Factors that Disturb Biogeochemical Cycles The Human Impact

Disturbing the Carbon Cycle Natural Events Forest fires – release large amounts of carbon dioxide Volcanoes – break down rock containing carbon and releases it into the atmosphere, the ash also keeps the sun from reaching plants Human Activities Deforestation – the cutting down of forests Burning fossil fuels – heat, automobiles, electricity

What can we do? Stop cutting down trees Plant more trees Recycle wood and paper Reduce the use of fossil fuels by walking or riding a bike Reduce the amount of electricity we use in our homes

Disturbing the Nitrogen Cycle Fertilizers – farmers add fertilizers containing nitrogen to their crops Manure and human sewage – if not properly disposed of can make their way into the water system adding nitrogen An excess of nitrogen in the water will cause algal blooms (an over growth of algae) Algal blooms grow when there is an abundance of nitrogen, sunlight and warmth These blooms produce dangerous toxins They also deplete the oxygen supply killing fish and other organisms

What can we do? Ensure proper disposal of sewage and waste (no leaks in septic tanks) Don’t use fertilizers

Questions Explain how deforestation, fire and burning of fossil fuels disrupts the balance between photosynthesis and cellular respiration? What are some obstacles humans face when trying to reduce human disruption to the carbon cycle? Why do algal blooms occur in the late spring? How do algal blooms affect other organisms in their ecosystem? (consider the food web) What can be done to prevent algal blooms? How are the nitrogen and carbon cycle related? (at least 3 points)