Cosmopolitan heterotrophic microeukaryotes are active bacterial grazers in experimental oil-polluted systems

We investigated the population dynamics and prevailing 18S rDNA phylotypes of microeukaryotes (<= 10 mu m) in microcosms containing seawater from either an unpolluted oligotrophic site or a chronically oil-polluted mesotrophic site of the Aegean Sea, amended with crude oil (100 p.p.m. final concentration) and crude oil plus emulsifier (10 p.p.m. final concentration). The addition of oil alone did not result in an important increase of bacteria or their predators, while the addition of oil and emulsifiers caused an important increase in bacteria followed by nanoflagellate predator response. We observed an important shift in the microeukaryotic community structure, which was characterized by the dominance of the same heterotrophic nanoflagellates in all oil-polluted treatments. Thus, the resulting 18S rDNA phylotypes were dominated (48.1-82.4%) by Paraphysomonas foraminifera in all treatments containing crude oil and crude oil plus emulsifier. The origin of the seawater, i.e. unpolluted versus chronically oil-polluted, had no effect on the dominant eukaryote, suggesting that the ubiquitous P. foraminifera is an effective opportunist in oil-polluted aquatic systems. The next dominant phylotypes were Monosiga brevicollis (<= 27.0%) and Pseudobodo tremulans (<= 23.1%). However, the addition of the emulsifier increased the dominance of P. foraminifera but decreased that of M. brevicollis and P. tremulans. Our study revealed that these dominant oil-tolerant eukaryotes, which are commonly found in the marine environments, are important grazers of bacteria and as such their dynamics should be taken into account in bioremediation practices in situ

