the Earths life support systems - P Flashcards
what is carbon
the chemical backbone of all life on Earth - used in DNA, found in the atmosphere
what is the carbon cycle
the way carbon atoms travel from the atmosphere into organisms and the earth and then back into the atmosphere over and over again in a cycle
what are the main carbon sinks
the ocean
stored in rocks and sediments
atmosphere
organisms
when do plants and animals produce carbon
by living and dying - remains can turn into fuels used in combustion which produces CO2
When is carbon taken in and released by plants
taken in during photosynthesis and released by respiration, burning materials
how does carbon form the bodies of living organisms
carbon atoms such as proteins, carbohydrates and nucleic acid are built on large molecules of carbon atoms
what are the four main spheres that water and carbon can move through
lithosphere
atmosphere
hydrosphere
biosphere
what is the lithosphere
the rigid outer part of the Earth, consisting of the crust and upper mantle
what is the atmosphere
the envelope of gases surrounding the Earth
what is the hydrosphere
all of the waters o the Earth’s surface, sometimes including water over the surface (clouds).
what is the biosphere
the regions of the surface and the atmosphere occupied by living organisms
what is the importance of carbon in 4 main points
life is carbon based - built on molecules of carbon
crops and trees store carbon - used for food, textiles, profit, timber
helps regulate earths temperature
an economic resource - fossil fuels used as raw materials
when measuring carbon what units do we use
a Petagram/Gigaton:
1015 g OR 1012 kg
what is residency time
the amount of time carbon remains in a store - shows us the capacity and duration that carbon was stored.
what do we use residency time to differentiate between
long term and short term stores of carbon
how do you calculate residency time
amount in reservoir / flows in or out
what happens in a closed system
energy is transferred, matter is contained
what happens in an open system
energy and matter are transferred
Since our planet is a closed system what does this mean about carbon
the amount of carbon on the Earth doesn’t change it is just transferred between stores.
what are the four sub systems of the carbon cycle
terrestrial (fast) carbon cycle
ocean carbon cycle
atmospheric carbon cycle
slow carbon cycle
what happens in the terrestrial (fast) carbon cycle
the uptake of CO2 through plants during photosynthesis. Released through respiration and decomposition - the cycling between the atmosphere, soil, vegetation happens relatively quickly
what happens in the ocean carbon cycle
carbon held in the ocean and oceanic organisms - inputs and outputs take place through gas exchange with atmosphere & continental runoff
what happens in the atmospheric carbon cycle
CO2 and methane - methane is powerful but short lived - CO2 is removed by terrestrial and oceanic carbon cycles
what happens in the slow carbon cycle
carbon cycling between rock stores, atmosphere, oceans through weathering over millions of years - Weathering creates net carbon sinks in oceans- chemical weathering produces carbonate run off transferred to the ocean - organisms use this then die - released through volcanic activity
what is the timescale of a slow carbon cycle
100-200 million years
which processes are involved in the slow carbon cycle
geological processes (weathering, volcanic eruptions, sedimentation)
which spheres are involved in the slow carbon cycle
the atmosphere, lithosphere and also oceans - a movement of 10 million to 100 million tonnes of carbon per year
what does the slow cycle affect
complex chemical feedbacks regulate the process so it rebalances over hundreds of years and has no clear affects.
what is the timescale of the fast carbon cycle
over years to decades
which processes does the fast carbon cycle involve
biological processes (photosynthesis, respiration, food chain)
how much carbon does the fast cycle move each year
about 1,000 times more carbon each year than the fast cycle.
what does the fast cycle affect
the atmospheric CO2 levels, with seasonal variations based on plant growth
what is a climate graph
a graph used to illustrate average temperature and rainfall simultaneously experienced at a particular place over the course of a year.
when interpreting a climate graph what should you consider
- highest & lowest temperatures and rainfalls
- the range for temperature & rainfall
- the trends
- links to store or flows in carbon/water cycle
what carbon cycle processes are affected by climate graphs
- rates of photosynthesis - light & temperature
- rates of decomposition - temperature & moisture
- rates of respiration - temperature, humidity, moisture
what are some limitations of a climate graph
- could be from an anomalous year
- don’t show diurnal changes
- don’t consider spatial variances within the area
- only show rainfall & temperature as variables
- graphs over a few years can hide changes in rainfall & temperature
what is Insolation
INcoming SOLar radiATION
what is differential heating due to
insolation
why is the sun more concentrated at the equator
insolation travels a shorter distance and is spread over a narrower range
why is the sun less concentrated at the poles
insolation travels through a deeper atmosphere causing greater heat loss as it is absorbed by clouds and gases
what is the albedo affect
when ice at the poles of the Earth reflect radiation
why is insolation weaker at the poles
spread over a greater distance at the pole so it is weaker
what happens to carbon levels at higher latitudes
growing season for vegetation is shorter so less carbon is stored as biomass in the biosphere in these regions.
