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Pyrodinium bahamense var. compressum is a toxic dinoflagellate that produces paralytic shellfish poisoning toxins. It is responsible for the chronic toxicity of shellfish in many coastal areas of the Philippines and other South East Asian countries. For the purpose of using antibiotic treatment to possibly generate axenic cultures and understand their growth requirements, the antibiotic tolerances of two local P. bahamense var. compressum isolates and their associated bacteria were determined. The antibacterial compounds ampicillin, chloramphenicol, ciprofloxacin, kanamycin, neomycin, penicillin G, and streptomycin were tested, as well as two antifungals, amphotericin B, and nystatin. All except chloramphenicol, amphotericin B, and nystatin were generally well-tolerated. An antibiotic mixture composed of ciprofloxacin, kanamycin, neomycin, and streptomycin completely inhibited the cultivable bacteria associated with P. bahamense var. compressum MZRVA, although epifluorescence microscopy revealed that residual bacteria were still present. From long-term tests with this antibiotic mix, it was observed that survival of isolate MZRVA post-antibiotic treatment appeared to be associated with re-growth of heterotrophic bacteria and that excess vitamins could potentially enhance dinoflagellate survival. These results suggest that the associated heterotrophic bacterial populations help support the growth of P. bahamense var. compressum MZRVA in culture and possibly in nature. This is the first report on the growth responses of P. bahamense var. compressum and associated cultivable bacteria to a variety of single and combinations of antibiotics.

Development of harmful algal blooms (HABs) in coastal waters of Kota Kinabalu, Malaysia, is a recurring problem. The blooms are caused by Pyrodinium bahamense var. compressum and Cochlodinium polykrikoides . Recently, another potential HAB species, Gymnodinium catenatum , was identified. The occurrence of these species is known to be related to a range of factors, including seasonal monsoons, nutrients, physical parameters and geomorphology. To understand the occurrence and distribution of the three species, extensive samplings were carried out over a period of one year, including the South West Monsoon (SWM), North East Monsoon (NEM) and Inter-Monsoon (IM) periods, at 5 stations located in 3 different bays off Kota Kinabalu. Cell density of the three HAB species and in situ physical parameters (salinity, pH and temperature) were recorded. Secondary data such as rain fall and wind speed were obtained from the Meteorology Department, Kota Kinabalu. C. polykrikoides and G . catenatum occurred year-round with the highest cell densities of 1.54 × 10 7 cells L −1 and 1.24 × 10 6 cells L −1 in December (NEM). P. bahamense var. compressum was found in low numbers with maximum cell density of 2 × 10 4 cells L −1 in August (SWM). The absence of P. bahamense var. compressum during the highest peak of C. polykrikoides and G . catenatum was related to nutrient concentrations and composition. The three species tended to occur at stations near the river and in a sheltered area. The results of the study indicate that the coastal area of Kota Kinabalu may continue to experience HAB problems, unless environmental conditions change significantly.

For the first time the potential of Noctiluca scintillans, a non-toxic mixotrophic dinoflagellate, in bioconverting and/or excreting saxitoxin has been illustrated, thus contributing to the limited knowledge on the aspects of toxin pathways in the food chain/web and predator-prey preferences. Noctiluca growth rate increased with higher Pyrodinium concentration but the ratio of Noctiluca to Pyrodinium should at least be 1:250 cells per mL. Noctiluca fed with Pyrodinium alone was found to decrease in number suggesting that the nutrients from this prey were insufficient. This was confirmed by the improved cell density of Noctiluca upon addition of 0.01% casitone to the Pyrodinium-fed Noctiluca. The alternative prey (Gymnodinium sanguineum) slowed down the grazing impact of Noctiluca on Pyrodinium. Noctiluca depleted Gymnodinium earlier than Pyrodinium showing preference over a prey with less saxitoxin. After the feeding experiments, total saxitoxin levels decreased to 72% in the Noctiluca-Pyrodinium setup whereas no saxitoxin was detected in the Noctiluca culture fed with Pyrodinium and G. sanguineum. It is possible that Gymnodinium can provide some nutrients needed to make Noctiluca more efficient in bioconverting saxitoxin.

Plankton feeders such as bivalves often become toxic. Human consumption of the toxic bivalve causes severe food poisoning, including paralytic shellfish poisoning (PSP) which is the most dangerous because of the acuteness of the symptoms, high fatality and wide distribution throughout the world. Accumulation of PSP toxins in shellfish has posed serious problems to public health and fisheries industry. The causative organisms of PSP toxins are known to be species of dinoflagellates including those belonging to the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense var. compressum. Bivalves accumulate PSP toxins during a bloom of these dinoflagellates. Thus, the dinoflagellate toxins have been considered as being concentrated in bivalves through food web transfer. However, field studies on the toxin level of bivalves in association with the abundance of toxic dinoflagellates could not support the idea. A kinetics study on toxins by feeding experiments of cultured dinoflagellate cells to bivalves also showed similar results, indicating that toxin accumulation of bivalves is not caused by simple accumulation of toxins due to food-web transfer. Based on the discovery of toxin-producing bacterium in the cells of toxic dinoflagellates, this study suggests that PSP toxins in toxic dinoflagellates are catabolites of bacterial substance in dinoflagellate cells. On the other hand, tetrodotoxin (TTX), a puffer toxin, is reported to be produced by some species of bacteria. Thus, the origin of TTX of puffer is considered to be bacteria. However, the mechanism for puffer to possess TTX through bacteria is unknown. The present study revealed that organisms bearing either TTX or PSP toxins possess both toxins, although the proportion of both is different among the specimens. In fact, a significant level of TTX is detected in A. tamarense. In addition, TTX-like toxin-producing bacteria are found to be infected in the liver of toxic specimens of puffer. These findings strongly suggest that a similar mechanism between bacteria and toxic organisms is involved in the production of TTX and/or PSP toxins in toxic organisms. Aqua-BioScience Monographs Vol. 3, No. 1, pp. 1–38 (2010) www.terrapub.co.jp/onlinemonographs/absm/ © 2010 TERRAPUB, Tokyo. All rights reserved. doi:10.5047/absm.2010.00301.0001 Received on September 8, 2009 Accepted on October 13, 2009 Published online on April 9, 2010

Harmful algal bloom occurrences worldwide have prompted the testing and use of methods to control and mitigate their detrimental effects. This study investigates the potential of Philippine clay minerals to physically remove phytoplankton cells under laboratory conditions. Ball clay had the highest removal efficiency (∼95%) for Pyrodinium bahamense (paralytic shellfish poisoning causative organism) cells. A slight decrease in the efficiency by 10–20% was seen when culture volume was increased from 50 mL to 1 L. Removal efficiency was reduced to ∼95% when water motion was introduced. Removal of other phytoplankton species (Gymnodinium sanguineum, Amphidinium carterae, Pyrophacus horologium, Chatonella marina, and Alexandrium sp.) using ball clay was less efficient (

This paper describes the results of 10 years of water quality monitoring in the Indian River Lagoon Florida, with special emphasis on the relationships between trends in climatic conditions and the distribution, composition, and abundance of the phytoplankton community. The Indian River Lagoon, which spans 220 km of Florida’s east coast, is a region of particular concern because of the rapid rate of human development throughout the region and the hydrologically restricted character of the lagoon, which heightens the potential for algal bloom. Water sampling was carried out on a monthly to twice-monthly basis at six sites located in the northern and central lagoon. The 10-year study included both extended periods of below and above average rainfall. A number of ecologically distinct regions exist within the lagoon, which differ considerably in water exchange properties and watershed inputs. The northern lagoon is characterized by longer water residence times, lower phosphorus concentrations, higher nitrogen concentrations, and more stable salinity conditions than the central lagoon. Mean phytoplankton biovolumes were substantially higher at the sites in the northern lagoon than at the sites in the central lagoon, and algal blooms were more common and intense in the former region. Inter-annual patterns of phytoplankton biovolume were also different in the northern and central lagoon. In the northern lagoon, phytoplankton biovolumes were lowest during the drought period, from the autumn of 1998 to the spring of 2001. By contrast, algal bloom events in the central lagoon were not only less frequent but were not tied to periods of high rainfall. The most widespread and common bloom formers were the potentially toxic dinoflagellate Pyrodinium bahamense var. bahamense and two centric diatoms, Dactyliosolen fragilissimus and Cerataulina pelagica. Many of the biovolume peaks observed over the study period were attributable to these three species. The results of time series modeling of phytoplankton dynamics further highlighted the disparities between the two regions of the lagoon in terms of the suite of parameters that best predict the observed trends in the biomass of phytoplankton. Overall, the outcome of this initial modeling effort in the Indian River Lagoon suggests that time series approaches can help define the factors that influence phytoplankton dynamics.

