Lecture 1 Flashcards
Where is freshwater accesible water?
Mainly in lakes (0.007% of total water)
What % do freshwater habitats make up of total land cover?
2%
Phytoplankton importance
Produce 50-80% of atmospheric oxygen
Salinity
- Number of disolved ions in water, mainly sodium and chloride
- Measured in Parts per thousand (PPT)
- Freshwater is 0-0.5ppt and marine is 30-38ppt
Lotic
Tunning water
Classified by Strahler order
Most are 1st or 2nd order
Lentic
Standing water
Ponds must be both small and shollow
Wetland must be shallow with more than 30% vegetation cover
Littoral zone
Shallows near edge
Pelagic zone
Open water
Benthic zone
Bottom sediments
Flow
Strong in Lotic waters
Organisms adapt to flow levels
Velocity (speed) or discharge (Volume)
Driven by seasonal patterns
Cateogorized by number of annual peak in flow
Mixing
- Vertical stratification occurs in deep lakes with distinct layers
Maintained by differences in water density
Caterogorized by stratification frequency and “turnover”
Temperature
Water has high heat capacity making habitat thermally stable
Eplimnion
Metalimnion
Hypoliminion
Thermocline is located in metalimnion where temp change is greatest
Floating ice acts as a isolating heat layer, the deepest water is warmest
Oxygen
Slower diffuse than in air
Gets into water via atmospheric diffusion and wind mixing
Solublity varies with abiotic factors, max con. possible decreases with temp and salinity
Oxygen saturation depends on biotic factors. Microial activity can fully deplete oxygen (hypoxia)
Nutrients
Drive microbial number and acitivity
Carbon Nitrogen and phosphorus
Measured by total phosphorous, chlorophyll-a or oxygen saturation
Light
Effect ecosystems and food chain
Decays exponentially with depth
Euphatic zone extends from surface to 1% light level
DOC absorbs light, sediments and particles blick light and increase turbidity
Estimated with secchi depth
