◽  
Hab Species

The intensity and frequency of harmful algal blooms (HABs) have increased, posing a threat to human seafood resources due to massive kills of cultured fish and toxin contamination of bivalves. In recent years, bacteria that inhibit the growth of HAB species were found to be densely populated on the biofilms of some macroalgal species, indicating the possible biological control of HABs by the artificial introduction of macroalgal beds. In this study, an artificially created Ulva pertusa bed using mobile floating cages and a natural macroalgal bed were studied to elucidate the distribution of algal growth-limiting bacteria (GLB). The density of GLB affecting fish-killing raphidophyte Chattonella antiqua, and two harmful dinoflagellates, were detected between 106 and 107 CFU g−1 wet weight on the biofilm of artificially introduced U. pertusa and 10 to 102 CFU mL−1 from adjacent seawater; however, GLB found from natural macroalgal species targeted all tested HAB species (five species), ranging between 105 and 106 CFU g−1 wet weight in density. These findings provide new ecological insights of GLB at macroalgal beds, and concurrently demonstrate the possible biological control of HABs by artificially introduced Ulva beds.

Using Fundamental Optical Property Sensors for Characterization of Biogeochemical Materials and Processes in Marine Waters

2008 ◽  
Vol 42 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Casey Moore
Keyword(s):  
Optical Properties ◽  
Optical Property ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Natural Waters ◽  
Harmful Algal Bloom ◽  
Light Level ◽  
Ecosystem Dynamics ◽  
Wide Range ◽  
Biogeochemical Parameters

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.

scholarly journals The Southeast Alaska Tribal Ocean Research (SEATOR) Partnership: Addressing Data Gaps in Harmful Algal Bloom Monitoring and Shellfish Safety in Southeast Alaska

Toxins ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 407 ◽  
Author(s):  
John R. Harley ◽  
Kari Lanphier ◽  
Esther G. Kennedy ◽  
Tod A. Leighfield ◽  
Allison Bidlack ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Sea Surface ◽  
Southeast Alaska ◽  
Paralytic Shellfish Toxins ◽  
Tribal Governments ◽  
Salinity Data

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.

scholarly journals Omics Analysis for Dinoflagellates Biology Research

2019 ◽  
Vol 7 (9) ◽  
pp. 288 ◽  
Author(s):  
Bi ◽  
Wang ◽  
Zhang
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Liquid Crystalline ◽  
Molecular Mechanisms ◽  
Harmful Algal Bloom ◽  
Biological Properties ◽  
Shellfish Poisoning ◽  
Omics Technologies ◽  
Metabolic Characteristics ◽  
Essential Components

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.

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