ENV100H1 Lecture Notes - Lecture 12: Carbon Sink, Geosphere, Water Cycle

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Published on 9 Oct 2016
School
UTSG
Department
School of Environment
Course
ENV100H1
Professor
Page:
of 5
Biogeochemical cycles
- Involves biological, geological, atmospheric reservoirs
- Substances move among reservoirs and may take several chemical forms
- Residence time in these reservoirs may be any time frame
- Size of reservoirs and rate of cycling varies in different ecosystems and over time
- Size of reservoirs and rate of cycling can be affected by human activities
- Source that leads into reservoir
oMaterial moving from a to b
- Reservoir leads out to sink
- Bathtub analogy
- Steady state
oSource = sink
- Flux – rate at which substance moves through the system
Generalized biogeochemical cycle
- Way things move around
- All kinds of linkages
- All things are closely linked together
- Transformation from organic to inorganic forms
- Movement through biotic and abiotic reservoirs
- Number of water molecules are more or less fixed
oJust moving around various kinds of reservoirs
In any cycle…
- What are the important reservoirs?
oBig ones, ones that have huge influence on living processes, etc.
- What scales (temporal and spatial) do these cycles function on?
oRate of co2 is what is important in the last 100 years
oMassive uptake in co2
oReally important
The hydrologic cycle influences all other cycles
- Water is both a participant in and the main transport medium for environmental processes
- Presence or absence of water has a big impact on other biogeochemical cycles
oDepend on it as
Physical agent
Ex. Erosion, weathering of rocks, etc.
oWater is driving the rate of all these other processes
The hydrologic cycle
- Do not memorize
- What is the biggest reservoir?
find more resources at oneclass.com
find more resources at oneclass.com
oOceans
- Greater evaporation from the oceans means to greater reservoir in the atmosphere
- Water in the atmosphere makes modelling climate change tricky because it can have two
functions
oIt can block radiation
oCan also trap heat
oMore precipitation
- By extracting groundwater we also tend to dirty it
- Think about what parts are affected by people and in what way
oEx. Pollution and where it is going to go
The hydrological cycle
- Oceans are the major reservoir (97%)
- Hard to desalinate water
oVery energy intensive
- We do not have that much water if we look at it as a whole
- Most freshwater is in ice caps and water
- Water moves between 3 states
Aquifers
- Important freshwater reservoir
- Not large reservoirs compared to the ocean
- Important for our drinking water and agriculture
- Underground reservoirs recharged by precipitation and surface water flows
- Different types of aquifers
oConfined aquifer – between two layers of bedrock
oUnconfined aquifer – rock substrate on the bottom and soil cap on top of it
- When you drain an aquifer (output higher than input) the ground can subside
- If we put stress on aquifers we can create problems for ourselves
Human impacts on the water cycle
- Damming rivers
oIncreases evaporation
oCreate a reservoir behind the dam so it backfills and creates kind of like a lake
there
oBig surface area moving slowly increases evaporation and raises temperature of
the water
oAffecting the rate at which surface water is moving into the atmosphere
oIncreasing flux of surface water into the atmosphere
- Hard surfaces
oPaved surfaces
oNormally water would have been absorbed right away into the soil
oA lot of hard surfaces forces the water to run off
oRunoff and erosion increases
oHard surfaces rapidly increase input into surface water reservoirs
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find more resources at oneclass.com
- Deforestation
oRoots of trees stabilize the soil
oRemoving trees allows for direct impact of rainfall on soil
oNo roots to stabilize soil = landslides, erosion
oSediments builds up in nearby water bodies
Mega-quarry in Melancthon, ON
- Nestle
oHorrible company
oStealing groundwater away from citizens of Aberfoil to bottle it
oWere going to build mega-quarry near Orangeville
oBuying up farms little by little
Kawalling the scene
Deceitful
Wanted to put parcels of land together
oSize of 200 football fields
oMassive impact on groundwater and aquifers
o600 million litres of water a day
ground subsidence
kill of agriculture in the area
- citizens of Melancthon killed the project of the meg-quarry
- we have more of a voice than we think
The carbon cycle
- carbon is a part of all organic molecules
othis is what defines organic molecules
- carbon moves out of atmosphere into biotic reservoirs via photosynthesis and from biota
to atmosphere via respiration
- main driver of climate change is how we are affecting the carbon cycle
- biodiversity sequesters carbon, creates carbon sinks = big part of climate change battle
ohealthy ecosystems have a huge impact on the carbon cycle
- highly complex because there are so many different reservoirs
- carbon can go through a whole lot of species
oex. Carbonate, methane, co2, etc.…
oa lot of forms carbon takes in the cycle
- fluxes vary in time and space
othings are happening on many time frames
long
short
oa lot of variation in time and space
find more resources at oneclass.com
find more resources at oneclass.com

Document Summary

Substances move among reservoirs and may take several chemical forms. Residence time in these reservoirs may be any time frame. Size of reservoirs and rate of cycling varies in different ecosystems and over time. Size of reservoirs and rate of cycling can be affected by human activities. Source that leads into reservoir: material moving from a to b. Flux rate at which substance moves through the system. Number of water molecules are more or less fixed: just moving around various kinds of reservoirs. What are the important reservoirs: big ones, ones that have huge influence on living processes, etc. What scales (temporal and spatial) do these cycles function on: rate of co2 is what is important in the last 100 years, massive uptake in co2, really important. Water is both a participant in and the main transport medium for environmental processes. Presence or absence of water has a big impact on other biogeochemical cycles: depend on it as.