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As part of an ongoing monitoring study of phytoplankton in Yemeni coastal waters we report, for the first time, a dense bloom (14.3x106 cell L-1) of the marine dinoflagellate species Protoperidinium quinquecorne (Abé ) Balech on June 6, 2012 from the coastal water of Al Hodeidah and Khor Al-Khateeb lagoon, southern Red Sea. Water temperature was 34°C and salinity was 36 during the bloom, indicating its tropical and subtropical nature. This bloom was accompanied by a massive kill of small pelagic fish, which were mostly sardines. Among the phytoplankton species reported during the P. quinquecorne bloom, the red tide-forming species, Trichodesmium erythraeum (cyanobacteria), Gonyaulax verior, and Prorocentrum micans, and the known toxic species, Dinophysis acuminata, were notable. [ABSTRACT FROM AUTHOR]

Active and passive sampling methods were employed over a four-month period, at a site off the South-West coast of Ireland, to characterise the occurrence of cyclic imines in the water column. The marine toxins 13-desmethyl-SPXC, 20-methyl SPXG toxins and pinnatoxin G were detected using active sampling from Diaion HP-20 resin. Seven water depths were sampled to determine stratification of the toxins in the water column using Solid Phase Adsorption and Toxin Tracking (SPATT). Both 13-desmethyl-SPXC and pinnatoxin G were detected using two different resin types; Diaion HP-20 and Amberlite XAD761. HP-20 proved more effective at accumulating the toxins, with a higher percentage of positive samples and a higher ratio of toxin adsorbed relative to XAD761. No temporal variation in toxin-quantities was detected, indicating that there was no change in density of causative algal species in the water column. Pinnatoxin G was detected more frequently from surface to 30 m depth, with a similar pattern observed for 13-desmethyl-SPXC occurrence using XAD761. No difference in the occurrence of 13-desmethyl-SPXC was observed between depths using HP-20 resin. This is the first reported incidence of pinnatoxin G in Irish waters and highlights cyclic imines as emerging toxins in European waters. [ABSTRACT FROM AUTHOR]

Populations of Vibrio parahaemolyticus in the environment can be influenced by numerous factors. We assessed the correlation of total (tl+) and potentially virulent (tdh+) V. parahaemolyticus in water with three harmful algal bloom (HAB) genera (Pseudo-nitzschia, Alexandrium and Dinophysis), the abundance of diatoms and dinoflagellates, chlorophyll-a and temperature, salinity and macronutrients at five sites in Washington State from 2008-2009. The variability in V. parahaemolyticus density was explained predominantly by strong seasonal trends where maximum densities occurred in June, 2 months prior to the highest seasonal water temperature. In spite of large geographic differences in temperature, salinity and nutrients, there was little evidence of corresponding differences in V. parahaemolyticus density. In addition, there was no evident relationship between V. parahaemolyticus and indices of HAB genera, perhaps due to a lack of significant HAB events during the sampling period. The only nutrient significantly associated with V. parahaemolyticus density after accounting for the seasonal trend was silicate. This negative relationship may be caused by a shift in cell wall structure for some diatom species to a chitinous substrate preferred by V. parahaemolyticus. Results from our study differ from those in other regions corroborating previous findings that environmental factors that trigger vibrio and HAB events may differ depending on geographic locations. Therefore caution should be used when applying results from one region to another. [ABSTRACT FROM AUTHOR]

