This research has proved the occurrence of pre-Tertiary palynomorphs within the Buya Formation of the Sula Island. Most palynomorphs have Australian affi nity and appear in most Mesozoic basins in Australia and in Papuan Basin of Papua New Guinea. The palynomorph assemblage mostly consists of spores as well as dinofl agellates. Three micro-fl ora zones can be defi ned referring to the existing index spores, including (from older to younger zone) Contignisporites cooksoniae zone, Murospora fl orida zone and Retitriletes watheroensis zone. Meanwhile, four dinofl agellate zones enable to be constructed such as (from older to younger zone) Caddasphaera halosa zone, Wanaea clathrata-Wanaea indotata zone, Dingodinium swanense zone and Criboperidinium perforans zone-younger zone. Both zonations suggest that the age of the Buya Formation is Middle to Late Jurrasic or Bathonian to Tithonian. From the palaeobiogeographic point of view, the similarity between palynomorphs from the Buya Formation of the Sula Island and those from the Mesozoic sediment of Australia suggests land connection between both areas during Middle to Late Jurassic. It suggests that, during this age, the study area attached the Australian Continent which was situated far South from the equatorial. The study area appears in its recent position during Neogene.

Modeling the life cycle of four types of phytoplankton and their bloom mechanisms in a benthic-pelagic coupled ecosystem

Microalgae such as dinoflagellate and diatom are the major food source of bivalve species, and sufficient food intake contributes to the immunity and the growth of bivalves. In the present study, a monoamine oxidase gene (named as CgMAO), which is the rate-limiting enzyme of norepinephrine (NE) biosynthesis, was cloned from C. gigas. After the oysters were fed with a diet rich in diatom for 21 and 40 d, the NE contents in oyster serum, as well as the mRNA expression of CgMAO in oyster haemocytes, increased significantly compared with control group. Besides, the mRNA expression of cytokines CgTNF-1 and CgIL17-5 in haemocytes and the activities of immune-related enzymes (SOD and LYZ) in oyster serum also increased significantly after diatom feeding. These results collectively suggested that sufficient microalgae intake might significantly enhance the antibacterial capacity in oyster by prompting the biosynthesis of NE and triggering the subsequent antibacterial processes modulated by NE.

Mitochondrial DNA (mtDNA) is a universal hallmark of aerobic eukaryotes. That is why the recent suggestion by John et al. (2019) that the aerobic dinoflagellate Amoebophrya sp. strain AT5 (Syndiniales) lacks mtDNA was so remarkable. Here, by reanalysing recently published genomic and transcriptomic data from three Amoebophrya strains, we provide evidence of a cryptic, highly reduced mtDNA in this clade. More work is needed before one can definitively say if Amoebophrya has or does not have a mtDNA, but for now the data are pointing towards the existence of one. Ultimately, we urge caution when basing supposedly absent genomic features on single line evidences.

Ostreopsis cf. ovata, a benthic toxic marine dinoflagellate, has been recorded along Italian coasts since the '90, but large bloom events have been reported only in recent years. In 2005, a monitoring programme started along the Ligurian coast (North-western Mediterranean), where time series of cell abundances have been collected for several sites, together with a range of related environmental variables. Data of cell abundances in 15 sites, together with environmental data provided by meteo-marine forecasting models used by the Regional Environmental Agency (ARPAL), have been used to implement a predictive modelling tool, able to forecast Ostreopsis cells concentration threshold exceedance as a function of meteo-marine forecasts. Starting from the experience of the predictive model implemented in 2015, the Quantile Regression Forest (QRF) has been applied: the model has been trained on past data (from 2015 until 2017) and tested with data taken during the two last available years (2018 and 2019). The use of this extremely adaptable regression model to evaluate threshold exceedance has shown a good capacity to predict overcoming events at a given spatial location. This tool can help the Regional Agency in the decision making process, providing an alert when/where a given alarm threshold is exceeded in order to trigger the emergency procedures. This is a first step in defining a predictive sampling strategy able to better capture bloom events. Keywords: classification, regression, machine learning, environmental data, Ostreopsis

Analysis of Poisoning Cases, Monitoring and Risk Warning for Marine Toxins (TTX, PSP and CTXs) in Taiwan

