Coastal Bacterioplankton Metabolism Is Stimulated Stronger by Anthropogenic Aerosols than Saharan Dust.

In oligotrophic regions, such as the Mediterranean Sea, atmospheric deposition has the potential to stimulate heterotrophic prokaryote growth and production in surface waters, especially during the summer stratification period. Previous studies focused on the role of leaching nutrients from mineral particles of Saharan (S) origin, and were restricted to single locations at given times of the year. In this study, we evaluate the effect of atmospheric particles from diverse sources and with a markedly different chemical composition [S dust and anthropogenic (A) aerosols] on marine planktonic communities from three locations of the northwestern Mediterranean with contrasted anthropogenic footprint. Experiments were also carried out at different times of the year, considering diverse initial conditions. We followed the dynamics of the heterotrophic community and a range of biogeochemical and physiological parameters in six experiments. While the effect of aerosols on bacterial abundance was overall low, bacterial heterotrophic production was up to 3.3 and 2.1 times higher in the samples amended with A and S aerosols, respectively, than in the controls. Extracellular enzymatic activities [leu-aminopeptidase (AMA) and ß-glucosidase (ß-Gl)] were also enhanced with aerosols, especially from A origin. AMA and ß-Gl increased up to 7.1 in the samples amended with A aerosols, and up to 1.7 and 2.1 times, respectively, with S dust. The larger stimulation observed with A aerosols might be attributed to their higher content in nitrate. However, the response was variable depending the initial status of the seawater. In addition, we found that both A and S aerosols stimulated bacterial abundance and metabolism significantly more in the absence of competitors and predators.

Viruses and Protists Induced-mortality of Prokaryotes around the Antarctic Peninsula during the Austral Summer.

During the Austral summer 2009 we studied three areas surrounding the Antarctic Peninsula: the Bellingshausen Sea, the Bransfield Strait and the Weddell Sea. We aimed to investigate, whether viruses or protists were the main agents inducing prokaryotic mortality rates, and the sensitivity to temperature of prokaryotic heterotrophic production and mortality based on the activation energy (Ea) for each process. Seawater samples were taken at seven depths (0.1-100 m) to quantify viruses, prokaryotes and protists abundances, and heterotrophic prokaryotic production (PHP). Viral lytic production, lysogeny, and mortality rates of prokaryotes due to viruses and protists were estimated at surface (0.1-1 m) and at the Deep Fluorescence Maximum (DFM, 12-55 m) at eight representative stations of the three areas. The average viral lytic production ranged from 1.0 ± 0.3 × 107 viruses ml-1 d-1 in the Bellingshausen Sea to1.3 ± 0.7 × 107 viruses ml-1 d-1 in the Bransfield Strait, while lysogeny, when detectable, recorded the lowest value in the Bellingshausen Sea (0.05 ± 0.05 × 107 viruses ml-1 d-1) and the highest in the Weddell Sea (4.3 ± 3.5 × 107 viruses ml-1 d-1). Average mortality rates due to viruses ranged from 9.7 ± 6.1 × 104 cells ml-1 d-1 in the Weddell Sea to 14.3 ± 4.0 × 104 cells ml-1 d-1 in the Bellingshausen Sea, and were higher than averaged grazing rates in the Weddell Sea (5.9 ± 1.1 × 104 cells ml-1 d-1) and in the Bellingshausen Sea (6.8 ± 0.9 × 104 cells ml-1 d-1). The highest impact on prokaryotes by viruses and main differences between viral and protists activities were observed in surface samples: 17.8 ± 6.8 × 104 cells ml-1 d-1 and 6.5 ± 3.9 × 104 cells ml-1 d-1 in the Weddell Sea; 22.1 ± 9.6 × 104 cells ml-1 d-1 and 11.6 ± 1.4 × 104 cells ml-1 d-1 in the Bransfield Strait; and 16.1 ± 5.7 × 104 cells ml-1 d-1 and 7.9 ± 2.6 × 104 cells ml-1 d-1 in the Bellingshausen Sea, respectively. Furthermore, the rate of lysed cells and PHP showed higher sensitivity to temperature than grazing rates by protists. We conclude that viruses were more important mortality agents than protists mainly in surface waters and that viral activity has a higher sensitivity to temperature than grazing rates. This suggests a reduction of the carbon transferred through the microbial food-web that could have implications in the biogeochemical cycles in a future warmer ocean scenario.