Currently Angola does not possess a monitoring programme for shellfish contamination with marine biotoxins. Among other potentially toxic microalgae, the presence of Gymnodinium catenatum and Pyrodinium bahamense has been reported at the Angola coast, two species associated worldwide with production of paralytic shellfish poisoning toxins (PSTs). A preliminary assessment of contamination with PSTs was carried out by HPLC with pre-column derivatization in samples of Semele proficua from Luanda Bay and samples of Senilia senilis from Mussulo Bay, collected between June 2007 and February 2008. An unusual profile was found, not matching any of the 10 oxidation products expected from the known hydrophilic PSTs normally reported in marine dinoflagellates: the N-sulfocarbamoyl, the decarbamoyl or the carbamoyl analogues of saxitoxin (STX). Four major compounds were noted, and designated A through D. These were not autofluorescent, additionally A and D presented much stronger response after peroxide oxidation than after periodate oxidation. Fluorescence emission and ultraviolet absorption maxima were similar to oxidation products of STX analogues. Separation carried out in two different C18 columns clearly showed the retention times did not match the oxidation products of standards. In the period of August through October 2007, samples of S. proficua from Luanda Bay presented a strong cross-reaction with a commercial antibody towards STX, in the range of 2600-5800STXequiv./kg, while for the same period levels in the samples of S. senilis from Mussulo Bay ranged between30 and 340STXequiv./kg. This reaction was directly proportional to the presence of the four unknown fluorescent peaks. The presence of these compounds was very persistent throughout the studied period, in particular in Luanda Bay. This contamination might not be characteristic of a dinoflagellate blooming, but could be related to a persistent cyanobacterial contamination, due to the strong sewage pollution of the area.

The morphology of Pyrodinium bahamense south of Isla San Jose in the Gulf of California, Mexico was described using light and scanning electron microscopy. Morphological and dimensional examination of whole cells and thecal patterns were conducted to discriminate between P. bahamense var. compressum and P. bahamense var. bahamense. Microscopic examinations confirmed that specimens of P. bahamense from Isla San Jose are closely related to P. bahamense var. bahamense. The main average dimensions were: cells 41.9 μm long, 43.8 μm wide, 55.6 μm amplitude, apical horn 7.2 μm long, and the left antapical spine 19.5 μm long. The highest cell concentration was 240 cells l−1 and occurred with a bloom of Pseudo-nitzschia spp. The presence of this dinoflagellate off the east coast of the Baja California Peninsula had not been previously reported. Recently, P. bahamense from Florida tested positive for saxitoxins. Paralytic shellfish poisoning from this species has occurred in Mexican waters. Here, significant aspects of taxonomy, toxicology, life cycle, and ecology are discussed.

Qualitative and quantitative analysis of recent organic-walled dinoflagellate cysts (dinocysts) was performed on surface sediment samples and a core from the continental shelf of the Gulf of Tehuantepec, Mexico, in order to document the spatial distribution of dinocyst assemblages in relation to upwelling and primary productivity, and to assess the environmental history of the last century. The analyses of surface sediment samples show a close relation between dinocyst assemblages and productivity on a regional scale. Polysphaeridium zoharyi and heterotrophic taxa (notably Brigantedinium spp.) dominate in the high productivity zone, whereas Spiniferites delicatus and other phototrophic taxa are more abundant in the lower productivity zone. Sediment in an eighteen cm long gravity core (dated using 210 Pb and 137 Cs) provided a record of the last century at annual to decadal resolution, thus yielding a unique opportunity to examine variations in dinocyst assemblages associated with environmental changes. Cyst concentrations in the core range between 477 and 2300 cysts g − 1 , giving cyst fluxes between 68 and 494 cysts cm − 2 yr − 1 . Twenty-three phototrophic and heterotrophic cyst taxa were identified. Brigantedinium spp., P. zoharyi and Bitectatodinium spongium are dominant, and are associated with the seasonal upwelling that characterizes the area. Cysts of potentially toxic species such as P. zoharyi (the cyst of Pyrodinium bahamense var. compressum and/or bahamense ) occur throughout the core. Despite slight variations in relative abundances of the taxa in the assemblages, there is no evidence for eutrophication following industrial development of the adjacent coastal zone. Core samples were also analyzed for benthic foraminiferal content in order to determine possible effects of high, upwelling-induced productivity on bottom water oxygenation. The benthic foraminiferal assemblages are dominated by Hanzawaia concentrica (over 50%), with less abundant Uvigerina excellens , Cancris spp. , Planulina ornata, Quinqueloculina lamarckiana, Epistominella sandiegoensis, Nonionella basispinata, Cassidulina modeloensis and Textularia foliacea . The benthic foraminiferal assemblages are characteristic of oxygen concentrations above 1 ml l − 1 , indicating that possible changes in productivity did not significantly affect bottom water oxygen concentrations over the last 100 years.

Temporal variation in the type and abundance of dinoflagellate cysts in Manila Bay, Philippines, is established using 210 Pb-dated sediment cores. At least 17 dinoflagellate cyst species, including those of the toxic species, Pyrodinium bahamense var. compressum , were identified. P. bahamense may have been present in the area since at least the 1920s. Total cyst density has increased beginning about 1988 to 1998 coinciding with records of P. bahamense blooms in the area. Heterotrophs have always dominated the cysts assemblage. These changes in the dinoflagellate record and the P. bahamense blooms in recent years may have been induced by the interplay of warmer temperatures, high rainfall leading to higher river discharge and less turbulent waters due to passage of few tropical cyclones.

This study describes spatial and temporal distributions of the zooplankton community in Tampa Bay, including their distributions during a bloom of the toxic dinoflagellate Pyrodinium bahamense. Three sites in the bay were sampled 30 times from April 2002 to April 2003. Abundances of holoplankton (copepod nauplii included), meroplankton and microzooplankton were determined using light microscopy. This is the first observation of microzooplankton in Tampa Bay. Phytoplankton composition, temperature, salinity, Secchi depth, total nitrogen, total phosphorus and chlorophyll a were also determined. Generally, the inner bay had higher zooplankton abundances than the mid- and outer regions of the bay. The dominant holoplankton species were copepod nauplii, Oithona colcarva, Acartia tonsa and the larveacean Oikopleura dioica. Bivalve larvae were the most abundant meroplanktonic taxa and tintinnids the most abundant microzooplankton. A major bloom of P. bahamense was observed in the inner bay during the summer. During the bloom, numerical abundances of O. colcarva and A. tonsa declined, while abundances of O. dioica mimicked the pattern of P. bahamense abundance. Picoplankton and diatom concentrations also decreased during the bloom. Spatial patterns and temporal trends in zooplankton distribution suggest that regional differences in water residence times, salinity regimes and grazing pressures are important driving factors in the composition and abundance of zooplankton in Tampa Bay. The results of the study are discussed within the context of historical observation of the zooplankton community.

