Ecosystem Ecology Flashcards
Dead Zone
Region of water so low in dissolved oxygen (hypoxia) that marine organisms must live or die
Gulf of Mexico’s Dead Zone
- 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
Landscape ecology
- 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
Metapopulation
network of subpopulations
GIS
- 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
Biosphere
- Sum total of Earth’s ecosystems
- “Biosphere 1” refers to planet Earth
Biosphere 2
- 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
Flow of energy vs. nutrients in an ecosystem
- 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
How are ecosystems akin to machines?
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
Water cycle
- Water vapor in the atmosphere condenses, falls as precipitation
- Water evaporates from land and transpires from plants to return to the atmosphere
Human effects on the water cycle
- Deforestation leads to erosion and decreased transpiration
- Pollution creates acid rain
- Depletion of groundwater leads to future water shortages
Carbon cycle
- Plants use CO2 from the atmosphere for photosynthesis
- Organisms use C from plants for structural growth (tissues)
- Cellular respiration returns CO2 to the atmosphere
Human effects on the carbon cycle
- 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
Human effects on the nitrogen cycle
- 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
Human effects on phosphorus cycle
- 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
Ecosystem services
- Benefits that are important to all life, including humans, provided by functioning ecosystems
- Nutrient cycling, air and water purification, ecosystem goods (food and fuel), pollination, climate regulation
Ecosystem Ecology basics
Living organisms interact with chemical and physical entities via interactions and feedback loops
- Earth = network of interlinked systems
- feedback loops maintain stable conditions
Deepwater Horizon oil spill
released a record of 4.9 million barrels of oil into Gulf
- disrupted Gulfs intimately interconnected ecosystems
- fouled marine life, closed fisheries, damaged coastline
- the area already under stress from other human activities (overdeveloped, polluted, overfished)
- restoration ecology will be expensive and ecosystem will remain stressed by climate change
Why is the Gulf of Mexico catching 50% less seafood compared to the 1980s?
past several decades , billions of marine organisms suffocating in ~20k km^2 dead zone in gulf.
Lessons and Benefits from Biosphere 2
ecosystems are intertwined in many complex ways to fully understand
- Exeimenental evidence of Earths responses to increasing CO2 levels
- learned how irreplaceable Earth / Biosphere 1 is