The digestive glands of marine molluscs are colonized by a large number of microorganisms, and the structure and function of bacterial community could be severely affected by diets. Microalgae is the main food and energy sources for bivalves, while the impact of phytoplankton composition on the bacterial community as well as the health of bivalves are still not well understood. In the present study, the bacterial communities in digestive glands of oyster Crassostrea gigas fed with different diets were compared based on the high-throughput sequencing of partial 16S rRNA gene. There were significant differences of bacterial composition rather than diversity in digestive glands between the oysters fed with diatom dominant diet (Group N, mainly made up of Nitzschia closterium f.minutissima) and dinoflagellate dominant diet (Group P, mainly made up of Prorocentrum micans). The abundances of Prevotella, Vibronaceae, Ruminococcaceae, and Polaribacter were significantly higher in Group N (p < 0.05), and the abundances of Streptophyta and Acidimicrobiales were significantly higher in Group P (p < 0.05). According to the functional prediction results, the bacterial community in Group P displayed weaker capacities of Kdo2-lipid A biosynthesis as well as taurine degradation, and a stronger capacity of glycolysis compared with the bacterial community in Group N. The higher phylogenetic clustering degree of the bacterial community in Group P (p < 0.05) indicated the higher host selectivity on bacteria. These results suggested that the change of phytoplankton composition of diet would have large effects on bacterial communities in oyster digestive glands. The bacterial community in digestive glands of oysters living in dinoflagellate dominant waters would produce harmful impact to hosts. The present study provided a new perspective to explore the potential mechanism for the massive mortalities of oysters.

This is the fi rst publication to present palynological study on the Permian marine sediments of West Timor. This is aimed to evaluate its palynomorph content. Similar studies have been performed on the Permian sediments which mostly focus on non-marine sediments. 15 surface samples were collected from Lilana river outcrop which comprises the alternation of calcareous shale and sandstone. This outcrop is assumed to represent some parts of Bisane Formation. Standard preparation methods were employed to extract palynomorphs including acid maceration and oxidation. This study applies quantitative method which requires counting of palynomorphs in each sample. This study provides low to moderate pollen recovery which mostly consists of striate and non-striate bisaccates as well as trilete monosaccates. The age restricted taxa appearing in the non-marine sediments also present in the studied samples to mark Permian age such as Protohaploxypinus samoilovichi, Lunatisporites pellucidus, Falcisporites australis, Plicatipollenites malabarensis and Cannanoropollis janakii. On the other hand, common occurrence of marine dinofl agellates of Dapsilidium langii and Veryhachim reductum combined with abundant macrofossil of chrinoids confi rm a shallow marine paleoenvironment. Common green algae of Tasmanites sp. is a firmed evidence for the appearance of potential source rock of hydrocarbon within the Permian shallow marine sediments of West Timor.

The dinoflagellates of the genus Ceratium Schrank are frequent inhabitants in many bodies of water of temperate regions of countries, such as Great Britain, Canada, Germany, Hungary, Japan, Romania, Spain, Sweden and the United States (Nicholls et al., 1980; Hickel, 1985 Lindstrom, 1992; Wu & Chou, 1998; Caraus, 2012), in subtropical regions of South Africa and Australia (Whittington et al., 2000) and since 1997, high densities have been found in tropical and subtropical bodies of water in South America, mainly in Argentina, southern Brazil, Chile and Bolivia (Guerrero & Echenique, 1997, Mac Donagh et al 2005, Santos-Wisniewski et al 2007, Matsumura-Tundisi et al., 2010, Oliveira et al. 2011, Boltovskoy et al 2013, Cavalcante et al. 2013, 2016, Moreira et al. 2015, Almanza et al. 2016, Marinelarena et al. 2016, Morales, 2016).

The genus Gambierdiscus is a recognized group of marine epiphytic-benthic dinoflagellates that produce the toxins that cause ciguatera fish poisoning (CFP). To date, thirteen species and six ribotypes of Gambierdiscus have been identified, and multiple species commonly co-occur within a single site or epiphyte community. Toxicity can vary by species, thus it is important to be able to differentiate among species for research and monitoring purposes. Gambierdiscus species have very similar morphological characteristics and are difficult or impossible to distinguish using light microscopy. DNA sequencing has been an important tool in the definition of Gambierdiscus species, but it can be time-consuming and relatively expensive. To provide an alternative approach, a PCR-RFLP protocol was developed for efficient, rapid, and cost-effective identification of Gambierdiscus strains isolated from the Gulf of Mexico and Caribbean Sea, where CFP cases and Gambierdiscus spp. have been reported. The assay targets the D1-D2 hypervariable regions of the large subunit ribosomal RNA gene and uses a single restriction enzyme, BsrI. This method produces distinct RFLP banding patterns for the six species of Gambierdiscus reported from the Gulf of Mexico and Caribbean Sea, and also distinguishes them from four Pacific endemic species. This method was successfully used to type 465 clonal isolates of Gambierdiscus from the U.S. Virgin Islands and Akumal Beach - Mexico This BsrI PCR-RFLP method expands the tools available to researchers and managers engaged in monitoring activities and ecological studies.