A radioassay method, i.e. the Receptor Binding Assay, was used for studying the uptake of Paralytic Shellfish Poisoning (PSP) toxins in the green bay mussel Perna viridis highly consumed in the Philippines. This method allowed working at low cell density of Pyrodinium bahamense var compressum (∼102-103 cells/L) representative of early stages of toxic algal blooms. The results indicated that within 16 hours toxic levels of PSP are reached in the tissues of P. viridis, confirming the suitability of the green mussel as an indicator organism for paralytic shellfish toxicity in bivalves during the early stages of the bloom. Results also demonstrated that the weight-specific toxicity significantly increased with mussel size reduction. This method, based on the competition between the labeled and unlabeled toxin for the sodium channel receptor, offers better sensitivity than the mouse bioassay method. With an increasing amount of toxins in the sample, the amount of radiolabeled toxin binding with the receptor d...

Pyrodinium bahamense var. compressum (Pbc) is one of the causative species of Paralytic Shellfish Poisoning (PSP). Incidents of PSP and red tides caused by Pbc are increasing, as well as the geographic distribution of Pbc expanding in Southeast Asia, where it has recently occurred in several areas that previously have not experienced blooms, such as Ambon Bay and Lampung Bay in Indonesia. Five factors including anthropogenic activities, natural activities, visual realization with red tide discoloration, development of techniques like RNA sequence and ELISA toxin kits, and the establishment of a regular monitoring system have been suggested to have led to the increase in reports of dinoflagellate blooms. Occurrence of dinoflagellate cysts in sediments has been used as evidence to which species of vegetative cells occurred in the water column. In this study, the vertical distribution of dinoflagellate cysts in sediments was investigated to confirm the first occurrence of Pbc cysts and to examine the floral changes of dinoflagellate cysts in Ambon Bay and Hurun Bay, Indonesia. In Ambon Bay, Pbc cysts first occurred in ca. 1850 and the cysts were continuously observed since ca. 1870. In Hurun Bay, Pbc cysts were found at 50-52 cm depth, and also at 42-44 cm depth. Cysts of Pbc first occurred at least in 1883, using depositional age calculated from the historical eruption of Mt. Krakatau. Cysts of Pbc have continuously occurred since ca. 1910, and the cyst densities rapidly increased in ca. 1960. Based on these findings, we consider that anthropogenic activities such as ballast water and transportation of shellfish seeds probably did not cause the introduction of Pbc in both bays.

The growth and toxin production of a Philippine Pyrodinium bahamense isolate in nutrient replete batch cultures were investigated under conditions affected by varying salinity, temperature and combined effects of salinity and temperature. Early exponential growth stage was reached after 7 days with a cell division rate of 0.26 div day(-1). The toxin content reached a peak of 298 fmol cell-1 at mid exponential phase and rapidly declined to 54 fmol cell-1 as it approached the death phase. Only three sets of toxins composed of STX, dcSTX and B1 were detected in which STX made up to 85-98 mol%toxincell-1. P. bahamense was able to grow in salinities and temperatures ranging from 26 per thousand to 36 per thousand and 23 to 36 degrees C, respectively. The optimum growth under varying salinity and temperature conditions was observed at 36 per thousand and 25 degrees C. Toxin content reached a peak of 376 fmol cell-1 at 25 degrees C and was lower (80-116 fmol cell-1) at higher temperatures (32-35 degrees C). Combined effects of salinity and temperature showed that P. bahamense was not able to grow at low salinity and temperature (i.e. below 26 per thousand-28 degrees C). Optimum growth was observed in higher salinities at all temperature conditions.

Harmful algal blooms (HABs) occur frequently in the South China Sea (SCS), causing enormous economic losses in aquaculture. We analyzed historical HAB records during the period from 1980 to 2003 in SCS. We found that HABs-affected areas have expanded and the frequency of HABs varied during this period. The seasonal and annual variations, as well as causative algal species of HABs are different among the four regions. Areas with frequent HABs include the Pearl River Estuary (China), the Manila Bay (the Philippines), the Masinloc Bay (the Philippines), and the western coast of Sabah (Malaysia). HABs occurred frequently during March–May in the northern region of SCS, May–July in the eastern region, July in the western region, and year-round in the southern region. Among the species that cause HABs, Noctiluca scintillans dominated in the northern region, and Pyrodinium bahamense in the southern and eastern regions. Causative species also varied in different years for the entire SCS. Both P. bahamense and N. scintillans were the dominant species during 1980–2003. Some species not previously recorded formed blooms during 1991–2003, including Phaeocystis globosa, Scrippsiella trochoidea, Heterosigma akashiwo, and Mesodinium rubrum. Variations in HABs are related to various regional conditions, such as a reversed monsoon wind in the entire SCS, river discharges in the northern area, upwelling in Vietnam coastal waters during southwest winds and near Malaysia coastal waters during northeast winds, and eutrophication from coastal aquaculture in the Pearl River estuary, Manila Bay, and Masinloc Bay.

As part of an ongoing monitoring study of phytoplankton in coastal lagoons on the east side of the Gulf of California, Pyrodinium bahamense Plate, 1906 var. bahamense was collected in the Topolobampo–Santa Maria–Ohuira coastal lagoon system in the Gulf of California in May 2005. Average concentrations of P. bahamense were 100 cells liter−1. This finding is the first observation of vegetative cells of this tropical species in the Gulf of California and represents its northernmost occurrence to date.

Pyrodinium bahamense var. compressum (Pbc) is one of the causative species of Paralytic Shellfish Poisoning (PSP). Incidents of PSP and red tides caused by Pbc are increasing, as well as the geographic distribution of Pbc expanding in Southeast Asia, where it has recently occurred in several areas that previously have not experienced blooms, such as Ambon Bay and Lampung Bay in Indonesia. Five factors including anthropogenic activities, natural activities, visual realization with red tide discoloration, development of techniques like RNA sequence and ELISA toxin kits, and the establishment of a regular monitoring system have been suggested to have led to the increase in reports of dinoflagellate blooms. Occurrence of dinoflagellate cysts in sediments has been used as evidence to which species of vegetative cells occurred in the water column. In this study, the vertical distribution of dinoflagellate cysts in sediments was investigated to confirm the first occurrence of Pbc cysts and to examine the floral changes of dinoflagellate cysts in Ambon Bay and Hurun Bay, Indonesia. In Ambon Bay, Pbc cysts first occurred in ca. 1850 and the cysts were continuously observed since ca. 1870. In Hurun Bay, Pbc cysts were found at 50-52 cm depth, and also at 42-44 cm depth. Cysts of Pbc first occurred at least in 1883, using depositional age calculated from the historical eruption of Mt. Krakatau. Cysts of Pbc have continuously occurred since ca. 1910, and the cyst densities rapidly increased in ca. 1960. Based on these findings, we consider that anthropogenic activities such as ballast water and transportation of shellfish seeds probably did not cause the introduction of Pbc in both bays., Plankton and Benthos Research, 2(4), pp.163-174; 2007

Harmful algal blooms of the dinoflagellate Pyrodinium bahamense have caused human and economic losses in the last decades. This study, for the first time, documents a bloom of P. bahamense in the Red Sea. The alga was recurrently present in a semi-enclosed lagoon throughout nearly 2 years of observations. The highest cell densities (10 4 –10 5 cells L −1 ) were recorded from September to beginning of December at temperatures and salinities of ∼26–32 °C and ∼41, respectively. The peak of the bloom was recorded mid-November, before a sharp decrease in cell numbers at the end of December. Minimum concentrations in summer were at ∼10 3 cells L −1 . A saxitoxin ELISA immunoassay of cultures and water samples confirmed the toxicity of the strain found in the Red Sea. Moreover, a gene expression analysis of the saxitoxin gene domain SxtA4 showed that transcript production peaked at the culmination of the bloom, suggesting a relation between transcript production, sudden cells increment-decline, and environmental factors.

