What are the 2 zones in a lake?
- Littoral zone 2. Open water
Oligotrophic
deep; low productivity; high oxygen levels (low decomposition)
Eutrophic
shallow; high productivity; low oxygen levels
Mesotrophic
intermediate in all features
BOD
Biological Oxygen Demand
What are the sources of Phosphorus?
sewage, agriculture runoff, detergents
What are the 3 types of sewage?
- Domestic (from homes) 2. Industrial 3. Storm runoff (from roads)
Primary Treatment
mechanical process-removes suspended solids
How much do the best primary treatments remove?
90% solids; 15% P; 50% BOD; 55% Fecal coliforms
Secondary Treatment
biological processes; culturing aerobic bacteria to break down sewage in a closed tank
How much do primary and secondary treatments remove?
30-50% P; 80-90% BOD; 90-99% Fecal coliforms
Tertiary treatment
Reduces phosphorous by 90% (from second treatment)
What are other pollutants to water?
industrial; pharmacological agents; endocrine disruptors; pesticides
Sludge
biosolids; spread on fields, incinerated; 27 kg/person/year produced
Instream Flow Needs
how much water we should leave in the river; based on water quality, health of fish population, riparian diversity, maintenance of river channel
Worldwide, how much water is wasted?
65-70%
What are advantages of dams? (4)
- control floods 2. use water for crops all through the summer 3. recreational fish population 4. power
What are disadvantages of dams? (7)
- can cause earthquakes because water is heavy 2. loss of habitat 3. risk-if dam breaks 4. silt shadow downstream of dam (less silt for plants) 5. decreased productivity of fish 6. expensive to build 7. loss of water through evaporation
Agroecosystems
ecosystem managed for agricultural production; domesticated plants and animals; reliant on the same ecosystem processes
What is sustainable agriculture based on?
- primary production-sun 2. soil (renewable-nutrient cycle) 3. water
What are the 7 factors of site productivity?
- Soil fertility 2. Soil organic matter 3. Bulk density 4. Resistance to erosion 5. Moisture status 6. Salinization 7. Prevalence of weeds
Organic pesticides
plant extracts; organochlorines (DDT, 2, 4-D); glyphosate
Inorganic pesticides
contain lead, arsenic, mercury
Biological pesticides
bacterial, viral, hormonal
Advantages of pesticides (6)
- save lives (from insect borne diseases) 2. increased food prod’n 3. decreased food costs 4.decrease food spoilage 5.increase farm profits 6.fast, effective, economical
What would the perfect pesticide be? (4)
- kill target species only 2. degrade into harmless products 3. cheaper than doing nothing 4. no genetic resistance
Disadvantages of pesticides (4)
- Human health 2. Wildlife threat 3. Hit more than the target 4. Genetic resistance
1st Generation Pesticides
poisons (lead, arsenic, mercury), plant extracts
2nd Generation Pesticides
synthetic compounds (DDT)
3rd Generation Pesticides
Biological compounds; insect hormones; birth control for insect pests
Integrated Pest Management (5)
biological controls; manage habitat-crop rotation; encourage natural predators and parasites; only spray when pests meet a threshold; use of crop varieties that are resistant to pests
What are other alternatives to pesticides?
hot water; mechanical (vacuum up pests); chicken and geese
What are the different cutting methods?
clear cut; selection harvest; shelterwood harvest; strip cuts; clear cut
Selection harvest
cut relatively mature trees; fastest regeneration
Shelterwood harvest
gradual clear cut (over 15-20 years)
Strip cuts
long, narrow strip is clear cut; regeneration gets going relatively easily
What are impacts of cutting? (6)
modify nutrients; more roads=more disturbance; weeds; affect wildlife; more competition for birds in other areas; soil erosion
Extant
still in existence
Extinct
a condition in which a species or other taxon no longer occurs anywhere on the Earth
Extirpated
A condition in which a species or other taxon no longer occurs in some place or region, but still survives elsewhere
Endemic
species with a local geographic distribution
What are the 4 greatest causes of extinction?
- habitat loss 2. over-harvest 3. exotics/invasive species 4. pollution
COSEWIC
Committee on the Status of Endangered Wildlife in Canada
What % of Canadian land area is protected?
9%
What % of Alberta land is protected?
12.3%
Remediation
repair some damage
Reclamation
reclaim and make it function ecologically
Restoration
replace biodiversity and functionality of what it was before
Food-web magnification
The tendency for top predators in a food web to have the highest residues of certain chemicals, especially organochlorines.
Bio-accumulation
The occurrence of chemicals in much higher concentrations in organisms than in the ambient environment. Herbivores will have a higher concentration than plants
Food-web magnification
The tendency for top predators in a food web to have the highest residues of certain chemicals, especially organochlorines. Progressive with age.
Pesticide treadmill
The inherent reliance of modern agriculture and public-health programs on pesticides, often in increasing quantities, to deal with pest problems
Nutrient capital
The amount of nutrients present in a site in soil, living organisms, and dead organic matter
Biodegradation
The breakdown of organic molecules into simpler compounds through the metabolic actions of microorganisms