Ciguatera fish poisoning is a common form of seafood poisoning caused by toxins (ciguatoxins) that accumulate in demersal (reef) food webs. The precursors of ciguatoxins are produced by dinoflagellates of the genus Gambierdiscus , and enter the food web via herbivory and detritivory. The Gambierdiscus genus was recently revised and new research on the physiology and ecology of the revised species is needed. While it has been demonstrated that Gambierdiscus spp. are predominately epiphytic, the variability in epiphytic behavior among the various Gambierdiscus species is not known. Five Gambierdiscus species isolated from the Greater Caribbean Region were the focus of this study ( G. belizeanus , G. caribaeus , G. carolinianus , G. carpenteri , and G. yasumotoi ). Cells of Gambierdiscus were grown in wells with algae fragments from eight different macroalgal host genera ( Acanthophora , Caulerpa , Dasya , Derbesia , Dictyota , Laurencia , Polysiphonia , and Ulva ) where the epiphytic behavior and growth of the different Gambierdiscus species were monitored over 29 days. The results of this experiment demonstrate that epiphytic behavior (growth and attachment) differs among the Gambierdiscus species toward the various macroalgal hosts. Results tended to be specific to Gambierdiscus – host pairings with few commonalities in the way a particular Gambierdiscus species interacted across hosts or how the various Gambierdiscus species responded to a particular host. The Gambierdiscus – host pairings that resulted in the highest growth and attachment combinations were examined in terms of known cellular toxicity and host palatability to determine which pairings could represent the most likely vectors for the transfer of ciguatoxins (or precursors) into the demersal food web. Two pairings, Gambierdiscus belizeanus – Polysiphonia and G. belizeanus – Dictyota , best met these criteria, providing a hypothetical approach to better focus sampling and monitoring efforts on such potential vectors in the benthic environment. [ABSTRACT FROM AUTHOR]

The Australian National System for the Prevention and Management of Introduced Marine Pest Incursions has identified seven Harmful Algal Bloom (HAB) toxic dinoflagellate species as target species of concern. Alexandrium minutum Halim, 1960, and Alexandrium cf. tamarense (Lebour) Balech, 1995, are currently known to occur in south-western estuaries and coastal waters but with no documented impact on the seafood industry or human health. Monitoring of these species is challenging, time-consuming, expensive, and often relies on traditional morphotaxonomy. This reports the first confirmed detection of another HAB species, Alexandrium catenella (Whedon and Kofoid) Balech, 1995, in Western Australia (WA), using both microscopic and molecular methods. The confirmed detection of A. catenella (A. pacificum Group IV genotype) in WA hopefully will motivate discussion about better monitoring and control of toxic HAB species. [ABSTRACT FROM AUTHOR]

Observaciones previas sobre el microplancton de la Bahía de Mazatlán, en el otoño de 1996, revelaron la existencia de altas densidades de Pseudo-nitzschia spp. Este mismo fenómeno se encontró en noviembre 1998 y un mes después se había desplazado al sur de la Bahía de Mazatlán, mientras que por esas mismas fechas, en California, EUA, se registraban accidentes de envenenamiento de mamíferos marinos, accidentes que en el noroeste de México se aprecian entre enero y marzo. Mensualmente se recolectaron muestras de agua superficial (< 0.5 m) y subsuperficial (10 m), de noviembre 1998 a enero 1999 y cada semana, entre febrero 1999 y mayo 2000; las muestras fueron analizadas por la técnica de Utermöhl a 400X. La cuantificación del microplancton presentó un amplio pulso invernal y otro menor en verano de cada ciclo anual. Con el empleo de microscopio electrónico (MEB y MET), se reconocieron cuatro especies de Pseudo-nitzschia y una más en estudio reciente. Las densidades de Pseudo-nitzschia fueron, en orden de importancia: 760 céls ml-1 (7 dic.1999), 610 (6 dic.1998), 335 (12 jul.1999), 198 (1º. feb. 1999), 170 (6 nov.1998), 123 (17 mar.1999), 108 (11 ago.1999). Otras especies de diatomeas (Thalassiosira spp., Asterionellopsis glacialis, Chaetoceros spp., Skeletonema costatum), dinoflagelados (Prorocentrum spp., Scripsiella trochoideda) y ciliados (Myrionecta rubra), manifestaron proliferaciones altas durante el período de este estudioObservations on microplankton in the autumn of 1996 revealed the existence of high densities of Pseudo-nitzschia spp. A similar phenomenon was found in November 1998 and November 1999 and a month later it shifted to the southern Mazatlán Bay while in California, USA, incidents of the poisoning of sea mammals were being recorded; this also happened on the Mexican Pacific coasts from January to March. Water samples collected at surface (

El Niño provides a partial explanation of the spectrum of marine biotoxins (red tides) on the coast of Mexico. Over 500 human poisoning cases with 20 fatalities in the last 25 years, and mass mortalities of fish, sea birds, marine mammals, and marine turtles have been documented. However, the eventual effect of El Niño on the incidence, frequency and severity of harmful microalgal blooms is uncertain. Because of geographical position and socioeconomical conditions, the impact of harmful microalgal blooms in Mexico will be severe, and a study of red tides is justified.

