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At least 19 recordsLinked to original sources

PubMed2006

Fiber-optic microarray for simultaneous detection of multiple harmful algal bloom species.

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 mum) 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.

Base Sequence↗

PubMed2003

[Research advance in effects of harmful algal bloom species on zooplankton].

The research on the effects of harmful algal bloom (HAB) algae on zooplankton has been drawn more and more attention. This paper summarized the adverse effects of HAB algae on zooplankton, which included reduced survival, inhibited growth, reduced fecundity of female, fertilization failure of eggs or hatching failure of zygote, inhibited embryo development, naupliar abnormal development or abnormality, inhibited grazing and changed behavior of zooplankton, etc. The main intoxication ways included decreased utilization of food, physiology impairment, damaged cell membrane, reduced gamete quality, and inhibited mitotic and embryo development by phycotoxins or exudations released by algae. Additionally, the lack of full nutrition, especially of polyunsaturated fatty acids in some algal species cells could also affect zooplankton growth and reproduction.

Animals↗

PubMed2004

Screening of surfactants for harmful algal blooms mitigation.

Screening experiments were conducted in order to find promising synthetic surfactants for harmful algal blooms (HABs) mitigation. The chemically synthesized surfactant cocamidopropyl betaine (CAPB) showed characteristics of relatively high inhibition efficiency, high biodegradability and low cost. The motility inhibition ratios of 10 mg/L CAPB on Cochlodinium polykrikoides and Alexandrium tamarense were about 60% after 5 min. The biodegradation test indicated that the half-life of CAPB in seawater was shorter than one day and 90% was biodegraded after five days under the initial concentration of 100 mg/L at 25 degrees C. Further cell lysis experiments revealed the selective lysis effect of CAPB on different HAB organisms. More than 90% of C. polykrikoides lysed at the concentration of 10 mg/L CAPB after 24 h and at 15 mg/L CAPB after 4 h, whereas the lysis effect of CAPB on A. tamarense was slight, no more than 10% after 2 h interaction with 50 mg/L CAPB. This research provided preliminary data for CAPB as a candidate in harmful algal blooms mitigation and pointed out unresolved problems for its practical application in the meantime.

Animals↗

PubMed2003

[Effects of terrestrial input on the harmful algal bloom area--with aluminum as an example].

In recent years, eutrophication and frequently occurred harmful algal blooms (HAB) become serious in the coastal area near Changjiang River estuary, and the nutrients came from Changjiang River may be the main sources for them. Aluminum could be used as a useful tracer for the terrestrial input and the movement of different water mass, since it enters into the natural water with the erosion products of soil and rock, and its residence time in the ocean is short and uneasy to be disturbed by the activities of human being. Based on our results, the concentration of dissolved Al was higher in Autumn than in Summer, and showed some relationships with the salinity and suspended particulate matter (SPM). The concentration of Al in the HAB area was higher than 0.04 mumol.L-1, which showed the significant influence from the terrestrial input. The concentration of dissolved Al decreased nearly 40% after the occurrence of HAB, and the flocculation of dissolved Al and its absorption onto the surfaces of biogenic particles might be the main reasons. There still need further study about the variation of Al forms and its mechanism during the occurrence of HAB.

Aluminum↗

PubMedDate not supplied

Controlling harmful algal blooms through clay flocculation.

The potential use of clays to control harmful algal blooms (HABs) has been explored in East Asia, Australia, the United States, and Sweden. In Japan and South Korea, minerals such as montmorillonite, kaolinite, and yellow loess, have already been used in the field effectively, to protect fish mariculture from Cochlodinium spp. and other blooms. Cell removal occurs through the flocculation of algal and mineral particles, leading to the formation of larger aggregates (i.e. marine snow), which rapidly settle and further entrain cells during their descent. In the U.S., several clays and clay-rich sediments have shown high removal abilities (e.g. > 80% cell removal efficiency) against Karenia brevis, Heterosigma akashiwo, Pfiesteria piscicida and Aureococcus anophagefferens. In some cases, the removal ability of certain clays was further enhanced with chemical flocculants, such as polyaluminum chloride (PAC), to increase their adhesiveness. However, cell removal was also affected by bloom concentration, salinity, and mixing. Cell mortality was observed after clay addition, and increased with increasing clay concentration, and prolonged exposure to clays in the settled layer. Mesocosm, field enclosure, and flume experiments were also conducted to address cell removal with increasing scale and flow, water-column impacts, and the possible benthic effects from clay addition. Results from these studies will be presented, especially those in regards to water quality, seawater chemistry, bottom erodibility and faunal impacts in the benthos. At this time, clay dispersal continues to be a promising method for controlling HABs and mitigating their impacts based on existing information and experimental data.

