|MadSci Network: Environment & Ecology|
That's a pretty broad question! If you're measuring pH in a creek,
river and pond, it will vary depending on many things- including the
chemical composition of the soils in the watershed, the mineral and
chemical composition in the lake/stream bed, and the presence/absence of
anoxia, for starts. Dissolved CO2 tells you basically how much
respiration has gone on, and silica (in lakes at least) can be a limiting
nutrient for diatoms. Phosphate is typically the limiting nutrient in
lakes, but in hypereutrophic lakes, it's possible for nitrate to become
limiting if there is a lot of phosphate inputs (such as a pond near a farm
that gets a lot of fertilizer runoff). I'd suggest you have a look at
Robert G. Wetzel's "Limnology" (1983: Saunders), which has some excellent
sections on lake chemistry.
Rob Campbell, MAD Scientist
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