Distribution Of Dinoflagellates Research Articles

Monthly Variations of Dinoflagellates in Relation to the Water Parameters Along Purnagad Estuary, Ratnagiri, Maharashtra, India

Water samples were collected from Purnagad estuary, southwest coast of India. The monthly surface water sampling was carried out during high tide to find out the variations in physicochemical parameters and distribution of dinoflagellates. Samples were collected for one year period during 2022–2023. Dinoflagellates and water quality parameters were investigated to changes of dinoflagellates community. Variation in atmospheric temperature 21.9 - 37.2 0C, water temperatures varied from 25.4 - 37 0C, salinity varied from 0-37.6 psu, pH ranges between 7-8.8, dissolved oxygen 3.2-10.8 mgl-1, nitrate varied from 0.1747 - 0.1796 mgl-1, nitrite concentration varied from 0.0076 - 0.0228 mgl-1, phosphate values varied from 0.1038 mgl-1 to 0.3899 mgl-1, Silicate was varied from 0.0050 - 0.6031 mgl-1. A quantitative approach was employed, involving the collection of quantitative data through field sampling and laboratory analysis. During the study 22 species of dinoflagellates were encountered among which Ceratium fusus was dominant. Relatively high density and diversity of dinoflagellates were discovered in May as compared to the other months. Temperature showed a positive correlation with the dinoflagellate community showing its importance in dinoflagellate growth.

A review on the diversity and distribution of athecate dinoflagellates in South Atlantic and in the Atlantic sector of the Southern Ocean: Research insights and gaps.

This review summarizes the state of knowledge on athecate dinoflagellates occurring within the South Atlantic Ocean and Atlantic sector of the Southern Ocean. We compiled data from 105 articles and selected 33 addressing any aspect of athecate dinoflagellate studies. Our aim is to discuss the patterns in athecate dinoflagellate distribution by building a thorough species list and an occurrence map based on species recorded in coastal and oceanic waters. We found 69 species totaling 141 occurrences in the entire South Atlantic Ocean basin. Contradicting global trends, most species distributed throughout this region are subtropical. We linked this trend to a higher local effort in dinoflagellate research instead of higher biodiversity, especially when compared to usual hotspots in biodiversity attributed to tropical oceans. The Subantarctic and Antarctic regions had a low number of occurrences, with 12 and 5, respectively. Except for the occurrence of Gyrodinium lachryma in the Antarctic Zone, all records are unique, poorly described and never recorded again for species such as Gymnodinium baccatum and Gymnodinium antarcticum. This demonstrates that the state of knowledge regarding athecate dinoflagellates in the South Atlantic and especially in the Antarctic region is still limited due to a lack of directed investigation.

Temporal and vertical dynamics of diatoms and dinoflagellates in the southeastern Mediterranean Sea

AbstractThe temporal distributions of microphytoplankton were studied monthly over 2 years in the shelf and the offshore waters of the “low nutrients low chlorophyll” (LNLC) southeastern (SE) Mediterranean Sea. The microphytoplankton were comprised mostly of diatoms (0–542 cells L−1, ~4 × 106–44 × 106 cells m−2) of the genera Rhizosolenia, Thalassionema, Chaetoceros, Leptocylindrus and Pseudo-nitzschia, and dinoflagellates (1–89 cells L−1, ~1 × 106–10 × 106 cells m−2) of the genera Tripos (formally known as Ceratium), Ornithocercus, Protoperidinium, Ceratocorys and Dinophysis. During the winter mixing, microphytoplankton abundance was ~2-fold higher than during the stratified summer months, in accordance with the higher inorganic nutrient levels. Diatoms were mostly found in the upper illuminated layers (0–100 m), while dinoflagellate distribution was patchy and spread from surface down to 200 m. We also calculated that diatoms and dinoflagellates contribute negligibly (~4%) to the total vertical carbon flux in the offshore water, suggesting fast recycling of organic matter at the photic layer. Our results provide a baseline to better understand carbon and biogenic silica fluxes at the LNLC SE Mediterranean Sea.

