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Biogeochemical Cycles• Bio means… – life• Geo means… – Of earth: parts of earth are • Land, air, water• Chemical means… – Molecules and/or compounds• Cycle means… – Repeatedly Plants obtain nitrogen• Cycling of materials between the environment and from nitrogen-fixing organisms bacteria and pass it to other organisms through• Chemical and biological processes the food chain• Examples – Water cycle – Nitrogen cycle – Phosphorus cycle – Carbon cycle
Cycles of Matter• No definite beginning or end like food chain (remember, energy flow is unidirectional)…matter is recycled• Does not use up matter…transforms it• Biogeochemical process – Pass same molecule/compound/element through biosphere over and over • Organism to organism • First Part of biosphere (air, land, water) • Second Part of biosphere (air, land, water)
• Water Cycle• Evaporation: water (in oceans, rivers, lakes) turns to water vapor and rises• Transpiration: water evaporates through the stomata of a plant’s leaves and becomes water vapor – Adhesion and cohesion enable water molecules to move from roots to leaves – Stomata: tiny openings in the leaves of plants• Condensation: water vapor cools down and condenses in atmosphere to make CLOUDS• Precipitation: water returns to surface as rain, snow, ice• Run-off: water that moves from mountains and hills to rivers and stream and then eventually to ocean• Seepage: water that seeps into the soil and is either taken up by plant roots or becomes part of ground water• Ground water: Water that exists beneath the earths surface in underground streams and aquifers that eventually becomes part of the ocean
Water Cycle Impact• Deforestation – Freshwater returns to atmosphere by TRANSPIRATION from tropical forests – Cut down tropical forest=reduce water vapor in air=changes in precipitation patterns and effects ecosystems• Irrigation and household water use – Draws water up from aquifers and rivers – If rate at which H2O is used is FASTER than the water cycle can replace it, rivers nad aquifers may run dry (effects ecosystems)
Carbon-oxygen cycle• Carbon is the main component of all living things• Carbon is found in glucose, which is the fuel for LIFE!• What other things do we fnd carbon in?
Carbon cycleCarbon released as Carbon is taken in by• Carbon dioxide • Plants – Animals and humans • When light is present, release CO2 by cellular plants use photosynthesis respiration to make CO2 and H2O – Volcanic eruptions into glucose and oxygen – Burning of fossil fuels (oils)• Methane (CH4) – Grasses and animals release• Bicarbonate ions – Found in rock and released during erosion
Carbon cycle impacts• Atmospheric CO2 levels have steadily risen (more industrialized)• Burning of wood and fossil fuels release CO2 into atm• Deforestation affects carbon cycle – Def: clearing of forests for lumber, agriculture, etc. – Eliminates plants that absorb excess CO2 from the air – “Slash and burn” removes plants and adds CO2 to air• Greenhouse effect – When atmospheric gases trap heat close to Earth’s surface – Makes Earth “liveable”…not a bad thing as long as it is controlled• Global warming (theory) – Theory that there is an overall rise in global temperatures b/c of increase in greenhouse gasses (CO2) – NOT proven
Nitrogen cycle• Where is nitrogen found in living things?• Proteins, nucleic acids, and more!• Do you think nitrogen is important?
Nitrogen cycle-Atmospheric nitrogen (N2) makes up nearly78%-80% of air.Organisms can not use it in that form.Lightning and bacteria convert nitrogen intousable forms.