We report the first occurrence of harmful algal bloom (HAB) caused by a non-toxic dinoflagellate, Cochlodinium sp. in Philippine waters, particularly, in Kalangahan Pt.-Manticao Pt., Iligan Bay on March 13-18, 2002. Two patches of Cochlodinium sp. bloom, associated with fish kills in Kalangahan Pt.-Mantacao Pt., Iligan Bay, caused localized water discoloration from the usual ocean blue to rusty brown or reddish brown to blackish. The first patch, located near fish-aggregating device (FAD) areas, spanned 2 km wide, while the second patch, located near a fish corral, spanned 500m wide. These patches occupied the water column from surface to 5 m depth, but a thick mat formed at 0.5 m to surface. Patches occupied the water column from surface to 5 m depth, but a thick mat formed at 0.5 m to surface. Patches decreased as the bloom began to decline. The observed dead demersal and pelagic fishes coincided with highest bloom density of 3.1 x 104 to 3.8 x 104 cells ml-1 of Cochlodinium. Dissected gills and stomach contents of fishes killed in HAB-affected areas did not reveal any indication of clogging of gills by Cochlodinium sp. Fishes covered by the “shading effect” of Cochlodinium bloom may have suffered anoxia or asphyxation due to oxygen depletion. No poisoning of people who consumed the dead fishes was reported. Laboratory analyses revealed lower DO values, 2.4 to 0.5 mg L-1from 2400 to 0600Hr; 14N:1P ratio; air-water temperature ranged from 28-29°C; pH 7.89-8.29; and salinity, 33-35°/oo. Favella sp., a tintinnid grazer of dinoflagellate was developing in the area at the termination of the Cochlodinium bloom on March 18.

• Cochlodinium polykrikoides exhibited limited diel vertical migration (DVM) behavior to avoid thermal stress during marine heatwave conditions. • C. polykrikoides exhibited an efficient DVM pattern based on thermotaxis under temperature difference between surface and bottom water by changing migration velocity. • We suggest that the thermotaxic DVM is an important ecological strategy used by C. polykrikoides to optimize environmental conditions for growth. The harmful dinoflagellate Cochlodinium polykrikoides , a species that causes mass mortality of farmed fish, uses diel vertical migration (DVM) as an ecological strategy. In summer 2018, a bloom of C. polykrikoides occurred on the southern coast of Korea when the surface water temperature exceeded 29 °C, as a result of a marine heatwave. To understand the effect of high temperature conditions on the DVM of C. polykrikoides , vertical profiles of environmental variables and the occurrence of the dinoflagellate were investigated through a 48 h field survey. In addition, a thermally stratified environment (6–12 °C difference between the surface and bottom layers) was established in a laboratory study to investigate the effect of temperature difference between water layers on the DVM of C. polykrikoides. In the field, most of the C. polykrikoides population was at a depth of 3–6 m during the day, where the water temperature was significantly lower (p < 0.01; Chi square = 57.98; Kruskal–Wallis test) than in the surface layer (0 m), and only the water temperature at 0 m was not correlated with weighted mean depth of C. polykrikoides , suggesting the usage of DVM to avoid high temperature stress. According to our field and laboratory results, there was a trend of greater DVM velocity by thermotaxis when moving from "unfavorable" water temperature (30 °C hot and 12 °C cold) to "favorable" water temperature for growth (optimal 24 °C) of C. polykrikoides. Our findings suggest that thermotaxic DVM is an important ecological strategy used by C. polykrikoides to optimize environmental conditions for growth through vertical positioning and changing migration velocity. [Display omitted] [ABSTRACT FROM AUTHOR]

