NUTRIENT CYCLES Water Carbon Nitrogen
NUTRIENT CYCLES Energy transfer through an ecosystem is ONE WAY Most energy is lost as heat Nutrients such as nitrogen, water and carbon are able to cycle through an ecosystem and be reused.
NUTRIENT CYCLES The Law of Conservation of Matter states that matter cannot be created nor destroyed. Thus is must be recycled!
Transpiration: Release of water through the leaves of plants into the atmosphere Evaporation: Liquid water converting to water vapor and rising to the atmosphere.
Transpiration Water is first absorbed by the root hairs of the plant
Transpiration From the roots, water moves to the leaves by means of the xylem
Transpiration Water exits the leaves through openings in the leaves called stomata stoma
Transpiration Water molecules have a slight attraction to each other and stick together. Water that evaporates out of the stomata, pull on water molecules still in the leaf, which in turn pull on water molecules in the xylem all the way down the roots. Watch this animation
Factors Affecting Transpiration 1) Humidity 2) Temperature Humidity : Transpiration Temperature : Transpiration
Transpiration affected by Air Currents 3) Wind removes water vapor that is in the area immediate to the plant. Since water moves from higher to lower concentration, the rate of transpiration increases
THE CARBON CYCLE
Carbon: The basic constituent of all organic compounds Photosynthesis and Respiration provide a link between the atmosphere and biosphere.
Link between Atmosphere and Biosphere: Plants acquire CO 2 thru stomata in their leaves and incorporate it in to organic molecules of their own biomass. This is called photosynthesis
Link between Atmosphere and Terrestrial: Some of this organic material becomes a carbon source for consumers Carbon is cycled quickly because of high demand from plants
Link between Atmosphere and Terrestrial: All organisms return CO 2 to the atmosphere thru respiration Decomposition recycles carbon to the soil and through the respiration of decomposers back to atmosphere Fires oxidize organic material to CO 2 (burning)
Just where exactly is carbon found? Carbon is all over! We call carbon sinks, places/objects that store carbon. We call carbon sources, places/objects that release carbon. Some things can do both. But technically a carbon sink absorbs more carbon than it releases.
Carbon Sink or Source? Source!
Carbon Sink or Source? SINK!
Carbon Sink or Source? SINK!
Carbon Sink or Source? Both!
Carbon Sink or Source? SINK!
Carbon Sink or Source? SOURCE!
Carbon Sink or Source? SINK!
Carbon Sink or Source? SINK!
Carbon can be found: In the atmosphere. The atmosphere is made up of: Nitrogen = 78% Oxygen = 21% Argon = 1% Carbon Dioxide = 0.04% More on why this tiny amount is causing so much trouble, next lecture!
Carbon can be found: On Land. Carbon is accumulated in plants through photosynthesis and then passed on to consumers that eat the plants. When living organisms die, the carbon in them is then transferred to the soil or to decomposers.
Carbon can be found: On Land. Under intense pressure/temperature and after millions of years- dead organic matter may turn into carbon rich coal, oil or natural gas (fossil fuels).
Carbon can be found: In the Ocean. Carbon dioxide can dissolve into water. The ocean actually is the largest carbon sink on Earth (because there is just so much of it!).
Carbon can be found: In the Ocean. When CO2 dissolves in water, it makes the water slightly acidic (more on this later), but it also transfers the carbon into bicarbonate ions.
Carbon can be found: In the Ocean. Bicarbonate can be used by certain sea creatures (like plankton) to make calcium carbonate shells. Depending on what happens to these creatures, the carbon here can be stored for a LONG time!
Carbon can be found: In the Ocean. When these creatures die they float to the bottom of the ocean. Over time, their shells will build up and with enough pressure are responsible for creating limestone, and large deposits of calcium carbonate.
The Nitrogen Cycle
The Nitrogen Cycle Nitrogen gas (N 2 ) makes up 78% of our atmosphere Nitrogen is needed by living things to make proteins and DNA It ranks fourth behind oxygen, carbon, and hydrogen as the most common chemical element in living tissues. Most organisms CAN NOT obtain nitrogen from the atmosphere however!
The Nitrogen Cycle Animals get the nitrogen they need by eating plants or other animals.
Certain plants can are able to fix nitrogen (pull it into themselves) through their roots through special nodules called rhizomes. These nodules contain colonies of nitrogen fixing bacteria. The Nitrogen Cycle Rhizomes
Nitrogen fixing bacteria turn atmospheric nitrogen (N2) into a form that is usable by living things called nitrate (NO3). Plants absorb the nitrate from the roots and animals get the nitrate from plants or other animals. The Nitrogen Cycle
The Nitrogen Cycle This nitrate from the bacteria can also seep back into the soil, providing a source of nitrogen for plants that grow next. Denitrifying bacteria turn NO3 back into N2, thus cycling it back into the atmosphere.
The Nitrogen Cycle Plants that exist in nitrogen poor soils, have adapted to these environments by becoming carnivorous. They still do photosynthesis to make glucose, but eat insects, birds and small mammals to get the nitrogen they need.