Many aspects of the biology and ecology of the toxic dinoflagellate Pyrodinium bahamense var. compressum are still poorly understood. In this brief note, we present identification of its associated intracellular bacteria or endosymbionts via PCR cloning and 16s rRNA gene sequencing and their localization by confocal microscopy, a first for Pyrodinium. The most frequently observed species in the endosymbiotic microflora were from Roseobacter clade (Alphaproteobacteria, 68 %) and Gilvibacter sediminis (Flavobacteriaceae, 20 %). Roseobacter lineage, the most abundant taxa in this study, is known to be involved in dimethylsulfoniopropionate metabolism which is highly produced in dinoflagellates—a possible strong factor shaping the structure of the associated bacterial community.

Puffer fish poisoning (PFP) is usually caused by ingestion of tetrodotoxins (TTXs) found naturally in certain species of puffer fish (Halstead 1967; Mosher and Fuhrmann 1984). In Japan, 20–100 people die annually from PFP, in spite of stringent controls by authorities (Ogura 1971). TTXs can cause fatal human poisoning, which is similar to paralytic shellfish poisoning (PSP) caused by saxitoxins (STXs). PSP is caused by the consumption of toxic shellfish (Shumway 1990) and rarely by fish that have have become toxic after feeding on STX-producing microalgae (Maclean 1979). As well as TTXs, STXs have also been found in at least 12 marine and freshwater puffer fish species in Asia (Ahmed et al. 2001; Kodama et al. 1983; Kungsuwan et al. 1997; Nakamura et al. 1984; Nakashima et al. 2004; Sato et al. 1997, 2000; Zaman et al. 1997), but their bioorigin has not been identified. TTXs are chemically distinct from STXs, but both neurotoxins produce similar symptoms in mammals because they act on site 1 of the voltage-dependent sodium channel, blocking the influx of sodium into excitable cells and restricting signal transmission along nerve and muscle membranes (Ahmed 1991). The symptoms of traditional PFP from TTXs and of PSP from STXs include tingling and numbness of the mouth, lips, tongue, face, and fingers; paralysis of the extremities; nausea; vomiting; ataxia; drowsiness; difficulty in speaking; progressively decreasing ventilatory efficiency; and finally in extreme cases, death by asphyxiation caused by respiratory paralysis (Ahmed 1991; Catterall 1985; Kao 1993). PFP cases in Europe (Kao 1993) and Mexico (Nunez-Vazquez et al. 2000) have occasionally been reported. In the United States, PFP has been associated with imports of puffer fish [Centers for Disease Control and Prevention (CDC) 1996]; rarely have fatalities occurred after the consumption of indigenous puffer fish. In Hawaii, white-spotted puffer fish, Arothron hispidus, were implicated in seven deaths (Ahmed 1991). Until 1974, seven PFP cases in Florida, outside of the Indian River Lagoon (IRL), were caused by the consumption of locally caught “blowfish” or puffer fish (Ahmed 1991; Benson 1956; Bigler 1999; Hemmert 1974; Mosher and Fuhrmann 1984). These cases included three fatalities, likely from TTX; for example, one woman died 45 min after consuming toxic liver from a checkered puffer fish (Sphoeroides testudineus) (Benson 1956). The toxins involved in the previous Florida PFP cases were not characterized, but because PFP is usually associated with TTX, investigators likely assumed that TTX was the cause (Benson 1956; Bigler 1999; Hemmert 1974). Tissues from Florida bandtail (Sphoeroides spengleri), checkered, and southern puffer fish (Sphoeroides nephelus) were found to be lethal in the mouse bioassay (MBA) (Burklew and Morton 1971; Lalone et al. 1963), but, again, the toxins were not determined. Until January 2002 the harvest and consumption of puffer fish from the IRL was not a risk to public health. Since then (until May 2004), however, 28 PFP cases occurring in Florida (n = 21), New Jersey (n = 3), Virginia (n = 2), and New York (n = 2) caused by puffer fish originating from the IRL were reported (Bodager 2002; CDC 2002a, 2002b). Analyses of toxins from unidentified puffer fish fillet remnants from one of the early 2002 PFP cases in New Jersey revealed STXs (Quilliam et al. 2004), not TTXs, a distinction that alone could not be made on the basis of consumer symptoms or traditional screening methods (i.e., MBA). During 2002–2004, all PFP cases were linked to puffer fish originating from the northern IRL and the Banana River on Florida’s east coast (Figure 1). Except for one case, where puffer fish were commercially harvested and reached a New Jersey fish market, puffer fish were caught recreationally [Bodager 2002; Florida Fish and Wildlife Conservation Commission (FWC) 2004]. In April 2002, state and federal officials issued health advisories, and the FWC banned puffer fish harvesting in the IRL, a ban that currently remains in effect. In New York on 14 October 2002, two PFP cases were caused from fish caught near Titusville, Florida, but frozen in March 2002 before the harvesting ban (Bodager D, personal communication). This case demonstrated the stability of toxins in puffer fish frozen for almost 9 months. Figure 1 Map showing locations (circles) in the Indian River Lagoon, Florida, where toxic puffer fish in the SPFP incidents originated (FWC 2004). Sample collections of puffer fish and Pyrodinium bahamense were conducted throughout this area and further south ... Because STXs had not previously been identified in Florida’s marine waters and their distribution, source, and origin were unknown in April 2002 (Abbott et al. 2003; Landsberg et al. 2002), we initiated an intensive survey of biota in the IRL. In this article we present a summary from 3 years of monitoring, as well as the first report of the putative toxin source.

Over the last half of the 20th century Pyrodinium bahamense var. bahamense has been observed in a variety of locations in the western North Atlantic. Recent evidence of the toxin- producing capacity of this variety of P. bahamense has heightened interest in its habitat requirements and preferences. The objective of this study was to examine the environmental factors that relate to the spatial and temporal patterns of the distribution and abundance of P. bahamense var. bahamense. Based on the results of this study we view the factors as operating in one or more ways: (1) eco- physiological limitations for survival and successful reproductive cycle, (2) environmental regulation of growth and standing crop, and (3) competitive advantages in relation to other species. The focus of the study was the Florida peninsula, but information from other environments in the tropical Atlantic and Gulf of Mexico was included in the interpretation of the results. In terms of physiological limitations, 20°C appears to be the lower temperature limit for a significant presence of P. bahamense var. bahamense, and the salinity tolerance ranged from 10 to 45. The bloom potential of P. bahamense var. bahamense was most closely associated with shallow ecosystems with long water residence times, and peak biomass levels were correlated to nutrient concentrations in regions of high abundance. The ability of P. bahamense var. bahamense to compete effectively for habitat with other euryhaline warm-water phytoplankton is viewed in terms of existing theories on succession and competition, including Margalef's Mandala, Reynolds' Intaglio and C-S-R life-form strategies proposed by Smayda & Reynolds.