Metabarcoding reveals marked seasonality and a distinctive winter assemblage of dinoflagellates at a coastal LTER site in the Gulf of Naples

AbstractDinoflagellates constitute an abundant and diversified component of marine plankton, mostly associated with stratified conditions typical of late spring through autumn in temperate regions. Yet, difficulties with the identification of many species limit the knowledge of their composition and seasonal succession. Here we use a 3‐year V4‐18S rDNA metabarcoding dataset (4,366,007 reads, 4650 Amplicon Sequence Variants, ASVs) collected on 48 dates at the Long‐Term Ecological Research site MareChiara (LTER–MC) to explore the diversity and temporal distribution of dinoflagellates in the Gulf of Naples (Mediterranean Sea). A large fraction of dinoflagellate ASVs (55%, 68% of the reads) were assigned to 187 species in 85 genera, while 33% (23% of the reads) were attributed to undetermined Syndiniales, and the remainder to unidentified groups. A total of 147 ASVs were assigned at 100% similarity to 135 reference sequences, corresponding to 116 species, 46 of which were putative new records for the Gulf of Naples. Cluster analysis conducted on a normalized dataset of 1199 ASVs identified four sample clusters that corresponded largely to the spring, summer, autumn and winter seasons, respectively, each including samples from all 3 years. Syndiniales were particularly abundant (43.1%) in the winter cluster, whereas Gyrodinium reached higher percentages in the summer and autumn ones (38.6% and 57.8%), Gymnodiniales sensu stricto were more abundant in spring (11.5%) and Gonyaulacales in summer (13.5%). Almost half of the ASVs analysed (561) were significantly associated with one of the four seasonal clusters (p < .05). The winter group of ASVs was particularly rich (348 ASVs) and mainly consisted of naked and parasitic taxa, which are impossible to identify in routine phytoplankton observations in light microscopy. Despite biases mainly ascribed to both the incompleteness of the reference dataset and the limited resolution of the marker gene, the metabarcoding approach has provided new insights into the ecology and distribution of this important component of the plankton, highlighting its marked seasonality along with the existence of a diversified and previously overlooked dinoflagellate community in winter.

Current Information on the Diversity of Dinoflagellates of Ukraine

Presenting current information on the diversity of <i>Dinoflagellata</i> in Ukraine. The use of electron microscopy, as well as molecular genetic research methods over the past 10 years have made it possible to observe significant changes in the taxonomic system of the<i> Miozoa</i> division of the superclass <i>Dinoflagellata.</i> Based on the analysis of 216 literary sources and bringing all the names of dinoflagellates in line with those accepted in the international database AlgaeBase, it was established that the current list of <i>Dinoflagellates</i> of Ukraine includes 368 species (395 infraspecific taxa), belonging to 3 classes, 14 orders, 45 families and 98 genera. The number of species found in Ukraine is an order of magnitude lower than that currently known for<i> Miozoa</i> in the world (3636), and their distribution by order almost coincides and is very uneven: 3 orders include 63% of currently known species in the peace and 71% - in Ukraine. The most diverse orders in Ukraine are<i> Peridiniales</i> (118 species, 32%),<i> Gymnodiniales</i> (82/22%) and<i> Gonyaulacales</i> (60/16%). In comparison with the most complete review by Krakhmalnyi (2011), the species richness of dinoflagellates of Ukraine and their taxonomy underwent significant changes in the last decade. The number of species, orders and genera has increased twice and number of new species and infraspecific taxa has increased by 85 units and one species has been described as new to science. But the species diversity of some dinoflagellates regions of Ukraine remains insufficiently studied, and some of them require additional research. The analysis of the distribution of dinoflagellates in the territorial waters of Ukraine confirmed that most of them inhabit the seas (302 species and infraspecific taxa), which is more then to three times higher than in estuaries (112) and is more to twice those in aquatic complexes on the land (134). Overall, 70% were unique (not found in other ecotopes), while 30% were shared. Naturally, most of them were found in the contact zone between seas and estuaries (14/7%), 4/3% - between the estuaries and land water bodies, 3% were found in the seas and in the land water bodies, and 8/1% were found in all studied ecotopes. This shows the high role of the estuaries, as water contact zones, for the dinoflagellates diversity and the necessity for their additional studies. Among the species occurring on the land water bodies, the largest number is assigned to the Dnieper-Black Sea, Middle Dnieper and Carpathian-Danube algofloristic subprovinces, due to the presence of water contact zones of different origins and greater study of these areas.

