Sediment includes decaying algae and weeds, marl, and soil and organic matter eroded from the lake's watershed. Lakes without a significant inlet or outlet, fed by rainfall and groundwater. Seepage lakes lose water through evaporation and groundwater moving on a down gradient. Lakes with little groundwater inflow tend to be naturally acidic and most susceptible to the effects of acid rain. Seepage lakes often have long residence times and lake levels fluctuate with local groundwater levels.
Water quality is affected by groundwater quality and the use of land on the shoreline.
The layering of water due to differences in density. Water's greatest density occurs at 39 Deg. As water warms during the summer, it remains near the surface while colder water remains near the bottom. The most common form of sulfur in natural waters. The amounts relate primarily to soil minerals in the watershed.