Ecosystem inputs biosphere constant inputof energy energy flowsthrough nutrients cycle nutrients can only cycle inputs • energy • nutrients
Biogeochemical Cycles • Matter is recycled and reused between the living and nonliving worlds through biogeochemical cycles • Water • Carbon • Nitrogen • Phosphorus
Water cycle Solar energy Transpiration Water vapor Evaporation Precipitation Oceans Runoff Lakes Percolation in soil Aquifer Groundwater
Nitrogen cycle Atmospheric nitrogen Carnivores Herbivores Birds Plants Plankton with nitrogen-fixing bacteria Death, excretion, feces Nitrogen-fixing bacteria (plant roots) Fish Decomposing bacteria amino acids excretion Nitrogen-fixing bacteria (soil) Ammonifying bacteria loss to deep sediments Nitrifying bacteria Denitrifying bacteria soil nitrates
Nitrogen Cycle • All organisms need nitrogen to make proteins and nucleic acids • Nitrogen gas makes up 78% of the Earths atmosphere • Most plants only use nitrates (NO3)
Nitrogen fixation • The process bacteria use to convert nitrogen gas (N2) to ammonia (NH3) • The bacteria are known as nitrogen-fixing bacteria • They live in the soil and inside swellings on the roots of some plants (beans, clover, etc) • The plants supply the carbohydrates for the bacteria and the bacteria provide usable nitrogen
Recycling Nitrogen • The bodies of dead organisms contain nitrogen (proteins & nucleic acids) • Urine and dung also contain nitrogen • Decomposers break down these materials and release the nitrogen as ammonia (NH3), which becomes ammonium (NH4 +) in the soil • Processes known as ammonification, and makes nitrogen available to other organisms again.
Recycling Nitrogen • Soil bacteria take up NH4 + and oxidize it into nitrites (NO2 -) and nitrates (NO3 -) through the nitrification process • Plants use nitrates to form amino acids
Denitrification • When anaerobic bacteria break down nitrates and release nitrogen gas into the atmosphere • How nitrogen gas returns to the atmosphere • Animals must obtain nitrogen by eating plants and other organisms
Phosphorus cycle Land animals Plants Animal tissue and feces Urine Soluble soil phosphate Decomposers (bacteria and fungi) Loss in drainage Rocks and minerals Phosphates in solution Decomposers (bacteria & fungi) Animal tissue and feces Plants and algae Aquatic animals Precipitates Loss to deep sediment
Phosphorous Cycle • The movement of phosphorous from the environment to the organisms and back again • Phosphorous is essential to animals for bones, teeth, and DNA/RNA • Plants get it from the soil; Animals get it from other organisms • Extremely slow cycle and doesn’t normally occur in atmosphere
Phosphorous Cycle • When rocks erode, small amounts of phosphorous dissolve as phosphate (PO3 -) • Plants absorb phosphates through their roots • Also added when wastes and organisms decompose • Some comes from fertilizer
CO2 in atmosphere Combustion of fuels Industry and home Photosynthesis Diffusion Respiration Plants Animals Dissolved CO2 Bicarbonates Photosynthesis Deposition of dead material Animals Plants and algae Fossil fuels (oil, gas, coal) Deposition of dead material Carbonates in sediment Carbon cycle
Carbon Cycle • Photosynthesis and cellular respiration form the basis of this cycle • In photosynthesis, plants and other autotrophs use CO2, water, and solar energy to make carbohydrates • Autotrophs and heterotrophs break down carbohydrates during cellular respiration
Carbon Cycle • The byproducts of cellular respiration are carbon dioxide and water • Decomposers also release CO2 into the atmosphere when they break down organic molecules
Human Influences on the Carbon Cycle • The concentration of atmospheric carbon has risen more than 30% in the last 150 years • Humans contribute by burning fossil fuels and organic matter to produce energy
Fossil Fuels • The remains of organisms that have been transformed by decay, heat, and pressure into energy rich molecules • Burning releases the energy and CO2 • When large areas of land are burned, more CO2 is produced, and less plants are there to absorb it
The Greenhouse Effect and Carbon Dioxide • The mean global temperature has increased about 1 °C since 1900, possibly because of trace gases like methane and CFC’s. • The atmospheric level of methane has more than doubled since 1951. What could have caused this? • Methane is the product of the bacterial decomposition of organic matter in the absence of oxygen. Mainly occurs in rice paddies and digestive tracts of termites (now in greater number because of the forests being destroyed).
Breaking the water cycle • Deforestation breaks the water cycle • groundwater is not transpired to the atmosphere, so precipitation is not created forest desert desertification
Effects of deforestation 40% increase in runoff • loss of water • 60x loss in nitrogen • 10x loss in calcium loss into surface water nitrate levels in runoff 80 40 loss out of ecosystem! Concentration of nitrate (mg/l ) 4 Deforestation 2 0 1965 1966 1967 1968 Year
T or F: The process that returns nitrogen to the atmosphere is called ammonification. FALSE! Denitrification!!
How could humans affect the nitrogen cycle at the bacterial level? The addition of toxic chemicals to the soils; construction and deforestation can cause soil erosion
Pick 2 and write me an essay about each.1. The role of bacteria in the carbon, nitrogen, and phosphorous cycles.2. Explain the statement that nutrients cycle , but energy flows.3. How do plants influence the various biogeochemical cycles?4. How do humans influence the various biogeochemical cycles?