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Phytoplankton abundance and seasonality in the northeastern Adriatic Sea were directly related to the annual regime of the Po River discharge in the period , there was a shift in the timing of the annual Po River maximum discharge and of phytoplankton maxima from spring to autumn. In addition, the eastern coastal area was greatly influenced by oligotrophic karstic rivers and the Eastern Adriatic Current. Dominant phytoplankton taxa were defined on the basis of abundance and frequency of appearance. Such an approach may help in the comparison of phytoplankton communities within different environments. The dominant taxa were the diatoms Cerataulina pelagica, Chaetoceros socialis, Chaetoceros vixvisibilis and Pseudo-nitzschia spp., which appeared at maximum abundances )10 6 cells l -1 in more than 20% of samples. Among other phytoplankton, the most common was the coccolithophorid Emiliania huxleyi (maximum abundance of 2=10 5 cells l -1 in 50% of samples), and the dinoflagellate Prorocentrum minimum (maximum abundance of 3=10 5 cells l -1 in 12% of samples). The present state of the phytoplankton community may provide valuable information for evaluation of possible future environmental changes in the shallow Mediterranean ecosystem.

Summary:During the June 2010 survey of phytoplankton and physicochemical parameters in the Krka River estuary (eastern Adriatic Sea), a cryptophyte bloom was observed. High abundance of cryptophytes (maximum 7.9×10 6 cells l -1 ) and high concentrations of the class-specific biomarker pigment alloxanthine (maximum 2312 ng l -1 ) were detected in the surface layer and at the halocline in the lower reach of the estuary. Taxonomical analysis revealed that the blooming species was Plagioselmis cf. prolonga. Analysis of the environmental parameters in the estuary suggested that the bloom was supported by the slower river flow as well as the increased orthophosphate and ammonium concentrations. The first record of a cryptophyte bloom in the Krka River estuary may indicate that large-scale changes are taking place in the phytoplankton community. Such changes could have a major impact on the natural ecosystem dynamics and the mariculture production in the area.Keywords: estuarine ecosystem; phytoplankton bloom; cryptophytes; chemotaxonomy; Mediterranean Sea; Krka River estuary.Proliferación de una criptófita en un estuario mediterráneo: alta abundancia de Plagioselmis cf. prolonga en el estuario del río Krka (Adriático) Resumen: Se observó una proliferación de una criptófita durante el estudio del fitoplancton y de los parámetros fisicoquími-cos en el estuario del río Krka (Adriático) en junio de 2010. La abundancia más alta de criptofitas (máximo 7.9×10 6 células l -1 ) y las mayores concentraciones del pigmento marcador específico de la clase, la aloxantina (máximo 2312 ng l -1 ), fueron detectados en la capa superficial y en la haloclina en el tramo inferior de la ría. El análisis taxonómico reveló que la especie que proliferó fue Plagioselmis cf. prolonga. El análisis de los parámetros ambientales del estuario sugirió que la proliferación estaba favorecida por el caudal lento del río, así como el aumento de las concentraciones de ortofosfato y amonio. El hecho de registrar por primera vez una proliferación de una criptófita en el estuario del río Krka podría indicar cambios a gran escala en la comunidad de fitoplancton. Tales cambios podrían tener un impacto importante en la dinámica de los ecosistemas naturales y la producción de la maricultura en la zona.Palabras clave: estuario; proliferación de fitoplancton; criptófitas; quimiotaxonomía; mar Mediterráneo; estuario del río Krka.Citation/Como citar este artículo: Šupraha L., Bosak S.,

Holographic microscopy has emerged as a tool for in situ imaging of microscopic organisms and other particles in the marine environment: appealing because of the relatively larger sampling volume and simpler optical configuration compared to other imaging systems. However, its quantitative capabilities have so far remained uncertain, in part because hologram reconstruction and image recognition have required manual operation. Here, we assess the quantitative skill of our automated hologram processing pipeline (CCV Pipeline), to evaluate the size and concentration measurements of environmental and cultured assemblages of marine plankton particles, and microspheres. Over 1 million particles, ranging from 10 to 200 μm in equivalent spherical diameter, imaged by the 4‐Deep HoloSea digital inline holographic microscope (DIHM) are analyzed. These measurements were collected in parallel with a FlowCam (FC), Imaging FlowCytobot (IFCB), and manual microscope identification. Once corrections for particle location and nonuniform illumination were developed and applied, the DIHM showed an underestimate in ESD of about 3% to 10%, but successfully reproduced the size spectral slope from environmental samples, and the size distribution of cultures (Dunaliella tertiolecta, Heterosigma akashiwo, and Prorocentrum micans) and microspheres. DIHM concentrations (order 1 to 1000 particles ml−1) showed a linear agreement (r2 = 0.73) with the other instruments, but individual comparisons at times had large uncertainty. Overall, we found the DIHM and the CCV Pipeline required extensive manual correction, but once corrected, provided concentration and size estimates comparable to the other imaging systems assessed in this study. Holographic cameras are mechanically simple, autonomous, can operate at very high pressures, and provide a larger sampling volume than comparable lens‐based tools. Thus, we anticipate that these characterization efforts will be rewarded with novel discovery in new oceanic environments.