Horizontal and Vertical Distributions of Transparent Exopolymer Particles (TEP) in the NW Mediterranean Sea Are Linked to Chlorophyll a and O2 Variability.

Transparent Exopolymer Particles (TEP) are relevant in particle and carbon fluxes in the ocean, and have economic impact in the desalination industry affecting reverse osmosis membrane fouling. However, general models of their occurrence and dynamics are not yet possible because of the poorly known co-variations with other physical and biological variables. Here, we describe TEP distributions in the NW Mediterranean Sea during late spring 2012, along perpendicular and parallel transects to the Catalan coast. The stations in the parallel transect were sampled at the surface, while the stations in the perpendicular transect were sampled from the surface to the bathypelagic, including the bottom nepheloid layers. We also followed the short-term TEP dynamics along a 2-day cycle in offshore waters. TEP concentrations in the area ranged from 4.9 to 122.8 and averaged 31.4 ± 12.0 µg XG eq L-1. The distribution of TEP measured in transects parallel to the Catalan Coast correlated those of chlorophyll a (Chla) in May but not in June, when higher TEP-values with respect to Chla were observed. TEP horizontal variability in epipelagic waters from the coast to the open sea also correlated to that of Chla, O2 (that we interpret as a proxy of primary production) and bacterial production (BP). In contrast, the TEP vertical distributions in epipelagic waters were uncoupled from those of Chla, as TEP maxima were located above the deep chlorophyll maxima. The vertical distribution of TEP in the epipelagic zone was correlated with O2 and BP, suggesting combined phytoplankton (through primary production) and bacterial (through carbon reprocessing) TEP sources. However, no clear temporal patterns arose during the 2-day cycle. In meso- and bathypelagic waters, where phytoplanktonic sources are minor, TEP concentrations (10.1 ± 4.3 µg XG eq l-1) were half those in the epipelagic, but we observed relative TEP increments coinciding with the presence of nepheloid layers. These TEP increases were not paralleled by increases in particulate organic carbon, indicating that TEP are likely to act as aggregating agents of the mostly inorganic particles present in these bottom nepheloid layers.

Estudo comparativo entre a histerossalpingografia e a laparoscopia como métodos diagnósticos de fatores canaliculares da infertilidade feminina / Comaprative study on hysterossalpingography and laparoscopy as diagnosis methods of tubal factor in female infertility

Foram estudadas, retrospectivamente, 45 pacientes do Ambulatório de Infertilidade do Hospital das Clínicas da Faculdade de Medicina de Ribeiräo Preto-USP, com o objetivo de comparar a HSG e a laparoscopia como métodos diagnósticos de fatores canaliculares da infertilidade feminina. A idade média das pacientes e o tempo médio de infertilidade foram 29,2 e 5,6 anos, respectivamente. NA HSG foram obtidas, em média, seis exposiçöes de raios-X, e durante a laparoscopia a permeabilidade tubária foi testada através da injeçäo de soluçäo aquosa de azul de metileno. Entre os diversos diagnósticos de alteraçöes tubárias, os dois métodos concordaram em 71,1 por cento dos casos. A laparoscopia apresentou maior percentual de falha no diagnóstico de obstruçäo (31,6 por cento). A HSG foi menos eficaz no diagnóstico de aderência peritubária, sendo de 13,3 por cento o valor de falso-negativo e de 8,9 por cento o de falso-positivo. Em pacientes que apresentaram obstruçäo tubária direita e/ou esquerda (perfazendo o número total de 38 trompas avaliadas), a localizaçäo desta obstruçäo foi firmada pela HSG e pela laparoscopia, respectivamente, para a trompa direita e esquerda: cornual - 7,9 por cento e 5,3 por cento; ístmica - 34,2 por cento e 18,4 por cento; distal - 42,1 por cento e 44,7 por cento e näo-determinada em 15,8 por cento e 31,6 por cento. Entre os achados diagnosticáveis por apenas um dos métodos encontrou-se, com maior freqüencia, aderências envolvendo outros órgäos pélvicos, alteraçöes de tamanho e aspecto ovariano, alteraçöes de forma do corpo uterino e falhas de enchimento da cavidade. As características dos métodos e os resultados obtidos sugeriram que a HSG e a laparoscopia säo métodos diagnósticos que se complementam, sendo imprescindíveis no estudo de fatores de infertilidade feminina.