The irruption of gas and oil into the Gulf of Mexico during the Deepwater Horizon event fed a deep sea bacterial bloom that consumed hydrocarbons in the affected waters, formed a regional oxygen anomaly, and altered the microbiology of the region. In this work, we develop a coupled physical-metabolic model to assess the impact of mixing processes on these deep ocean bacterial communities and their capacity for hydrocarbon and oxygen use. We find that observed biodegradation patterns are well-described by exponential growth of bacteria from seed populations present at low abundance and that current oscillation and mixing processes played a critical role in distributing hydrocarbons and associated bacterial blooms within the northeast Gulf of Mexico. Mixing processes also accelerated hydrocarbon degradation through an autoinoculation effect, where water masses, in which the hydrocarbon irruption had caused blooms, later returned to the spill site with hydrocarbon-degrading bacteria persisting at elevated abundance. Interestingly, although the initial irruption of hydrocarbons fed successive blooms of different bacterial types, subsequent irruptions promoted consistency in the structure of the bacterial community. These results highlight an impact of mixing and circulation processes on biodegradation activity of bacteria during the Deepwater Horizon event and suggest an important role for mixing processes in the microbial ecology of deep ocean environments.oil spill | well blowout | intrusion layers O il and gas from the Macondo well flowed freely into the deep Gulf of Mexico for a period of 83 d after the explosion and sinking of the Deepwater Horizon (DWH) mobile offshore drilling unit. The environmental release of crude oil occurred at ∼1.5 km water depth with an estimated magnitude of 4.1 × 10 6 barrels (1). Large volumes of gas also emanated from the ruptured well, with reported ratios of gas to oil ranging from 1,600 to 2,800 standard cubic feet of gas (15.6°C, 1 bar) per barrel of oil (2-4). Mass fluxes estimated from these values are 5.4 × 10 11 g for liquid oil and 1.8-3.1 × 10 11 g for natural gases, defined here as alkanes with one to five carbons.Oil and gas entered the ocean initially through multiple openings in the ruptured riser pipe and later, from the top of the blowout preventer after the riser pipe was cut away on June 1, 2010 (1). The hydrocarbon droplets ejected ranged in size from several millimeters down to small droplets with slow ascent rates; 771,000 gal dispersant were applied at depth to promote formation of such small, slow-rising droplets. On release, the bulk of oil and gas began a rapid ascent from the sea floor, entraining sea water as it rose. The entrainment of sea water cooled the oil and gas rapidly (3) and initiated both dissolution of the soluble components and formation of gas hydrate. Kinetically controlled chemical fractionation seems to have persisted for several hundred meters of ascent until the entrained waters separated from the ascending oil (3, 5, 6). These waters f...

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We consider the nonstationary 3-D flow of a compressible viscous heat-conducting micropolar fluid in the domain to be the subset of R 3 bounded with two concentric spheres that present the solid thermo-insulated walls. In the thermodynamical sense the fluid is perfect and polytropic. We assume that the initial density and temperature are bounded from below with a positive constant and that the initial data are sufficiently smooth spherically symmetric functions. The starting problem is transformed into the Lagrangian description on the spatial domain ]0, 1[. In this work we prove that our problem has a generalized solution for any time interval [0, T], T ∈ R + . The proof is based on the local existence theorem and the extension principle.

We consider nonstationary 3-D flow of a compressible viscous heat-conducting micropolar fluid in the domain to be the subset of R 3 bounded with two concentric spheres that present solid thermoinsulated walls. In thermodynamical sense fluid is perfect and polytropic. Assuming that the initial density and temperature are strictly positive we will prove that for smooth enough spherically symmetric initial data there exists a spherically symmetric generalized solution locally in time.