Сучасні відомості щодо різноманіття Dinoflagellata України

Present current information on the diversity of Dinoflagellata in Ukraine. The study of the species composition of microalgae in modern climate change remains relevant. Dinoflagellates, especially luminous species, are sensitive to anomalies in the warm Black Sea and can serve as a convenient indicator of the state of aquatic ecosystems due to the rapid response to external influences. The use of electron microscopy, as well as molecular genetic research methods over the past 10 years have made it possible to observe significant changes in the taxonomic system of the Miozoa division of the superclass Dinoflagellata. Based on the analysis of 204 literature sources and revision of the taxonomic composition of dinoflagellates of Ukraine, according to the international database AlgaeBase, it is established that the current list of Dinoflagellates of Ukraine includes 370 species (397 watts), belonging to 3 classes, 14 orders, 45 families and 98 genera. The number of species found in Ukraine is an order of magnitude lower than that currently known for Miozoa in the world (3636), and their distribution by order almost coincides and is very uneven: 3 orders include 63% of currently known species and 71% found in Ukraine. The most diverse in Ukraine are the orders Peridiniales (121 species, 32.4%), Gymnodiniales (82, 22%) and Gonyaulacales (61, 16.4%). Analysis of the distribution of dinoflagellates in the territorial waters of Ukraine by main algae-floristic areas confirmed that most of them live in marine waters (273, 55%), which is twice as large as terrestrial (128, 26%) and a significant proportion occurs in estuaries – 92, 19%). Among the species found on land, the largest number is attributed to the Dnieper–Black Sea (108 taxa) and Carpathian-Danube algae sub-provinces (71) due to the fact that they include contact zones of the main rivers of Ukraine and the Black Sea–Azov waters. Over the last decade, the species composition of dinoflagellates of Ukraine and their taxonomy have undergone significant changes. The number of species, orders and genera has increased, but as a result of the fact that some species have been renamed, the actual number of new species and WWT has increased by 85 units and one species has been described as new to science. But the species diversity of some dinoflagellates regions of Ukraine remains insufficiently studied, and some of them require additional research.

Use of Mass Spectrometry to Determine the Diversity of Toxins Produced by Gambierdiscus and Fukuyoa Species from Balearic Islands and Crete (Mediterranean Sea) and the Canary Islands (Northeast Atlantic).

Over the last decade, knowledge has significantly increased on the taxonomic identity and distribution of dinoflagellates of the genera Gambierdiscus and Fukuyoa. Additionally, a number of hitherto unknown bioactive metabolites have been described, while the role of these compounds in ciguatera poisoning (CP) remains to be clarified. Ciguatoxins and maitotoxins are very toxic compounds produced by these dinoflagellates and have been described since the 1980s. Ciguatoxins are generally described as the main contributors to this food intoxication. Recent reports of CP in temperate waters of the Canary Islands (Spain) and the Madeira archipelago (Portugal) triggered the need for isolation and cultivation of dinoflagellates from these areas, and their taxonomic and toxicological characterization. Maitotoxins, and specifically maitotoxin-4, has been described as one of the most toxic compounds produced by these dinoflagellates (e.g., G. excentricus) in the Canary Islands. Thus, characterization of toxin profiles of Gambierdiscus species from adjacent regions appears critical. The combination of liquid chromatography coupled to either low- or high-resolution mass spectrometry allowed for characterization of several strains of Gambierdiscus and Fukuyoa from the Mediterranean Sea and the Canary Islands. Maitotoxin-3, two analogues tentatively identified as gambieric acid C and D, a putative gambierone analogue and a putative gambieroxide were detected in all G. australes strains from Menorca and Mallorca (Balearic Islands, Spain) while only maitotoxin-3 was present in an F. paulensis strain of the same region. An unidentified Gambierdiscus species (Gambierdiscus sp.2) from Crete (Greece) showed a different toxin profile, detecting both maitotoxin-3 and gambierone, while the availability of a G. excentricus strain from the Canary Islands (Spain) confirmed the presence of maitotoxin-4 in this species. Overall, this study shows that toxin profiles not only appear to be species-specific but probably also specific to larger geographic regions.

