5.2 Cycles of matter + Global warming and climate change

oxygen details

essential in cellular respiration

earth has a fixed supply of useful breathable gaseous oxygen

reservoirs of oxygen

atmosphere 0.49 percent

lithosphere/earth’s crust 99.5

biosphere/ living organisms 0.01 percent

atmosphere oxygen cycle

oxygen exists as o2 and o3 (ozone), in compounds H20 and CO2

photolysis: oxygen is formed through UV light converting water to oxygen and hydrogen

2H2O+ energy→ 2H2+O2

biosphere oxygen cycle

oxygen dissolves in oceans and is available for uptake by marine organisms

release- photosynthesis releases oxygen

absorption- decaying organisms, weather exposed rock, cellular respiration

nitrogen details

necessary for synthesis of proteins and nucleic acids (DNA and RNA)

makes up 78 percent of all gases in atmosphere, not usable by most living organisms

cycles in atmosphere and lithosphere

humans impact through fertilizers

nitrogen process

bacteria turn gaseous N2 into usable forms

nitrogen fixing bacteria lives in root nodules of legumes (peas and beans): N2→ ammonium ions (NH4+)

nitrifying bacteria: N2→ nitrates (NO3-) and nitrites (NO2-)

denitrifying bacteria: return all forms of nitrogen to atmosphere as N2

phosphorous details

essential in energy for ATP, DNA and RNA (phosphate forms the backbone)

slowest of cycles, doesn’t have a gaseous phase

is available to organisms from sedimentary rocks and soil, isn’t a common element so farmers use fertilizers to help

process of phosphorous cycle

1. Rain weathers rocks, releasing phosphate ions into the soil
2. Plants absorb phosphate ions via roots (this is how phosphorus enters food chains)
3. Phosphorus absorbed by any organism returns to soil via urine, faeces and
decomposition of dead organism when it dies
4. Phosphorus is ‘locked’ (not available to living things) in sediments and rocks for
many years before it is released by weathering + erosion
5. Cycle continues (back to step 1

Eutrophication

phosphorous is mined to be used for fertilisers
1. Run-off from agricultural land results in excess phosphorus in
waterways
2. Phosphorus encourages plant growth sp increased growth of plankton + algae
3. Increased oxygen consumption so suffocate fish + blocking sunlight

eutrophication is blocking sunlight by algae

ways carbon is extracted/ cycled

• fossil fuel extraction: extracting oil, natural gas, coal for enrgy production+ cars. large scale extraction+ use→increased atmospheric CO2→ enhanced greenhouse effect

• geological carbon cycle: hundreds to millions of years- bulk of carbon gers locked inrocks and sediments as fossil fuels

• biological carbon cycle: cycling of carbon through photosynthesis and cellular respiration.

• returnign carbon to the atmosphere:

  1. fire consumes biomass+organic matter- produces CO2, methane, smoke, carbon monoxide

  2. carbon is long term stored intrunks and branches, temporrality stored in organsims’ bodies. whent he dy die the CO2 is returned to the atmosphere by decomposers.

carbon sink

any feature of the environment that basorbs carbon, ekeeping it from the atmosphere.

forests, oceans (dissolved CO2), organic matter in soil some rocks, fossil fuels, shels

human impact on the carbon cycle

• removing forest (carbon sink), burning forest

• fossil fuel burning in factories and cars- releasing CO2 to the atmosphere

• breeding livestock that produce methane

• destroying habitats- desertification, deforestation, ocean acidity.

greenhouse effect

critical for maintinag life on Earth. otherwise temperatures would make earth inhabitale. temperatures would drop at ngihta nd rise during the day

1. Sunlight passes through atmosphere and warms the ocean, surface, atmosphere. some of it is absorbed

2. Infrared radiation (heat) is released back toward space

3. Greenhouse gases (CO2, methane, water vaport) trap some heat instead of letting it all escape

   • is necessary for survival, but increased production of CO2 and decreased absorption ( because of deforestation) leads to climate change and global warming. this is the enhanced greenhosue effect

Greenhouse gases

CO2- released by fossil fuel burning

Mehtane- relased by livestock, biomeass burning, landfills

Ocean in relation to the carbon cycle

is a carbon sink and absorbs 90 percent of solar radiation. sea ice reflects radiation.

the warmer water (due to the enhanced greenhouse effect) melts the ice so the ocean absorbs more heat. the warmer water also heats the atmosphere about it, creating a cycle. (the atmosphere is warmer, more ice melts, water gets warmer, atmosphere gets warmer)

global warming

long term increase ing lobal tempreatures

climate change

• loss of biodiversity: organisms live within a range of limits of temperatures, water availability etc.

melting permafrost

permanently frozen ground that stores carbon from plant material, melting will cause it to release thousands of years worth of carbon

extreme weather

global warming affects ocean temperatures→ more cyclones, intense storms, flooding, damage to buildings

health and diseases

higher summer temperatures acan cause death. some diseases (malaria) can spread more easily in hot conditions so global warming can increase these zones. when warm air+ pollutants→ smog, causing serious respiratory issues

loss of biodiveristy

organisms live within a range of limits of temperatures, water availability etc.

• melting ice reduces habitat availability for polar organisms

• warmer waters affect aquatic ecosystems (coral bleaching)

• organisms are affected by hot/dry conditions or rising sea levels

• organisms can survive year to year climate fluctuations, but only within a range of temperatures. they are vulnerable to rapid and sustained long term increase of 1-2C

rising sea levels

• increasing temperatures melt polar ice caps, high altitutde regiosn that are covered in ice.

• releases water into oceans , increasing sea levels

• increased flooding, removes small islands

ocean currents

increasing temperatures change the temp and salt concentration in oceans, affecting ocean currents. these currents affect the climate and storms.

(colder denser (saltier) water sinks, warmer less dense/salty water rises, cools and sinks gets denser etc.)

arguements against climate change

climate is always changing, CO2 is good for plants, water is the biggest greenhouse gas

reducing impact of climate change/global warming

Kyoto protocol: international treaty stating global warming is a result of CO2 emissions. countries agreed to reduce CO2 emission

limiting CO2 emissions: carbon tax for each ton of carbon a business emits. carbon trading scheme- allowance of emissions that can be sold to those who want to emit more.

Geo sequestration: captures+ storage of CO2 underground. CO2 from power station chimneys can be separated, liquified, pumped into empty oil/gas wells

carbon farming: planting trees (carbon sinks),

small changes: taking public transport, renewable energy, local produce, plant trees

reducing methane production: modify gut bacteria to stop grass fermentation in the (increased population) of cattle’s stomachs

Water cycle

global cycle so water is not equally available in all ecosystems

evaporation + transpiration, condensation, precipitation →onshore winds and surface run off,

infilitration into soil, percolation (movement through groundwater)