Nitrogen cycle• Nitrogen gas N2 – Nitrogen-fixation by bacteria on roots of legumes to change it into…• Ammonia NH4+ – Nitrification by bacteria in soil to change it into… nitrates and nitrites – Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi- aquatic environments like rice paddies.• Nitrates NO3- and Nitrites NO4- – Denitrification by denitrifying bacteria in soil into…• Nitrogen gas N
Atmospheric Nitrogen Cycle Lightning nitrogen Denitrification by bacteria Animals Nitrogen fixing bacteria Plants Decomposers Nitrification by Nitrites NitratesAmmonium bacteria
Terms to know…• Fixation – When N2 gas is made into a useable form (NH4) ammonia• Nitrification – Conversion of ammonia (NH4) into nitrates (NO3-) and nitrites (NO2-)• Assimilation – when plants take up nitrates and nitrites and incorporate into their tissue as amino acids which become proteins• Ammonification/Mineralization – When plants and animals die and decomposers convert amino acids back into ammonia (NH4) and return to soil
Nitrogen Cycle Impacts• Humans move large amounts of nitrogen into air or water – Sewage treatments, fertilizers• Lots of Nitrogen in water (and phosphorus) enables algae to grow rapidly on the surface…eutrophication – As algae dies, bacteria that consumes them use up so much available oxygen in the water that there isnt enough for the other marine organisms• Lots of Nitrogen (and sulfur) in Air – Smokestacks and car exhaust pipes release nitrogen dioxide – NO2 reacts with oxygen to make O3 (ozone) in low levels of the atmosphere….this is very bad for living organisms – These nitrogen and sulfur containing compounds mix with water in the air to make NITRIC ACID and SULFURIC ACID – These acids evaporate, condense and come down as ACID PRECIAPTATION (acid rain) – Acid Rain causes damage to soils and aquatic ecosystems
Do NOT copy word-for-word!!! -Fertilizers used in farming -cause run-off into nearby water=increase in nutrient levels=phytoplankton to grow and reproduce rapidly=algal blooms -This bloom of algae disrupts normal ecosystem & increases bacteria -bacteria uses up all the oxygen in the water -none left for other marine life -causes death of many aquatic organisms that need the oxygen -Blooms also block sunlight penetrating the surface -photosynthetic marine plants can’t get sunlight -Blooms also produce toxins that are harmful to higher forms of life -Cause problems along the food chain and affect any animal that feeds on them.
Phosphorus cycle• Where do we find phosphorus?• Part of DNA, cell membranes, ATP and ADP, activates and inactivates enzymes• Do you think phosphorus is important?
Phosphorus Cycle• NO phosphorus in the atmosphere – Only cycles in soil and land• Found as Phosphorus (P) or Phosphate (PO4-)• Primarily found in the form of mineral apatite – found in rocks and phosphorus minerals
Four Phase of Phosphorus Cycle(Terrestrial)• Weathering – Weathering away of phosphate rocks leached phosphate into soil• Plant Uptake – Plants take up P from soil and incorporate into tissues and the animals eat the plants and ASSIMILATE phosphorus into their tissue• Decomposer release – Plants and animals die, decomposer break down tissue and release phosphorus back into soil• Animal excrements – Contain phosphorus and return to soil
Four Phase of Phosphorus Cycle (Aquatic)• Weathering – Weathering away of phosphate rocks and soils leach phosphate into rivers and streams• Aquatic plant and Phytoplankton Uptake – Take up P in water and incorporate into tissues and the marine vertebrates and invertebrates eat the plants/plankton and ASSIMILATE phosphorus into their tissue• Decomposer release – Aquatic plants and animals die, decomposer break down organic phosphate in tissue and release inorganic phosphate back into water• Animal excrement – Contain phosphorus and return to water• Phosphate Loss – Phosphate lost to marine sediment which is eventually converted into phosphate containing rock by geological processes
Sulfur Cycle• Sulfur import in proteins – Amino acids cysteine and cystine• Sulfur MAINLY found in rock and soil (coal, oil, peat) as sulfate minerals• Weathering exposes sulfates from rocks into the soil and aquatic ecosystems• Plants and animals ASSIMILATE sulfates into tissues• Death and decomposition convert organic sulfates into inorganic sulfates• Animal excrements add sulfates to water or soil• Sulfates then recycle