Dinoflagellate community structure under a metacommunity perspective: Assessing the relative importance of local filters and spatial dynamics

Metacommunity dynamics, which often underpin species distribution, may provide insights into the mechanisms structuring phytoplankton communities. Contrary to the effects of local filters (e.g., physicochemical parameters), the role of regional scale dispersion on phytoplankton community structure remains far less studied. While most of our knowledge on dinoflagellate community structure relies on niche-based assumptions, local habitats processes may likewise play a significant structuring role. Our aim is to determine the relative contribution of dispersal and local filters to predict the distribution of dinoflagellates, and how they compose local communities. To this effect, metacommunity theory may serve as a basis to describe community changes and to predict harmful algal blooms. Over four annual campaigns, we sampled several biological and physico-chemical attributes along a salinity gradient of three rivers associated to a tropical estuarine complex, the Camamu Bay (Bahia, Brazil). We conducted variance partitioning and multivariate analysis to detect patterns associated to community composition and distribution and to quantify the importance local filters and space (e.g., dispersal) may have in structuring dinoflagellate metacommunities. While our results indicate that local filters had better explanatory power over the biological variability during the dry seasons, when dispersal processes were included in our analysis, greater explanatory power was achieved. In the entire estuary, salinity acts as the most important variable for structuring dinoflagellates, and its effect remained significant during all the sampling campaigns. The differences between the dry and rainy season campaigns may mostly be understood in term of hydrological regimes (e.g., stratification and runoff), which directly impact the dispersal patterns responsible for structuring dinoflagellate community.

Spatial distribution of dinoflagellates from the tropical coastal waters of the South Andaman, India: Implications for coastal pollution monitoring

Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, India, was investigated to assess the anthropogenic impact on coastal water quality. At the densely inhabited Port Blair Bay, the dominance of mixotrophs in water and Protoperidinoids in sediments was attributed to anthropogenic nutrient enrichment and prey availability. A significant decrease in dinoflagellate abundance from inner to outer bay emphasize the variation in nutrient availability. The dominance of autotrophs and Gonyaulacoid cysts at the North Bay highlight low nutrient conditions with less anthropogenic pressure. The occurrence of oceanic Ornithocercus steinii and Diplopsalis sp. could evince the oceanic water intrusion into the North Bay. Nine potentially harmful and red-tide-forming species including Alexandrium tamarense complex, A. minutum were identified in this study. Although there are no harmful algal bloom (HABs) incidences in this region so far, increasing coastal pollution could support their candidature towards the future HABs initiation and development.

Effects of ocean warming on growth and distribution of dinoflagellates associated with ciguatera fish poisoning in the Caribbean

Projected water temperatures at six sites in the Gulf of Mexico and Caribbean Sea were used to forecast potential effects of climate change on the growth, abundance and distribution of Gambierdiscus and Fukuyoa species, dinoflagellates associated with ciguatera fish poisoning (CFP). Data from six sites in the Greater Caribbean were used to create statistically downscaled projections of water temperature using an ensemble of eleven global climate models and simulation RCP6.0 from the WCRP Coupled Model Intercomparison Project Phase 5 (CMIP5). Growth rates of five dinoflagellate species were estimated through the end of the 21st century using experimentally derived temperature vs. growth relationships for multiple strains of each species. The projected growth rates suggest the distribution and abundance of CFP-associated dinoflagellate species will shift substantially through 2099. Rising water temperatures are projected to increase the abundance and diversity of Gambierdiscus and Fukuyoa species in the Gulf of Mexico and along the U.S. southeast Atlantic coast. In the Caribbean Sea, where the highest average temperatures correlate with the highest rates of CFP, it is projected that Gambierdiscus caribaeus, Gambierdiscus belizeanus and Fukuyoa ruetzleri will become increasingly dominant. Conversely, the lower temperature-adapted species Gambierdiscus carolinianus and Gambierdiscus ribotype 2 are likely to become less prevalent in the Caribbean Sea and are expected to expand their ranges in the northern Gulf of Mexico and farther into the western Atlantic. The risks associated with CFP are also expected to change regionally, with higher incidence rates in the Gulf of Mexico and U.S. southeast Atlantic coast, with stable or slightly lower risks in the Caribbean Sea.

