The genetic diversity of Mesodinium and associated cryptophytes

Ciliates from the genus Mesodinium are globally distributed in marine and freshwater ecosystems and may possess either heterotrophic or mixotrophic nutritional modes. Members of the Mesodinium major/rubrum species complex photosynthesize by sequestering and maintaining organelles from cryptophyte prey, and under certain conditions form periodic or recurrent blooms (= red tides). Here, we present an analysis of the genetic diversity of Mesodinium and cryptophyte populations from 10 environmental samples (eight globally dispersed habitats including five Mesodinium blooms), using group-specific primers for Mesodinium partial 18S, ITS, and partial 28S rRNA genes as well as cryptophyte large subunit RuBisCO genes (rbcL). In addition, 22 new cryptophyte and four new M, rubrum cultures were used to extract DNA and sequence rbcL and 18S-ITS-28S genes, respectively, in order to provide a stronger phylogenetic context for our environmental sequences. Bloom samples were analyzed from coastal Brazil, Chile, two Northeastern locations in the United States, and the Pribilof Islands within the Bering Sea. Additionally, samples were also analyzed from the Baltic and Barents Seas and coastal California under non-bloom conditions. Most blooms were dominated by a single Mesodinium genotype, with coastal Brazil and Chile blooms composed of M. major and the Eastern USA blooms dominated by M. rubrum variant B. Sequences from all four blooms were dominated by Teleaulax amphioxeia-like cryptophytes. Non bloom communities revealed more diverse assemblages of Mesodiniurn spp., including heterotrophic species and the mixotrophic Mesodinium Chamaeleon. Similarly, cryptophyte diversity was also higher in non-bloom samples. Our results confirm that Mesodinium blooms may be caused by M. major, as well as multiple variants of M, rubrum, and further implicate I amphioxeia as the key cryptophyte species linked to these phenomena in temperate and subtropical regions.Peer reviewe

Multidisciplinary scientific cruise to the Rio Grande Rise

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Seasonal contrasts in abundance and reproductive parameters of Penilia avirostris (Cladocera, Ctenopoda) in a coastal subtropical area

We studied the population dynamics and the reproductive biology of Penilia avirostris during three consecutive years on the inner shelf off Ubatuba, Brazil. Penilia avirostris individuals and its eggs and embryos were counted, measured, and classified into stages. The species occurred throughout the studied period, in a wide temperature range (14.8-28.2A degrees C). Cladoceran densities were usually higher (> 2,000 ind m(-3)) in warm seasons, when the water column was stratified as a consequence of bottom intrusions of the cold- and nutrient-rich South Atlantic Central Water. Juveniles, non-reproducing females, and parthenogenic females were the dominant developmental stages. Males and gamogenic females were rare and only occurred when females reached peak abundances. This suggests that in tropical and subtropical coastal seas gamogenesis in P. avirostris is not as common as in temperate seas, but may play a significant role in the density-dependent control of the population preceding unfavourable periods.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2007/56931-1]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[306266/2007-5]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Assessment of plankton community and environmental conditions in São Sebastião Channel prior to the construction of a produced water outfall

Plankton community and hydrological conditions were assessed as a part of ao environmental diagnosis in São Sebastião Channel, before the building of a submarine outfall of produced water from the oil maritime terminal of PETR08RÁS. Samples were collected in twenty oceanographic stations located in the oil terminal neighboring area, during the springtime of 1991. Oissolved inorganic nutrients and chlorophyll-a concentrations observed indicate an oligo-mesotrophic environment. Phenols and sulfides were absent, 800 values, except for three sampling points, were characteristic of unpolluted environments, although oil and grease were found in half of the sampled stations. Phytoplankton and zooplankton communities presented high diversity and evenness indices for the entire area. Phytoplankton was dominated by phytoflagel1àtes and zooplankton was dominated by copepods, mostly Paracalanus quasimodo. Plankton community composition was similar to that from adjacent regions under low anthropogenic influence.<br>A comunidade planctônica e condições hidrológicas foram avaliadas como parte de um diagnóstico ambiental no Canal de São Sebastião, previamente à construção de um emissário submarino de água de produção, oriunda do terminal marítimo da PETROBRÁS. As amostras foram coletadas em vinte estações oceanográficas situadas na área adjacente ao terminal petrolífero, durante a primavera de 1991. As concentrações de nutrientes inorgânicos dissolvidos e de cIorofila-a obtidas, indicam um ambiente oligo-mesotrófico. Fenóis e sulfetos não foram detectados e os valores de 080, com exceção de três pontos, foram característicos de ambientes não poluídos, apesar da contaminação por óleos e graxas ter sido observada em metade das estações amostradas. O fito e o zooplâncton apresentaram altos índices de diversidade e equitatividade para toda área estudada. O fitoplâncton foi dominado por fitoflagelados, enquanto que o zooplâncton foi dominado por copépodos, especialmente Paracalanus quasimodo. A composição da comunidade planctônica foi similar à de outras áreas adjacentes, sob baixa pressão aotropogênica

