Transcript Water Cycle
Biogeochemical Cycles o Energy Flows Through Ecosystem o Water—Nitrogen—Carbon—Phosphorus Are Recycled! o They Move Thru A Biogeochemical Cycle: o Abiotic (Non-living) Portion Of Environment (Atmosphere) Living Thingsthen Back Again Water Cycle o Cells Contain 70-90% H20 o Very Little Of Earths Available H20 Is In Living Things o Rivers / Lakes / Streams / Oceans Contain A Big % o Atmosphere Contain Water = Water Vapor o Ground Water = In Soil Or Underground In Porous Rock o Water Cycle = Movement Of H20 between Reservoirs o Evaporation o Transpiration o Precipitation Evaporation o Adds H2O vapor to atmosphere o Heat causes water to evaporate o 90% of evaporated water from terrestrial ecosystem passes through plants in a process called…. transpiration Transpiration o Plants take in H2O thru roots o Release water & take in CO2 (carbon dioxide) o Animals drink/ eat to take in H2O o Animals release it when: o Breathing o Sweating o Excretion Precipitation o Water leaves atmosphere o Temperature & air pressure (abiotic factors) determine how much water can be held o Once atmosphere is saturated w/vapor = snow, rain, sleet, hail or fog Carbon Cycle o Photosynthesis + cellular respiration o Photosynthesis = plants & other autotrophs use: o CO2 + H2O & sunlight = carbohydrates CELLULAR RESPIRATION o Process in which autotrophs & heterotrophs use oxygen (O2) to breakdown carbs. o Cells make ATP (energy) by breaking down organic compounds o A compound that results from living things & contains carbon HUMAN INFLUENCE ON THE CARBON CYCLE o In the past 150 years CO2 in the atmosphere has risen 30% almost ½ in the last 40 years o Due to human activity o Burning fossil fuel: o Remains of organisms that have been transformed by decay, heat, & pressure Energy rich organic molecules o Burning releases energy & CO2 o Burning vegetation releases CO2 o Tropical rainforest destruction o With no plants CO2 is not absorbed Nitrogen Cycle o Nitrogen is needed to make proteins & nucleic acids: o Organic molecule, DNA or RNA, that stores & carries important info for cell function o N2 (nitrogen gas) makes up 78% of the atmosphere o N2 is however limited to ammonia (NH3)for most living things NITROGEN FIXATION o Conversion of N2 to ammonia o Certain bacteria can convert NH3 = nitrogen-fixing bacteria o Live in soil & in some roots Recycling Nitrogen o Bodies of dead organisms contain “N” o Urine & dung o Decomposers break down corpses & waste of organisms give off nitrogen as ammonia = ammonification o Nitrification = bacteria in soil take in ammonia & oxidize it into nitrites, NO2 & nitrates, NO3 Back into the environment DENITRIFICATION o Returning nitrogen to atmosphere o Plants can absorb nitrates & ammonia from soil o Animals cannot! o Animals obtain it by eating other organisms o They digest the proteins & nucleic acids Phosphorus Cycle o The phosphorus cycle may also be referred to as the mineral cycle. o Phosphorus is mainly found in water, soil, and rock. o Phosphorus is essential for life. o Component of DNA o Building block of our bones and teeth. Phosphorus Cycle o Unlike the other cycles, phosphorus cannot be found in air in the gaseous state. o The phosphorus cycle is the SLOWEST cycle. o Phosphorus is most commonly found in rock formations and ocean sediments as phosphate salts. o Phosphate salts that are released from rocks through weathering usually dissolve in soil water and will be absorbed by plants. o Animals absorb phosphates by eating plants or plant-eating animals. o When animals and plants die, phosphates will return to the soils or oceans again during decomposition. o 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.