Cladocera

• "Water fleas"
• They eat diatoms - which makes them BAD! organisms
• Very pretty:
  !bioindicators_I, p.38
• A bit bigger than diatoms in general, form a large part of zooplankton for fish
• Known since the Permian period and have not changed much in the last 11,000 years
• Primarily freshwater, but also in marine, wetlands, puddles, caves and tree depressions

General

• Most feed on microalgae, bacteria and detritus
• Different taxa have different habitat preferences (planktic (like Daphnia) vs littoral)

Structure

• Egg-carrying like structures (Epippium) are a useful ID feature
• headshield shape
• order, shape and number of head pores

Habitats

• Diverse genera live in different habitats (littoral to planktonic to benthic)

Factors affecting species occurence

• Biogeography - how likely is it that a species will colonize a basin?
• Physical/chemical properties
• Eutrophy/oligotrophy
• Predators
• Competition

Use as bioindicators

• They have a fast resposne to env change, there is a relatively low number of species and occur widely and are well preserved (their subfossils are anyways)
• Can be used to identify acidification, nutrient level chanes, catchment area disturbance, changes in water level....
• Also can identify fish abundance