what happens with carbon stores when there is low precipitation
fewer plants grow throughout the year so lower amounts of carbon are stored
what happens with carbon stores in tropical regions
there is a lot of precipitation and a long growing season so more carbon is stored in plants
where are tropical/subtropical forests in the world
the equator
which forests store the most carbon
tropical/subtropical forests
which forests store the most carbon after tropical/subtropical
Boreal forests, then temperate forests
which biomes stores the least carbon
Tundra biomes
what are forests for carbon
natural carbon sinks - they store carbon in living biomass, dead biomass and soil
what are the ideal conditions for the storage of carbon
cold, wet soils - wetlands have the most soil storage
what is carbon sequestration
a natural or artificial process of capturing carbon dioxide from the atmosphere and storing it in solid or liquid form.
how much CO2 stays in the atmosphere
45% - the rest is sequestered naturally
how much CO2 (from fossil fuels) is taken in by the oceans
30% - of CO2 from fossil fuels is taken in by the upper layer of the oceans.
how much CO2 is taken in by Earth’s forests, farms and grasslands
25%
what is the residence time of deep oceans
1250 years
what are the two main ways the ocean acts as a carbon sink
physical carbon pump
biological carbon pump
what is a summary of the processes in a biological pump
driven by phytoplankton and autotrophs which absorb CO2 through photosynthesis, converting it into organic matter
what are the 3 main steps in a biological pump
- carbon moves up the food chain.
- when plants & animals die they sink into deeper water then decompose releasing CO2 into the water.
- carbon is also stored in hard body parts like shells in the form of calcium carbonate
what does the biological pump do
transports carbon to the deep ocean
what is the thermohaline circulation
an ocean current pattern:
- lower temperatures at poles so ocean waters sink as they are dense which is called downwelling
- higher temperatures at equator so ocean waters rise as they are less dense which is called upwelling
what are the main steps in a physical pump
- atmospheric circulation pattern and resultant regional air temperature differences affect ocean temperatures
- water temperatures determine circulation patterns: cool water sinks, warm water rises.
what is a summary of the processes in the physical pump
refers to carbon dissolving into the ocean surface and then being driven deep down into the lower oceans by currents and downwelling
which percentage of the ocean is surface currents
10%
which percentage of the ocean is deep ocean currents
90%
what do surface currents do by the shore
driven by winds and tides - drawing waters back and fourth as the water levels rise and fall
what do surface currents do in the open ocean
wind is the main force - as wind blows it drags the top layer of the ocean along with it - this then moves the water below it
what do surface currents form
huge loops called gyres - travel clockwise in northern hemisphere - travel anticlockwise in the southern hemisphere
what is the Coriolis effect
when major streams of wind form loop like patters around the ocean basin.
what do deep ocean currents do
are driven primarily by changes in density of seawater - as water moves north it gets colder and had a higher concentration of salt - this water is dense so sinks - warmer surface water takes its place
what do current help to do globally
redistribute warmth around the globe
what is the global conveyor belt
the combination of thermohaline circulation of deep water and wind driven currents forming a large winding loop
what affect does increasing temperatures have on the ocean currents
they are slowing down
what is downwelling
CO2 dissolved at surface is brought down and stored in deep water - This occurs when winds push water towards the coastline, where it is forced downwards and cools as it sinks, This sequesters CO2 where it will stay for hundreds of years.
what is upwelling
currents bring nutrients and carbon to the surface - this occurs when winds push surface water away from the coastline, leading to carbon-rich deeper ocean currents rising to replace the water, increasing surface water dissolved CO2 transfer to the atmosphere.
what happens in locations with upwelling
cold deep ocean water is nutrient rich - upwelling provides high biological productivity due to the nutrient rich water rising from the deep ocean
where do Phytoplankton blooms form
nutrient rich areas
why is downwelling important
it supplies the deeper ocean with dissolved gases such as CO2 where it stays as a carbon sink
what is a phytoplankton bloom
when phytoplankton photosynthesise and act as a biological carbon pump - absorbing and storing carbon
what type of changes are el Nino and La nina
seasonal changes
what is el nino
if conditions are right - trade winds can be weakened or reversed - this means there’s less warm water to the western side of the ocean and less cold water to the eastern side of the ocean - this allows colder parts of the ocean to warm - this affects temperature and rainfall around the world.
where are the main impacts of el nino
around the tropics