Seasonal variation of bivalve toxicity was monitored in association with the abundance of the toxic dinoflagellate Pyrodinium bahamense var. compressum in Masinloc Bay, Luzon Island. Among 7 species of bivalve, 6 species became toxic during a bloom of the dinoflagellate. However, remarkable difference in the toxicity was observed among the species. The toxicity of thorny oyster Spondylus squamosus was the highest among the species, showing more than 30 times that of safety consumption level after the peak bloom of the dinoflagellate, while other bivalve species showed much lower toxicity. The toxicity of thorny oyster decreased under absence of the dinoflagellate, but this species maintained a considerably high toxicity throughout a year. Similar trend was observed in penshell Atrina vexillum in a small scale, indicating that these species in the bay are not safe for human consumption almost throughout a year. The toxicity of green mussel Perna viridis increased to significant level during a bloom, but it decreased rapidly when the dinoflagellate disappeared. Toxin analysis of cultured and natural cells showed typical toxin profile of the dinoflagellate. Toxin profile of all the bivalve species reflected the characteristic toxin profile of the dinoflagellate.

The tropics possess some of the world's richest marine environments, most notably coral reefs. Concealed within these ecosystems are a group of potent neurotoxins called the paralytic shellfish toxins (PSTs), the most famous of which is saxitoxin. Thirty years ago, PSTs were recognized as a major danger to seafood consumers in the tropics. The tropical dinoflagellate Pyrodinium bahamense biosynthesizes PSTs and its contamination of seafood has caused more illnesses and deaths than any other PST-producing microalga. Apart from this and other dinoflagellates, PSTs have been confirmed in tropical benthic algae, molluscs, echinoderms, crustacea, and other arthropods. Some of these organisms are unique in that, to date, they have only been found to be toxic in tropical oceans. For example, species of grazing and predatory gastropods, crabs, and more recently cephalopods have been discovered to contain PSTs in a number of intertidal tropical locations. These animals are thought to accumulate the toxins from ben...

SUMMARY The present study is a report of data of planktonic dinoflagellates which includes a list of 252 species, with 10 985 entries in the southern Gulf of Mexico along with information concerning their occurrence. Material for the present study consists of water and net samples obtained during 11 cruises collected at 608 sites between June 1979 and December 2002. Ceratium (47 spp.), Protoperidinium (28 spp.), Dinophysis (26 spp.), Oxytoxum (19 spp.) and Prorocentrum (15 spp.) were the most diverse genera. The most common species found are Ceratium breve, Ceratium contortum, Ceratium furca, Ceratium furca var. eugranum, Ceratium fusus. Ceratium fusus var. seta, Ceratium kofoidii, Ceratium macroceros, Ceratium massiliense, Ceratium pentagonum, Ceratium teres, Ceratium trichoceros, Ceratium tripos, Dinophysis caudata, Ornithocercus magnificus, Podolampas palmipes, Prorocentrum com-pressum, Prorocentrum gracile, Prorocentrum micans, Protoperidinium divergens and Pyrophacus steinii. Thirteen species are potential toxin producers, among which Karenia brevis was responsible for fish mass mortalities. Other toxic species such as Amphidinium carterae, Dinophysis acuta, Dinophysis caudata, Dinophysis fortii, Dinophysis mitra, Dinophysis rotundata, Dinophysis tripos, Prorocentrum mexicanum, Prorocentrum micans and Prorocentrum minimum were present mostly in net samples. The non-toxic species Ceratium furca, Pyrodinium bahamense var. bahamense, Scripp-siella trochoidea and Gonyaulax polygram ma were found in blooms during the summer. Qualitative data show that dinoflagellates occurred mostly during July and August, associated with hydrographic conditions. A checklist of the species and their occurrence are given.

SUMMARY The lateral variation of sediment properties and associated cyst content of sediment in Manila Bay were determined and their possible role/s in the occurrences of Pyrodinium bahamense Plate var. compressum (Bohm) Steidinger, Tester et Taylor toxic blooms were assessed. Manila Bay's surface sediment was determined to be silt dominated. Clay generally increased towards the coast, probably as a result of flocculation and rapid deposition upon entry of sediments from the rivers. High sand content characterized the southeastern part of the bay attributed to the greater sand inputs and relatively strong currents in this area. Bulk densities were lower in the eastern side of the bay from dilution by high organic load from sewage and urban areas. Benthic flux calculations, particularly NH3, suggest more than 50% nutrient contribution comes from sediments. In general, dinoflagellate cyst density increased from the center of the bay towards the coast, except in Pampanga Bay where it deceased near the coasts. A maximum of 23 dinoflagellate species were identified: 5 were autotrophic (Lingulodinium polyedrum (Stein) Dodge, Gonyaulax spp., Pyrophacus steinii (Schiller) Wall et Dale, Protoceratium reticulatum (Claparede et Lachmann) Butschli, and Pyrodinium bahamense var. compressum), and the rest were predominantly composed of Protoperidinium spp. and Diplopsalis spp. Heterotrophs comprised about 70% of the total cyst counts. Pyrodinium counts increased towards the northwestern part of the bay where it was the dominant autotroph species. Negative correlations were observed for live Pyrodinium cyst density and N flux, P flux, ratio of N to P and total organic carbon (TOC) content. However, areas with high N:P ratio contain abundant Pyrodinium live cysts.

The primary focus of this paper is to provide a detailed description of Pyrodinium bahamense from the Indian River Lagoon, Florida. Recent reports of saxitoxin production by P. bahamense from the Indian River lagoon has heightened interest in the similarities between the Atlantic and Indo-Pacific forms of this species. Microscopic examinations of samples from the Indian River Lagoon using light and scanning electron microscopy suggest that the Atlantic form deserves the separate varietal designation of bahamense assigned to it in recent years, distinguishing it from the Indo-Pacific var. compressum. This conclusion was based on key morphological and dimensional characteristics.

A 2 year study of the phytoplankton community was carried out in the Indian River Lagoon, USA. In terms of biovolume, the phytoplankton community was generally dominated by dinoflagellates, diatoms or cyanobacteria. Mean phytoplankton standing crops were highest in the most flow-restricted regions of the lagoon, which had the lowest mean salinity values and comparatively high total nitrogen:total phosphorus ratios. In this region, blooms of dinoflagellates were common in the first year of the study, which was characterized by an El Nino event that yielded exceptionally high rainfall levels and freshwater outflow. Picoplanktonic cyanobacteria blooms became more prominent in the second year of the study, which was characterized by below average rainfall conditions. In unrestricted flow regions of the lagoon, located near inlets to the Atlantic Ocean, diatoms were most often the dominant taxa. Regions of intermediate water turnover rates and high external loading of phosphorus had a prevalence of diatom blooms. However, the average phytoplankton standing crops in the latter regions did not reach the levels experienced in the flow-restricted parts of the lagoon. In terms of individual phytoplankton taxa, the most common bloom-forming diatoms in the Indian River Lagoon system included: Skeletonema costatum, Dactyliosolen fragilissimus, Skeletonema menzelii, Cerataulina pelagica, Odontella regia, Chaetoceros lorenzianus, Rhizosolenia setigera and Thalassionema nitzschioides. The major bloom-forming dinoflagellate species included: Pheopolykrikos hartmannii, Akashiwo sanguinea, Prorocentrum micans, the potentially toxic species Pyrodinium bahamense var. bahamense and Prorocentrum minimum. Several picoplanktonic cyanobacteria were also prominent members of the phytoplankton community, including Synechococcus elongates. The spatial and temporal patterns observed in some of these dominant species were attributable to patterns in key environmental variables, including salinity, temperature and nutrient concentrations.