Aluminum Hydroxide↗

PubMed2025

Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.

Intraspecific biodiversity can have ecosystem-level consequences and may affect the accuracy of ecological forecasting. For example, rare genetic variants may have traits that prove beneficial under future environmental conditions. The cyanobacterium responsible for most freshwater harmful algal blooms worldwide, Microcystis aeruginosa, occurs in at least three types. While the dominant type occurs in eutrophic environments and is adapted to thrive in nutrient-rich conditions, two additional types have recently been discovered that inhabit oligotrophic and eutrophic environments and have genomic adaptations for survival under nutrient limitation. Here, we show that these oligotrophic types are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we found that the eutrophic type may be most susceptible to climate warming. In comparison, oligotrophic types maintained their growth better and persisted longer under warming. As a mechanistic explanation for these patterns, we found that oligotrophic types responded to warming by widespread elevated expression of heat shock protein genes. Reduction of nutrient loading has been a historically effective mitigation strategy for controlling harmful algal blooms. Our results suggest that climate warming may benefit oligotrophic types of M. aeruginosa, potentially reducing the effectiveness of such mitigation efforts. In-depth study of intraspecific variation may therefore improve forecasting for understanding future whole ecosystem dynamics.

Microcystis↗

PubMed2005

Use of two-dimensional gel electrophoresis to differentiate morphospecies of Alexandrium minutum, a paralytic shellfish poisoning toxin-producing dinoflagellate of harmful algal blooms.

Contamination of shellfish with paralytic shellfish poisoning toxins (PST) produced by toxic harmful algal blooms (HABs) have been negatively affecting the shellfish and aquaculture industries worldwide. Therefore, accurate and early identification of toxic phytoplankton species is crucial in HABs surveillance programs that allow fish-farmers to take appropriate preventive measures in shellfish harvesting and other aquaculture activities to overcome the negative impacts of HABs on human health. The identification of toxic dinoflagellates present in the water is currently a time-consuming operation since it requires skillful taxonomists and toxicologists equipped with optical and scanning electron microscopes as well as sophisticated equipment, for example, high-performance liquid chromotography-fluorescence detection. In this paper, a two-dimensional gel electrophoresis (2-DE)-based proteomic approach was applied to discriminate between toxic and nontoxic strains of Alexandrium minutum. Variation in morphological features between toxic and nontoxic strains was minimal and not significant. Also, variation in 2-DE protein patterns within either toxic or nontoxic strains was low, but pronounced differences were detected between toxic and nontoxic strains. The most notable differences between these strains were several abundant proteins with pIs ranging from 4.8 to 5.3 and apparent molecular masses between 17.5 and 21.5 kDa. Groups of proteins, namely NT1, NT2, NT3, and NT4, were consistently found in all nontoxic strains, while T1 and T2 were prominent in the toxic strains. These specific protein spots characteristic for toxic and nontoxic strains remained clearly distinguishable irrespective of the various growth conditions tested. Therefore, they have the potential to serve as "taxonomic markers" to distinguish toxic and nontoxic strains within A. minutum. Initial studies revealed that the expression pattern of T1 was tightly correlated to toxin biosynthesis in the examined alga and may be used to serve as a potential toxin indicator.

Amino Acid Sequence↗

PubMed2005

Characterization of different viruses infecting the marine harmful algal bloom species Phaeocystis globosa.

Twelve lytic viruses (PgV) infecting the marine unicellular eukaryotic harmful algal bloom species Phaeocystis globosa were isolated from the southern North Sea in 2000-2001 and partially characterized. All PgV isolates shared common phenotypic features with other algal viruses belonging to the family Phycodnaviridae and could be categorized in four different groups. Two main groups (PgV Group I and II) were discriminated based on particle size (150 and 100 nm respectively), genome size (466 and 177 kb) and structural protein composition. The lytic cycle showed a latent period of 10 h for PgV Group I and latent periods of 12 h and 16 h for PgV Group IIA and IIB. Host specificity and temperature sensitivity finally defined a fourth group (PgV Group IIC). Our results imply that viral infection plays an important role not only in P. globosa dynamics but also in the diversity of both host and virus community.

