Some Essential Ecological Chemical CYCLES There are some major cycles that are important for biologists to understand. There are some major cycles that are important for biologists to understand. The BIG PICTURE HERE… The BIG PICTURE HERE… Substances (Carbon, Nitrogen, and Water) move back and forth through the BIOTIC (ORGANIC) world and the ABIOTIC (INORGANIC) world.

1. WATER CYCLE: a continuous process wherein water moves from the Earth’s surface to the atmosphere and back. There are some basic part to this cycle. There are some basic part to this cycle. 1. Evaporation 2. Condensation 3. Precipitation 4. Transpiration (Evapotranspiration) 5. Runoff, snowmelt, ice storage, and groundwater storage

WATER CYCLE EVAPORATION: LIQUID water absorbs energy (heats up) and turns into a GAS (Surface to atmos.). EVAPORATION: LIQUID water absorbs energy (heats up) and turns into a GAS (Surface to atmos.). CONDENSATION: Water vapor (GAS) in the atmosphere looses energy (cools) and turns into a liquid (clouds). CONDENSATION: Water vapor (GAS) in the atmosphere looses energy (cools) and turns into a liquid (clouds). PRECIPITATION: occurs when droplets of water that are formed during condensation get bigger and fall back to Earth. PRECIPITATION: occurs when droplets of water that are formed during condensation get bigger and fall back to Earth. Transpiration (Evapotranspiration): water is absorbed by plants and subsequently released back into the atmosphere through their leaves. Transpiration (Evapotranspiration): water is absorbed by plants and subsequently released back into the atmosphere through their leaves.

2. CARBON & OXYGEN CYCLES PHOTOSYSNTHESIS & RESPIRATION PHOTOSYSNTHESIS & RESPIRATION Producers take in carbon from CO 2 and produce oxygen while consumers take in the oxygen and give off CO 2 Producers take in carbon from CO 2 and produce oxygen while consumers take in the oxygen and give off CO 2 Photosynthesis (in the chloroplasts): Photosynthesis (in the chloroplasts): 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 Cellular Respiration (in the mitochondria): Cellular Respiration (in the mitochondria): 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + ATP (Energy) 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + ATP (Energy) Sunlight

The Essence! Carbon is cycled (converted) from Inorganic Carbon is to Organic Carbon…and the other way around. Photosynthesis: Plants make FOOD from ENERGY Cellular Respiration: Organisms make ENERGY from FOOD.

The NITROGEN CYCLE Nitrogen is another important element for living things. Nitrogen is another important element for living things. Most organisms cannot get it directly from the atmosphere. Most organisms cannot get it directly from the atmosphere. Nitrogen by itself in the atmosphere is called FREE nitrogen. Nitrogen that is attached to other elements is called FIXED nitrogen…that’s the kind we need. Nitrogen by itself in the atmosphere is called FREE nitrogen. Nitrogen that is attached to other elements is called FIXED nitrogen…that’s the kind we need.

Organisms require nitrogen-compounds, (proteins and nucleic acids). Organisms require nitrogen-compounds, (proteins and nucleic acids). Air is about 78% nitrogen gas (N 2 ). That’s where most of the nitrogen hangs out. Air is about 78% nitrogen gas (N 2 ). That’s where most of the nitrogen hangs out. Most organisms can’t use atmospheric (free) nitrogen as is. They need it changed into nitrogen compounds. Most organisms can’t use atmospheric (free) nitrogen as is. They need it changed into nitrogen compounds. Plants need their nitrogen "fixed", which means as part of compounds such as: Plants need their nitrogen "fixed", which means as part of compounds such as: ammonia (NH 3 ) ammonia (NH 3 ) urea (NH 2 ) 2 CO urea (NH 2 ) 2 CO nitrate ions (NO 3 − ) nitrate ions (NO 3 − )

NITROGEN FIXATION This is the process that changes free nitrogen into the usable fixed kind. This is the process that changes free nitrogen into the usable fixed kind. Bacteria in the soil and in water change the nitrogen into compounds called nitrates /NO 3 - (nitrobacter) and nitrites /NO 2 - (nitrosomonas). Bacteria in the soil and in water change the nitrogen into compounds called nitrates /NO 3 - (nitrobacter) and nitrites /NO 2 - (nitrosomonas). These can be used by other living thing to make proteins and other needed compounds. These can be used by other living thing to make proteins and other needed compounds. Lightning and industrial processes do this too. Lightning and industrial processes do this too.

When an organism dies, the nitrogen compounds return to the ecosystem and are reused. When an organism dies, the nitrogen compounds return to the ecosystem and are reused. Eventually they are broken down completely (denitrification) and return to the atmosphere…and the cycle begins again…that’s why its called a cycle! Eventually they are broken down completely (denitrification) and return to the atmosphere…and the cycle begins again…that’s why its called a cycle!

FYI…if you’re gonna take biology in college… There are four sub-processes involved in the Nitrogen Cycle. You don’t have to know this now, but…someday… There are four sub-processes involved in the Nitrogen Cycle. You don’t have to know this now, but…someday… 1. Nitrogen Fixation : breaks N 2 apart so it can form compounds. 2. Decay: waste from life processes 3. Nitrification: bacteria converting ammonia to nitrites and nitrites to nitrates 4. Denitrification: bacteria converting nitrates to nitrogen gas again.