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We studied the diel variation of in situ coral temperature, irradiance and photosynthetic performance of hemispherical colonies of Porites lobata and branching colonies of Porites cylindrica during different bulk water temperature and tidal scenarios on the shallow reef flat of Heron Island, Great Barrier Reef, Australia. Our study presents in situ evidence that coral tissue surface temperatures can exceed that of the surrounding water under environmental conditions typically occurring during low tide in shallow reef or lagoon environments. Such heating may be a regular occurrence on shallow reef flats, triggered by the combined effects of high irradiance and low water flow characteristic of low Spring tides. At these times, solar heating of corals coincides with times of maximum water temperature and high irradiance, where the slow flow and consequent thick boundary layers impede heat exchange between corals and the surrounding water. Despite similar light-absorbing properties, the heating effect was more pronounced for the hemispherical P. lobata than for the branching P. cylindrica. This is consistent with previous laboratory experiments showing the evidence of interspecific variation in coral thermal environment and may result from morphologically influenced variation in convective heat transfer and/or thermal properties of the skeleton. Maximum coral surface warming did not coincide with maximum irradiance, but with maximum water temperature, well into the low-tide period with extremely low water flow in the partially drained reef flat, just prior to flushing by the rising tide. The timing of low tide thus influences the thermal exposure and photophysiological performance of corals, and the timing of tidally driven coral surface warming could potentially have different physiological impacts in the morning or in the afternoon., Introduction Diurnal fluctuations in irradiance affect the photophysiology of the endosymbiotic dinoflagellates (zooxanthellae) of corals (Brown et al. 1999; Ralph et al. 1999; Jones and Hoegh-Guldberg 2001; Winters et al. [...]

Abstract: The existence of C .sup.1,[alpha]-solutions of the nonlinear system that describes plane stationary flow of a class of non-Newtonian fluids is proved. In particular, this class includes various power-type models. It is assumed that the nonlinear operator has the p-potential structure, and the Dirichlet problem is considered. In the case of p &gt 3/2, the global C .sup.1,[alpha]-solution is constructed. In the case of p &gt 6/5, a solution that possesses interior C .sup.1,[alpha]-regularity is obtained. Bibliography: 24 titles. Article History: Registration Date: 12/10/2004

Byline: A. A. Arkhipova (1), O. A. Ladyzhenskaya (2) Abstract: The proof of a new variant of Gehring's lemma on reverse Holder inequalities is presented. The modification considered is motivated by the investigation of a flow of inhomogeneous incompressible fluid. Bibliography: 11 titles. Author Affiliation: (1) St. Petersburg State University, Russia (2) St. Petersburg Department of the Steklov Mathematical Institute, Russia Article History: Registration Date: 12/10/2004

Abstract: We consider the problem of the two-dimensional motion of a nonviscous incompressible fluid in the field of gravity. To calculate the flow field, we use the method of the asymptotic expansion of the solution with respect to a small parameter. The constructed algorithm allows one to obtain a picture of the flow functions for the exact (nonlinear) problem of a perturbed flow of a stratified fluid. The main limitations of the algorithm are the absence of backflow zones (rotors) and a large typical horizontal size of the solution as compared with the depth of the flow. We give results of the calculations. Article History: Registration Date: 06/10/2004

Byline: V. G. Vyskrebtsov (1) Abstract: We investigate self-similar solutions of the Navier--Stokes equations for the axisymmetric flow of a viscous incompressible fluid. The original equations are transformed by the Slezkin method. On the basis of analysis of physical properties of the flow and the Slezkin general equation, we show that, in parallel with the known solutions of this equation, there exist several other solutions with physical meaning. We consider the simplest case of irrotational flows for which current lines may be circles, ellipses, parabolas, and hyperbolas. Unlike the Landau and Squire solutions, these flows are interpreted as nonjet flows of fluid flowing into and out of a homogeneous porous axially symmetric body. Author Affiliation: (1) Moscow Auto-Mechanical Institute, Russia Article History: Registration Date: 11/10/2004

Byline: Norihisa Imasato (1), Taiyo Kobayashi (2), Shinzou Fujio (3) Keywords: Oxygen minimum layer; Lagrangian oxygen consumption rate; contribution rate to oxygen concentration; labeled particle tracking Abstract: By using the Euler-Lagrangian method, we examine water movements within the layer of minimum oxygen concentration and estimate local oxygen consumption rates for 15 regions of the global ocean. To do this, a number of labeled particles (which represent water parcels) are deployed at the center of a grid with 15 depth levels and tracked backward in time for 50 years in a three-dimensional velocity field. We assume that a particle picks up oxygen when it encounters the point of maximum oxygen concentration along the 50 years segment of its path. We introduce a contribution rate from waters distributed throughout the global ocean to the oxygen concentration of a local layer under consideration. Water parcels which are assumed to pick up oxygen within the oxygen minimum layer of an oceanic region under consideration make a very small contribution to the overall oxygen concentration of this layer. In addition, these parcels move out of the layer and water parcels from the upper layers take their place. The averaged Lagrangian local oxygen consumption rate is 0.033 ml/l/yr for the depth of the oxygen minimum layer, 0.20 ml/l/yr at 100 m depth (euphotic layer), 0.043 ml/l/yr for layers from 150 m to 800 m depth and 0.012 ml/l/yr for deep layers from 800 m to 3000 m. The present Lagrangian numerical experiment produces a maximum difference between observed and calculated concentrations of oxygen and, therefore, a maximum oxygen consumption rate. Although the present method has an ambiguity as to how oxygen is picked up, we nevertheless were able to identify regions in which the water parcels pick up oxygen of maximum concentration. We found that the South Equatorial Current (SEC) transports oxygen of higher concentration to the middle latitude regions of both the North Atlantic and the North Pacific across the equator. Author Affiliation: (1) Faculty of Information Science and Technology, Aichi Prefectural University, Kumahari, Ibaragahazama 1522-3, Nagakute-cho, Aichi, 480-1198, Japan (2) Center for Climate System Research, University of Tokyo, Komaba 4-6-1, Meguro-ku, Tokyo, 153-8904, Japan (3) Ocean Research Institute, University of Tokyo, Minamidai 1-15-1, Nakano-ku, Tokyo, 164-8639, Japan Article History: Registration Date: 07/10/2004

Modeling methodology, data integration and the resulting water flow models that focus on the quaternary deposits and the upper 150 m of the bedrock is discussed. It is shown how the Geographical Information System-based modeling can be used to limit the number of surface flow paths that are needed to be characterized for safety assessment.