Ecosystem Ecology Flashcards
1
Q
Dead Zone
A
Region of water so low in dissolved oxygen (hypoxia) that marine organisms must live or die
2
Q
Gulf of Mexico’s Dead Zone
A
- Gulf produces 1 billion lbs/yr of seafood, but today’s catch 1/2 of 1980’s levels. Why?
- Dead zone ~20,000km^2 has been growing for past several decades
- N/K pollution result in phytoplankton blooms
- Phytoplankton die/feed bacteria
- Bacteria deplete dissolved oxygen leading to hypoxia/eutrophication
3
Q
Landscape ecology
A
- How landscape structures affect abundance, distribution, and interactions of organisms
- Organisms travel from patch to patch in the landscapes
- When subpopulations become isolated, increased risk of extinction
4
Q
Metapopulation
A
network of subpopulations
5
Q
GIS
A
- Layer different types of data (natural landscape features, human land uses) to produce maps integrating data
- Explore correlations among data sets, help in regional planning
6
Q
Biosphere
A
- Sum total of Earth’s ecosystems
- “Biosphere 1” refers to planet Earth
7
Q
Biosphere 2
A
- Attempt to model many ecosystems in a single location in Tuscon, AZ
- Size of 2.5 football fields, contained rainforest, savanna, desert, ocean, and agriculture
- 8 scientists lived there for 8 years
- Lack of sunlight penetration and soil microbe activity led to decreased O2/increased CO2 levels
- Had to install CO2 scrubbers/deemed failure
8
Q
Flow of energy vs. nutrients in an ecosystem
A
- Energy flow is an open system
- Energy enters biosphere as solar radiation and passed between organisms with some lost as heat until there is no usable energy left
- Nutrient flow is a closed system
- Nutrients do not leave the biosphere, but flow between organisms and are recycled indefinitely
9
Q
How are ecosystems akin to machines?
A
Ecosystems receive inputs of energy, process and transform it to produce outputs
- matter cycles internally
- energy flows
- one way flow of E
- E enters (as radiation from sun) , powers system and E exists as heat, water, flow, waste
10
Q
Water cycle
A
- Water vapor in the atmosphere condenses, falls as precipitation
- Water evaporates from land and transpires from plants to return to the atmosphere
11
Q
Human effects on the water cycle
A
- Deforestation leads to erosion and decreased transpiration
- Pollution creates acid rain
- Depletion of groundwater leads to future water shortages
12
Q
Carbon cycle
A
- Plants use CO2 from the atmosphere for photosynthesis
- Organisms use C from plants for structural growth (tissues)
- Cellular respiration returns CO2 to the atmosphere
13
Q
Human effects on the carbon cycle
A
- mining and burning of fossil fuels moves carbon from underground reservoirs to the atmosphere
- Carbon returned to the Earth and water bodies is not enough to offset the increase in carbon emissions since the mid-18th century
14
Q
Human effects on the nitrogen cycle
A
- Spreading nitrogen fertilizers depletes the soil of other nutrients, and can also cause nitrogen to leach out of soils and pollute waterways (-> eutrophication)
- Fossil fuels release nitrogen compounds, leading to smog and acid rain
15
Q
Human effects on phosphorus cycle
A
- Fertilizers and animal wastes can alter plant growth and nutrient cycling; pollute waterways (-> eutrophication)
- Dust released through mining or in eroded areas can release phorsphorus into the environment at higher-than-normal levels