The magnitude of submarine groundwater discharge (SGD) and its contribution to nitrogen biogeochemistry in a small embayment in the Western Coast of Ireland subject to occasional hypoxia were investigated during summer. Time series (24 h) of Rn, NO, NO, NH, dissolved reactive silicate (DRSi) and salinity (June 2010, July and September 2011 and July 2013), total dissolved phosphorus (TDP) (September 2011 and July 2013) and dissolved organic nitrogen (DON) (July 2013) were measured at the mouth of the bay and coupled with relevant sediment-water fluxes and input loadings to derive nutrient budgets. In-situ activity ratios of the naturally occurring radium isotopes Ra and Ra were employed in parallel to the freshwater fraction method to determine the timescale of freshwater retention in the system. Based on Rn mass balances (n = 4), the mean groundwater (±SE) discharge into Kinvara Bay was 10.4 ± 6.3×10 m days, delivering average loads of 376 ± 67 kg Si day (as DRSi), 1.6 ± 0.2 kg P day (as TDP) and ~280 kg N day of dissolved nitrogen (272 ± 49 DIN, essentially as NO, and 8.2 ± 1.6 DON), which correspond to ~98.8, 49.1 and ~93.5 % of total allochthonous nutrient inputs respectively. Expressed on an areal basis and annual scale the exogenous N summer loading of Kinvara is equivalent to 25.9 g N m year. Our biogeochemical budgets indicate that tight benthic-pelagic coupling contributes to the very high retention levels of N within the bay with subtidal sediments acting as a link in the internal N cycle via DNRA, while ~18 % of the exogenous N load is removed by benthic denitrification. Rapid cycling of DON into bioavailable forms of N within the timescale of freshwater retention in the system (~7 days) contributes ~50 % to local biological N fixation. Nutrient availability ratios are N:P ~173 and Si:P ~503, indicating that primary production is P-limited while the carbon yield (~3.01 × 10 mol C day, or ~0.313 kg C m year) suggests the bay is eutrophic during the summer. SGD-borne Nitrogen loading is therefore the major driver of eutrophication in Kinvara Bay. Our biogeochemical characterization is consistent with the observed phytoplankton community composition and species succession and justifies the local observation of HAB's. In addition, the relative magnitude of DNRA-promoted N retention compared to N removal by denitrification, coupled with seasonal hypoxia, suggests that the system is advanced in the chronological sequence of eutrophication effects on shallow coastal systems. [ABSTRACT FROM AUTHOR]

The toxic microalgal species Prymnesium parvum and Prymnesium polylepis are responsible for numerous fish kills causing economic stress on the aquaculture industry and, through the consumption of contaminated shellfish, can potentially impact on human health. Monitoring of toxic phytoplankton is traditionally carried out by light microscopy. However, molecular methods of identification and quantification are becoming more common place. This study documents the optimisation of the novel Microarrays for the Detection of Toxic Algae (MIDTAL) microarray from its initial stages to the final commercial version now available from Microbia Environnement (France). Existing oligonucleotide probes used in whole-cell fluorescent in situ hybridisation (FISH) for Prymnesium species from higher group probes to species-level probes were adapted and tested on the first-generation microarray. The combination and interaction of numerous other probes specific for a whole range of phytoplankton taxa also spotted on the chip surface caused high cross reactivity, resulting in false-positive results on the microarray. The probe sequences were extended for the subsequent second-generation microarray, and further adaptations of the hybridisation protocol and incubation temperatures significantly reduced false-positive readings from the first to the second-generation chip, thereby increasing the specificity of the MIDTAL microarray. Additional refinement of the subsequent third-generation microarray protocols with the addition of a poly-T amino linker to the 5′ end of each probe further enhanced the microarray performance but also highlighted the importance of optimising RNA labelling efficiency when testing with natural seawater samples from Killary Harbour, Ireland. [ABSTRACT FROM AUTHOR]

Domoic acid toxicosis in the California sea lion ( Zalophus californianus) is difficult to diagnose using presence of toxin alone because the duration of domoic acid presence in blood and urine is generally less than 48 hr following exposure. Because domoic acid toxicosis is often suggested by presentation of behavioral abnormalities, we asked whether assessment of behavior might be useful for diagnostic purposes. We developed an ethogram to categorize behavioral data collected via continuous focal animal sampling. In total, 169 subjects were observed at a rehabilitation center. Sea lions with domoic acid toxicosis displayed head weaving ( P < 0.0001) and muscle fasciculations ( P < 0.01) significantly more often than animals in a comparison group. Dragging hind flippers and swift scanning were observed exclusively in animals from the domoic acid toxicosis group. The data show that behavioral diagnostic criteria can be effective in the diagnosis of domoic acid toxicosis in the California sea lion. Zoo Biol. 34:314-320, 2015. © 2015 Wiley Periodicals Inc. [ABSTRACT FROM AUTHOR]