Bio-optical characteristics along the Strait of Magallanes

The Straits of Magallanes at the tip of South America connects the Atlantic and Pacific Oceans. The variability in the absorption characteristics by phytoplankton (a(440)), non-pigmented particles, NPP (aNPP(440)), and chromophoric dissolved organic matter, CDOM (aph(440)), measured along the Straits in late summer 2011 (R/V Melville MV1102 cruise), was analyzed. Satellite-derived monthly PAR data showed that at the time of the cruise the western sector was exposed to a low-light environment (~16 mol quanta m-2d-1) while the eastern sector received higher irradiance (~28 mol quanta m-2 d-1). In the Patagonian Shelf total absorption was dominated by phytoplankton (up to 76%; aphy(440)=0.265 m-1), while in the Atlantic Sector of the Straits, the major contributor was NPP (up to 42%; aNPP(440)=0.138 m-1), and in the Pacific Sector of the Straits CDOM contributed up to 80% of the total absorption (ay(440)=0.232 m-1). These changes could be related in part to the input of fresh water from glacier melting and rain in the Pacific Sector (ay(440) vs salinity r=0.98). The carbon biomass (C) was composed in its majority by pico-phytoplankton and secondly by nano-phytoplankton, with exception of the Atlantic Sector where the micro-phytoplankton dominated. Carbon to chlorophyll-a ratios (C:Chla) were very low throughout the Straits (average of 6) because of photoacclimation to the extremely lowlight. Complementary pigments data obtained in spring 2003 by the BEAGLE expedition indicated the predominance of diatoms all along the Straits, but the bio-optical trend resembled the one found in late summer 2011, i.e., NPP dominated the absorption in the well mixed Atlantic Sector, phytoplankton in the Middle Sector, and CDOM in the Pacific Sector. These results emphasize that underwater light is the major factor affecting phytoplankton growth and physiology, and that prevalent physical and geochemical conditions play an important role regulating the bio-optical properties in this heterogeneous area. These effects should be considered to adjust parameters (such as C:Chla) when running biogeochemical models for this region.Fil: Lutz, Vivian Alicia. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Frouin, Robert. University Of California At San Diego. Scripps Institution Of Oceanography; Estados UnidosFil: Negri, Ricardo Martin. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Silva, Ricardo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Pompeu, Mayza. Universidade de Sao Paulo; BrasilFil: Rudorff, Natalia. Centro de Previsao de Tempo e Estudos Climaticos. Instituto Nacional de Pesquisas Espaciais; BrasilFil: Cabral, Anderson. Universidade Federal Do Rio de Janeiro. Instituto de Biología; BrasilFil: Dogliotti, Ana Inés. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Martinez, Gustavo. Ministerio de Agricultura, Ganadería y Pesca; Argentin

Comparação de produtos MODIS-Aqua de cor do oceano com dados in situ em águas costeiras de Ubatuba (SP), plataforma continental sudeste brasileira

Ocean colour remote sensing is an important tool for environmental monitoring, especially involving climate change and anthropogenic impacts. Besides the chlorophyll a concentration (Chla) and the remote sensing reflectance (Rrs) of the oceans surface layers, new products, such as, the diffuse attenuation coefficient ((Kd(490)), Coloured Dissolved Organic Matter (CDOM) index, and particulate organic matter concentration (POC), have multiplied remote sensing applications for oceanographic researches. However, the estimation of these parameters in coastal zones, with optically complex waters, is still a great challenge. In this context, the present work aimed to evaluate the performance of MODIS-Aqua ocean colour products in coastal waters of Ubatuba (SP/Brazil), with in situ validation at the ANTARES-Ubatuba station. The station is characterized by a mixture of Case 1 and 2 waters. The Rrs (412, 443, 490, 510 e 555 nm) showed higher errors associated to the 412 and 443 nm bands, which have greatest challenges in the atmospheric correction. Anyway, the Chla and Kd(490) showed very good association with in situ data (R 2 = 0.81 and 0.82, respectively). The CDOM index did not work, because the dependency relationship between CDOM and Chla, used in the index model, wasnt encountered in the study area. Other models that derive the constituents separately (e.g. semi-analytical) should be tested for the CDOM retrieval. The POC, on the other hand, showed a reasonable performance (R2 = 0.44), with good potential of application for the Ubatuba coastal waters.Pages: 7168-717