Questions and Answers
What is the general term for the creation of new organic matter?
What is the primary source of energy for freshwater ecosystems?
What is the term for the rate of generation of biomass in an ecosystem?
What is the term for the productivity of autotrophs such as plants?
Signup and view all the answers
Where are phytoplanktons typically found in freshwater ecosystems?
Signup and view all the answers
What adaptation allows phytoplankton to maintain their presence in the water column?
Signup and view all the answers
Which mechanism do phytoplankton use to change their density and avoid sinking?
Signup and view all the answers
What is the primary role of both phytoplankton and periphytic algae in aquatic ecosystems?
Signup and view all the answers
What do top-down processes imply about prey abundance in trophic relationships?
Signup and view all the answers
What distinguishes periphytic algae from phytoplankton?
Signup and view all the answers
Study Notes
Production and Productivity
- Production refers to the creation of new organic matter through processes like photosynthesis.
- Photosynthesis converts light energy into energy stored in chemical bonds within plant tissue, fueling metabolic processes and growth.
Primary and Secondary Productivity
- Productivity refers to the rate of biomass generation in an ecosystem, usually measured in units of mass per unit surface (or volume) per unit time.
- Primary productivity refers to the productivity of autotrophs like plants, while secondary productivity refers to that of heterotrophs like animals.
Production in Freshwater Ecosystems
- Freshwater ecosystems gain most of their energy from photosynthesis by aquatic plants and algae.
- Photosynthesis in freshwater systems is affected by light attenuation, with rates decreasing with depth, and inhibited by ultraviolet light at the surface.
- The rate of photosynthesis depends on factors like biomass of photosynthesizing cells, light-attenuating materials, and abundance of light-absorbing pigments.
Photosynthesizers in Freshwater Ecosystems
- Algae, including phytoplankton and periphyton, are the primary photosynthesizers in ponds and lakes.
- Phytoplankton have adaptations to maintain their presence in the water column, such as forming vacuoles and gas vesicles, changing shape, or using flagella.
- Periphytic algae are attached to a substrate and can cover all benthic surfaces.
Trophic Relationships in Freshwater Ecosystems
- Freshwater biota are linked in complex web of trophic relationships, with organisms loosely associated with specific trophic groups.
- Top-down processes dictate that the abundance of prey taxa is dependent upon the actions of consumers from higher trophic levels.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Understand the process of production and productivity in ecosystems, including photosynthesis and biomass generation.
