scholarly journals Toxic Characteristics and Action Mode of the Mixotrophic Dinoflagellate Akashiwo sanguinea on Co-Occurring Phytoplankton and Zooplankton

2021 ◽  
Vol 19 (1) ◽  
pp. 404
Author(s):  
Xiaoer Wu ◽  
Ying Yang ◽  
Yeyin Yang ◽  
Ping Zhong ◽  
Ning Xu
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Brachionus Plicatilis ◽  
River Estuary ◽  
Lethal Effect ◽  
Inhibitory Effect ◽  
Toxic Effects ◽  
Action Mode ◽  
Rotifer Brachionus Plicatilis ◽  
Akashiwo Sanguinea

The mixotrophic dinoflagellate Akashiwo sanguinea frequently forms harmful algal blooms around the world and has caused massive deaths of shellfish, finfish and birds, yet its toxic mechanism is still unclear. In this study, toxic effects of A. sanguinea on co-culturing phytoplankton and zooplankton were investigated. The results showed that sonicated cultures of A. sanguinea JX13 and JX14, isolated from the Pearl River Estuary, had a significant lethal effect on the rotifer Brachionus plicatilis, with the highest mortality rate of 80%. The highest inhibition rates of A. sanguinea cultures JX13 (90%) and JX14 (80%) on R. salina were much higher than that of AS2 (20%). Toxicity varied with the growth stage, during which A. sanguinea cells in the exponential stage showed the highest toxicity (40%), while A. sanguinea filtrate had the highest toxicity (10%) in the decline stage. The action mode of A. sanguinea toxicity on plankton was explored through an osmotic membrane culture device. It was found that A. sanguinea JX13 displayed an inhibitory effect on coexisting phytoplankton, whether they had contact or not, but the inhibition rate increased by 25% with contact. A lethal effect of A. sanguinea JX13 on rotifer Brachionus plicatilis was observed only in contact treatment. This study suggests that direct contact is the key action mode to trigger the release of toxins and induce toxic effects of A. sanguinea on co-occurring plankton.

scholarly journals Algicidal Activity of Novel Indigenous Bacterial Strain, Paracoccus Sp., Against Harmful Algal Bloom Species, Karenia Mikimotoi

2021 ◽  
Author(s):  
Ning Ding ◽  
Wenjun Du ◽  
Yanlou Feng ◽  
Yuhao Song ◽  
Chao Wang ◽  
...  
Keyword(s):  
Bacterial Strain ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Growth Conditions ◽  
Inhibitory Effect ◽  
Algicidal Bacteria ◽  
Rrna Gene ◽  
Negative Effects ◽  
Karenia Mikimotoi

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.

scholarly journals Transport Processes in the Gulf of Mexico Along the River-Estuary-Shelf-Ocean Continuum: a Review of Research from the Gulf of Mexico Research Initiative

2021 ◽  
Author(s):  
Dubravko Justić ◽  
Villy Kourafalou ◽  
Giulio Mariotti ◽  
Songjie He ◽  
Robert Weisberg ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
River Estuary ◽  
Deep Ocean ◽  
Open Ocean ◽  
Transport Processes ◽  
Spatial And Temporal Scales ◽  
Research Initiative ◽  
New Findings

