Ecosystem ecology - nutrient cycling

Nutrient cycling

• nutrients assim_____ into pl___ ti____

• Passed up trop___ lev____

• Detritus deco_____

• Soil organic matter - mix of partially and completely deco_____ detritus

• Eventually converts nut_____ to inor_____ form (NO3)

• Nutrients assimilated into plant tissues

• Passed up trophic levels

• Detritus decomposed

• Soil organic matter – mix of partially and completely decomposed detritus

• Eventually converts nutrients to inorganic form (eg. NO3)

Why does decomposition often limit nutrient cycling in ecosystems?

• Abiotic conditions - temp____, ox____, avail_____ & preci______

• Type of detritus - lig___ vs cell____e

• Abundance and diversity of detri_____s

Abiotic conditions – temperature, oxygen availability & precipitation

• Type of detritus – eg. lignin vs cellulose

• Abundance and diversity of detritivores

The Nitrogen Cycle

Why is N important to biological systems?

Cycling nutrients between li___ and non-li____ components of the eco_______

Cycling nutrients between living and non-living components of the ecosystem

The Nitrogen Cycle

Major nitrogen reservoir?

The atm_____e

the atmosphere

How does N enter biological systems?

Through bac____l nitr____ fixation and denitr_____

Through bacterial nitrogen fixation and denitrification

How are humans altering the natural N cycle?‘

• synthetic fert_____

• Concentrated live_____

• R__-o__

• Eutro______

synthetic fertilization

Concentrated livestock

Run-off

Eutrophication

Eutrophication - excessive richness of nu_____ in a la__ or other body of w_____

• due to ru_o__ from the la__

• Causes a dense growth of al__l life and death of an___ life from lack of ox____

excessive richness of nutrients in a lake or other body of water

• due to runoff from the land

• causes a dense growth of algal life and death of animal life from lack

of oxygen

The phosphorus cycle:

• Major Reservoirs?

  • Ro___(phosphate mineral), bios____(D__, A__, phosp_____s)

Rocks, biosphere (DNA, ATP, phospholipids)

How does P enter the biosphere?

Through weath_____g, ero___, deco_____

weathering, erosion, decomposition

The Carbon Cycle

• Major carbon reservoirs?

  • Bios____, fos___ fu____ (organic) & atm____, and oc___ (inorganic: CO2, H2CO3)

biosphere, fossil fuels, atmosphere, and ocean

How does carbon enter and exit the biosphere?

• photo______, resp_____, dec______, comb____

Photosynthesis, respiration, decomposition, combustion

How have humans interfered with the global C cycle?

• Burning of for____, fuelw____, and organic deb___

• Combustion of fos___ fu____ for veh____, elec____, and he__

burning of forests, fuelwood, and organic debris

Combustion of fossil fuels for vehicles, electricity, and heat

How is the carbon cycle related to climate change?

Climate pattern changes

• Dri__ and wet___

Melting gla___ and i__ sheets

• 80% of earths gla___ retreating

• Rising s__ le___

Ocean aci______n

Biodiversity l__s

Climate pattern changes

• Drier and wetter

Melting glaciers and ice sheets

• 80%+ of Earth’s glaciers retreating

• Rising sea level

Ocean acidification

Biodiversity loss

The greenhouse effect

99% of atmosphere = _2 and _2

Gas molecules ab___ he___

• W___ va____ (H__)

• Ca____ di____ (C_2)

• Met_____(C_4)

• Nit___s ox___ (N__)

Traps h___ from earth sur___

Exacerbated by defo_______

99% of atmosphere = N2 and O2

Gas molecules absorb heat

• Water vapor (H2O)

• Carbon dioxide (CO2)

• Methane (CH4)

• Nitrous oxide (N2O)

Trap heat from Earth’s surface

Exacerbated by deforestation