Nutrient Cycles

FLOW OF NUTRIENTS THROUGH ECOSYSTEMSS In Ecosystems What are nutrients? Substances that provides nourishment essential for

growth and the maintenance of life Oxygen, Water, Carbon, Nitrogen, Phosphorous, etc How are Nutrients Cycled? Three main nutrients cycles: 1. Carbon cycle

2. Nitrogen cycle 3. Phosphorous cycle How does the Carbon Cycle Work? MOST of the carbon is found in long-terms stores in geosphere but is also found in the atmosphere, and in

all living things. Carbon moves between stores via six main processes: 1. Photosynthesis Converts CO2 gas from atmosphere into chemical energy.

2. Cellular respiration CO2 is a waste product of cellular respiration when organisms consume nutrients to make energy.

3. Decomposition Decomposers release carbon and other nutrients into the soil and atmosphere by breaking down dead organisms 4. Ocean processes

Oceans are HUGE stores of dissolved CO2 from atmosphere. Marine organisms store carbon-rich carbonate in their shells 5. Volcanic Eruptions

6. Forest Fires Human Activities affect the Carbon Cycle Burning Fossil Fuels: Fast release of Carbon from long term stores (geosphere) into atmosphere

Land clearing, agriculture, and urban expansion Burning plants releases their stored carbon into the atmosphere Removing plants reduces photosynthesis Effects of Excess Carbon in the Atmosphere:

Excess carbon in atmosphere Green House Gases Global Warming. So What? People like warm weather Warmer Temperatures may cause: 1. Extreme Weather more heat waves, droughts, fires

possible fatalities 2. Sea ice melts sea level rises coastal flooding climate refugees 3. Warmer seawater absorbs more CO2 ocean acidification coral reef harmed, declining fish populations

Ocean Acidification Check your Understanding 1. 2.

3. 4. Why is the carbon cycle important? How is carbon stored? How is carbon cycled?

Name several human activities that affect the carbon cycle. Practice Nutrient Cycle WS In groups: Sustainability WS

View remainder of PPT for Nitrogen and Phosphorous Cycles and how to destroy a lake. Nitrogen Largest store is N2 gas in the atmosphere

In every living thing (DNA and proteins) Much of the nitrogen cycle involves making nitrogen available to plants and animals.

Nitrogen Cycle Nitrogen Fixation: bacteria in the soil convert Nitrogen to Ammonia (NH2) Nitrification: bacteria convert Ammonia to Nitrite (NO2) to Nitrate (NO3)

Uptake: Plants take up nitrate/nitrite Ammonification: Decomposers convert nitrogen in dead organisms back to ammonium (NH4+) Denitrification: Other soil bacteria convert nitrate back into N2 gas to atmosphere

Human Activities Affecting Nitrogen Cycle 1.Burning fossil fuels 2.Land-clearing by burning Both release nitrogen compounds into the atmosphere which combine with water to form nitric acid (HNO3) which comes down as acid rain.

3. Overfertilization of crops: Nitrogen in excess fertilizers can be washed or leached from the soil by rain, collects in streams and lakes. Leaching is the

removal of a substance dissolved in soil by water Excess nitrogen in lakes

causes Eutrophication: overly enriched with nutrients causes excessive algae growth (algal bloom). Algal bloom

Excess algae growth can deprive other aquatic plants of sunlight and of oxygen. When algae die, the oxygen used in decomposition also deprives aquatic animals of oxygen and can lead to the death of all fish in a lake.

Algal Bloom Some algae produce neurotoxin that enter the food web to shellfish, seabirds, marine mammals and humans. Eg. Red Tide

Check your Understanding 1. 2. 3. 4.

Why is the nitrogen cycle important? How is nitrogen stored? How is nitrogen cycled? Name several human activities that affect the nitrogen cycle?

Phosphorous Important for healthy root, stem and seed development. Essential element in bones and in the energy molecule, ATP. Mostly in long-term

stores as phosphate (PO4-) in rock and ocean floor sediment. How does Phosphorous Cycle? 1. Weathering (breaking down rock into smaller

fragments) is the main method of cycling phosphorous. 2. Uptake - Plant take up phosphorous from the soil by their roots. 3. Decomposition - bacteria release phosphorous back into the soil by breaking down dead organisms. 4. Geologic Uplift - a major geological event uncovers

buried rock Human Activity and Phosphorous Cycle Phosphate is used in fertilizers and detergents Slash and burn also releases excess Phosphorous

Excess Phosphorous Also leads to algal blooms and possible dead zones (low-oxygen) areas in oceans and lakes. Check your Understanding 1. 2.

3. 4. Why is the phosphorous cycle important? How is phosphorous stored? How is phosphorous cycled?

Name several human activities that affect the phosphorous cycle? How are human activities harming the environment? Do you think these practices are sustainable? How long can we keep doing this?

Are there alternatives? Assignment 1. Research a topic where human activity is disrupting the delicate balance of nature. Eg. overhunting/fishing, introduction of non-native species,

destruction of natural habitats, pollution, burning fossil fuels 2. Research what is being done to help curb or counteract the actions/effects or offer your own solution Eg. Bioremediation, banning pesticides, reforestation, fishing

caps, greener sources of energy. 1. Nitrogen Fixation Nitrogen Fixation is the process by which nitrogen gas (N2) is converted into nitrate (NO3-) and ammonium

(NH4+), which are usable by plants. Soil: Nitrogen fixation occurs mainly in the soil when nitrogen-fixing bacteria convert Nitrogen gas (N2) to forms usable by plants like ammonium (NH4+), Nitrite and

Nitrate. 1. Nitrogen Fixation Water: Cyanobacteria also fix nitrogen into ammonium Atmosphere: A very small

amount of atmospheric nitrogen is fixed by lightning. 2. Nitrification Ammonium is converted into nitrite (NO2-) and then nitrate (NO3-) by nitrifying bacteria.

3. Uptake Once nitrates are made available by the nitrifying bacteria, plants can take up this usable form of nitrogen into their roots and incorporated it into plant proteins

Consumers (herbivores and omnivores) incorporate nitrogen into their tissues by eating the plants. 4. Ammonification Some types of decomposer bacteria

and fungi uptake nitrogen trapped in the proteins and DNA of dead orangisms and convert it back to ammonium (NH4+).

5. Denitrification Denitrifying bacteria convert nitrate back into atmospheric nitrogen.