Chapter 27

Ecosystems

What is an Ecosystem?
Overview An ecosystem is the interaction between all abiotic and biotic factors in an environment and can be classified as terrestrial or aquatic.…
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 food…
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?
The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in…
The Water Cycle
27.7: The Water Cycle
The Earth’s hydrosphere includes all of the areas 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 in two primary processes: one in which carbon is exchanged…
The Nitrogen Cycle
27.9: The Nitrogen Cycle
Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of…
The Phosphorus Cycle
27.10: The Phosphorus Cycle
Unlike carbon, water, and nitrogen, phosphorus is not present in the atmosphere as a gas. Instead, most phosphorus in the ecosystem exists as…
The Sulfur Cycle
27.11: The Sulfur Cycle
Sulfur, an important element in the chemical makeup of proteins, is recycled through the atmosphere and aquatic and terrestrial environments. Found…
Bioremediation
27.12: Bioremediation
Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful…
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…