4.3 carbon cycling Flashcards
what are phototrophs!
plants! use light energy to convert co2 from envt into carbon compounds
what are autotrophs!
organism making organic molecules using abiotic envt
how do aquatic plants take up carbon
dissolved co2 / hydrogen carbonate in water diffuses into leaves
co2s role in photosynthesis?
used in the calvin cycle to make carbohydrates and more complex carbon compounds
co2 is (weight) and thus tends to rise/sink?
heavier than other gases
sink
= readily available to photosynthesisers
solubility of CO2
quite low – 0.88-0.65cm3 of co2 / g of water (temps 20-30degC)
how does solubility of co2 change with pressure
incr pressure = incr solubility of CO2
how does co2 dissolve into water (solutbility and pressure r/s)
co2 heavy = sinks = incr pressure on water surface + waves = dissolve
state the co2 concentration changes in the winter vs spring+summer
winter: co2 conc incr
spring/summer: co2 conc decr
why does co2 concentration incr in the winter
- plants dormant, leaves lost
- more fuel – heat houses
- organisms still respiring
why does co2 concentration decr in spring/summer
trees more leaves!
methane is oxidised into….
co2 and water
what is methane produced by
methanogenic archaeans (single-cell prokaryotes)
what is methane produced from + conditions + what happens after
from organic matter
anaerobic conditions
released into atmos / accumulated underground
what are Ruminants
mammals that have a MUTUALISTIC r/s with metahnogenic archaeans
help them digest cellulose from cell walls of plants they eat = creates methane
eg cow
4 steps of methane production through ruminants
- ruminants chew on plants = breaking down the molecules
- organic matter first changed to organic acids and alcohol (Acidogenesis)
- other bacteria convert org. acids and alcohol –> acetate + co2 + hydrogen
- methanogenic bacteria prod methane thru: reaction of co2 + h2 OR breakdown of acetate
2 ways that metahnogenic bacteria in ruminants can produce methane
- reaction of co2 and h2
CO2 + 4H2 –> CH4 + 2H2O - breakdown of acetate (methanogenesis)
CH3COO- + H+ –> CH4 + CO2
define hydrolysis
chemical process of breaking large polymers into dimers/monomers using WATER
define acidogenesis
chemical process by which bacteria convert organic matter –> organic acids + alcohol
define acetogenesis
chemical process in which bacteria converts organic acids and alcohol into acetate
define methanogenesis
chem process in which metahnogenic bacteria produces methane thru co2 + h2 OR breakdown of acetate
arrange these in order: acidogenesis, methanogenesis, acetogenesis
- acidogenesis – org matter –> org acids + alcohol
- acetogenesis –> acetate
- methanogenesis –> breakdown of acetate
what is methane oxidised into
co2 and water
when does peat form
when organic matter is NOT fully decomposed bc of acidic/anaerobic conditions in waterlogged soils
how do waterlogged areas lead to peat formation 4
- stagnant water = anaerobic envt
- envt progressively acidified = saprotrophs die
- remaining org matter only PARTIALLY digested
- new materials compress the layer = peat
what is peat?
partially digested dead organic matter
that forms in acidic, water-saturated soil
- contains large amts of carbon, can be compressed into coal after time
uses of peat 4
- substitute for firewood
- incr moisture holding capacity of soil (horticulture)
- incr water infiltration rate
- acidify soils
what are fossil fuels
organic material that has been compressed over time to form coal, oil, and fas
what does coal form from!
peat
how are oil and gas formed
similar to peat and coal! but at the bottom of lakes and oceans
where can
1. coal
2. gas and oil
be found?
coal: thick layers beneath the surface hashtag minecraft
oil and gas: porous rock
eg gas reservoirs: deep in earth, high pressure conditions = gas in liquid form
how does combustion release carbon!
as carbon dioxide
what happens (rock-wise) when molluscs, coral, and crustaceans die?
high carbon content in shells and exoskeletons
= calcium carbonate becomes part of sedimentary rock (if conditions arent too acidic)
what is a resevoir?
place where a certain element has accumulated / pooled
when carbon moves from one resevoir to another its called a _____
flux
draw a diagram of the carbon cycle
include interactions between
- co2 in atmos + hydrosphere
- carbon in fossil fuels
- carbon in dead organic matter
- carbon in consumers
- carbon in producers
what unit is used when measuring carbon
gigatonnes (Gt): 10^15 g
2 human acitivities adding to incr atmospheric co2 and methane
incr fossil fuel combustion
incr livestock farms
why is estimating carbon fluxes important
predict impacts of climate change, reduce carbon emissions
- can calculate atmospheric carbon increases
how is methane oxidised
reaction with hydroxyl radicals – highly reactive
= co2 + h2o