Algal blooms have become a major concern in coastal areas and the great lakes of the world. Because of their various consequences for aquatic ecosystems and resources, algal blooms are called 'harmful algal blooms' (HABs). HABs often become severely detrimental when they involve one or more toxin-producing microalgae of various taxonomic origins. The accumulation of algal biomass also has deleterious effects on the ecological status of water. However, appropriate management strategies can allow the beneficial utilization of these events by consuming the biomass feedstock in the production of valuable biocommodities, including biofuels, functional food ingredients, UV-absorbing compounds, pharmaceutical products, etc. However, if the algal biomass can be harvested prior to the onset of their death phase, nutrients (carbon, nitrogen, and phosphorus) can also be removed from the ecosystem by harvesting the algal blooms. Great progress has been made in the last decade in monitoring and predicting HABs, and a demand is emerging for persuasive postevent management policies that focus on the potential utilization of these blooms as natural renewable bioresources. This review summarizes various potential applications of nuisance algal blooms and the need for scientific research into their economic and industrial potential. Major algal products with great ecological and economic significance and their contemporary global utilization are analyzed. [ABSTRACT FROM AUTHOR]

Over the past 15 years or so, several Scottish harbour seal ( Phoca vitulina ) populations have declined in abundance and several factors have been considered as possible causes, including toxins from harmful algae. Here we explore whether a link could be established between two groups of toxins, domoic acid (DA) and saxitoxins (STXs), and the decline in the harbour seal populations in Scotland. We document the first evidence that harbour seals are exposed to both DA and STXs from consuming contaminated fish. Both groups of toxins were found in urine and faeces sampled from live captured (n = 162) and stranded animals (n = 23) and in faecal samples collected from seal haul-out sites (n = 214) between 2008 and 2013. The proportion of positive samples and the toxins levels measured in the excreta were significantly higher in areas where harbour seal abundance is in decline. There is also evidence that DA has immunomodulatory effects in harbour seals, including lymphocytopenia and monocytosis. Scottish harbour seals are exposed to DA and STXs through contaminated prey at potentially lethal levels and with this evidence we suggest that exposure to these toxins are likely to be important factors driving the harbour seal decline in some regions of Scotland. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking. [ABSTRACT FROM AUTHOR]

The Danube Delta represents an open socio-ecological system of international importance. The services provided by this environmental complex to human society are endangered. The aim of this study was to understand the driving mechanisms triggering harmful algal blooms, in the context of environmental changes and their consequences for food webs. The cyanobacterial blooms are triggered by a combination of abiotic factors: nutrient content, increasing temperatures, light intensity. The bloom risk increases by removing natural competitors (green algae, macrophytes), by affecting the natural grazers which control the algal growth. The results of our investigations carried out in 26 ecosystems belonging to the 4 lake complexes (Roşu-Puiu, Matiţa-Merhei, Gorgova-Uzlina, Şontea-Fortuna) indicated a higher frequency of cyanobacterial blooms in late summer or early fall. The quantification of algal community performed in situ with a field fluorometer (Fluoroprobe III, bbe Moldaenke, DE) indicated that 4 major algal groups were present in all the lakes: Chlorophyta, Bacillariophyta, Cryptophyta, Cyanobacteria. The structural parameters fluctuated in a wide range. The complex most affected by the algal blooms was Roşu - Puiu. The results of multiple regression analysis evidenced a strong relationship between Cyanobacteria and TP (p<0.001) and marginally with NO3 and PO4. The light and TP were significant factors that influenced the Chlorophyceae development. The phytoplankton biomass, expressed as chlorophyll a content, was explained by the TP (89%, p<0.001). The zooplankton analysis of the samples collected in spring evidenced 95 taxa, Rotifera (44 sp.), Ciliata (21 gen), Cladocera (18 sp.) and Copepoda (6 sp.). The minimum value of zooplankton abundance was in Gorgostel (1.67 ind L-1) and maximum values in Roşu (29.93 ind L-1). An analysis of the similarity degree highlighted a 50% resemblance among the following lakes that belongs to Matiţa-Merhei complex: Dracului, Lung, Babina, Rădăcinoasele. Future analyses will focus on the cyanobacteria effects on food web. [ABSTRACT FROM AUTHOR]