AbstractEstuarine and coastal geomorphology, biogeochemistry, water quality, and coastal food webs in river-dominated shelves of the Gulf of Mexico (GoM) are modulated by transport processes associated with river inputs, winds, waves, tides, and deep-ocean/continental shelf interactions. For instance, transport processes control the fate of river-borne sediments, which in turn affect coastal land loss. Similarly, transport of freshwater, nutrients, and carbon control the dynamics of eutrophication, hypoxia, harmful algal blooms, and coastal acidification. Further, freshwater inflow transports pesticides, herbicides, heavy metals, and oil into receiving estuaries and coastal systems. Lastly, transport processes along the continuum from the rivers and estuaries to coastal and shelf areas and adjacent open ocean (abbreviated herein as “river-estuary-shelf-ocean”) regulate the movements of organisms, including the spatial distributions of individuals and the exchange of genetic information between distinct subpopulations. The Gulf of Mexico Research Initiative (GoMRI) provided unprecedented opportunities to study transport processes along the river-estuary-shelf-ocean continuum in the GoM. The understanding of transport at multiple spatial and temporal scales in this topographically and dynamically complex marginal sea was improved, allowing for more accurate forecasting of the fate of oil and other constituents. For this review, we focus on five specific transport themes: (i) wetland, estuary, and shelf exchanges; (ii) river-estuary coupling; (iii) nearshore and inlet processes; (iv) open ocean transport processes; and (v) river-induced fronts and cross-basin transport. We then discuss the relevancy of GoMRI findings on the transport processes for ecological connectivity and oil transport and fate. We also examine the implications of new findings for informing the response to future oil spills, and the management of coastal resources and ecosystems. Lastly, we summarize the research gaps identified in the many studies and offer recommendations for continuing the momentum of the research provided by the GoMRI effort. A number of uncertainties were identified that occurred in multiple settings. These include the quantification of sediment, carbon, dissolved gasses and nutrient fluxes during storms, consistent specification of the various external forcings used in analyses, methods for smooth integration of multiscale advection mechanisms across different flow regimes, dynamic coupling of the atmosphere with sub-mesoscale and mesoscale phenomena, and methods for simulating finer-scale dynamics over long time periods. Addressing these uncertainties would allow the scientific community to be better prepared to predict the fate of hydrocarbons and their impacts to the coastal ocean, rivers, and marshes in the event of another spill in the GoM.

scholarly journals Dynamic bacterial community response to Akashiwo sanguinea (Dinophyceae) bloom in indoor marine microcosms

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seung Won Jung ◽  
Junsu Kang ◽  
Joon Sang Park ◽  
Hyoung Min Joo ◽  
Sung-Suk Suh ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Community Response ◽  
Ecological Interactions ◽  
Bacterial Composition ◽  
Group I ◽  
Similarity Group ◽  
Akashiwo Sanguinea ◽  
Generation Sequencing

AbstractWe investigated the dynamics of the bacterial composition and metabolic function within Akashiwo sanguinea bloom using a 100-L indoor microcosm and metagenomic next-generation sequencing. We found that the bacterial community was classified into three groups at 54% similarity. Group I was associated with “during the A. sanguinea bloom stage” and mainly consisted of Alphaproteobacteria, Flavobacteriia and Gammaproteobacteria. Meanwhile, groups II and III were associated with the “late bloom/decline stage to post-bloom stage” with decreased Flavobacteriia and Gammaproteobacteria in these stages. Upon the termination of the A. sanguinea bloom, the concentrations of inorganic nutrients (particularly PO43−, NH4+ and dissolved organic carbon) increased rapidly and then decreased. From the network analysis, we found that the A. sanguinea node is associated with certain bacteria. After the bloom, the specific increases in NH4+ and PO43− nodes are associated with other bacterial taxa. The changes in the functional groups of the bacterial community from chemoheterotrophy to nitrogen association metabolisms were consistent with the environmental impacts during and after A. sanguinea bloom. Consequently, certain bacterial communities and the environments dynamically changed during and after harmful algal blooms and a rapid turnover within the bacterial community and their function can respond to ecological interactions.

Evaluating the toxic effects of three priority hazardous and noxious substances (HNS) to rotifer Brachionus plicatilis

2017 ◽  
Vol 24 (35) ◽  
pp. 27277-27287 ◽  
Author(s):  
Lei Zheng ◽  
Luqing Pan ◽  
Pengfei Lin ◽  
Jingjing Miao ◽  
Xiufen Wang ◽  
...  
Keyword(s):  
Brachionus Plicatilis ◽  
Toxic Effects ◽  
Rotifer Brachionus Plicatilis ◽  
Noxious Substances

scholarly journals Abundant Allelochemicals and the Inhibitory Mechanism of the Phenolic Acids in Water Dropwort for the Control of Microcystis aeruginosa Blooms

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2653
Author(s):  
Jixiang Liu ◽  
Yajun Chang ◽  
Linhe Sun ◽  
Fengfeng Du ◽  
Jian Cui ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Phenolic Acids ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Inhibitory Effect ◽  
Simultaneous Action ◽  
Inhibitory Effects ◽  
Chl A ◽  
Ferulic Acids ◽  
Water Dropwort