Seasonality in the distribution of dinoflagellates with special reference to harmful algal species in tropical coastal environment, Bay of Bengal.

A study was carried out in the coastal waters of Kalpakkam, southeast coast of India, to find out the seasonal variation in dinoflagellate community structure. Samples were collected for a period of 4 years during 2006-2010. During the study 69 species of dinoflagellates were encountered among which Ceratium furca and Prorocentrum micans were most common during all the seasons. Genus Ceratium was found to be the most diverse one with 23 species which was followed by genus Protoperidinium with 16 species. Of 69 species, 27 species were considered as dominant based on their abundance during pre-monsoon (PRM), monsoon (MON) and post-monsoon (POM) periods. Relatively high density and diversity of dinoflagellates were encountered during the PRM period as compared to the MON and POM periods. Abundance pattern of dinoflagellates for three seasons showed the following trend: PRM > POM > MON. Salinity showed a positive correlation with dinoflagellate community showing its importance in dinoflagellate growth and sustenance. Ammonia and phosphate developed negative correlation with dinoflagellate density indicating the utilization of these nutrients by the dinoflagellate community. The presence of three dinoflagellate associations, broadly representing the three seasons experienced at this location, was evident from the cluster analysis. The study revealed presence of 19 relatively abundant toxic/red tide forming dinoflagellate species in the coastal waters of Kalpakkam.

Species-specific dinoflagellate vertical distribution in temperature-stratified waters

Thermal stratification is increasing in strength as a result of higher surface water temperature. This could influence the vertical distribution of vertically migrating dinoflagellates. We studied the diel vertical distribution of the dinoflagellates Heterocapsa triquetra and Prorocentrum minimum using stratified laboratory columns with two thermoclines of different strength (ΔT° = 10 or 17 °C), with below cline temperature of 8 °C. Above the thermocline, nutrient depletion simulated the natural summer conditions in the Baltic Sea. Our study shows that H. triquetra and P. minimum can behave differently in terms of their vertical occurrence, both in space and in time when subjected to thermoclines of different strength. Also, both dinoflagellate species showed species-specific distribution patterns. In the ΔT° = 10 °C treatment, H. triquetra cells performed a diel vertical migration (DVM) behavior just above the thermocline, but not in the ΔT° = 17 °C. In the ΔT° = 17 °C, the cells did not migrate and cell densities in the water column decreased over time. Opposing results were observed for P. minimum, where a DVM pattern was found exclusively below the thermocline of ΔT° = 17 °C, while in the ΔT° = 10 °C treatment, no clear DVM pattern was observed, and the highest number of cells were found in the cold bottom water. These results indicate that an increase in thermal stratification can influence species-specific dinoflagellate distribution, behavior, and survival.

Harmful algal blooms (HABs) associated with phycotoxins in shellfish: What can be learned from five years of monitoring in Bizerte Lagoon (Southern Mediterranean Sea)?

The dynamic of three potentially toxic dinoflagellate genera (Alexandrium spp., Prorocentrum spp., and Dinophysis spp.) and one diatom genus (Pseudo-nitzschia spp.) were studied in the Bizerte Lagoon (Tunisia) over a 5-year period (from 2007 to 2011) and sampled at four sites. Concomitantly, the toxicity of three biotoxin groups, DSP (diarrheic shellfish poisoning), PSP (paralytic shellfish poisoning) and ASP (amnesic shellfish poisoning) were measured in both mussels and oysters collected on farms corresponding to the sampled sites. No correlations between phytoplankton abundances and PSP and DSP toxicity were found in either mussels or oysters, despite toxicity occurrence recorded on or just after the sampling dates. Several hypotheses may explain these results: (i) spatial heterogeneity of dinoflagellate distribution may lead to difficulties in quantitatively assessing harmful algae abundance, (ii) toxin production may not be associated exclusively with phytoplankton abundance, and (iii) mussel or oyster toxicity may better reflect the toxin environment than punctual samplings. Our results support the highly unpredictable nature of blooms and the associated toxicity of HABs. This suggests that monitoring for shellfish safety should include both toxigenic species determination and enumeration along with the use of shellfish as sentinels and bio-integrators of toxins.

