Recycling nutrients - carbon and nitrogen cycles

Where is carbon found

carbon is found in all organic molecules -lipids, proteins and carbs and in the air from photosynthesis and more in recent years due to deforesation and burning of fossil fuels

Its also found in magnesium and calcium carbonate in mollusc shells and athropod exoskeletons which when they die turn into chalk, marble and limestone and if exposed to the air add co2 back

Explain the 3 biological processes in the carbon cycle

1. photosynthesis

2. respiration

3. decomposition

Explain the carbon cycle

Explain the human impacts on the carbon cycle

1. deforestation - releases carbon sinks and little trees to photosynthesise

2. climate change - deforestation and burning of fossil fuels

3. The enhanced green house effect is the greenhouse effect behond its naturality

   High energy short wavelength solar radiation can pass through the greenhouse gases to the earths surface where it much is absorbed by the earth and heated up and changed into lower energy infrared long wavelength radaition that can be reflected by the greenhouse gases so some is trapped under the surface and heats it up

4. Consequences of global warming -

   1. polar ice caps melt

   2. increased extreme weather

   3. change in rainfall and wind patterns

   4. ocean expansion

   5. increase pests

   6. change in farming belts

   7. too warm

5. Co2 on oceans

   • migration

   • acidic as co2 dissolves in water to lower pH as creates carbonic acid

   • kills coral due to temps and skells of mollusc

What is a carbon footprint and explain how agriculture increases the carbon footprint

Carbon footprint is the amount of carbon dioxide production by an individual, product or service by comparing it to an equivilent greenhouse gas

agriculture increases the carbon footprint:

1. machines

2. production of machines

3. transport

4. making fertilisers and insecticides

What was created in response to this

the 3 Rs - reduce, reuse and recycle

1. plant trees

2. avoid food waste

3. change diet

4. recycle and reuse packaging

5. drive less

6. use lesson air con and heating - insulation

Problems with agriculture caused by greenhouse gases and human acticity and how to solve them

CO2 from decomposers-

1. crop rotations - to allow pests to be reduced and lack of mineral depletion

2. cover crop - legumes

3. conservation tillage - leave crop remains to add to nutrients

methane from animals

1. change of diet

methane from rice paddies

1. select varieties with higher yield and for drier conditions

nitric oxide from waterlogged soil

1. improve aeration of soil

low rainfall

1. drought tolerant crops

raised sea levels

• salt tolerant crops

Where is nitrogen found

Inorganic

• nitrite

• nitrate

• Air N2 79%

• ammonium

Organic

• nitrogenous bases

• amino acids

• chlorofil

• r groups

Explain the nitrogen cycle

The 4 main biological processes

1. Ammonification - bacteria and fungi (saprotrophs) - proteases in them breakdown protein into amino acids which are then broken down into NH2 by deaminases

2. nitrification - oxidation - lose o2

3. dentriphication

4. Nitrogen fixation - azobacter and rhizobium

   rhizobium in legumes

   newly synthesised legume radicles don’t contain rhizobium but they grow toward rhizobium and the RH use a flagella (with new bacteria) to invade the cortex radicle and swell it with rhizobium

   1. Nitrogen diffuses into the legume root

   2. Nitrogenase catalase reduces nitrogen into ammonium and diffuses into vascular tissue

   3. leghaemoglobin bind oxygen to prevent oxygenation

How can farmers increase the nitrogen in the soil for their plants and what are the disadvantages

1. Ploughing and draining the land to aerate the soil to promote aerobic bacteria like nitrogen fixing and rhizobium and de-favour psuedomonas

2. legumes - promote rhizobiums

3. artificial NPK fertilisers made using the habour process from ammonium and hydrogen

4. natural fertilisers - slurry, manure and compost that can be made using sewage sludge - biosolids and less smelly through herbivore manure

Disadvantages

• eutriphication

• some plants favour less nitrogen

• ploughing destroys habitats

What is eutriphication and explain how it occurs and how to reduce it

Eutriphication = the artificial enrichment of aquatic habitats by excess nutrients

1. Fertiliser is spread across the land and when it rains occurs so water eneters the soil and creates small streams in the soil

2. Nitrate is very soluble so it is carried in the streams in the soil to rivers and lakes.

3. the excess nitrogen causes an increase in plant growth

4. Algae grows on the surface causing algael gloom so no sunlight can reach to photosynthesising plants so they die

5. This creates a lot of dead matter for lots of bacteria so bacteria take the oxygen and cause dystrophic effects - fish die as no oxygen

6. aerobic bacteria take all the oxygen and turn nitrate into nitrite - smell

eutrophic - just right nutrients

How to reduce this

1. reduce fertiliser

2. man made streams to concentrate minerals

3. only put it on during crop growth so it can be absorbed not leached

4. no fertiliser 10m from rivers