structure of aquatic ecosystems. relative importance of allochthonous versus autochthonous sources...
TRANSCRIPT
Structure of Aquatic Ecosystems
Relative importance of allochthonous versus autochthonous sources of
• nutrients• sediments• organic matter (dissolved and particulate)
Productivity within a Watershed
• Wetland very productive• Terrestrial systems moderately productive• Aquatic systems least productive
Zones of a Lake
Zones of a Reservoir
Zonation of Littoral Vegetation
Aufwuchs
Categories of Aufwuchs
• Epiphytic • Epipelic
• Episammic
• Epilithic
Phytoplankton
Zooplankton
Benthos
Nekton
Trophic Structure
Primary Producers
Primary Consumers
Secondary Consumers (carnivores)
Decomposers
Food Web
River Continuum
Productivity
Rate at which energy enters one trophic level from a lower trophic level.
Efficiency
Energy transfers not very efficient because of dissipation through metabolism, etc. Also, mechanisms of energy transfer not inherently efficient. For example photosynthesis is less than 1% efficient in water.
Diversity
Complexity of a community
Relative Sizes
Biomass
Ways to determine:• Volume and number• Weight –fresh and dry• Oxidize living matter to CO2• Total ATP• For primary producers, extract chlorophylls
Production
• New organic mass per unit of time
• Σ [new organic biomass - respiration -excretion - secretion – injury – death – grazing]
Energy Flow in an Ecosystem