Lec 26 (Nutrient cycle part 1) Flashcards
Nutrient Cycling?
Whereas energy flows through ecosystems, nutrients cycle.
Flow = One-way trip (energy) Cycle = Continuously recycled (nutrients)
Reservoirs?
Nutrients?
-Stores of water or nutrients in a cycle.
-Elements that are required for the
development, maintenance, and reproduction of
organisms.
Macro vs. Micro Nutrients
Macronutrients: essential elements required in
large concentrations in an organism.
Examples: carbon, hydrogen, oxygen, nitrogen,
phosphorus
Micronutrients: essential elements required
only in small concentrations in an organism
Examples: iron, magnesium, iodine, selenium, zinc
Facts About Phosphorus
• Essential to energetics, genetics and structure
of living systems.
– Is the main component of ATP, RNA, DNA, and
phospholipid molecules. Kinda important
• Not very abundant in the biosphere
• Does not have an atmosphere reservoir
• Can be a limiting factor for aquatic primary
production, not usually for terrestrial primary
production
Cycle units for phosphorus?
Reservoir/Pool = 1012 g of nutrient
Fluxes = 1012 g of nutrient per year
The Phosphorus Cycle?
• Plants take up phosphate ions from soil or water and
incorporate them directly into tissue
• Animals gain phosphate by eating these tissues, or
from the tissues of other organisms
• Animals eliminate excess phosphorus through urine
The largest pool of phosphorus is?
In marine sediment
Facts About Nitrogen?
• Important to structure and functioning of
organisms.
• May limit rates of primary production in
terrestrial and marine systems.
• One of the biggest reservoirs is the
atmosphere (Earth’s atmosphere = 78% N)
• Microbes play a BIG role in the nitrogen cycle
• Its cycle is way more complicated than
phosphorus’
Forms of N….?
- Ammonia: NH3
- Ammonium: NH4+
- Nitrite: NO2-
- Nitrate: NO3-
- Nitrogen gas: N2
- Nitric oxide: NO
The important forms of nitrogen are?
Nitrate NO3 and Ammonia are the forms organisms take in nitrogen
Nitrogen gas N2 is the most common form nitrogen is in
-What are the Five Transformations of N?
- Nitrogen fixation:
- Immobilization
- Mineralization (ammonification)
- Nitrification
- denitrification
-What is Nitrogen fixation?
-the process of converting
atmospheric nitrogen into forms primary producers
can use
Immobilization?
the conversion of mineral forms of
nitrogen (ex. ammonia and nitrate) into organic
forms (ex. proteins).
Mineralization (ammonification)?
the conversion of
organic forms of nitrogen (ex. proteins) into mineral
forms (ex. ammonia and nitrate).
Nitrification?
the conversion of ammonium(NH4+) to nitrite (NO2), and then nitrite (NO2) to nitrate (NO3-)
Denitrification?
the process of converting nitrate (NO3-) into nitrogen gas (N2)
The biggest reservoir of N is the?
atmosphere (as N2 gas). over land and ocean
Explain the nitrogen cycle. (Fixation)
Nitrogen can be fixed, through nitrogen fixation, by certain prokaryotes. It also can be fixed by lightning!
During nitrogen fixation, N2 gas is reduced to ammonia, NH3… N2 + 8 H+ → 2 NH3 + H2
Explain the nitrogen cycle. (Immobilization)
• After fixation, nitrogen it is available to primary producers and can be immobilized (assimilated into
their tissue).
• Consumers can gain nitrogen by eating
these primary producers or other organisms.
• Once an organism dies, nitrogen is released from its
tissues by fungi and bacteria during decomposition.
Explain the nitrogen cycle. (mineralization)
Nitrogen released through mineralization, also called
ammonification. During this process the organic nitrogen is converted into ammonium NH4+
This ammonium can then be converted into
nitrate through nitrification (a two-step process)
Explain the nitrogen cycle. (denitrification)
Nitrogen re-enters the atmosphere
reservoir through denitrification, when denitrifying
bacteria convert nitrate into N2 gas
Facts About Carbon
It makes organic molecules organic
We humans are messing up the balances in the
carbon cycles, thus are creating global climate
change
Explain the Carbon cycle.
• Some of the big carbon reservoirs are the atmosphere, terrestrial soils, all organisms, and the oceans.
• Carbon moves between organisms and the
atmosphere through respiration and photosynthesis.
• Respiration moves carbon to the atmosphere
Photosynthesis removes carbon from the atmosphere
We humans are messing up the balances in the carbon
cycles, thus are creating global climate change… How?
Burning:
- Fossil fuels
- Vegetation
- Peat
The largest actively cycled nitrogen occurs?
-Human activity is a substantial source of nitrogen in the atmosphere. True or False
In the ocean
True
-What contains the largest amount of carbon?
Carbonate rocks
In_____ ecosystems CO2 has to be dissolved into
the water before it is available to primary
producers.
aquatic
When dissolved in water, CO2 turns into?
two compounds (in equilibrium):
- Bicarbonate HCO 3-
- Carbonate CO3 2-
CO3 2- can combine with dissolved calcium and
precipitate out as calcium carbonate CaCO3
Decomposition?
the breakdown of organic matter accompanied by the release of CO2
Factors that influence decomposition?
– Temperature
– Moisture
– Chemical composition of decaying matter
– Chemical composition of the environment
Comparing Decomposition Rates:
Precipitation…
The more precipitation you have the more decomposition you will have.
Comparing Decomposition Rate:
Leaf Characteristics
-Decomposition rates dependent on %lignin: %N ratio
Higher the ratio of lignin to N, the longer it took to decompose
Also, the more N in the soil (North Carolina), the
higher the decomposition rate
Comparing Decomposition Rates:
Temperature and Moisture (AET)
-In warmer and moisture climates we see more decomposition
Decomposition in Aquatic Ecosystems?
Influenced by the same three factors: – Temperature – Nutrient content of the decaying matter – Nutrient content of the water
