Unit 6 Flashcards
Properties of Water
- High heat capacity – holds lots of heat, slowly releases heat
- Moderates climate
- Ice floats on water!
- Ice expands when it freezes and decreases in density, maximum water density of the water is in liquid form (4 degrees Celsius)
- Universal solvent-dissolves a lot, used as a physiological solvent in the body
Hydrologic Cycle
Water is continuously cycling through the environment and purified
- Evaporation (goes to the atmosphere, liquid to vapour)
- Condensation (vapour to liquid)
- Precipitation (rain/snow)
- Transpiration (occurs through plants and trees, stomata, equivalent to evaporation)
Water Quality
The physical, chemical (other chemicals in the water, oxygen), and biological characteristics of water necessary to sustain desired water uses
Water Pollution
Contaminants discharged into water that adversely affects humans and aquatic life
Local Problem
-Lake Winnipeg
Global problem (UN)
-87% of world’s population without safe drinking water
Point source pollution
out of a pipe concentrated discharge such as sewage effluent
Non-point source
over a large area within the watershed, diffuse and much more difficult to control and regulate
-Example Lake Winnipeg
Lake Processes
Particles in the water deflect the sunlight, so sunlight can’t get all the way down
- More particles, less sunlight
- Where there is light there are plants that generate oxygen (dissolved oxygen) (produce)
- Plants in the bottom of the lake are likely dead and eaten by decomposers
- Fish and bacteria are respiration and decomposition activities (consume oxygen)
- You have to have enough oxygen and light, and a balance between photosynthesis and respiration
Sediment Pollution
Soil particles enter a water body likely due to erosion along a shoreline
These eventually settle out and accumulate on the bottom of a body of water.
Problems include:
-Turbidity - reduces light penetration and photosynthesis
-Siltation that destroys fish habitat (spawning)
-Adhered pollutants (fertilizers, pesticides)
Protect Stream Banks from Erosion
- Examples of sediment pollution
- Construction workers will lay down juke fabric to allow growth and stabilization of banks
Eutrophication
- Release of nitrogen and phosphorus
- Chemicals stimulate plant photosynthesis and production
- Removes limiting factors that would otherwise restrict the carrying capacity for the plant population
- Large mats of plants produced which overall reduce the health of the ecosystem
- Eutrophication is a Big Problem in Lake Winnipeg
Eutrophication Process
- Oligotrophic=low nutrients, lots of biodiversity
- Nutrients added, algae growth is promoted, and taking all the sunlight, other plants are lost, fish community begins to suffer
- Dead algae die and sink to the bottom, decomposers over work and deplete the oxygen for the fish
- Sewage, runoff, fertilizers, are all sources of nutrients inputs
Eutrophication Occurring in Marine Ecosystems Due to Land Runoff
- Starting to occur in oceans, not just in land water masses
- Chlorophyll biomasses=dead zone in the Gulf of Mexico, west coast
Decomposition and Oxygen Sag
- Any time we stimulate decomposition, we reduce the availability of oxygen within the aquatic food web
- Adding any potential energy to the water will contribute to the increase of decomposition
- Relates to the quantity of organic matter in the water body
Decomposition and Oxygen Sag Natural sources
include wastes from aquatic organisms, debris from the surrounding watershed such as leaf litter, fallen trees and branches and the occasional terrestrial animal that meets its demise by drowning
Decomposition and Oxygen Sag Human sources
include point and nonpoint sources of manure and sewage associated with agricultural activities and urban centers, as well as industrial discharges of organic wastes.