The effect of irradiance on photosynthesis of the green form of the dinoflagellate Noctiluca scintillans was studied. Photosynthesis, measured in cells collected from the field and without the addition of prey, increased with irradiance to ca. 200 ng C cell -1 d -1 at an irradiance of ∼250 to 300 pmol photons m -2 s -1 . N. scintillans cells were observed to prey and grow actively on a number of different algae, including the dinoflagellate Pyrodinium bahamense var. compressum which produces paralytic shellfish toxin. However, in all cases, N. scintillans lost its endosymbionts when grown in the laboratory for more than 3 wk and became colourless, irrespective of food item, concentration and irradiance. A factor necessary for endosymbiont growth was apparently missing, which was not provided to them by N. scintillans when fed the selected prey types. Thus, further experiments were carried out with freshly collected organisms. The growth rate of N. scintillans when grown without prey was 0.058 and 0.14 d -1 at irradiances of 45 and 150 pmol photons m -2 s -1 at a light:dark cycle of 12:12 h and a temperature of 26°C. When supplied with P. bahamense as food, N. scintillans increased its growth rate to 0.09 and 0.24 d -1 , at irradiances of 45 and 150 pmol photons m -2 s -1 and prey concentrations of 1610 and 2740 μg C l -1 , respectively. Ingestion rates were only measured at 150 pmol photons m -2 s -1 . At this irradiance, the ingestion rate increased linearly with prey concentration and showed no signs of satiation at a prey concentration of ∼2700 μg C l -1 . A comparison of the contribution of photosynthesis and phagotrophy to the carbon metabolism revealed that phagotrophy only contributed significantly (30%) to the direct growth of the green N. scintillans at an irradiance of 150 pmol photons m -2 s -1 , when the prey concentration was very high. Clearance decreased with prey concentration, from ∼0.06 ml N. scintillans -1 d -1 at 25 μg C l -1 to ∼0.03 ml N. scintillans -1 d -1 at a prey concentration of 2740 μg C l -1 . This indicates that N. scintillans, when it occurs at bloom concentrations in nature (1 to 10 cells ml -1 ), may have a significant impact on the bloom dynamics of P. bahamense var. compressum.

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.

The occurrence of potentially toxic phytoplankton species was examined over a 5-year period in a region of the Indian River Lagoon in Florida that has recently been subject to ecologically significant events, putatively related to algal toxins. The results of the study reveal a significant presence of two species of phytoplankton that have been shown to be toxic in Florida or other regions of world, the dinoflagellate Pyrodinium bahamense var. bahamense and the diatom Pseudo-nitzschia pseudodelicatissima. Concentrations of the former species reached 638,000 cells l−1 and concentrations of the latter reached 23.9 million cells l−1. In addition, the abundance of one of these species, P. bahamense var. bahamense appears to have increased over the 5-year study period from 1997 to 2002. It may be hypothesized that rainfall events following a regional drought period resulted in a flushing of bioavailable phosphorus and nitrogen into the Indian River Lagoon that stimulated P. bahamense var. bahamense blooms. The significance of these results is discussed within the context of the ecology of this flow-restricted lagoon.

Toxin assays namely: the mouse bioassay, the receptor binding assay (RBA) and, the immuno-chromatography assay using MIST Alert™ rapid test kit were used to determine the concentrations of Paralytic Shellfish Poisoning (PSP) toxins from untreated and heat shocked Philippine green mussels, Perna viridis contaminated with Pyrodinium bahamense var. compressum. Toxin levels ranging from 4–15 μg STXeq/100 g sample were quantified in the mussel samples analyzed using RBA. Higher levels of PSP toxins at about 30 μg STX eq/100 g sample were recorded using mouse bioassay, which was attributed to interfering factors that could induce mouse death resulting in false positive reactions. The MIST Alert™ test kit showed positive reaction in the samples evaluated based on the reported average profile of PSP toxin analogues at about 40 μg STX eq/100 g sample. The test heat treatments did not elicit definitive change in the PSP toxin profiles of heat shocked mussels relative to the untreated samples.

The present work is a first attempt to document the latest reports on the occurrence of algal blooms in shrimp farm ponds worldwide. Particular emphasis is placed on discussing the relation of algal blooms with nutrients, with special reference to the northwest of Mexico. Typically, shrimp pond waters are enriched with organic matter and nutrients whose concentrations depend mostly on the management (i.e. higher stocking densities, water use, food and fertilizers). Generally, more intensive culture systems produce higher loads of nutrients in their discharge (e.g. N and P). Nitrogen and P concentrations vary in pond waters; N/P ratio ranges from 1.1 to 67 with values being more frequently between 1.1 and 6.8. Such variations are closely related with the cycling and supply of nutrients in the ponds. In shrimp farms located in NW Mexico, phytoplankton abundance varies widely, having a higher abundance in advanced stages of the culture cycle. In the most common pond types (intensive and semi-intensive), Synechocystis diplococcus (cyanobacteria) was the dominant species (>88.9%), followed by Peridinium trochoideum ( Scrippsiella trochoidea ) and eventually Prorocentrum minimum and Gymnodinium spp. (dinoflagellates). The numerous occurrences of large blooms of dinoflagellates and other functional groups such as cyanobacteria, diatoms, chlorophytes and flagellates mean economic losses for farm industry on account of shrimp mortality or growth diminution due to poisoning, anoxic or mucus production effects, in which shrimp were mortality provoked in different regions: in China, the dinoflagellates Alexandrium tamarense ( Gonyaulax tamarensis ) and Gymnodinium ; in Malaysia, the raphidophyte Hornellia ( Chattonella ) and the dinoflagellate Pyrodinium bahamense var. compressum ; in Vietnam, the diatom Nitzchia navis - varingica ; in Ecuador, the dinoflagellate Gyrodinium instriatum ; and in NW Mexico the cyanobacteria S. diplococcus , Schizothrix calcicola , and the dinoflagellates P. minimum , and lastly Gymnodinium catenatum from supply waters.

Cultures were established from cysts of the cyst-based taxa Spiniferites elongatus and S. membranaceus. Motile cells and cysts from both cultures and sediment samples were examined using light and scanning electron microscopy. The cyst- theca relationship was established for S. elongatus. The motile cells have the tabulation pattern 2 pr, 4', 6'', 6c, greater than or equal to 4s, 6''', 1p, 1'''', but they remain unattributable to previously described Gonyaulax species. There was large variation in process length and process morphology in cysts from both cultures and wild samples and there was variation in ornamentation and in the development of spines and flanges in motile cells. A new combination, G. elongata (Reid) Ellegaard et al. comb. nov. is proposed, following new rules of the International Code of Botanical Nomenclature that give genera based on extant forms priority over genera based on fossil forms. Extreme morphological variation in the cyst and motile stages of S. membranaceus is described and this species is also transferred to the genus Gonyaulax, as G. membranacea (Rossignol) Ellegaard et al. comb. nov. Approximately 1500 bp of large subunit (LSU) rDNA were determined for these two species and for G. baltica, G. cf. spinifera (= S. ramosus) and G. digitalis (= Bitectatodinium tepikiense). LSU rDNA showed sequence divergences similar to those estimated between species in other genera within the Gonyaulacales; a phylogeny for the Gonyaulacales was established, including novel LSU rDNA sequences for Alexandrium margalefii, A. pseudogonyaulax and Pyrodinium bahamense var. compressum. Our results show that motile stages obtained from the germination of several cysts of the 'fossil-based' Spiniferites and B. tepikiense, which were previously attributed to 'Gonyaulax spinifera group undifferentiated', belong to distinct species of the genus Gonyaulax. These species show small morphological differences in the motile stage but relatively high sequence divergence. Moreover, this group of species is monophyletic, supported by bootstrap values of 100% in parsimony and maximum likelihood analyses. Copyright © (2003) International Phycological Society. Reprinted by permission of Alliance Communications Group, a division of Allen Press, Inc.