Gas Transfer at Water Surfaces 2010

PrefaceSection 1: Interfacial Turbulence and Air-Water Scalar TransferJ. Hunt, S. Belcher, D. Stretch, S. Sajjadi, J. Clegg [1]S.A. Kitaigorodskii [13]S.A. Kitaigorodskii [29]Y. Toba [38]D. Turney, S. Banerjee [51]J.G. Janzen, H.E. Schulz, G.H. Jirka [65]S. Komori, R. Kurose, N. Takagaki, S. Ohtsubo, K. Iwano, K. Handa, S. Shimada [78]J. Beya, W. Peirson, M. Banner [90]S. Mizuno [104]M. Sanjou, I. Nezu, A. Toda [119]M. Sanjou, I. Nezu, Y. Akiya [129]K. Takehara, Y. Takano, T.G. Etoh [138]G. Caulliez [151]Section 2: Numerical Studies on Interfacial Turbulence and Scalar TransferL.-P. Hung, C.S. Garbe, W.-T. Tsai [165]A. E. Tejada-Martínez, C. Akan, C.E. Grosch [177]W.-T. Tsai, L.-P. Hung [193]P.G. Jayathilake, B.C. Khoo, Zhijun Tan [200]H.E. Schulz, A.L.A. Simões, J.G. Janzen [208]Section 3: Bubble-Mediated Scalar TransferD.P. Nicholson, S.R. Emerson, S. Khatiwala, R.C. Hamme [223]W. Mischler, R. Rocholz, B. Jähne [238]R. Patro, I. Leifer [249]K. Loh, K.B. Cheong, R. Uittenbogaard [262]N. Mori, S. Nakagawa [273]Section 4: Effects of Surfactants and Molecular Diffusivity on Turbulence and Scalar TransferA. Soloviev, S. Matt, M. Gilman, H. Hühnerfuss, B. Haus, D. Jeong, I. Savelyev, M. Donelan [285]S. Matt, A. Fujimura, A. Soloviev, S.H. Rhee [299]P. Vlahos, E.C. Monahan, B.J.Huebert, J.B. Edson [313]K.E. Richter, B. Jähne [322]X. Yan, W.L. Peirson, J.W. Walker, M.L. Banner [333]Section 5: Field MeasurementsP.M. Orton, C.J. Zappa, W.R. McGillis [343]U.Schimpf, L. Nagel, B. Jähne [358]C.L. McNeil, E.A. D'Asaro, J.A. Nystuen [368]D. Turk, B. Petelin, J.W. Book [377]M. Ribas-Ribas, A. Gómez-Parra, J.M. Forja [394]A. Rutgersson, A.-S. Smedman, E. Sahlée [406]H. Pettersson, K. K. Kahma, A. Rutgersson, M. Perttilä [420]Section 6: Global Air-Sea CO2 FluxesR. Wanninkhof, G.-H. Park, D.B. Chelton, C.M. Risien [431]N. Suzuki, S. Komori, M.A. Donelan [445]Y. Suzuki, Y. Toba [452]M.T. Johnson, C. Hughes, T.G. Bell, P.S. Liss [464]Section 7: Advanced Measuring TechniquesO. Tsukamoto, F. Kondo [485]R. Rocholz, S. Wanner, U. Schimpf, B. Jähne [496]B.C.G. Gonzalez, A.W. Lamon, J.G. Janzen, J.R. Campos, H.E. Schulz [507]E. Sahlée, K. Kahma, H. Pettersson, W.M. Drennan [516]D. Kiefhaber, R. Rocholz, G. Balschbach, B. Jähne [524]C.S. Garbe, A. Heinlein [535]Section 8: Environmental Problems Related to Air-Water Scalar TransferW.L. Peirson, G.A. Lee, C. Waite, P. Onesemo, G. Ninaus [545]Y.J. Choi, A. Abe, K. Takahashi [559]Y. Baba, K. Takahashi [571]R. Onishi, K. Takahashi, S. Komori [582][593]Turbulence and wave dynamics across gas-liquid interfacesThe calculation of the gas transfer between the ocean and atmosphereThe influence of wind wave breaking on the dissipation of the turbulent kinetic energy in the upper ocean and its dependence on the stage of wind wave developmentMarvellous self-consistency inherent in wind waves : Its origin and some items related to air-sea transfersNear surface turbulence and its relationship to air-water gas transfer ratesTurbulent gas flux measurements near the air-water interface in an oscillating-grid tankSensible and latent heat transfer across the air-water interface in wind-driven turbulenceRainfall-generated, near-surface turbulenceEffects of the mechanical wave propagating in the wind direction on currents and stresses across the air-water interfaceTurbulent transport in closed basin with wind-induced water wavesPIV measurements of Langumuir circulation generated by wind-induced water wavesStudy of vortices near wind wave surfaces using high-speed video camera and MLSWind wave breaking from micro to macroscaleValidation of Eddy-renewal model by numerical simulationMass transfer at the surface in LES of wind-driven shallow water flow with Langmuir circulationCharacteristics of gas-flux density distribution at the water surfacesNumerical simulation of interfacial mass transfer using the immersed interface methodStatistical approximations in gas-liquid mass transferAn inverse approach to estimate bubble-mediated air-sea gas flux from inert gas measurementsExperimental setup for the investigation of bubble mediated gas exchangeGas transfer velocity of single CO2 bubblesMass transfer across single bubblesAeration of surf zone breaking wavesModification of turbulence at the air-sea interface due to the presence of surfactants and implications for gas exchange. Part I: laboratory experimentModification of turbulence at the air-sea interface due to the presence of surfactants and implications for gas exchange. Part II: numerical simulationsWind-dependence of DMS transfer velocity: Comparison of model with recent southern ocean observationsA laboratory study of the Schmidt number dependency of air-water gas transferOn transitions in the Schmidt number dependency of low solubility gas transfer across air-water interfacesAn autonomous self-orienting catamaran (SOCa) for measuring air-water fluxes and forcingThe 2009 SOPRAN active thermography pilot experiment in the Baltic SeaObservations of air-sea exchange of N2 and O2 during the passage of Hurricane Gustav in the Gulf of Mexico during 2008The effect of high wind Bora events on water pCO2 and CO2 exchange in the coastal Northern AdriaticSeasonal sea-surface CO2 fugacity in the north-eastern shelf of the Gulf of Cádiz (southwest Iberian Peninsula)Including mixed layer convection when determining air-sea CO2 transfer velocityAir-sea carbon dioxide exchange during upwellingImpact of small-scale variability on air-sea CO2 fluxesThe effect of wind variability on the air-sea CO2 gas flux estimationFuture global mapping of air-sea CO2 flux by using wind and wind-wave distribution of CMIP3 multi-model ensembleA Rumsfeldian analysis of uncertainty in air-sea gas exchangeAccurate measurement of air-sea CO2 flux with open-path Eddy-CovarianceCombined Visualization of wind waves and water surface temperatureMicroscopic sensors for oxygen measurement at air-water interfaces and sediment biofilmsDamping of humidity fluctuations in a closed-path systemImproved Optical Instrument for the Measurement of Water Wave Statistics in the FieldFriction Velocity from Active Thermography and Shape AnalysisEvaporation mitigation by storage in rock and sandDevelopment of oil-spill simulation system based on the global ocean-atmosphere modelStructure variation dependence of tropical squall line on the tracer advection scheme in cloud-resolving modelHigh-resolution simulations for turbulent clouds developing over the oceAuthor Inde

Impact of Distance Determinations on Galactic Structure. I. Young and Intermediate-Age Tracers

Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, ∼40kpc in diameter, is a cross-road of studies on the methods of measuring distances, interstellar extinction, evolution of galaxies, and other subjects of interest in astronomy. A&nbsp;proper treatment of interstellar extinction is, for example, crucial for estimating distances to stars in the disk outside the small range of the solar neighborhood. We’ll review the current status of relevant studies and discuss some new approaches to the extinction law. When the extinction law is reasonably constrained, distance indicators found in today and future surveys are telling us stellar distribution and more throughout the Galactic disk. Among several useful distance indicators, the focus of this review is Cepheids and open clusters (especially contact binaries in clusters). These tracers are particularly useful for addressing the metallicity gradient of the Galactic disk, an important feature for which comparison between observations and theoretical models can reveal the evolution of the disk