Biogeochemical Cycles The movement of materials through the biotic (living) and abiotic (non-living) parts of an ecosystem

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 Cycle:

Carbon Cycle Carbon is the backbone for many of the most important molecules used by living things. carbohydrates, fats, protein, nucleic acid Carbon exists as CO2 in the atmosphere - CO2 in the atmosphere cannot be used by living things – it must be converted into a usable form - How does CO2 get converted? – Photosynthesis in plants - CO2 is used to make glucose – the carbon in glucose can be used by living things

Coal Oil CO2 in atmosphere Photosynthesis Limestone Fossil Fuels Combustion Cellular Respiration CO2 is absorbed in water Death & Decomposition Coal Limestone Fossil Fuels Oil

CARBON CYCLE *2

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 CO2 back to the atmosphere - causing a rapid increase in CO2 in the atmosphere - CO2 is a greenhouse gas which traps heat, warming the Earth - Increasing CO2 is leading to Global Climate Change

CARBON CYCLE RESPIRATION / PHOTOSYNTHESIS LONG TERM VS SHORT TERM WHY IS IT IMPORTANT? RESPIRATION / PHOTOSYNTHESIS LONG TERM VS SHORT TERM LIMESTONE DEPOSITS CONNECTION TO FOSSIL FUELS GREENHOUSE GAS CARBON SINKS

Nitrogen Cycle Nitrogen is used by living things to make proteins and nucleic acids (DNA & RNA) Nitrogen exists in the atmosphere as N2 - the N2 molecule will not react and so must be converted to be used by living things - Large amounts of energy are needed to split the N2 molecule – lightning will split Nitrogen

Nitrogen Cycle - Certain bacteria contain the enzymes necessary to convert N2 into useable forms of nitrogen called nitrates -NO2 or NO3 - 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 Legumes Assimlation N2 in the atmosphere Plant Protein Ammonification Nitrogen fixing Bacteria convert N2 into nitrates Denitrification Bacteria convert ammonia back to N2 and release it back to the atmosphere Nitrification – Bacteria convert ammonia into nitrate Nitrogen Assimilation = plants taking up nitrates from the soil Ammonification = bacteria convert Nitrogen in waste into ammonia

NITROGEN CYCLE *2

NITROGEN CYCLE LIMITING NUTRIENT NITROGEN FIXING NITRAFICATION / NITRIFICATION EUTROPHICATION ACID RAIN COMPONENT

NUTRIENT CYCLING FIXATION: CONVERTING N2(GAS) INTO AMMONIUM THE NITROGEN CYCLE - TRANSITIONS FIXATION: CONVERTING N2(GAS) INTO AMMONIUM NITRIFICATION: CONVERTING NH4 INTO NO3 (NITRITE) -DENITRIFICATION: CONVERTING NITRITE BACK INTO N2

Phosphorus Cycle

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 Weathering of Rock Rock Phosphorus locked up in the rock Phosphorus Cycle Uplifting of Rock Assimilation by Plants Weathering of Rock Death and Decomposition Dissolved Phosphates Phosphates in Soil Precipitated Phosphates Rock

Water Cycle

Water Cycle 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

Plant leaves have openings on the bottom called stomata Transpiration Plant leaves have openings on the bottom called stomata - the stomata open during photosynthesis to allow CO2 into the leaf - water evaporates from the leaf while the stomata are open

Condensation Transpiration Precipitation Evaporation Run-off Surface Water Infiltration / Percolation Ground Water

WATER CYCLE *

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.

IMPORTANCE OF OXYGEN EUTROPHICATION *7

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, Red = least oxygen Blue = most 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

Vocabulary Biogeochemical/Nutrient Cycles Biotic and abiotic reservoirs Carbon Sink- Definition and examples Assimilation Nitrification Denitrification transpiration Infiltration / Percolation limiting nutrient eutrophication