In August and September 2001, Kuwait Bay, a semi-enclosed embayment of the Arabian Gulf, experienced a massive fish kill involving over >2500 metric tons of wild mullet ( Liza klunzingeri ), due to the bacterium Streptococcus agalactiae . In the Bay, this event was preceded by a small fish kill (100–1000 dead fish per day) of gilthead sea bream ( Sparus auratus ) in aquaculture net pens associated with a bloom of the dinoflagellate Ceratium furca . Sea bream were found to be culture positive for S. agalactiae , but did not show any visible signs of disease. Unusually warm temperatures (up to 35 °C) and calm conditions prevailed during this period. As the wild fish kill progressed, various harmful algae were observed, including Gymnodinium catenatum , Gyrodinium impudicum , and Pyrodinium bahamense var. compressum . Cell numbers of G. catenatum and G. impudicum exceeded 10 6 l −1 in some locations. All fish tested below the limits of detection for paralytic shellfish poisoning (PSP) and brevetoxins. Clams ( Circe callipyga ) were positive for PSP but at levels below regulatory limits. Nutrient concentrations, both inorganic and organic, were highly variable with time and from site to site, reflecting inputs from sewage outfalls, the aquaculture operations, a high biomass of decomposing fish, and other sources. It is hypothesized that many factors contributed to the initial outbreak of the bacterial disease, including unusual warm and calm conditions. The same factors, as well as enriched nutrient conditions, also apparently were conducive to the subsequent HAB outbreaks. The detection of PSP, while below regulatory limits, warrants further monitoring to protect human health.

Aims: Decimal reduction times (D-values) of the vegetative cells of Pyrodinium bahamense var. compressum and Escherichia coli in ultraviolet- and chlorine-treated seawater were established. Methods and Results: The cells of the test organisms were exposed to ultraviolet- and chlorine-treated seawater and maintained at 20–35 ppt salinity and 20 to 35°C. The dinoflagellate cells which cause Paralytic Shellfish Poisoning (PSP) were found to be more resilient than the bacterial cells. Ultraviolet treatment was found to be more effective than chlorine to both test organisms. Irreversible morphological changes in the treated dinoflagellate cells were noted, including protoplast discoloration, cellular membrane leakage and damage to the thecal armour. Conclusions: The vegetative cells of both test organisms in seawater were more sensitive to ultraviolet treatment than to chlorine exposure. Generally, the dinoflagellate cells were less susceptible than bacterial cells to both disinfection treatments. Significance and Impact of the Study: Results of this study may have significant implications in depuration procedures for molluscs and cleaning protocols for ballast waters of ships.

Bioluminescent bays and lagoons are unique natural environments and popular tourist attractions. However, the bioluminescence in many of these water bodies has declined, principally due to anthropogenic activities. In the Caribbean, the bioluminescence in these bays and lagoons is mostly produced by the dinoflagellate Pyrodinium bahamense var. bahamense. Laguna Grande is one of the three year-round bioluminescent water bodies in Puerto Rico that are known to remain but P. bahamense var. bahamense density fluctuations have not been studied. In this study we describe water quality parameters and density fluctuations of the most common dinoflagellates in Laguna Grande, P. bahamense var. bahamense and Ceratium furca, over a three-year period. For this, three sampling stations were established in Laguna Grande from which water samples were collected in triplicate and analyzed for temperature, phosphates, nitrates, salinity, water transparency, fluorescence, and dinoflagellate densities, at the water surface and at 2m depth, from May 2003 to May 2006. The results showed a density fluctuation pattern for P. bahamense var. bahamense, where higher densities were observed mainly from April to September, and lower densities from October to February. Density fluctuations of C. furca were more erratic and a repetitive pattern was not observed. Densities of P. bahamense var. bahamense ranged from 0.48 to 90 978 cells/L and densities of C. furca ranged from 0 to 11 200 cells/L. The mean population density throughout the sampling period was significantly higher in P. bahamense var. bahamense (mean=18 958.5 cells/L) than in C. furca (mean=2 601.9 cells/L). Population densities of P. bahamense var. bahamense were negatively correlated with C. furca densities during the first year of sampling; however, they were positively correlated during the third year. Non-significant differences between surface and 2m depth samples were observed for temperature, phosphates, nitrates, salinity, fluorescence, and densities of P. bahamense var. bahamense and C. furca, suggesting a vertically mixed water column. Water transparency was positively correlated with salinity and negatively correlated with fluorescence. Fluorescence was negatively correlated with salinity. The mean population densities of P. bahamense var. bahamense and C. furca observed in this study were within the range of previous reports in other bioluminescent water bodies in Puerto Rico and Florida, USA. In order to conserve the continuous P. bahamense var. bahamense populations in Laguna Grande, as well as its bioluminescence, it is recommended to maintain the existing water flow levels in the 1.5km long inlet/outlet channel; to maintain unpolluted water quality parameters within the bay, the hydrographical basin and adjacent waters, and to preserve mangrove communities within the basin and adjacent areas. Results of this study may help to develop management plans aiming to conserve P. bahamense, its bioluminescence and the lagoon attraction.

The paralytic shellfish poisoning (PSP) causative dinoflagellate Pyrodinium bahamense Plate var compressum (Bohm) Steidinger, Tester et Tayler was recently reported in Ambon Bay of Ambon Island and Kao Bay of Halmahera Island in the eastern part of Indonesia where serious PSP-outbreaks have occurred. However, neither cysts nor motile cells of this variety have ever been recorded from central to western Indonesia. Intensive investigations carried out on surface sediments of Jakarta Bay revealed that empty cysts of not only Pyrodinium bahamense but also other dinoflagellate cysts. These dinoflagellate cysts may represent recent depositions. because they were recovered near the surface of sediments., 長崎大学水産学部研究報告. 1999, 80, p.49-54

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A sensitive HPLC method for determination of paralytic shellfish poisoning (PSP) based on ion-pair chromatographic separation of PSP toxins, post-column oxidation with periodic acid, and fluorescence detection has been used to determine toxin profiles ofPyrodinium bahamense and several strains ofAlexandrium. The HPLC chromatograms revealed clear differences betweenPyrodinium bahamense andAlexandrium strains.

We integrate taphonomic data on vertebrate and invertebrate paleontology, micropaleontology and palynology to explain the formation of a late Pliocene death assemblage of marine birds and fish in the “Pinecrest Sand”, Gulf Coastal Florida. Stereonet plots of orientation data on over 1500 cormorant (Phalacrocoracidae: Phalacrocorax) bones indicate that this fossil assemblage formed first from gradual accumulation of bone, shell and sediments on a barrier island beach, and second by rapid sedimentation in a quiet, back-beach setting associated with multiple episodes of breaching of the barrier. This latter event resulted in the preservation of 137 partial and complete cormorant skeletons and thousands of isolated bones that show a high angle of dip and a preferred orientation to the northeast. Invertebrate fossils exhibit taphonomic signatures characteristic of high-energy reworking with a large percentage of abraded shell fragments similar to beach deposits. Moreover, these data indicate that more than a single depositional episode caused the formation of the deposits referred to as the bird layers. Palynological evidence supports this conclusion. The pollen recovered from the deposits is highly abraded and broken and does not represent an in situ vegetational environment as compared to other deposits of this age in Florida and Georgia. The large number of cormorant and other seabird and fish remains in the bird layers appears to have been caused by a series of toxic red tides that occurred on the Gulf Coast of Florida. These events today cause die offs of large flocks of cormorants and bottom-dwelling fish similar to those recovered from the site. Palynological analysis of the sediments revealed abundant cysts of a dinoflagellate species known to produce toxic red tides. The most likely cause of the death of the cormorants and other vertebrates at this site is a toxic bloom of a variety of Pyrodinium bahamense, the thecate form of the dinoflagellate cyst Polysphaeridium zoharyi, which has a stratigraphic range from the lower Eocene to the Holocene.