春季海南岛近岸海域尿素与浮游生物的脲酶活性

2011年春季(4-5月),对海南岛的海口湾、澄迈湾、文昌八门湾、陵水新村湾和大东海5个海湾的尿素浓度及浮游生物的脲酶活性开展调查研究,结合其它理化环境因子,分析海南岛近岸海域尿素的可利用性及其对该海区浮游植物生长可能产生的影响。结果表明,海南岛近岸水体中尿素平均浓度为2.07-3.30 μmol/L,占总溶解态氮TDN含量的14%-38%,尿素占TDN比例由北向东、南方向递增。浮游生物脲酶活性为0.30-0.84 μmolN·L^-1·h^-1,海口湾最高,从北部向东、南部逐渐减少。各海湾较高水平的尿素和脲酶活性主要分布在排污口、养殖区或旅游区的近岸海域。 硅藻为优势种,甲藻种类少且密度低,部分甲藻密度达到10⁴-10⁵个/L的水体,尿素和脲酶活性也处于较高水平。海区浮游植物细胞密度与脲酶活性或尿素占TDN比例等因子存在相关性,表明尿素是海南海域浮游植物生长不可忽略的重要氮源。尿素在一定程度上促进春季海南岛近岸海域甲藻等浮游植物的生长,可能对浮游植物群落结构的改变产生重要影响。;Field cruises were carried out in the coastal waters of Hainan Island to survey urea concentrations and urease activities together with other environmental parameters. The bioavailability of urea for phytoplankton growth was analyzed based on these results. Results showed that the average concentrations of urea varied from 2.07 to 3.30 μmol/L, which accounted for 14%-38% of total dissolved nitrogen (TDN) and showed the trend to increase from the north to the south and the east. The urease activities of plankton were between 0.30-0.84 μmol N·L^-1·h^-1 with the maximum in the Haikou Bay. Most of the high values of urea concentrations and urease activities were detected in the nearshore waters where sewage draining exit, aquaculture area and the tourist area located. Diatoms were the dominant species in the phytoplankton communities. However, in some stations with dinoflagellates densities as high as 10⁴-10⁵ cells/L, the urea concentrations and the urease activities were also higher comparing with other sites. The phytoplankton biomass correlated well with the urease activities or urea/TDN atomic ratios which suggested the significance of urea as one nitrogen source in the coastal waters of Hainan Island. Urea and NH₄⁺ concentrations were the most important factors responsible for the distribution of dinoflagellates in the northern and the southern waters respectively. The terrestrial input of urea promoted the growth of phytoplankton, in particularly dinoflagellates, therefore urea might play an role in the competition and succession in the phytoplankton community in the coastal waters of Hainan Island during the spring period.

Dominant impact of water exchange and disruption of stratification on dinoflagellate vertical distribution

The vertical positions of four dinoflagellate species in three 48 h periods in late summer in a Swedish fjord (the Gullmar Fjord) reflect changes to the depth of the halocline. During stable, stratified conditions, the chlorophyll a maximum exhibited a diurnal migration pattern, which was disrupted when the halocline was forced closer to the surface by the inflow of more saline water. While conditions were stable, all studied dinoflagellate species were most abundant below the halocline at 06:00 in contrast to the other times of the day when the highest cell concentrations were above the halocline, indicating diurnal vertical migration. However, when wind-induced inflow of more saline water forced the halocline closer to the surface, these patterns were disrupted and there was no sign of diurnal vertical migration. Despite this, there was a vertical heterogeneity in the distribution of dinoflagellates with Dinophysis spp. found mainly above the halocline, while Ceratium spp. also occurred in high cell numbers below the halocline. We acknowledge the importance of representative resolution when sampling in the field, both in time and concerning vertical resolution.

