recycling in ecosystem [carbon cycle and nitrogen cycle]

why is carbon needed for organisms?

to make essential compounds such as glucose

How is carbon released into the atmosphere in the carbon cycle?

How is carbon taken in from the atmosphere in the carbon cycle?

released

-combustion [physical]

-respiration

-decomposition

taken in

-photosynthesis

photosynthesis

-Producers (plants) absorb CO₂ from the atmosphere for photosynthesis

-carbon is converted into organic molecules

respiration

-release CO₂ back into the atmosphere

decomposition

-decomposers break down dead organic matter→ releases CO₂ into the environment

-decomposers secrete enzymes to break down carbon compounds in dead organic matter and absorb the products of digestion for use in respiration

more info

-Carbon enters the food chain when a primary consumer eats the producer. Carbon is then passed to secondary consumers and tertiary consumers when organisms feed on each other.

-carbon, stored in dead organic matter, can be turned into fossil fuels

-CO₂ dissolves into oceans

carbon cycle

why is nitrogen needed for organisms?

to make proteins and nucleic acids (DNA and RNA)

nitrogen gas is present in the atmosphere but cannot be used directly by plants. They use microorganisms to convert it into nitrogen compounds

processes used in nitrogen cycle [mention the bacteria used→ underlined are named bacteria MUST KNOW]

-Nitrogen fixation

→Azotobacter [found in soil]

→Rhizobium [lives in root nodules]

[nitrogen-fixing bacteria]

-Ammonification

→decomposers used

-Nitrification

→Nitrosomonas

→Nitrobacter

[tip: start with nitro for nitrification

the processes starting with nitr have the bacteria u should know]

-Denitrification

→denitrifying bacteria

ions/ molecules used in nitrogen cycle (5)

N₂

NH₃ (ammonia)

NH₄⁺ (ammonium ions)

NO₂^- (nitrite)

NO₃^- (nitrate)

[tip: ate→ 3 letters = 3 oxygen. ite not real word lol so remember ate]

describe the processes in nitrogen cycle

[mention conditions]

nitrogen fixation

N₂ → NH₃

-nitrogen gas in the atmosphere is converted into ammonia by Azotobacter and Rhizobium

-occurs under anaerobic conditions

ammonification

organic nitrogen compounds → NH₄⁺

-organic nitrogen compounds in dead organic matter or animal waste are converted into ammonium ions by decomposers

-release ammonium ions

nitrification

NH₄⁺ → NO₂^- → NO₃^-

[Nitrosomonas] [Nitrobacter]

-ammonium ions are converted into nitrites ( NO₂^- ) by Nitrosomonas

-nitrites ( NO₂^- ) are converted into nitrates ( NO₃^- ) by Nitrobacter

denitrification

NO₃^- → N₂

-nitrates are converted into nitrogen gas by denitrifying bacteria

-occurs under anaerobic conditions e.g.in waterlogged soils

what can be absorbed by plants and what cannot?

what plants absorb

-nitrate ( NO₃^- )→ converted into proteins/ amino acids for growth

-ammonia ( NH₃ )

what plants cannot absorb

-nitrite ( NO₂^- )

-N₂

Other ways nitrogen enters an ecosystem (2)

Lightning [involved in nitrogen fixation]

artificial fertilisers

nitrogen cycle

[tip for remembering whats absorbed by plant: everything on the right except N_{2 .}

nitrate→ ate= food]