The abundance of gammacerane is often associated with OM deposition in hypersaline environments  and may record input from bacterivorous ciliates living at or below the chemocline
in stratified lakes .
The team relied on the use of rare earth element patterns to demonstrate that the deposit formed in, or near, a chemocline
in a stratified iron-rich basin.
Specific conductivity fluctuated between 116 and 190 [micro]Si/cm, with lower values in the epilimnion, and a clear chemocline
at 20 m depth, which however became deeper with time ([F.sub.1,21] = 30.8; p = 0.00002).
The herein documented complex distribution patterns of elements imply that other factors besides redox should be considered as potential sources of variance, including the influence of the presence of free [HS.sup.-], possible role of particulate shuttles, position and stability of the chemocline
in the enrichment environment, influence of microbial mediation, bioturbation and redeposition.
Table A1 Physical and chemical characteristics for MDV lakes used in this study Abiotic Parameter West Lobe Fryxell Bonney Max depth 41.5 m 20 m Ice thickness 3-6 m 3-6 m % Transmission of PAR 7.0 % 1.5 % Max salinity (PSU) 125 6.2 Temperature ([degrees]C) -5.4 to 3.2 0 to 3.2 [degrees]C [degrees]C Depth of chemocline
15 m 9 m Molar N:P * -mixo -chemo + mono 164 (37) 2.41 (0.60) 670 (94) 11.0 (0.57) * For N:P ratios, the integrated mean (standard error) for the mixolimnion (mixo) and the chemocline
and monolimnion (chemo+mono) are reported.
Could be a nearshore drop-off or the slope off an openwater hump, or where boulder outcropping meets finer substrate, or a shadow line, or a thermocline, or a chemocline
. But where the green goes kaput is a place to make a solid bet.
Close interval sampling of migrating Chaoborus larvae across the chemocline
of meromictic Lake Fidler, Tasmania.
The few dissolved sulfates that wash in are consumed by chemical reactions that occur within the chemocline
, the thin layer of water that separates the oxygenated surface waters from the anoxic depths.
Ecology of Cryptomonas at the chemocline
of a karstic sulfate-rich lake.
This sulfide usually changes into a benign sulfate salt when the dissolved gas encounters oxygen to flourish at an underwater boundary called a chemocline
. However, if enough hydrogen sulfide accumulates in an oxygen-free, or anoxic, zone, the gas can abruptly rise and belch into the atmosphere, Kump says.
The relative abundances of photoautotrophic bacteria (e.g., purple sulfur bacteria and green nonsulfur bacteria) and chemolithotrophic sulfide-oxidizing bacteria can be affected by the amount of light that reaches the chemocline
(Jorgensen and Des Marais, 1986).