Ostreopsis sp. is a toxic marine benthic dinoflagellate that causes high biomass blooms, posing a threat to human health, marine biota and aquaculture activities, and negatively impacting coastal seawater quality. Species-specific identification and enumeration is fundamental because it can allow the implementation of all the necessary preventive measures to properly manage Ostreopsis spp. bloom events in recreational waters and aquaculture farms. The aim of this study was to apply a rapid and sensitive qPCR method to quantify Ostreopsis cf. ovata abundance in environmental samples collected from Mediterranean coastal sites and to develop site-specific environmental standard curves. Similar PCR efficiencies of plasmid and environmental standard curves allowed us to estimate the LSU rDNA copy number per cell. Moreover, we assessed the effectiveness of mitochondrial COI and cob genes as alternative molecular markers to ribosomal genes in qPCR assays for Ostreopsis spp. quantification. [ABSTRACT FROM AUTHOR]

This article presents the fluorescent characteristics of eight microalgae cultures of the genus Pseudo-nitzschia. We show that the normalized fluorescence temperature curves of the studied Pseudo-nitzschia cultures are very similar. Due to this similarity, the authors obtained the "passport" characteristic, averaged on the measured characteristics, which with high accuracy approximates the fluorescence temperature curves of each studied species of Pseudo-nitzschia algae. The similarity indexes between the fluorescence temperature curves of each test sample and the passport curve were obtained using the modernized cosine method. The authors introduce the concept of the scaling factor α, which allows for achieving a reliable determination of the presence/absence of Pseudo-nitzschia microalgae both in monoculture samples and in samples from two cultures. The article shows the possibility of determining Pseudo-nitzschia microalgae in a mixture of two cultures with 10% content. • Fluorescence of all strains Pseudo-nitzschia in our work has a similar character. • We can determine Pseudo-nitzschia by fluorescence and the modernized cosine method. • In mixtures, we determine the relative content more than 10% of Pseudo-nitzschia. [ABSTRACT FROM AUTHOR]

Solid phase adsorbent and toxin tracking (SPATT) enables temporally and spatially integrated monitoring of biotoxins in aquatic environments. Monitoring using two adsorbent resins was performed over a four-month period at Lough Hyne Marine Reserve, Ireland. A range of Diarhettic Shellfish Poisoning (DSP) toxins were detected from SPATT extracts throughout the study period. The majority of biotoxins were detected in the top 20-30 m of the water column and a spike in toxin accumulation was measured during August 2010. Phytoplankton analysis confirmed the presence of toxin-producing species Dinophysis acuta and Dinophysis acuminata during the bloom. SPATT has the potential to provide useful information on phycotoxin distribution in the water column; enabling evidence-based decisions regarding appropriate depths for obtaining phytoplankton and shellfish samples in marine biotoxin monitoring programmes. Active sampling was performed continuously over 7-days and high quantities of toxins were successfully accumulated in the HP-20 resin, okadaic acid (~13 mg), dinophysis toxin-2 (~29 mg), pectenotoxin-2 (~20 mg) and pectenotoxin-2-seco acid (~6 mg) proving this an effective method for accumulating DSP toxins from the marine environment. The method has potential application as a tool for assessing toxin profiles at proposed shellfish harvesting sites. [ABSTRACT FROM AUTHOR]

Harmful algae blooms (HABs), often composed of oceanic plants called phytoplankton, are potentially harmful to the marine life, water quality, human health, and desalination plants, a chief source of potable water in the Arabian Gulf. The last decade has seen a noticeable increase in the frequency of HAB outbreaks in the Arabian Seas. This increase is mainly caused by the unprecedented economic growth in the region. The increased human activities in the region have added more stress to the marine environment and contributed to the changes observed in the properties of the marine ecosystem: high temperature and salinity, high evaporation rates, limited freshwater inflow, shallow nature, pollution. However, very few studies that cover the HAB outbreaks, causes, impacts and biological characteristics over the region have been published. This work presents a comprehensive overview of historical HAB outbreaks recorded in the region, and investigate their causes and impact, and seasonal variability. [ABSTRACT FROM AUTHOR]