Eukaryota↗

PubMed2004

Synergistic effect of sophorolipid and loess combination in harmful algal blooms mitigation.

The inhibition effect of sophorolipid and removal efficiency of loess on Cochlodinium polykrikoides and Alexandrium tamarense was investigated separately in the laboratory. Based on this, the combination of sophorolipid and loess for harmful algal bloom mitigation was proposed. Algal sedimentation tests in the laboratory and in the field revealed that the combination of sophorolipid and loess showed synergistic effects both on the removal efficiencies and on the mitigation cost. The concentration of 1 g/l loess and 5 mg/l sophorolipid was determined as the optimum ratio for C. polykrikoides mitigation. In the field test, the effective concentration of loess and sophorolipid in the combination group was reduced to 10% and 25%, respectively, compared to the non-combination group, and the cost decreased more than 60%. The combination of loess and sophorolipid was considered as a promising novel method in harmful algal bloom mitigation.

Animals↗

PubMed2004

Application of 210Pb-derived sedimentation rates and dinoflagellate cyst analyses in understanding Pyrodinium bahamense harmful algal blooms in Manila Bay and Malampaya Sound, Philippines.

The number of areas affected by toxic harmful algal bloom (HAB) in the Philippines has been increasing since its first recorded occurrence in 1983. Thus far, HAB has been reported in about 20 areas in the Philippines including major fishery production areas. The HAB-causing organism (Pyrodinium bahamense var. compressum) produces a cyst during its life cycle. Pyrodinium cysts which are deposited in the sediment column may play a role in initiating a toxic bloom. 210Pb-derived sedimentation rate studies in the two important fishing grounds of Manila Bay and Malampaya Sound, Palawan have shown that Pyrodinium cysts may have been present in the sediment even before the first recorded toxic algal bloom in these areas. High sedimentation rates (approximately 1 cm/year) have been observed in the northern and western parts of Manila Bay. The results indicate that the sedimentation processes occurring in these bays would require subsurface cyst concentration analysis in evaluating the potential of an area to act as seed bed.

Animals↗

PubMed1998

Algicidal effects of a novel marine pseudoalteromonas isolate (class Proteobacteria, gamma subdivision) on harmful algal bloom species of the genera Chattonella, Gymnodinium, and Heterosigma.

During a bacterial survey of the Huon Estuary in southern Tasmania, Australia, we isolated a yellow-pigmented Pseudoalteromonas strain (class Proteobacteria, gamma subdivision), designated strain Y, that had potent algicidal effects on harmful algal bloom species. This organism was identified by 16S rRNA sequencing as a strain with close affinities to Pseudoalteromonas peptidysin. This bacterium caused rapid cell lysis and death (within 3 h) of gymnodinoids (including Gymnodinium catenatum) and raphidophytes (Chattonella marina and Heterosigma akashiwo). It caused ecdysis of armored dinoflagellates (e.g., Alexandrium catenella, Alexandrium minutum, and Prorocentrum mexicanum), but the algal cultures then recovered over the subsequent 24 h. Strain Y had no effect on a cryptomonad (Chroomonas sp.), a diatom (Skeletonema sp.), a cyanobacterium (Oscillatoria sp.), and two aplastidic protozoans. The algicidal principle of strain Y was excreted into the seawater medium and lost its efficacy after heating. Another common bacterial species, Pseudoalteromonas carrageenovora, was isolated at the same time and did not have these algicidal effects. The minimum concentrations of strain Y required to kill G. catenatum were higher than the mean concentrations found in nature under nonbloom conditions. However, the new bacterium showed a chemotactic, swarming behavior that resulted in localized high concentrations around target organisms. These observations imply that certain bacteria could play an important role in regulating the onset and development of harmful algal blooms.

Animals↗

PubMed2006

[Phytoplankton biomass and high frequency of Prorocentrum donghaiense harmful algal bloom in Zhoushan sea area in spring].

