Stratified water column

In the water column, ammonification and nitrification can sometimes lead to the formation of subsurface ammonium and nitrite concentration maxima that are usually located toward the base of the euphotic zone in stratified water columns. This is called the primary nitrite maximum. Some of this nitrite is also contributed by releases... 

Primary nitrite maximum Subsurface concentration maximum in nitrite found toward the base of the euphotic zone in stratified water columns. Mainly caused by ammonification and nitrification. 

Figure 9. Shellfish toxin data from Newagen, Maine. Upper panel is times of State closure to the taking of shellfish (>80pg/100g) for years 1972 to 1982. Bottom panel is "start dates" indicating when initial levels over quarantine are witnessed. These dates fall in categories 1) transition from mixed to stratified water column (May) and vice versa (Sept.) and 2) during summer meteorological events.

Therefore, the so-called stability frequency is often used to describe the stability of a fluid system. In the case of a vertically stratified water column, the appropriate quantity is called the Bmnt-Vaisala frequency, N. It is defined by... 

Loss rates of total P from the stratified water column, based on changes in integrated standing-crop concentrations, ranged from a high of 5.5 mg/m2 per day (mid-July to late August) to a much lower rate of 0.74... 

Abiotic oxidation of sulfide by oxygen cannot supply sulfate at rates comparable to rates of sulfate reduction. Unless high concentrations of sulfide develop and the zone of oxidation is much greater than 1 cm, rates of chemical oxidation of sulfide by oxygen will be much less than 1 mmol/m2 per day (calculated from rates laws found in refs. 115-118). Such conditions can exist in stratified water columns in the Black Sea water column chemical oxidation rates may be as high as 10 mmol/m2 per day (84). However, in lakes in which sulfide is undetectable in the water column and oxygen disappears within millimeters of the sediment-water interface (e.g., 113), chemical oxidation of sulfide by oxygen is unlikely to be important. 

Ward, B. B. (1990). Relationship between substrate concentration and oxidation of ammonium and methane in a stratified water column. Continental Shelf Research 12, 1193—1208. 

Fuller, N.J., Marie, D., Partensky, F., Vaulot, D., Post, A. F., andScanlan, D.J. (2003). Clade-specific 16S ribosomal DNA ohgonucleotides reveal the predominance of a single marine Synechococcus clade throughout a stratified water column in the Red Sea. Aprpl. Environ. Microbiol. 69, 2430-2443. 

Figure 24.4 Schematic diagram of potential N substrate profiles in a stratified water column, mapped against the known partitioned distribution of specific Prochlorococcus genotypes/ecotypes from molecular ecological studies (e.g., see Moore et ah, 1998 Steglich et ah, 2003 West and Scanlan 1999).

West, N. J., and Scanlan, D. J. (1999). Niche-partitioning of Prochlorococcus populations in a stratified water column in the eastern North Atlantic Ocean. Appl. Environ. Microbiol. 65, 2585—2591. 

Effect of Eddy Diffusivity on Transport in a Stratified Water Column... 

Fig. 3. The seasonal evolution of calculated monthly averaged equilibrium calcite (S OEq.caidte) fot Loch Sunart (black line), a fjord in NW Scotland, and the Celtic Sea (mixed water column - grey line, stratified water column - dashed grey line).

Cud) was measured In the water column off the Florida Coast on the SOLARS III cruise. Results from a cast taken at a station west of Tampa are shown In Figure 6. The cast was made at 1400 on a sunny, flat calm day optimal conditions for photochemical activity. Hydrographic data, obtained during a CTD cast Immediately afterwards Indicated a well stratified water column. The profile Indicates that Cu(I) Is present at the surface where It constitutes about 15Z of the total copper. The concentration declines with depth and Is below the limit of detection at 90m. The H 02 profile shows similar characteristics, with a surface maximum. 

A highly stratified water column with bottom water stagnation without oxygen renewal, which would increase organic carbon preservation. 

The geometry (width and depth) of an estuary controls its water circulation. In deep estuaries, the outflowing river water rides over the tidal inflowing water, forming a vertically stratified water column in shallow estuaries, fresh- and saltwaters tend to mix. The funnel shape of the estuaries restricts wave penetration and promotes strong tidal currents (0.5-1.5 m/s) along its axis (Darlymple, 1992). 

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