4.3 nutrient cycling

Recycling in nature

-matter and energy are essential to life and flow through trophic levels in similar ways

-energy flow is a one time one way stream

-matter flows through trophic levels-> then flows through cycles that reuse or recycle nutrients within and between ecosystems

-biogeochemical cycles are powered by flow of energy: as matter/energy is recycled, it is often transformed-> but it is never created or destroyed

Biogeochemical cycles

-biological processes: activities performed by living organisms and include eating, breathing, “burning” food, and eliminating waste products

-geological processes: volcanic eruptions, formation and breakdown of rock, and major movements of matter within and below earth

-chemical processes: include formation of clouds and precipitation, flow of running water, and action of lightning

-human activities: affect cycles greatly-> ex. Mining, burning fossil fuels, clearing land for building and farming, burning forests, and manufacture and use of fertilizers

-these processes pass the same atoms and molecules around again and again

Water cycles

-water cycles including bodies of water, atmosphere, living things, and earth

-affects life and is affected by living organisms

Nutrient cycles

-every organism needs nutrients to build tissues and carry out life functions

-nutrients pass through organisms and the environment through biogeochemical cycles

-3 cycles that are the nutrient cycles (important for life and ecosystems): carbon, nitrogen and phosphorus

-another element, oxygen, participates in parts of the carbon, nitrogen and phosphorus cycles by-> oxygen combine with these elements and cycling with them through parts of their journeys

-matter (like energy) is conserved on earth and atoms cannot be created or destroyed-> they are combined and recombined with other atoms to form different compounds

Carbon cycles

-carbon = major component of all organic compounds (ex. Carbs, lipids, proteins, and nucleic acids)

-biological (biological process included in this cycle): plants take in co2 during photosynthesis and use carbon to build glucose

-geological: nature can turn gathered carbon into carbon containing rocks (fossil fuels) -> co2 is released into the atmosphere by volcanic eruptions

-chemical and physical: co2 is continuously exchanged between the atmosphere and oceans-> carbons can dissolve in rainwater and enter the oceans when it falls down or be taken in by photosynthetic organisms in the ocean

-human activities: burning of fossil fuels by human and the clearing and burning of forests release carbon in the atmosphere

Nitrogen cycle

-all organisms require nitrogen to make amino acids (to form proteins) and to make nucleotides (to form DNA and RNA)

-many different forms of nitrogen appear naturally in earth 

-nitrogen gas (N2) makes up 78% of earth

-biological, chemical and physical processes: nitrogen gas is abundant (풍족하다)-> but most organisms can’t absorb nitrogen from the air-> they must rely on certain types of bacteria to convert nitrogen gas from air into ammonia, in a process called denitrification

-human activities: humans use nitrogen to manufacture fertilizers-> if too much fertilizers flows into rivers, lakes, and coastal waters, it adds nitrogen too much-> disrupts the nitrogen cycles and causes changes in food webs (REMEMBER that fertilizers help plants grow)

Recycling in nature

-productivity of an ecosystem change depending on the availability of nutrients

-rate of producers creating organic material and long term survival of animals-> depends on changing resources that are limited (ex. Plant growth depends on fertilizers that have nitrogen in it)

-nutrients that are scarce and hard to find are called limiting nutrient

-in the ocean-> nitrogen is often limiting nutrient

-in streams, lakes, and freshwater environments-> phosphorus is often the limiting nutrient