BIOL 2Q04 Lecture Notes - Lecture 4: Ekman Spiral, Hydrothermal Vent, Northern Hemisphere
13 Oct 2016
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Connecting: autochthonous sources the sources of energy derived from photosynthesis within the aquatic system, allochthonous sources nutrients and organic materials from the terrestrial systems. River continuum: low-order streams usually have a higher oxygen concentration, lower temperature, and lower nutrient content. An area of small lakes, swamps, and marshy islands. Lakes and ponds: ponds are shallow and warm and sunlight can usually reach the bottom. Lakes are larger and colder where sunlight barely reaches the bottom. Lake origins: glacial erosion and deposition (kettle lakes and potholes, formed when sediment and debris dam up water behind them (oxbow lakes, shifts i(cid:374) the earth"s (cid:272)rust, beaver dam, human-created dams, quarries and surface mines. Wetlands: aquatic ecosystems that have a thin layer of water covering soil that is wet most of the time, contain freshwater, saltwater, or both, wetland trap sediments and purify water. Take home points: the fundamental dichotomy in freshwater systems is whether the water is flowing or standing.