Dynamics of harmful dinoflagellates driven by temperature and salinity in a northeastern Mediterranean lagoon

To attempt to determine the effects of temperature and salinity on the dynamics of the dinoflagellate community, a monthly sampling was carried out from October 2008 to March 2009 at eight sampling stations in Ghar El Melh Lagoon (GML; Mediterranean Sea, Northern Tunisia). Dinoflagellates were dominant among plankton, accounting for 73.9% of the lagoon's overall plankton community, and were comprised of 25 different species among which 17 were reported in the literature as harmful. While no significant difference was found in the distribution of dinoflagellates among the stations, a strong monthly difference was observed. This temporal variability was due to an increase in the abundance of Prorocentrum micans from December to February, leading to a strong decrease in the Shannon diversity index from station to station. At the onset of P. micans development, dinoflagellate abundances reached 1.26.10(5) cells l(-1). A redundance analysis indicates that both temperature and salinity have a significant effect on the dynamics of the dinoflagellate community. Using a generalized additive model, both temperature and salinity appear to have significant nonlinear relationships with P. micans abundances. Model predictions indicate that outbreaks of P. micans may occur at a temperature below 22.5°C and with salinity above 32.5. We discuss our results against a backdrop of climate change which, by affecting temperature and salinity, is likely to have an antagonistic impact on P. micans development and subsequently on the dinoflagellate dynamics in GML.

Dinoflagellates Associated with Freshwater Sponges from the Ancient Lake Baikal

Dinoflagellates are a diverse group of protists that are common in both marine and freshwater environments. While the biology of marine dinoflagellates has been the focus of several recent studies, their freshwater relatives remain little-investigated. In the present study we explore the diversity of dinoflagellates in Lake Baikal by identifying and analyzing dinoflagellate sequences for 18S rDNA and ITS-2 from total DNA extracted from three species of endemic Baikalian sponges (Baikalospongia intermedia,Baikalospongia rectaand Lubomirskia incrustans). Phylogenetic analyses of these sequences revealed extensive dinoflagellate diversity in Lake Baikal. We found two groups of sequences clustering within the order Suessiales, known for its symbiotic relationships with various invertebrates. Thus they may be regarded as potential symbionts of Baikalian sponges. In addition,Gyrodinium helveticum, representatives from the genus Gymnodinium, dinoflagellates close to the family Pfiesteriaceae, and a few dinoflagellates without definite affiliation were detected. No pronounced difference in the distribution of dinoflagellates among the studied sponges was found, except for the absence of the Piscinoodinium-like dinoflagellates inL. incrustans. To the best of our knowledge, this is the first study of the diversity of dinoflagellates in freshwater sponges, the first systematic investigation of dinoflagellate molecular diversity in Lake Baikal and the first finding of members of the order Suessiales as symbionts of freshwater invertebrates.

Saxitoxin effects on the levels of neurotransmitters in different rat brain regions

Event Abstract Back to Event Saxitoxin effects on the levels of neurotransmitters in different rat brain regions Rosa C. Cervantes1*, Rafael Duran1, Lilian F. Faro1 and Miguel Alfonso1 1 Vigo University, Department of Functional Biology and Health Sciences, Spain The health-related environmental relevance of freshwater and marine phytoplankton is principle related to their ability to produce a wide range of toxins. These toxins are dangerous to different life form including man. Saxitoxin (STX) is one of several related toxins that cause paralytic shellfish poisoning (PSP). These toxins are produced by different genus of dinoflagellates (e.g. Alexandrium catenella, Alexandrium tamarense, Karenia brevis). They are powerful neurotoxic compounds which blocks the sodium channels voltage sensitive, entailing to the appearance of the main symptoms of the poisoning by PSP: Muscular paralysis and respiratory depression. Due to the wide geographical distribution of dinoflagellates and its implications in harmful algae bloom, an assessment of the potential risk to human health is needed. The aim of this study was to know the effect that the systemic administration of 5 and 10 μg/Kg STX doses (body weight) produce on the levels of neurotransmitters (biogenic amines) in different male rat brain regions. After three time intervals, 30, 60 and 120 min for the first dose and 30 min for the second one, animals were sacrificed by cervical dislocation. The results obtained showed that STX produced alterations in the levels of neurotransmitters. Conference: 11th Meeting of the Portuguese Society for Neuroscience, Braga, Portugal, 4 Jun - 6 Jun, 2009. Presentation Type: Poster Presentation Topic: Neuronal Communication Citation: Cervantes RC, Duran R, Faro LF and Alfonso M (2009). Saxitoxin effects on the levels of neurotransmitters in different rat brain regions. Front. Neurosci. Conference Abstract: 11th Meeting of the Portuguese Society for Neuroscience. doi: 10.3389/conf.neuro.01.2009.11.124 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Aug 2009; Published Online: 11 Aug 2009. * Correspondence: Rosa C Cervantes, Vigo University, Department of Functional Biology and Health Sciences, Vigo, Spain, rosacarminac@yahoo.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Rosa C Cervantes Rafael Duran Lilian F Faro Miguel Alfonso Google Rosa C Cervantes Rafael Duran Lilian F Faro Miguel Alfonso Google Scholar Rosa C Cervantes Rafael Duran Lilian F Faro Miguel Alfonso PubMed Rosa C Cervantes Rafael Duran Lilian F Faro Miguel Alfonso Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Marine planktonic dinoflagellates of the order Dinophysiales (Dinophyta) from coasts of the tropical Mexican Pacific, including two new species of the genusAmphisolenia

