Environmental Science Midterm 2 - Ecosystem Ecology and Biochemistry

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Environmental Studies Flashcards on Environmental Science Midterm 2 - Ecosystem Ecology and Biochemistry , created by abby Radske on 17/03/2018.
abby Radske
Flashcards by abby Radske, updated more than 1 year ago
abby Radske
Created by abby Radske over 6 years ago
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Question Answer
What is the Watershed? The largest water system in North America, any processes taking place in the drainage and watershed of the st. Lawrence will affect the Great Lakes
System a network of relationships among parts of elements of components that interact with and influence one another change of energy, matter, or info receives inputs, processes, then produces outputs
Feedback Loop a system's output serves as input to that same system
Negative Feedback Loop output that results from a system moving in one direction acts as the input that moves the system in the other direction = dynamic equilibrium eg: inc. prey --> inc predators --> dec. prey --> decrease predators --> increase prey etc
Positive Feedback Loop instead of stabilizing a system, it drives it further toward one extreme (increase changes in system) eg. albedo affect global warming
Dynamic Equilibrium (steady state) system processes moce in opposing directions at equivalent rates, balancing their effects
Equilibrium no work or change in free energy
homeostasis a system maintains constant or stable internal conditions
emergent properties system characteristics not evident in the components alone a property which a collection or complex system has, but which the individual members do not have
Lithosphere Rock and sediment
Atmosphere the air
Hyrosphere Liquid, or water vapour
Biosphere all the planet's living organisms and the abiotic portions of the environment
Ecosystems all organisms and non living entities that occur and interact in a particular area at the same time includes abiotic and biotic components
Ecosystems: Interactive Living and Non-Living Entities energy entering the system is processed and transformed matter is recycled within ecosystem, resulting in outputs such as heat, water flow, and waste products
light energy --> chemical energy stored in bonds of organic matter by primary producers using CO2 which is an inorganic molecule primary consumers break down these bonds to harness energy part of the light energy is lost at each trophic level is lost as heat
Primary production conversion of solar energy --> chemical energy by autotrophs
Gross Primary Production (GPP) the absorption/digestion of energy by autotrophs
Net Primary Production (NPP) Energy remaining after respiration, and is used to generate biomass available for heterotrophs (begins secondary production)
Secondary Production biomass generated by heterotrophs
Where does most production of biomass on land occur? most production on land occurs in tropical forests, due to the high heat and high light
Where does most production of biomass in water occur? in Northern water, because there is less stratification and the water mixes, nutrients are brought back up where light is present and this stimulates primary production
Net Primary Productivity high net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass variation in net primary productivity among ecosystems & biomes result in geographic patterns of variation across the globe
Nutrients elements and compounds required for survival that are consumed by organisms
Macronutrients nutrients required in relative large amounts nitrogen, carbon, phosphorus
Micronutrients nutrients needed in smaller amounts
Nutrient (biogeochemical) Cycle the movement of nutrients through ecosystems atmosphere, hydrosphere, lithosphere, and biosphere
Pools (reservoirs) where nutrients reside for varying amounts of time
Flux movement of nutrients among pools, which change over time and are influenced by human activities
Sources VS Sinks Sources : pools that release more nutrients than they accept Sinks: accept more nutrients than they release
Evaporation Water moves from aquatic and land systems to air
Transpiration Release of water vapour by plants
Precipitation condensation of water vapour as rain or snow
Aquifers underground reservoirs of sponge-like regions of rock and soil that hold groundwater
water table the upper limit of groundwater held in an aquifer
Human Impacts on the Hydrological Cycle Damming rivers increases evaporation and infiltration Altering the surface & vegetation increases runoff and erosion Removing forests and vegetation reduces transpiration and lowers water tables most threatening : overdrawing groundwater for drinking, industrial etc.
The Carbon Cycle carbon is found in carbohydrates, fats, proteins, bones photosynthesis moves carbon from the air to organisms respiration returns carbon to the air and oceans decomposition returns carbon to the sediment (largest reservoirs) oceans second largest
Humans affect on the carbon cycle burning fossil fuels moves carbon from the ground to the air cutting Forrests and burning fields moves carbon from organisms to air atmosphere carbon dioxide is highest its been in a long time, driving force for climate change the missing carbon sink: 1-2 billion tons of carbon unaccounted for - may be in plants/soils of Northern temperate and boreal forests
Methanogenasis only occurs in the absence of oxygen process where dissolved organic matter (DOM) is converted to methane
Biological Pump the ocean's biologically driven sequestration of carbon from the atmosphere to deep sea water and sediment driven by photosynthesis
Microbial Carbon Pump the transformation of bioavailable carbon (which could be transformed to CO2 and leave ocean) into a pool of refractory organic carbon that will remain in the deeper part of the ocean
Microbial Loop the transformation of dissolved organic carbon into particulate organic carbon by heterotrophic bacteria this mechanism enables the recycling of organic carbon back to food webs
The Nitrogen Cycle nitrogen is 78% of our atmosphere N2 gas is inert (not usable form) Nitrogen Fixation: N2 gas is fixed (made into ammonia) by bacteria. this makes a usable form
Nitrification bacteria that convert ammonium ions --> nitrite ions --> nitrate ions plants can take up these ions animals obtain nitrogen by eating plants or other animals
Denitrifying Bacteria convert nitrates in soil or water to N2, releasing it back into the atmosphere only occurs when oxygen is present
How Humans Affect the Nitrogen Cycle humans are fixing as much nitrogen as nature does (haber-bosch process = production of fertilizers, fixes nitrogen) increased emissions of nitrogen greenhouse gases
Consequences of Humans Affecting the Nitrogen Cycle Ca & K in soil washed out by fertilizers acidified water & soils reduced biodiversity of plants adapted to low nitrogen soils changes estuaries and coastal ecosystems
Eutrophication process of nutrient over-enrichment, blooms of algae, increased production of organic matter, ecosystem degradation
Steps of Eutrophication 1) nitrogen input 2) phytoplankton flourish at the surface 3) dead phytoplankton and their waste move to the bottom, providing more food to decomposers 4) decomposer pop. grows and consumes more O2 5) too low O2 kills fish, makes dead zone
Phosphorus Cycle involves no organisms most phosphorus is within rocks and is released with weathering with naturally low [environment], phosphorus is a limiting factor for plant growth plants take up phosphorus when it is dissolved in water
How we Affect the Phosphorus Cycle mining rocks for fertilizer moves phosphorus from the soil to water systems wastewater discharge also releases phosphorus runoff containing phosphorus causes eutrophication of aquatic systems household detergents have phosphorus
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