Chapter 27

Ecosystems

What is an Ecosystem?
An ecosystem is the interaction between all abiotic and biotic factors in an environment, and can be separated into two main categories: terrestrial…
Trophic Levels
27.2: Trophic Levels
All organisms in an ecosystem occupy a trophic level in the food chain. The lowest level consists of primary producers, which synthesize their own…
Primary Production
27.3: Primary Production
The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers…
Production Efficiency
27.4: Production Efficiency
Net production efficiency (NPE) is the efficiency at which organisms assimilate energy into biomass for the next trophic level. Due to low metabolic…
Trophic Efficiency
27.5: Trophic Efficiency
Trophic level transfer efficiency (TLTE) is a measure of the total energy transfer from one trophic level to the next. Due to extensive energy loss…
What are Biogeochemical Cycles?
27.6: What are Biogeochemical Cycles?
Molecules like water and elements such as carbon, nitrogen, sulfur and phosphorus are only available in the ecosystem in limited amounts. Therefore,…
The Water Cycle
27.7: The Water Cycle
The hydrosphere includes all of the area on the Earth where the storage and movement of water occurs. Since water is the basis of all living…
The Carbon Cycle
27.8: The Carbon Cycle
Carbon is the basis of all organic matter on Earth and is recycled through the ecosystem by two primary processes: one in which carbon is exchanged…
The Nitrogen Cycle
27.9: The Nitrogen Cycle
Nitrogen atoms, essential for the production of proteins and DNA in organisms, are recycled between abiotic and biotic components in the ecosystem.…
The Phosphorous Cycle
27.10: The Phosphorous Cycle
Phosphorus is not present in the atmosphere as a gas, much like carbon, water and nitrogen. Instead, it exists in the ecosystem in two forms, as…
The Sulfur Cycle
27.11: The Sulfur Cycle
Sulfur, and important element in the chemical make-up of proteins, is recycled through the atmosphere, aquatic and terrestrial environments. It…
Bioremediation
27.12: Bioremediation
Bioremediation is the use of prokaryotes or other small microbes to remove pollutants from the environment. This process has been used to remove…
Elemental Analysis
27.13: Elemental Analysis
Elemental Analysis is a method used to determine elemental composition of a material, such as the amounts of carbon and nitrogen in…
Environment: Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems
27.14: Environment: Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems
Dissolved organic matter provides an important source of energy and food to streams; however, in situ studies are difficult to reproduce. This…
Biology: Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside
27.15: Biology: Removal of Exogenous Materials from the Outer Portion of Frozen Cores to Investigate the Ancient Biological Communities Harbored Inside
The cryosphere offers access to preserved organisms from past conditions and proper processing of frozen samples to study them is essential. The…
Bioengineering: A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
27.16: Bioengineering: A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
Oil pollution is among the most serious causes of environmental contamination. In this protocol, an engineered E. coli strain is designed and…