Significant seabird mortality on the Oregon (OR) and Washington (WA) coast in 2009 has been attributed to a massive bloom of the dinoflagellate Akashiwo sanguinea (K. Hirasaka) G. Hansen & Ø. Moestrup. Initial, albeit limited, observations suggested this bloom began in WA and reached OR waters through southward transport. Here, we explore a combination of remote sensing products and an exceptional latitudinal dataset of plankton counts collected in the surfzone and offshore in OR and WA coastal waters. Records of satellite ocean color for this period support the new finding that blooms were concurrent in OR and WA waters, with no evidence for latitudinal propagation as had been previously suggested. Plankton analyses further indicate that there was a rapid and synchronized increase of A. sanguinea between late August and mid-September of 2009 along wide swaths of the OR and WA coasts. Bloom onset occurred during a prolonged quiescent and warm period in late August-early September, near the end of the March-October upwelling phase. An upwelling event in October likely contributed to foam production through vertical mixing of A. sanguinea rich waters. Bloom intensity peaked earlier and at higher levels in WA waters as compared to OR with cell concentrations exceeding 1.5 × 106 cells L-1 (WA) and ~350,000 cells L-1 (OR). In OR samples, A. sanguinea cells comprised upwards of 90% of dinoflagellate cell counts and ~30% of total phytoplankton cells. At some locations, A. sanguinea persisted well into November-December of 2009, during which time satellite sea surface temperature records indicated anomalously warm surface waters (up to ~5 °C greater than climatological means). Taken together, the data reveal a HAB event of a magnitude unprecedented in over a decade of observations. We hypothesize that these blooms originated from either a cryptic cyst bed and/or a pelagic seed bank of viable vegetative cells. [ABSTRACT FROM AUTHOR]

The purpose of this study is to assess the performance of an adaptive model (AM) in estimating chlorophyll-a concentration (Chl-a) in optically complex inland waters. Chl-a modeling using remote sensing data is usually based on a single model that generally follows an exponential function. The estimates produced by such models are relatively accurate at high Chl-a concentrations, but accuracy drops at low concentrations. Our objective was to develop an approach combining spectral response classification and three semi-empirical algorithms. The AM discriminates between three blooming classes (waters poorly, moderately, and highly loaded in Chl-a), with discrimination thresholds set using the classification and regression tree (CART) technique. The calibration of three specific estimators for each class was achieved using a multivariate stepwise regression. Compared to published models (Floating Algae Index, Kahru model, and APProach by ELimination) using the same data set, the AM provided better Chl-a concentration estimates (R2 of 0.96, relative RMSE of 23%, relative Bias of -2%, and a relative NASH criterion of 0.9). Moreover, the AM achieved an overall success rate of 67% in the estimation of blooming classes (corresponding to low, moderate, and high Chl-a concentration classes). This was done using an independent data set collected from 22 inland water bodies for the period 2007-2010 and for which the only information available was the blooming class. [ABSTRACT FROM AUTHOR]

Abstract: Development of forecasting systems for harmful algal blooms (HABs) has been a long-standing research and management goal. Significant progress has been made in the Gulf of Maine, where seasonal bloom forecasts are now being issued annually using Alexandrium fundyense cyst abundance maps and a population dynamics model developed for that organism. Thus far, these forecasts have used terms such as “significant”, “moderately large” or “moderate” to convey the extent of forecasted paralytic shellfish poisoning (PSP) outbreaks. In this study, historical shellfish harvesting closure data along the coast of the Gulf of Maine were used to derive a series of bloom severity levels that are analogous to those used to define major storms like hurricanes or tornados. Thirty-four years of PSP-related shellfish closure data for Maine, Massachusetts and New Hampshire were collected and mapped to depict the extent of coastline closure in each year. Due to fractal considerations, different methods were explored for measuring length of coastline closed. Ultimately, a simple procedure was developed using arbitrary straight-line segments to represent specific sections of the coastline. This method was consistently applied to each year’s PSP toxicity closure map to calculate the total length of coastline closed. Maps were then clustered together statistically to yield distinct groups of years with similar characteristics. A series of categories or levels was defined (“Level 1: Limited”, “Level 2: Moderate”, and “Level 3: Extensive”) each with an associated range of expected coastline closed, which can now be used instead of vague descriptors in future forecasts. This will provide scientifically consistent and simply defined information to the public as well as resource managers who make decisions on the basis of the forecasts. [Copyright &y& Elsevier]

