Oxygen Uptake at the Sediment–water Interface Simultaneously Measured Using a Flux Chamber Method and Microelectrodes: Must a Diffusive Boundary Layer Exist?

1998 ◽  
Vol 46 (1) ◽  
pp. 143-156 ◽  
Author(s):  
S. Güss
Keyword(s):  
Boundary Layer ◽  
Oxygen Uptake ◽  
Water Interface ◽  
Diffusive Boundary Layer ◽  
Flux Chamber ◽  
Chamber Method ◽  
Diffusive Boundary

scholarly journals Kinetic bottlenecks to respiratory exchange rates in the deep-sea – Part 1: Oxygen

2013 ◽  
Vol 10 (7) ◽  
pp. 5049-5060 ◽  
Author(s):  
A. F. Hofmann ◽  
E. T. Peltzer ◽  
P. G. Brewer
Keyword(s):  
Boundary Layer ◽  
Oxygen Uptake ◽  
Oxygen Supply ◽  
Chemical Properties ◽  
Rate Dependency ◽  
Diffusive Boundary Layer ◽  
Upper Limit ◽  
Physico Chemical ◽  
Supply Potential ◽  
Diffusive Boundary

Abstract. Ocean warming is now reducing dissolved oxygen concentrations, which can pose challenges to marine life. Oxygen limits are traditionally reported simply as a static concentration threshold with no temperature, pressure or flow rate dependency. Here we treat the oceanic oxygen supply potential for heterotrophic consumption as a dynamic molecular exchange problem analogous to familiar gas exchange processes at the sea surface. A combination of the purely physico-chemical oceanic properties temperature, hydrostatic pressure, and oxygen concentration defines the ability of the ocean to provide the oxygen supply to the external surface of a respiratory membrane. This general oceanic oxygen supply potential is modulated by further properties such as the diffusive boundary layer thickness to define an upper limit to oxygen supply rates. While the true maximal oxygen uptake rate of any organism is limited by gas transport either across the respiratory interface of the organism itself or across the diffusive boundary layer around an organism, controlled by physico-chemical oceanic properties, it can never be larger than the latter. Here, we define and calculate quantities that describe this upper limit to oxygen uptake posed by physico-chemical properties around an organism and show examples of their oceanic profiles.

Countercurrent convection in a double-diffusive boundary layer

1985 ◽  
Vol 160 ◽  
pp. 181-210 ◽  
Author(s):  
R. H. Nilson
Keyword(s):  
Boundary Layer ◽  
Vertical Wall ◽  
Similarity Solutions ◽  
Relative Strength ◽  
Diffusive Boundary Layer ◽  
Buoyancy Forces ◽  
Diffusive Boundary ◽  
Laminar Convection ◽  
Similar Solutions ◽  
Double Diffusive

Countercurrent flow may be induced by opposing buoyancy forces associated with compositional gradients and thermal gradients within a fluid. The occurrence and structure of such flows is investigated by solving the double-diffusive boundary-layer equations for steady laminar convection along a vertical wall of finite height. Non-similar solutions are derived using the method of matched asymptotic expansions, under the restriction that the Lewis and Prandtl numbers are both large. Two sets of asymptotic solutions are constructed, assuming dominance of one or the other of the buoyancy forces. The two sets overlap in the central region of the parameter space; each set matches up with neighbouring unidirectional similarity solutions at the respective borderlines of incipient counterflow.Interaction between the buoyancy mechanisms is controlled by their relative strength R and their relative diffusivity Le. Flow in the outer thermal boundary layer deviates from single-diffusive thermal convection, depending upon the magnitude of the parameter RLe. Flow in the inner compositional boundary layer deviates from single-diffusive compositional convection, depending upon the magnitude of $RLe^{\frac{1}{3}}$.

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