The International Berriasian Working Group (ISCS) suggested primary and secondary marker “datums” to fix the basal Berriasian boundary and thus to define the Jurassic-Cretaceous boundary (Wimbledon et al., 2011, 2013). Two primary markers Calpionella , as well as calcareous nannoplankton, are practically unknown in the Boreal Realm. Testing and calibration of these markers, as well as of fossils of radiolarians and other signals, in the most complete sections, were declared as an important task for the near future. In the Tethys, the Jurassic-Cretaceous boundary based on radiolarians falls inside zone UAZ 13 of Baumgartner et al. (1995), whereas in the palaeo-Pacific it corresponds to the boundary between zones 4 and 5 of Pessagno et al. (2009), and in boreal Siberia it probably falls between the biohorizons of Parvicingula haeckeli and P. khabakovi . The radiolarian events at the Jurassic-Cretaceous boundary in the boreal successions of Russia can be proposed to be used as an additional biomarker to help develop new integrated boundary criteria. Thus, as the first appearance of the zonal species Calpionella alpina , which defines the Jurassic and Cretaceous boundary, coincides with the first occurrence of the calcareous dinocyst zonal species Stomiosphaerina proxima (Rehakova, 2000), it is logical to propose a calcareous dinoflagellate, widely represented in the Upper Jurassic-Lower Cretaceous Bazhenovo Formation of Siberia, as a secondary marker

Los dinoflagelados bentonicos nocivos (DBN) pueden generar intoxicaciones severas, de alli la importancia de su estudio. Objetivo: Se evaluaron la composicion y abundancia de DBN asociadas con el sustrato arenoso en dos playas de la isla de Margarita, Venezuela. Metodologia: Los microorganismos se recolectaron mensualmente entre enero y julio de 2015 en la zona infralitoral de cada playa. Se midio la salinidad y la temperatura superficial del agua de mar. Para cuantificarlos se uso el metodo de Utermohl y se examinaron en un microscopio invertido. Resultados: Se identificaron 22 especies, siendo el genero mas abundante Prorocentrum (35%). La abundancia total de DBN no vario entre ambas localidades (p>0,05). En playa Pampatar, la variacion mensual fue evidente, los mayores valores (48 Cel/cm2) se presentaron en mayo, al igual que por tamano de malla (30 μm=49 Cel/cm2). No se detecto relacion directa entre las variables ambientales y las especies de DBN. Por otra parte, en playa Barbasco se detectaron diferencias significativas entre las estaciones y con el tamano de poro, registrandose la mayor abundancia en la estacion S6 y la abertura de malla de 30 μm (41 Cel/cm2 y 36 Cel/cm2 respectivamente). Conclusiones: La mayoria de las especies reportadas en este estudio poseen un estatus nocivo considerable y pueden desencadenar floraciones algales nocivas (FAN) en areas donde se realiza la pesca artesanal de peces y moluscos de interes comercial en la isla de Margarita, Venezuela.

Ostreopsis cf. ovata is a toxic epiphytic dinoflagellate widely distributed in warm waters that often co-occur with species of the genera Coolia , Fukuyoa , Gambierdiscus and Prorocentrum . We investigated a strain isolated from the coast of Ubatuba, Brazil (South-West Atlantic Ocean) by light and epifluorescence microscopies; we also report molecular data based on the LSU rDNA and ITS markers. Cells were 35-65 µm in the dorso-ventral diameter and 20-40 µm wide. We obtained the sequence of a ~1900 base pair region of the rRNA gene cistron. In the LSU rDNA phylogeny, the sequences under the names O. ovata and O. cf. ovata branched into three clades. The ITS marker showed greater resolving power and the sequences of O. ovata / O. cf. ovata split into five clades. Our ITS sequence branched in a clade with sequences of strains from the Mediterranean Sea, European Atlantic coasts, subtropical NE Atlantic, other sequences from Brazil at Rio de Janeiro, and a few sequences from Japan. The cell dimensions and thecal plate arrangement were under the variability range reported in other ocean regions. Our observations confirm O. cf. ovata as the most commonly recorded species of Ostreopsis in the SW Atlantic Ocean. Ostreopsis cf . ovata co-occurred with Coolia malayensis in Brazil and Asia, but it has been commonly reported from the Mediterranean Sea, where C. malayensis has not yet been recorded; while Coolia malayensis has been reported from the Caribbean Sea, but not O. ovata . With the current knowledge, it is difficult to understand the factors that determine the biogeography of the tropical epiphytic dinoflagellates.

Physical and chemical data including temperature and transparency of the water, pH, dissolved oxygen, hardness and alcalinity, as well as primary production and details of the phytoplankton structure in the lake of Tequesquitengo, Morelos, Mexico between March 7 and May 22, 1981 are presented here. Fifteen species were identified: 13 in bottle samples and 2 in one series taken with net, five taxa could be identified to genus level; all taxa belong to five algal lasses; the diatom Navicula cryptocephala and the dinoflagellate Peridinium cinctum were the most abundant species. During this study, while dominance decreased by one single species the diversity and eveness indices were increasing. At the end of May the green and the blue-green algae increase in numerical importance. Gross primary produ ction and phytoplankton biornass were significantly related. Influence by stratification and mixed periods over the variation of some variables and phytoplankton species succession is discussed.

