Presentation on theme: "The movement of materials through the biotic (living) and abiotic (non-living) parts of an ecosystem Biogeochemical Cycles."— Presentation transcript:
The movement of materials through the biotic (living) and abiotic (non-living) parts of an ecosystem Biogeochemical Cycles
Nutrient Cycles Biogeochemical Cycles are also known as Nutrient Cycles -They are the pathways that 4 materials vital to life follow through an ecosystem - - Carbon - Nitrogen - Phosphorus - Water These materials cycle through both biotic and abiotic reservoirs in an ecosystem -biotic reservoirs are the living things that these materials move through -abiotic reservoirs are the non-living things that these materials move through
Carbon is the backbone for many of the most important molecules used by living things. carbohydrates, fats, protein, nucleic acid Carbon exists as CO 2 in the atmosphere - CO 2 in the atmosphere cannot be used by living things – it must be converted into a usable form - How does CO 2 get converted? – Photosynthesis in plants - CO 2 is used to make glucose – the carbon in glucose can be used by living things Carbon Cycle
CO 2 in atmosphere Photosynthesis Cellular Respiration Combustion Coal Oil Death & Decomposition Fossil Fuels CO 2 is absorbed in water Limestone
Carbon Cycle Carbon returns to the atmosphere - cellular respiration - combustion All living things are biotic reservoirs The atmosphere and water are abiotic reservoirs Carbon Sink – A sink is a part of the cycle which removes a nutrient from the cycle for long periods of time - Limestone - Fossil Fuels
Carbon Cycle The carbon in fossil fuels has been stored in the earth for millions of years- Burning them for energy releases the CO 2 back to the atmosphere - causing a rapid increase in CO 2 in the atmosphere - CO 2 is a greenhouse gas which traps heat, warming the Earth - Increasing CO 2 is leading to Global Climate Change
RESPIRATION / PHOTOSYNTHESIS LONG TERM VS SHORT TERM LIMESTONE DEPOSITS CONNECTION TO FOSSIL FUELS GREENHOUSE GAS CARBON SINKS WHY IS IT IMPORTANT?
Nitrogen is used by living things to make proteins and nucleic acids (DNA & RNA) Nitrogen exists in the atmosphere as N 2 - the N 2 molecule will not react and so must be converted to be used by living things - Large amounts of energy are needed to split the N 2 molecule – lightning will split Nitrogen Nitrogen Cycle
- Certain bacteria contain the enzymes necessary to convert N 2 into useable forms of nitrogen called nitrates -NO 2 or NO 3 - these nitrogen fixing bacteria are found in the soil and in symbiotic relationships with certain plants called legumes – beans, peas etc…. - The nitrates enter the food chain when plants assimilate them – take them up and use them
Nitrogen Cycle N 2 in the atmosphere Plant Protein Assimlation Legumes Nitrogen fixing Bacteria convert N 2 into nitrates Ammonification Nitrification – Bacteria convert ammonia into nitrate Denitrification Bacteria convert ammonia back to N 2 and release it back to the atmosphere Nitrogen Assimilation = plants taking up nitrates from the soil Ammonification = bacteria convert Nitrogen in waste into ammonia
THE NITROGEN CYCLE - TRANSITIONS - FIXATION: CONVERTING N2(GAS) INTO AMMONIUM - NITRIFICATION: CONVERTING NH4 INTO NO3 (NITRITE) -DENITRIFICATION: CONVERTING NITRITE BACK INTO N2
The Phosphorus Cycle Phosphorus in needed to make Nucleic Acids – DNA and RNA It is scarce in the biosphere – most is locked away in rocks and ocean sediment - The phosphorus enters an ecosystem when rocks are weathered (eroded) - some of the phosphorus is retained in soil and some finds its way into water - The phosphorus enters the food chain when it is assimilated by plants
Phosphorus Cycle Rock Uplifting of Rock Phosphorus locked up in the rock Weathering of Rock Phosphates in Soil Assimilation by Plants Death and Decomposition Dissolved Phosphates Precipitated Phosphates
The water cycle is powered by the sun - water evaporates and moves into the atmosphere to begin the cycle. - transpiration: the evaporation of water from plants – accounts for large amounts of water moving into the atmosphere -the moisture cools and condenses to become clouds -the moisture falls back to earth as precipitation – rain, snow, sleet, hail etc… -some of the water percolates back into the ground and becomes ground water -some of the water runs off and finds its way through rivers to lakes and the ocean
Transpiration Plant leaves have openings on the bottom called stomata - the stomata open during photosynthesis to allow CO 2 into the leaf - water evaporates from the leaf while the stomata are open
Surface Water Evaporation Condensation Precipitation Transpiration Run-off Infiltration / Percolation Ground Water
Limiting Nutrient Nutrients like nitrogen and phosphorus are typically in limited supply in an ecosystem. - the limited supply of nutrients limits the overall productivity of a given ecosystem - If additional quantities of the limited nutrient are added to an ecosystem, productivity increases.
Limiting Nutrient - people have learned how to use chemical processes to fix nitrogen, and mine phosphorus - the use of fertilizer has led to a boom in food production called the Green Revolution.
Eutrophication In aquatic ecosystems, additional quantities of a limiting nutrient cause algae to multiply out of control - when the algae die, they sink to the bottom and are decomposed- unfortunately the decomposers remove oxygen from the water creating dead zones area without enough oxygen to support life - this process is called Eutrophication
Eutrophication This map shows the dead zone in the Gulf of Mexico, which is the result of eutrophication caused by nitrogen and phosphorus carried by the Mississippi River