Sulfur Cycle in the Atmosphere• Natural: During decomposition in both soil and water, decomposers convert SULFATES into HYDROGEN SULFIDE gas that can escape into air, water, soil and marine sediments• Natural: Volcanic eruptions also contribute HYDROGEN SULFIDE gas (HS) into atmosphere• Unnatural: Power plant emissions emit HYDROGEN SULFIDE gas (HS)
Fates of Hydrogen Sulfide• In Soil – Chemosynthetic bacteria convert HS back into inorganic sulfates, sulfuric acid, and/or elemental sulfur • If IRON is present, elemental sulfur is changed into iron sulfide, which gets into soil and sediments by geological processes• In Water – Photosynthetic bacteria and other bacteria convert hydrogen sulfide into inorganic and organic sulfates• In Atmosphere – HS gas breaks down into sulfuric dioxide (SO2) – SO2 combines with water and becomes sulfuric acid in the atmosphere – Precipitates as acid rain, returning sulfur to soil and water – Acid rain kills vegetation and erodes rocks
Negative Effects• Coal burning power plants dump enormous amounts of SO2 and sulfur particles into atmosphere• Prevailing winds and storm systems carry particles over large distances• Precipitate acid rain falls in places far from source – Acid rain=global problem
Pollution and the Environment • Pollution: addition of substances to the environment that result in a NEGATIVE effect • Biological Magnification – Animals take in water and nutrients and sometimes pollutants w/them – While energy decreases as it moves up the food chain, toxins increase in potency. – PCBs • Disposed in industrial wastes and Soluble in lipids of animals • Concentration of PCBs increases in organisms tissuesdichlor-diphenyl- increase as you move up trophic levelstrichlorethylene – DDTsC14H9Cl5 • Chemical used to control mosquitoes and crop pests • Soluble in fatty tissue • Birds had high levels of DDT in their tissue and in egg shells, which causes shells to be brittle and young birds cannot survive
Damage to Ozone • Ozone: gas in atmosphere (O3) • Ozone absorbs UV radiation from the sun (protects organisms on earth from harmful rays) • Chlorofluorocarbons (CFCs) is a chemical released from aerosol cans, refrigerator units and certain manufacturing processes – Chlorine from CFCs pull off an oxygen from a molecule of O3, making chlorine monoxide, ClO and ozone into regular O2 – ClO binds with another ClO making chlorine peroxide (Cl2 O2) – There’s one less molecule of O3 in the atmosphere to protect organisms from harmful UV radiation – Sun also breaks the chlorine peroxide (Cl2 O2) into chlorine atoms and another O2 molecule and the cycle continues with more carbons interacting with ozone molecules – “Holes in the Ozone”
Biodiversity• Definition: # of species in an ecosystem; the variety of ecosystems; the variety of individuals in a species• Why is biodiversity important? – Species in ecosystem are interconnected and depend on each other – If one species disappears, many others affected – Humans depend on biodiversity as well (food, shelter, clothing, medicine)
Threats to Biodiversity• Habitat destruction• Introduced Species• Over Exploitation of resources
Conservation Biology• Def: application of biology to counteract the threats to biodiversity – Focus on hot spots • Small geographic areas with high conc. of species • Cover less than 1.5% of earth’s surface • Hotspots of extinction • Contain 1/3 of all plants and vertebrates – Understand Organism’s habitats • Helps maintain org. habitat or create new habitats • Biologists can protect key habitat factors of species – Balance demand for resources • Save species or meet economic and social needs of people • Save a forest to protect and owl but put many loggers out of work? – Planning for a Sustainable future • Ways nations protect environment for future: • Zoned reserves-areas of land that are relatively undisturbed by humans – Encourage long term ecosystem conservations • Buffer zones-areas that surround “zoned” reserve; these buffers are minimally impacted by people...no major envir. disturbances – Ex. Costa Rica- 8 zoned reserves • Sustainable development- developing natural resources so that the can renew themselves and be available to the future… – Ex. Forest corridor between farmlands
Biogeochemical activity• Each member in group needs to have their own paper• Fold paper in 4• Title each box (carbon cycle, water cycle, phosphorus cycle, nitrogen cycle)• Diagram each of the cycles in a box, make sure each arrow is labeled and each animal/plant is labeled• On the back of each square, name the different forms the matter takes, key players (bacteria, plants, animals, activities)• Processes that change/transform the matter