Unravelling the functional genetics of dinoflagellates: a review of approaches and opportunities

As early as 1925, the great protozoologist Edouard Chatton classified microorganisms into two categories, the prokaryotic and the eukaryotic microbes, based on light microscopical observation of their nuclear organization. Now, by means of transmission electron microscopy, we know that prokaryotic microbes are characterized by the absence of nuclear envelope surrounding the bacterial chromosome, which is more or less condensed and whose chromatin is deprived of histone proteins but presents specific basic proteins. Eukaryotic microbes, the protists, have nuclei surrounded by a nuclear envelope and have chromosomes more or less condensed, with chromatin-containing histone proteins organized into nucleosomes. The extraordinary diversity of mitotic systems presented by the 36 phyla of protists (according to Margulis et al., Handbook of Protoctista, 1990) is in contrast to the relative homogeneity of their chromosome structure and chromatin components. Dinoflagellates are the exception to this pattern. The phylum is composed of around 2000 species, and characterized by unique features including their nucleus (dinokaryon), dinomitosis, chromosome organization and chromatin composition. Although their DNA synthesis is typically eukaryotic, dinoflagellates are the only eukaryotes in which the chromatin, organized into quasi-permanently condensed chromosomes, is in some species devoid of histones and nucleosomes. In these cases, their chromatin contains specific DNA-binding basic proteins. The permanent compaction of their chromosomes throughout the cell cycle raises the question of the modalities of their division and their transcription. Successful in vitro reconstitution of nucleosomes using dinoflagellate DNA and heterologous corn histones raises questions about dinoflagellate evolution and phylogeny. [Int Microbiol 18(4):209-216 (2015)].

Fil: Guler, Maria Veronica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Bahia Blanca. Instituto Geologico del Sur; Argentina. Universidad Nacional del Sur; Argentina

본 연구는 마이크로코즘에서 적조생물 Cochlodinium polykrikoides을 살조하기 위해 사용된 화학물질과 황토의 처리 후 미소생물그룹의 단주기 변화를 파악하였다. 황토 4g 과 10g에서 적조생물의 살조효과는 20%이하로 낮게 관찰된 반면, 화학물질(TD49)의 0.8 μM 에서는 대상생물이 85%이상 제어되었다. 미소생물그룹에서 박테리아는 모든 실험군에서 조사 1 일 후 현저하게 증가하였고, 2일 후 가장 높게 관찰된 후 점차적으로 감소하는 경향을 관찰하였다. 대조적으로 종속영양편모 충은 조사 3-5일 경과 후 현저하게 높게 증가하였다. TD49처리군에서 박테리아가 2일후 점차적으로 감소한 것은 포식자인 HNF의 증가로 기인된 것으로 파악되었다. 또한 피각을 형성하지 않는 섬모충 Uronema sp.,의 증가는 박테리아의 증가 후 2-3일의 시간차를 두고 반응하는 특색을 관찰하였다. 즉 이는 적조생물이 살조된 후 분해되는 과정에서 박테리아의 현저한 증식을 일으켰고, 이와 함께 포식자 HNF와 Uronema sp.는 일정의 시간차를 두고 높은 개체수를 유지 한 것으로 판단되었다. 이와 같은 경향은 살조물질 TD49처리군에서 두드려졌다. 특히. 사이즈가 큰 무각섬모충 Euplotes sp. 개체수는 HNF와 Uronema sp.의 현저한 증가 후 높게 관찰되는 특성을 보였다. 결과적으로 살조제 TD49물질은 미소생물그룹에 긍정적인 효과 를 가져왔고, 이는 박테리아, HNFs 섬모충으로 이어지는 먹이망의 에너지 흐름이 효율적으로 작용하고 있다는 것을 시사할 수 있었다.

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A paleoenvironmental characterization of the Santana Formation sedimentary rocks (4-BO-1-PE well), Araripe Basin, Late Aptian-Early Albian, was accomplished through qualitative and quantitative analyses of the palynofl ora. Palynological and lithological evidence indicate a predominantly continental depositional environment for this section, composed by a fl uvial, lacustrine deltaic system in a semi-arid climate. The detection of a single dinofl agellate cyst suggests that small sea ingressions took place during Aptian-Albian times in the region, as also verifi ed in other coeval strata of marginal Brazilian Cretaceous basins. Comparisons with palynofl oras from other continents support the hypothesis that this assemblage belongs to the North-Gondwana microfl oristic province.