Biogeochemical Cycles

Energy Flows Through Ecosystem Water—Nitrogen—Carbon—Phosphorus Are Recycled! They Move Thru A Biogeochemical Cycle: Abiotic (Non-living) Portion Of Environment (Atmosphere)  Living Thingsthen Back Again

Water Cycle Cells Contain 70-90% H20 Very Little Of Earths Available H20 Is In Living Things Rivers / Lakes / Streams / Oceans Contain A Big % Atmosphere Contain Water = Water Vapor Ground Water = In Soil Or Underground In Porous Rock Water Cycle = Movement Of H20 between Reservoirs Evaporation Transpiration Precipitation

Evaporation transpiration Adds H2O vapor to atmosphere Heat causes water to evaporate 90% of evaporated water from terrestrial ecosystem passes through plants in a process called…. transpiration

Transpiration Plants take in H2O thru roots Release water & take in CO2 (carbon dioxide) Animals drink/ eat to take in H2O Animals release it when: Breathing Sweating Excretion

Precipitation Water leaves atmosphere Temperature & air pressure (abiotic factors) determine how much water can be held Once atmosphere is saturated w/vapor = snow, rain, sleet, hail or fog

Carbon Cycle Photosynthesis + cellular respiration Photosynthesis = plants & other autotrophs use: CO2 + H2O & sunlight = carbohydrates

CELLULAR RESPIRATION Process in which autotrophs & heterotrophs use oxygen (O2) to breakdown carbs. Cells make ATP (energy) by breaking down organic compounds A compound that results from living things & contains carbon

HUMAN INFLUENCE ON THE CARBON CYCLE In the past 150 years CO2 in the atmosphere has risen 30% almost ½ in the last 40 years Due to human activity Burning fossil fuel: Remains of organisms that have been transformed by decay, heat, & pressure  Energy rich organic molecules

Burning releases energy & CO2 Burning vegetation releases CO2 Tropical rainforest destruction With no plants CO2 is not absorbed

Nitrogen Cycle Nitrogen is needed to make proteins & nucleic acids: Organic molecule, DNA or RNA, that stores & carries important info for cell function N2 (nitrogen gas) makes up 78% of the atmosphere N2 is however limited to ammonia (NH3)for most living things

NITROGEN FIXATION Conversion of N2 to ammonia Certain bacteria can convert  NH3 = nitrogen-fixing bacteria Live in soil & in some roots

Recycling Nitrogen Bodies of dead organisms contain “N” Urine & dung Decomposers break down corpses & waste of organisms give off nitrogen as ammonia = ammonification Nitrification = bacteria in soil take in ammonia & oxidize it into nitrites, NO2 & nitrates, NO3 Back into the environment

DENITRIFICATION Returning nitrogen to atmosphere Plants can absorb nitrates & ammonia from soil Animals cannot! Animals obtain it by eating other organisms They digest the proteins & nucleic acids

Phosphorus Cycle The phosphorus cycle may also be referred to as the mineral cycle. Phosphorus is mainly found in water, soil, and rock. Phosphorus is essential for life. Component of DNA Building block of our bones and teeth.

Phosphorus Cycle

Unlike the other cycles, phosphorus cannot be found in air in the gaseous state. The phosphorus cycle is the SLOWEST cycle. Phosphorus is most commonly found in rock formations and ocean sediments as phosphate salts. Phosphate salts that are released from rocks through weathering usually dissolve in soil water and will be absorbed by plants.

Animals absorb phosphates by eating plants or plant-eating animals. When animals and plants die, phosphates will return to the soils or oceans again during decomposition. After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over.

Human Imapcts on the Phosphorus Cycle Like nitrogen, increased use of fertilizers increases phosphorus runoff into our waterways.

REMEMBER THIS!!! Most phosphorus is found in rocks and soil. The phosphorus cycle is the slowest cycle. Excess phosphorus contributes to eutrophication.