The diatom genus Proschkinia is a common element of biofilms covering diverse substrata in saline inland or shallow coastal environments. It can be distinguished from other naviculoid taxa by its lanceolate valves with a fistula located within the central area and numerous open girdle bands with a U-shaped cross-section and a single row of perforations on the internal side of the fold. Despite this distinct morphology, frustules of Proschkinia are typically weakly silicified and often overlooked when cleaned diatom material is analysed. The current paper describes six new species of Proschkinia: P. browderiana sp. nov., P. lacrimula sp. nov., P. maluszekiana sp. nov., P. sulcata sp. nov., P. torquata sp. nov. and P. vergostriata sp. nov., found in numerous samples of marine organisms, such as sea turtles (including sea turtle museum specimens), sea turtle-associated barnacles and seagrass from across the three oceans. Some of the newly described taxa were found on multiple individuals belonging to different sea turtle species, whereas others were in samples collected from different continents. Molecular phylogenetic analysis indicated that examined Proschkinia strains formed a monophyletic clade, sister to Fistulifera.

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Bosak, Sunčica; Godrijan, Jelena; Šilović, Tina. Dynamics of the marine planktonic diatom family Chaetocerotaceae in a Mediterranean coastal zone // Estuarine, coastal and shelf science, 180 (2016) 69-81. ABSTRACT 13 The planktonic diatoms belonging to two genera Chaetoceros and Bacteriastrum, included 14 within the family Chaetocerotaceae, are ecologically important as they represent a constitutive 15 component of the phytoplankton in the coastal regions and are often among bloom-forming 16 taxa. We analysed the chaetocerotacean species composition and abundances in the coastal 17 area of northeastern Adriatic in a biweekly study conducted from September 2008 to October 18 2009 with the aim of investigating seasonal dynamics and species succession on the finer 19 temporal scale and determining the most important ecological factors influencing their 20 distribution. The study identified seven Chaetoceros and three Bacteriastrum species as major 21 phytoplankton components showing the clear annual succession and two types of blooms (one 22 species/multi species) governed by differing ecological conditions. Autumn bloom was 23 composed of 20 chaetocerotacean species with Chaetoceros contortus and C. vixvisibilis 24 alternating in dominance. Summer period was characterized by spreading of freshwater from 25 the Po River up to the eastern coast increasing availability of phosphate which triggered the 26 monospecific Chaetoceros vixvisibilis bloom. We explained the chaetocerotacean dominant 27 species succession pattern by the environmental parameters, with the temperature, salinity and 28 phosphate availability as most important factors driving the species seasonality.29 30 31 32 33 34 Highlights 35  First coherent investigation of temporal dynamics and species succession of 36 marine planktonic diatom family Chaetocerotaceae 37  Two types of blooms (one species/multi species) are governed by differing 38 ecological conditions 39  The succession pattern of dominant chaetocerotacean species was explained by 40 temperature, salinity and phosphate availability as the most important factors 41 driving the species seasonality 42 43 1. Introduction 44 The family Chaetocerotaceae Ralfs in Pritchard (1861) include cosmopolitan diatoms, 45 notably thriving in the phytoplankton of coastal regions (Rines and Hargraves, 1988), and 46 play an important role in neritic food webs and biogeochemical carbon and silica cycles. The 47 hallmarks of this family are setae, long and hollow silicate spine-like projections protruding 48 from the valve surface (Round et al., 1990). The strong and robust setae can irritate fish gills 49 and cause excess mucus secretion and damage, thus certain species have been characterized as 50 nuisance and harmful to fish and invertebrates (Hallegraeff et al., 2003; Smayda, 2006). 51Members of this family are important model species in not only in ecology and physiology, 52 but also in toxicology and nanomaterial studies (Nagao et al., 2010; Peng et al., 2011; 53 Osterholz et al., 2014). 54Cha...