Pore water Little Rock Lake

Little Rock Lake. Net IAG in LRL takes place primarily in or near the sediment. It can be evaluated by measurements of pore-water chemistry, comparison of hypolimnetic and epilimnetic chemistry, and calculation of ion budgets. An example of each approach follows. 

Figure 3. Sediment core from Little Rock Lake (3 m) depicting dry bulk particle (A) and pore-water (A) HgT concentration. Sediments were dated by 13rCs and 210Pb. Inset Coal use in the United States according to a 1986 report to the National Academy of Sciences.

Processes and mechanisms responsible for recycling at the sediment-water interface cannot be explained by a single process, but are most likely a combination of many biogeochemical processes. Although pore-water HgT concentrations were higher than in lake waters, direct release of pore waters below about 2 cm could not totally account for the observed buildup in the hypolimnion of Little Rock Lake. Remineralization of recently deposited biogenic particulate matter and release of particle-bound Hg from this source most likely accounted for the observed water-column buildup. 

Sherman, L.A., Baker, L.A., Weir, E.P., Brezonik, P.L., 1994. Sediment pore-water dynamics of Little Rock Lake, Wisconsin geochemical processes and seasonal and spatial variability. Limnol. Oceanogr. 39, 1155-1171. 

Apart from lakes and ground water, noble gases are also useful in the study of other continental water reservoirs, such as pore waters in sediments and rocks. However, little work has been done in these areas so far. The one aqueous system that has received considerable attention in recent years is ice. The polar ice sheets have proven to be excellent archives of past environmental conditions, and noble gases as conservative tracers play a role in extracting information from these archives. A short review of recent applications of noble gases in ice is therefore included at the end of this chapter. 

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