1. Freshwater Biome, Estuaries, Nitrogen Cycle

2. Aquatic Biomes
Freshwater
Marine
Estuaries

3. Freshwater Biomes Rivers, streams, lakes Organisms: fish, frogs, algae
Often surrounded by a variety of plants.

4. Estuaries
Area where fresh and salt water mix (where rivers enter ocean)
Examples: lagoons, mangrove swamps
Many species of plants, fish, crabs, shrimp, and birds live here.
“Nurseries of the Sea” – many species reproduce or raise young in estuaries.

5. Nitrogen Cycle
1. Nitrogen is removed from the atmosphere through nitrogen fixation (bacteria convert nitrogen gas to nitrates)
2. Plants use nitrates to make proteins.
3. Animals get nitrogen by eating plants (or animals that ate plants)
nitrogen in
atmosphere
animals
denitrifying
bacteria
nitrifying
ammonium
ammonification
decomposers
plant
nitrogen-fixing
bacteria in soil
bacteria in roots
nitrates
nitrites

6. Nitrogen Cycle (cont.)
4. Animal waste and dead plant/animal matter are decomposed by bacteria, nitrogen is returned to the soil.
5. Bacteria return nitrogen to atmosphere through the process of denitrification.
nitrogen in
atmosphere
animals
denitrifying
bacteria
nitrifying
ammonium
ammonification
decomposers
plant
nitrogen-fixing
bacteria in soil
bacteria in roots
nitrates
nitrites

7. Nitrogen is excreted by animals in the form of urine or feces
Nitrogen Fixation:Nitrogen is taken from the atmosphere and fixed as nitrates by bacteria
Nitrogen from dead plants and animals is broken down by bacteria returning nitrogen to the soil
Denitrification: Nitrogen is returned to the atmosphere by bacteria
Nitrogen Cycle
Nitrates are absorbed by plants from the soil and used to build proteins
Plants are eaten by consumers and nitrogen is taken up

8. Eutrophication
Increase of phosphorus and nitrogen concentrations in bodies of water, usually from run off
Causes algal blooms
Leads to lack of oxygen in body of water