Despite a recent revision of the dinoflagellates of the order Dinophysiales on Mexican coasts and a checklist of dinoflagellates from the Mexican Pacific, many records still need to be confirmed, for there are very few reliable illustrations and/or descriptions. In this paper, species composition and distribution of dinoflagellates belonging to the Dinophysiales, the product of the analysis of net phytoplankton material collected from coasts of the tropical Mexican Pacific (Jalisco to Chiapas) are presented. The material has been studied using light microscopy, although a few species were also studied by scanning electron microscopy (SEM). Forty-one species from five genera were identified, with two new records annotated for the Mexican Pacific:Amphisolenia thrinaxandMetaphalacroma skogsbergii, and two new species of the genusAmphisolenia,Amphisolenia fusiformissp. nov. andAmphisolenia michoacanasp. nov. Illustrations, dimensions and distribution data are provided for each species, and descriptions of the new species are also given.Amphisolenia palmata,A. rectangulata,A. truncata,Dinophysis apicata,D. hindmarchii,Histioneis biremis,H. crateriformis,H. pulchra,Ornithocercus cristatus,O. heteroporoidesandO. orbiculatusare illustrated for the first time in the waters of the Mexican Pacific. The number of species found in this study is relatively low. The speciesDinophysis norvegicaandD. sacculus, reported in previous papers, do not seem to occur in Mexican waters, as their distribution is rather limited to the Mediterranean Sea and the North Atlantic, respectively. Finally, the identity of certain species ofDinophysisand the nature of the new species described here are discussed.

Dinoflagelados em diversos habitats e hidroperíodos na zona costeira do sul do Brasil

Informações sobre a riqueza, densidade, diversidade e distribuição de dinoflagelados em habitats aquáticos (lagoas abertas e fechadas, canais, açudes e áreas úmidas), em relação aos períodos de águas altas e baixas, são apresentadas. O estudo baseou-se em amostragens realizadas em 23 pontos, localizados nas margens leste (área da Lagoa do Casamento) e oeste (área do Butiazal de Tapes) da laguna dos Patos, no ano de 2003. Foram identificados 11 táxons, cuja distribuição teve maior homogeneidade no período de águas altas. Durinskia baltica (Levander) Carty & Cox foi o único táxon cuja distribuição não se alterou pelo hidroperíodo. Peridinium gatunense Nygaard foi uma espécie indicadora de águas altas e P. umbonatum Stein foi indicadora de habitats associados à área do Butiazal de Tapes. Esta área mostrou ter mais alta diversidade de Dinophyceae em relação à área da Lagoa do Casamento, independente do hidroperíodo, refletindo a maior diversidade e especificidade de habitats aquáticos. O tipo de habitat influenciou significativamente (p<0,01) a riqueza, densidade e diversidade de dinoflagelados, e a densidade foi significativamente (p<0,01) influenciada pelo hidroperíodo. A análise de agrupamento mostrou que pH e temperatura da água foram as variáveis abióticas que mais influências tiveram sobre a estrutura da comunidade de dinoflagelados neste estudo.