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