Abstract: A major goal in harmful algal bloom (HAB) research has been to identify mechanisms underlying interannual variability in bloom magnitude and impact. Here the focus is on variability in Alexandrium fundyense blooms and paralytic shellfish poisoning (PSP) toxicity in Maine, USA, over 34 years (1978–2011). The Maine coastline was divided into two regions – eastern and western Maine, and within those two regions, three measures of PSP toxicity (the percent of stations showing detectable toxicity over the year, the cumulative amount of toxicity per station measured in all shellfish (mussel) samples during that year, and the duration of measurable toxicity) were examined for each year in the time series. These metrics were combined into a simple HAB Index that provides a single measure of annual toxin severity across each region. The three toxin metrics, as well as the HAB Index that integrates them, reveal significant variability in overall toxicity between individual years as well as long-term, decadal patterns or regimes. Based on different conceptual models of the system, we considered three trend formulations to characterize the long-term patterns in the Index – a three-phase (mean-shift) model, a linear two-phase model, and a pulse-decline model. The first represents a “regime shift” or multiple equilibria formulation as might occur with alternating periods of sustained high and low cyst abundance or favorable and unfavorable growth conditions, the second depicts a scenario of more gradual transitions in cyst abundance or growth conditions of vegetative cells, and the third characterizes a ”sawtooth” pattern in which upward shifts in toxicity are associated with major cyst recruitment events, followed by a gradual but continuous decline until the next pulse. The fitted models were compared using both residual sum of squares and Akaike's Information Criterion. There were some differences between model fits, but none consistently gave a better fit than the others. This statistical underpinning can guide efforts to identify physical and/or biological mechanisms underlying the patterns revealed by the HAB Index. Although A. fundyense cyst survey data (limited to 9 years) do not span the entire interval of the shellfish toxicity records, this analysis leads us to hypothesize that major changes in the abundance of A. fundyense cysts may be a primary factor contributing to the decadal trends in shellfish toxicity in this region. The HAB Index approach taken here is simple but represents a novel and potentially useful tool for resource managers in many areas of the world subject to toxic HABs. [Copyright &y& Elsevier]

Highlights: [•] Genetic and morphological analysis identified three Gambierdiscus species and three previously unreported ribotypes from Marakei, Republic of Kiribati. [•] All Gambierdiscus isolates tested exhibited low or moderate ciguatoxin-like content. [•] Gambierdiscus distribution patterns corresponded with previous patterns of fish toxicity. [Copyright &y& Elsevier]

A monitoring program for seasonal dynamics of A. tamarense and paralytic shellfish poisoning toxins (PSTs) in bivalves was carried out from April 2006 to March 2007 in Nanji Islands, East China Sea. Low abundances of A. tamarense (fewer than 4.0 x 10² cells L-1) were first observed on 15 April 2006. During middle May, blooms of A. tamarense were documented, with the mean density of 3.8 x 10³ cells L-1 and 0.75 x 10³ cells L-1, corresponding to surface and bottom water columns, respectively. Environmental conditions of temperature range 18-20°C and salinity range 29.5-31 coincided with a high abundance of A. tamarense in the region, and the bloom collapse was likely to be a response to P limitation. Toxin concentrations in cultured Patinopecten yessoensis, Mytilus galloprovincialis and wild Mytilus coruscus during A. tamarense blooms ranged from 68.9 to 96.3 µg STXeq per 100 g flesh. Toxin profiles were similar among bivalve shellfish samples, dominated by C1 and C2 in 51.4-64.6 mol% of toxins, with an average of 60.6 mol%, followed by GTX5, GTX1-GTX4, dcGTX2 and dcGTX3. However, from January to March 2007, lower toxin concentrations, 18.9-40.8 µg STXeq per 100 g were found only in the wild Oyster sp., comprising GTX4, GTX5 and GTX1. Dynamics of Alexandrium tamarense and the factors that influence its blooms, as well as the relationship between A. tamarense and paralytic shellfish poisoning toxins (PSTs) in shellfish, have only been rarely studied in the East China Sea. This investigation showed that nutrient concentrations and temperature played important roles in determining the amplitude of A. tamarense blooms and an increase in cell numbers of A. tamarense coincided with the detection of PSTs in shellfish. This research provides a basis for the establishment of effective toxin-monitoring strategies. [ABSTRACT FROM AUTHOR]