Deep Creek Lake is complex and dynamic ecosystems. The lake, viewed as a water system, is influenced by the hydrologic conditions in the watershed (streams, bogs, seeps, wetlands and groundwater draining into the lake) the shape of the lake basin, the lake water and bottom sediments. The physical and chemical components of the lake system, in turn, support a community of organisms. These organisms enrich the complexity of the lake system, having numerous links to one and other as well as affecting the lake's physical and chemical features. All of the components of the lake system, physical, chemical and biological, are in constant change.
Certain physical processes that occur in the lake have an effect on lake dwelling organisms. Sunlight penetration, known as the depth of the littoral zone, determines the amount and extent of photosynthesis - dependent algae and submerged aquatic vegetation. In spring and early summer, the combination of solar heating and wind mixing of near-surface water layers brings about the warming of the upper portion of the lake water column. This causes stratification of the lake into layers of water with different temperatures and densities. During summertime thermal stratification, a warmer, less dense layer of water (epilimnion) floats on a cooler, denser layer (hypolimnion). Water does not mix from top to bottom, causing oxygen levels in the hypolimnion to decrease. When temperature-controlled zonation breaks down in the fall, the lake waters mix from top to bottom and oxygen levels at depth increase.
Lakes constantly receive materials from their watersheds. It is a natural geologic process for lakes of moderate depth to eventually fill in and become wetlands. Excessive or accelerated sedimentation and nutrient delivery due to landscape changes in the watershed is a process known as eutrophication.
There are no natural lakes in Maryland due to the fact that glaciers did not advance as far south as the region during the last ice age. Glacier lakes tend to be deeper and more uniform in shape than reservoirs created by dams. Deep Creek Lake was created by flooding a river valley. As a result, the lake is long, narrow and has a convoluted shoreline.