Since 1983, San Pedro Bay in the Philippines had been reported to be the site of episodic Pyrodinium bahamense var. compressum blooms that cause paralytic shellfish poisoning in its nearby coastal communities. This bay is also subjected to numerous typhoons, the strongest of which was super typhoon Haiyan in November 8, 2013. Phytoplankton ecology of this bay must have unique characteristics. For the first time, the seasonal dynamics of potentially toxic and harmful phytoplankton in this bay is elucidated. This is also the first record of a bloom of the cyanobacteria, Trichodesmium erythraeum that reached 90,000 cells/L in April 2013. There were 19 other potentially toxic and harmful phytoplankton encountered during the sampling period. This consisted of a haptophyte, Phaeocystis globosa, the diatom Pseudo-nitzschia and 17 dinoflagellates. Seven of these harmful algae had densities high enough to be traced through time. Normally, diatoms abound during the dry season. But here, Pseudo-nitzschia increased in abundance during the wet season of 2012 and 2013. The dinoflagellates behaved as expected and exhibited a relative increase in cell density during the rainy season of both years. Phaeocystis globosa also increased during the wet season. High nutrient availability during this season must have influenced the behavior of the phytoplankton despite differences in temperature and light intensity among seasons. Other notable but rare harmful species found only in plankton net tows during the study were Pyrodinium bahamense var. compressum, Alexandrium tamiyavanichii, Cochlodinium polykrikoides, and Noctiluca scintillans.

The dinoflagellate Pyrodinium bahamense var. compressum has been known to be the major cause of harmful algal blooms or H.A.B. recurring in Manila Bay and other bodies of water in the Philippines. This paper proposes a framework for modeling the growth and spread of an algal bloom population over a hypothetical geographic area. The model is comprised of a networked system of nodes where each node contains an instantiation of a system of difference equations describing the population dynamics of the different life cycle stages of the dinoflagellate.

As part of a continuing toxic microalgae monitoring program, 22 phytoplankton samples were collected from July to November 2010 at several sampling stations along the southern coast of the Baja California Peninsula. For the first time, the toxic dinoflagellate Pyrodinium bahamense var. compressum was found along the southeastern and southwestsern coasts of the peninsula. P. bahamense var. bahamense was first observed off San Jose del Cabo, which is an extension of the range of this variety. Both varieties occur as solitary cells. P. bahamense var. compressum occurred at temperatures ranging between 24.5 °C and 31 °C, whereas var. P. bahamense occurred at 28.5 °C to 29 °C, indicating its tropical and subtropical nature. Occurrence of P. bahamense var. compressum along this coastline may be related to El Nino 2009–2010.

First described by Plate (1906), Pyrodinium bahamense is a bioluminescent dinoflagellate species which forms a resting cyst as part of its life cycle. P. bahamense forms large dense cyst beds in the flocculent layer of sediments and can remain dormant for decades before excysting and forming blooms. The Atlantic strain has recently been discovered to produce a neurotoxin called saxitoxin. Although saxitoxins are most commonly associated with paralytic shellfish poisoning, saxitoxin produced by P. bahamense has been implicated in a number of human illnesses following the consumption of contaminated puffer fish originating from the Indian River Lagoon, Florida. The discovery of P. bahamense cysts on seagrass blades during an ongoing bloom raised the question of whether manatees, whose diet is composed mainly of seagrass, could be at risk of exposure to saxitoxins. The aim of this study was to determine whether P. bahamense cysts can be digested in the manatee gastrointestinal tract or if they would pass through intact. There are no known methods for purifying P. bahamense cysts from the contents of the manatee gastrointestinal tract, so it was necessary to develop an appropriate protocol using cysts purified from sediments in Tampa Bay, Florida. These methods were then to be used to test whether P. bahamense cysts added to manatee digesta break down over time, and also to test archived digesta samples for presence of cysts. A successful method for purifying cysts from manatee digesta could not be developed during the span of this study, and so no conclusions could be drawn about the likelihood of digestion. However, archived samples were found to contain P. bahamense cysts, confirming that manatees are ingesting them while feeding.

Red tides of the toxic dinoflagellate Pyrodinium bahamense var. compressum have occurred almost annually since 1976 in the coastal waters of the west coast of Sabah, Malaysia. Field obServations have indicated that the timings of these outbreaks could be linked to meteorological forcings. All the red tides have occurred during either the northeast or southwest monsoon periods. Matching of red tide outbreaks with total monthly rainfall, monthly-averaged index of wind-induced surface water mixing, and monthly-averaged upwelling index for the period from 1975 to 1989 failed to show any definite pattern. However, more red tide events occurred in months with high mixing index values. The absence of definable patterns could be due to the use of monthly, rather than daily, values in the calculations.

SUMMARYDinoflagellate bioluminescence serves as a model system for examining mechanosensing by suspended motile unicellular organisms. The response latency, i.e. the delay time between the mechanical stimulus and luminescent response, provides information about the mechanotransduction and signaling process, and must be accurately known for dinoflagellate bioluminescence to be used as a flow visualization tool. This study used a novel microfluidic device to measure the response latency of a large number of individual dinoflagellates with a resolution of a few milliseconds. Suspended cells of several dinoflagellate species approximately 35 μm in diameter were directed through a 200 μm deep channel to a barrier with a 15 μm clearance impassable to the cells. Bioluminescence was stimulated when cells encountered the barrier and experienced an abrupt increase in hydrodynamic drag, and was imaged using high numerical aperture optics and a high-speed low-light video system. The average response latency for Lingulodinium polyedrum strain HJ was 15 ms (N>300 cells) at the three highest flow rates tested, with a minimum latency of 12 ms. Cells produced multiple flashes with an interval as short as 5 ms between individual flashes,suggesting that repeat stimulation involved a subset of the entire intracellular signaling pathway. The mean response latency for the dinoflagellates Pyrodinium bahamense, Alexandrium monilatumand older and newer isolates of L. polyedrum ranged from 15 to 22 ms,similar to the latencies previously determined for larger dinoflagellates with different morphologies, possibly reflecting optimization of dinoflagellate bioluminescence as a rapid anti-predation behavior.

Harmful Algal Blooms (HABs) are becoming an increasing problem to human health and environment (including effects on natural and cultured resources, tourism and ecosystems) all over the world. In Mexico a number of human fatalities and important economic losses have occurred in the last 30 years because of these events. There are about 70 species of planktonic and non-planktonic microalgae considered harmful in Mexican coasts. The most important toxin-producing species are the dinoflagellates Gymnodinium catenatum and Pyrodinium bahamense var. compressum, in the Mexican Pacific, and Karenia brevis in the Gulf of Mexico, and consequently the poisonings documented in Mexico are Paralytic Shellfish Poisoning (PSP) and Neurotoxic Shellfish Poisoning (NSP). Although there is evidence that Amnesic Shellfish Poisoning (ASP), Diarrhetic Shellfish Poisoning (DSP) and Ciguatera Fish Poisoning (CFP) also occur in Mexico, these problems are reported less frequently. The type of phytoplankton and epiphytic microalgae, their toxins and harmful effects as well as current methodology used to study these phenomena are presented in this paper. As an experienced group of workers, we include descriptions of monitoring and mitigation programs, our proposals for collaborative projects and perspectives on future research.