Based on the two cruises comprehensive survey on Prorocentrum donghaiense harmful algal bloom (HAB) in Zhoushan sea area in spring 2002 and 2003, this paper studied the distribution pattern of phytoplankton biomass and its relationships with environmental factors. As to the grid station, the mean Chla concentration in surface water layer in spring 2002 was 1.09 +/- 1.63 mg x m(-3), ranged from 0.25 to 9.08 mg x m(-3). While in spring 2003, the survey was conducted in the sea area with an isobath of 50 m, where the topography changed suddenly and HAB happened frequently, the mean Chla of surface water layer was 4.21 +/- 5.33 mg x m(-3), ranged from 0.44 to 24.32 mg x m(-1). The maximum phytoplankton biomass appeared at the Changjiang Diluted Water frontal zone between 122.5 degrees E and 123 degrees E, where had ample nutrients and good conditions for light penetration in the water column. During the tracking investigation, the Chla concentration in surface water layer in spring 2002 and 2003 was 18.45 +/- 11.04 mg x m(-3) and 12.47 +/- 8.15 mg x m(-3), respectively. By the tracking investigation of P. donghaiense HAB, four results were found: a) the optimum salinity was between 26 and 30, b) the large scale and long lasted HAB algae was limited by P, c) suitable light condition, nutrients enrichment and water column stabilization were the three important conditions for HAB, and d) the convergent zone in plume front enhanced the gathering of P. donghaiense.

Biomass↗

PubMed2026

Chromosome-level genome assembly of a cosmopolitan marine harmful algal bloom diatom species Chaetoceros socialis (Chaetocerotaceae).

Chaetoceros socialis is a cosmopolitan diatom species that is crucial for maintaining marine ecosystem structure and driving elemental cycles. C. socialis can form harmful algal blooms (HABs) that may cause a negative impact on the marine ecosystems. Whole-genome information for C. socialis is still unavailable, which may hinder more targeted studies on its ecological adaptive responses and evolutionary drivers. To address this gap, we employed cutting-edge genomic technologies including PacBio single-molecule real-time (SMRT) sequencing and high-throughput chromatin conformation capture (Hi-C) to achieve the first chromosome-level genome assembly of C. socialis. The assembled genome is 60.22 Mb in size with a scaffold N50 of 7.81 Mb and has been anchored to eight pseudochromosomes. A total of 13,378 protein-coding genes were predicted, of which 12,069 (90.22%) were functionally annotated. This high-quality genomic resource provides a fundamental data platform for systematically elucidating the ecological adaptation mechanisms of C. socialis.

Chromosomes↗

PubMedDate not supplied

Initial results from a multi-institutional collaboration to monitor harmful algal blooms in South Carolina.

The rapid rate of development in the South Carolina (SC) coastal zone has heightened public concern for the condition of the state's estuaries, and alerted scientists to the potential that novel and adverse effects on estuarine ecosystems may result. Although well-developed databases from long-term monitoring programs exist for many variables valuable in predicting and following system responses, information on phytoplankton distributions in SC estuaries has lagged. Knowledge of the dynamical relationship between environmental (e.g., nutrient quantity and quality) and biological (e.g., grazing) regulation, and phytoplankton biomass and composition is critical to understanding estuarine susceptibility to eutrophication or harmful algal blooms (HABs). Recently, SC scientists from federal, state, and academic institutions established a collaborative monitoring program to assess HAB distribution and ecology statewide. The South Carolina Harmful Algal Bloom Program includes: a) intensive temporal monitoring at areas of known HAB occurrence or those exhibiting symptoms potentially related to HABs (e.g., prevalent fish lesions), b) extensive spatial monitoring in coordination with existing statewide efforts, c) a citizen volunteer monitoring network, d) nutrient response bioassays, and e) laboratory-based physiological experiments on HAB isolates. By combining "trip-wire" surveillance and rapid response systems, routine monitoring of environmental parameters and HAB distribution, and process-oriented studies examining the physiological functioning of HAB species, an enhanced understanding of the impact and environmental control of HABs in SC estuaries will be achieved. The application of this approach to studies on the distribution and physiological ecology of a new widespread SC red tide, and to the discovery of several potentially toxic blooms (including Pfiesteria) in SC holding ponds, are described.

Biomass↗

PubMed2004

Environmental and health effects associated with Harmful Algal Bloom and marine algal toxins in China.

