Ecology - Plankton Ecology Model Flashcards
Plankton Ecology Model
A description of repeated community assembly, where the interactions are accurately studied.
What interactions occur in PEG?
Herbivory, predation and competition.
What controls biotic interactions?
Abiotic control factors at start and end of growing seasons.
Importance of food availability…
Allows zooplankton development with a spring peak of grazing zooplankton with a then decline in phytoplankton biomass.
Clear Water Phase
Is where algal biomass is markedly reduced in late spring-early summer.
Importance of algal food quality…
Eutrophic systems experience increased algal biomass, with high inedible phytoplankton.
What does light increase initiate?
Community assembly, whilst autumnal light decrease terminates it.
Critical Depth
This describes how maximal mixing depth, allowing phytoplankton photosynthesis in excess of the respiration rate, thus positive growth rates.
Strategies of overwintering…
Akinets, spores, resting eggs or diapause.
How might copepods overwinter?
Accumulate lipid reserves
How do zooplankton respond to overwintering?
Sink to lower depths.
Example of seasonal responsiveness…
Spring bloom of phytoplankton with early emergence can increase potential biomass
How does the clear water phaseemerge?
Grazing, where zooplankton consume the phytoplankton biomass resulting in a minimum proceeding their bloom in spring.
Example of the parasitsm in the PEG…
Chytrid fungi..
Example of food quality importance in zooplankton….
P or N limitation despite limit increase may prevent devlopment of communtieis
Deep Chlorophyll Maxima
The region below surface water with maximum concentration of chlorophyll.
What does DCM coincide with?
Zooplankton distribution, algae maxing in spring and autumn, lack of light in the winter and too much nutrient use in the summer despite the sunlight.
How do herbivores increase exponentially?
Until density of the zooplankton exceeds the density of phytoplankton reproduction rate.
What is present in the spring bloom?
Phytoflagellates and chlorphytes and centric diatoms
Features of the summer time bloom..
Lower quality food as phosphorous becomes limited, thus diatoms dominate.
What happens when diatom population silica is reduced?
Cyanobacteria blooms, resulting in nitrogen limitation and filamentous cyanobacteria which are inedible mostly.
What does termination of winter result in?
Availability of nutrients and increasing light allowing phytoplankton to grow, especially fast growing ones.