In recent years, with the frequent global occurrence of harmful algal blooms, the use of plant allelopathy to control algal blooms has attracted special and wide attention. This study validates the possibility of turning water dropwort into a biological resource to inhibit the growth of harmful Microcystis aeruginosa blooms via allelopathy. The results revealed that there were 33 types of allelopathic compounds in the water dropwort culture water, of which 15 were phenolic acids. Regarding water dropwort itself, 18 phenolic acids were discovered in all the organs of water dropwort via a targeted metabolomics analysis; they were found to be mainly synthesized in the leaves and then transported to the roots and then ultimately released into culture water where they inhibited M. aeruginosa growth. Next, three types of phenolic acids synthesized in water dropwort, i.e., benzoic, salicylic, and ferulic acids, were selected to clarify their inhibitory effects on the growth of M. aeruginosa and their mechanism(s) of action. It was found that the inhibitory effect of phenolic acids on the growth of M. aeruginosa increased with the increase of the exposure concentration, although the algae cells were more sensitive to benzoic acid than to salicylic and ferulic acids. Further study indicated that the inhibitory effects of the three phenolic acids on the growth of M. aeruginosa were largely due to the simultaneous action of reducing the number of cells, damaging the integrity of the cell membrane, inhibiting chlorophyll a (Chl-a) synthesis, decreasing the values of F0 and Fv/Fm, and increasing the activity of the antioxidant enzymes (SOD, POD, and CAT) of M. aeruginosa. Thus, the results of this study indicate that both culture water including the rich allelochemicals in water dropwort and biological algae inhibitors made from water dropwort could be used to control the growth of noxious algae in the future.

scholarly journals Zooming in on dynamics of marine microbial communities in the phycosphere of Akashiwo sanguinea (Dinophyta) blooms

2020 ◽  
Author(s):  
Seung Won Jung ◽  
Joonsang Park ◽  
Junsoo Kang ◽  
Hyun-Jung Kim ◽  
Hyung Min Joo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Microbial Communities ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Close Association ◽  
Time Lag ◽  
Inorganic Phosphorus ◽  
Dna Viruses ◽  
Akashiwo Sanguinea ◽  
Nucleocytoplasmic Large Dna Viruses

Abstract Background: Characterising ecological relationships between viruses, bacteria, and phytoplankton in the ocean are critical to understanding the ecosystem, yet these relationships are infrequently investigated together. To understand the dynamics of microbial communities and environmental factors in harmful algal blooms (HABs), we examined the environmental factors and microbial communities during Akashiwo sanguinea HABs in the Jangmok coastal waters of South Korea by metagenomics. Results: Specific bacterial communities showed synergistic and antagonistic relationships with A. sanguinea bloom. Endoparasitic dinoflagellate Amoebophrya sp. 1 controlled the bloom dynamics, as an increase in their abundance was correlated with HAB decline. In the nucleocytoplasmic large DNA viruses, abundance of Pandoraviridae increased following an increase in HAB. Operational taxonomic units and environmental factors associated with A. sanguinea were also visualized by network analysis: A. sanguinea-Amoebophrya sp. 1 (r=0.81, Time-lag: 2 day) and A. sanguinea-Pandoravirus dulcis (0.64, 0 day) relationships showed close association. A. sanguinea-dissolved organic carbon and -dissolved inorganic phosphorus relationships were also very closely correlated (each 0 day time-lag, respectively). Conclusions: Microbial communities and the environment dynamically and complexly changed in A. sanguinea bloom, and a rapid turnover of microorganisms could respond to ecological interactions. A. sanguinea bloom dramatically changes the environments through their exudation of dissolved carbohydrates by autotrophic processes, followed by changes in microbial communities involving host-specific viruses, bacteria, and parasitoids. Thus, microbial communities in HAB ecology are composed of various organisms and they interact in a complex way. Therefore, to interpret their ecosystem, the complex reactions among various microorganisms should be studied rather than studying a simple 1:1 reaction, such as a prey-predator interaction.

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