The frequency and scale of Harmful Algal Bloom (HAB) and marine algal toxin incidents have been increasing and spreading in the past two decades, causing damages to the marine environment and threatening human life through contaminated seafood. To better understand the effect of HAB and marine algal toxins on marine environment and human health in China, this paper overviews HAB occurrence and marine algal toxin incidents, as well as their environmental and health effects in this country. HAB has been increasing rapidly along the Chinese coast since the 1970s, and at least 512 documented HAB events have occurred from 1952 to 2002 in the Chinese mainland. It has been found that PSP and DSP toxins are distributed widely along both the northern and southern Chinese coasts. The HAB and marine algal toxin events during the 1990s in China were summarized, showing that the HAB and algal toxins resulted in great damages to local fisheries, marine culture, quality of marine environment, and human health. Therefore, to protect the coastal environment and human health, attention to HAB and marine algal toxins is urgently needed from the environmental and epidemiological view.

Amnesia↗

PubMedDate not supplied

A pilot project to detect and forecast harmful algal blooms in the northern Gulf of Mexico.

More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-driven, end-to-end (measurements to applications) observing system. A key strategy of the project is to coordinate existing state, federal and academic programs at an unprecedented level of collaboration and partnership. Resource managers charged with protection of public health and aquatic resources require immediate notice of algal events and a forecast of when, where and what adverse effects will likely occur. Further, managers require integrated analyses and interpretations, rather than raw data, to make effective decisions. Consequently, a functional observing system must collect and transform diverse measurements into usable forecasts. Data needed to support development of forecasts will include such properties as sea surface temperature, winds, currents and waves; precipitation and freshwater flows with related discharges of sediment and nutrients; salinity, dissolved oxygen, and chlorophyll concentrations (in vivo fluorescence); and remotely-sensed spatial images of sea surface chlorophyll concentrations. These data will be provided via a mixture of discrete and autonomous in situ sensing with near real-time data telemetry, and remote sensing from space (SeaWiFS), aircraft (hyperspectral imagery) or land (high-frequency radar). With calibration across these platforms, the project will ultimately provide a 4-dimensional visualization of harmful algae events in a time frame suitable to resource managers.

Aircraft↗

PubMed2005

Neurobehavioral effects of harmful algal bloom (HAB) toxins: a critical review.

Human exposure to naturally occurring marine toxins has been associated with a range of neurobehavioral abnormalities. The toxins are produced by harmful algal blooms (HABs) and are typically contracted through seafood consumption. The primary target of many of the HAB toxins is the neurologic system, and the neurobehavioral symptoms associated with the HAB illnesses have influenced public health policy. The HAB-related illnesses most frequently linked to neuropsychological disturbance are Amnesic Shellfish Poisoning, Ciguatera Fish Poisoning, and Possible Estuarine Associated Syndrome, which is associated with exposure to the Pfiesteria piscicida organism. Although the neurophysiologic mechanisms underlying many of the HAB illnesses have been well delineated, the literature examining the neuropsychological impairments is unclear and needs to be defined. This review is intended to introduce an emerging area of study linking HAB illnesses with neuropsychological changes.

Amnesia↗

PubMed2003

Harmful algal blooms: causes, impacts and detection.

Blooms of autotrophic algae and some heterotrophic protists are increasingly frequent in coastal waters around the world and are collectively grouped as harmful algal blooms (HABs). Blooms of these organisms are attributed to two primary factors: natural processes such as circulation, upwelling relaxation, and river flow; and, anthropogenic loadings leading to eutrophication. Unfortunately, the latter is commonly assumed to be the primary cause of all blooms, which is not the case in many instances. Moreover, although it is generally acknowledged that occurrences of these phenomena are increasing throughout the world's oceans, the reasons for this apparent increase remain debated and include not only eutrophication but increased observation efforts in coastal zones of the world. There is a rapidly advancing monitoring effort resulting from the perception of increased impacts from these HABs, manifested as expanding routine coastal monitoring programs, rapid development and deployment of new detection methods for individual species, toxins, and toxicities, and expansion of coastal modeling activities towards observational forecasts of bloom landfall and eventually bloom prediction. Together, these many efforts will provide resource managers with the tools needed to develop effective strategies for the management and mitigation of HABs and their frequently devastating impacts on the coastal environment.

Environment↗