Bio 346 - Freshwater Eco. (Chpt 23) --> Zooplankton Flashcards
Typically what are the macrozooplanktons that are larger than 200um?
Crustaceans
Typically what are the microzooplanktons that are smaller than 200um?
Rotifers
Zooplankton
Any plankton thats an animal
What was used in the 20th century to sample zooplankton?
Nets made out of silk bolting cloth (60-70um) that would catch both crustaceans and rotifers
Negative effects to the net cloths for sampling?
It provides resistance to flow of water through them and allow water to flow from the mouth resulting in an underestimation of the biomass of organisms
What has been introduced in order to fix the negative effects of the net cloths for sampling?
Traps –> Schindler Patalas Traps
Schindler Patalas Traps
- 2 hinged door swings upward and the trap is lowered and closed at the desired depth when the hauling up commences
- Water then flows out and all is caught in the traps
- Provides little warning to the light sensitive zooplankton (best to collect at night)
What is the best way to collect samples of protozoans?
bottles or pumps rather than nets
What are 8 ways the heterogeneous distribution of the lake zooplankton occurs?
- System morphometry (lake depth and shape)
- The configuration of inflows and outflows
- Prevailing winds
- Current patterns
- Upwellings
- Competition for food resources between zooplankton species
- Predators
- Vertical migrations in deeper lakes and horizontal or transversal migrations in shallow lakes
What are determinants for accurate production that link abundance patterns to environmental factors in all organisms?
Good and frequent abundance of species
Keystone species
A species now which other species in an ecosystem largely depend on, such that if it were to be removed the ecosystem would change drastically
Eg) Daphina (Water Fleas)
What are the most important soft bodied multicellular invertebrates in the plankton family?
Rotifers
What are 2 important aspects of rotifers?
- Important food source
2. Contributes to the decomposition of soil organic matter
Multivoltine
Invertebrates producing more then one generation per year
Bivoltine
Those completing 2 life cycles per year
Univoltine
Those that produce one generation per year
Semivoltine
Species requiring 2 years to complete a life cycle
Merovoltine
Those with a longer life cycle
What life cycle do rotifers have?
Multivoltine
- because they produce unfertilized but diploid 2N) eggs
What happens to the reproduction rate as temperature increases?
Increases
- Larger organisms need higher temps to reproduce compared to smaller organisms
Cladocerans
- Type of crustacean
- Normally covered by a hard chitinous cover
- Respiration occurs though gills or through body surface
- 2 large antennae give them the name “water flea” and uses them for rowing through the water
- Produce many offsprings
- Regulated by egg production
Copepods
- Type of crustacean
- Regulated by longevity and survival rate
- Dependent on sexual reproduction
- Development time is determined by water temperature
What are 3 examples of copepods?
- Cyclopoid copepods
- Generally predatory (carnivore) - Calanoid copepods
- Omnivore - Harpecticoid copepods
- Primarily benthic
Ostracods
- Type of crustacean
- Benthic
- Frequently vert common in sediments and on macrophytes
- Bodies are flattened from side to side and protected by a bivalve-like shell (chitinous)
Malacostracans
- Larger crustaceans
- eg) crabs, lobsters, catfish, shrimp, krill….
- Segmented bodies (head, thorax and abdomen)
What is the principle predictor of crustaceans and rotifer specie abundance?
Lake area
What type of lake are invertebrate species abundance greatly reduced?
Saline lakes
Habitat diversity hypothesis
Theory that explains the relationship between species abundance and the surface area of oceanic islands
What is the 2nd predictor of crustaceans and rotifer specie abundance?
Annual phytoplankton primary production
Whats happens to species abundance as area increases
Increases
What are season cycles affected by? (3 things)
- Size distribution and their algal and bacterial prey
- Disease and selective predation by fish
- Invertebrate predators
What happens with huge variability in temperate zones?
2 things
- Leads to increase in zooplankton and nanoplankton
2. Decrease in temp decreases abundance in zooplankton
What happens to the pronounced seasonality at mid/high latitudes when shifted to lower latitudes?
Becomes more muted
What 6 things affect water column stability?
- Mixed-layer light climate
- External and internal nutrient loading
- Primary production
- Fish reproduction
- Zooplankton
- Population dynamics
What are 4 patterns shown at lower latitudes?
- More modest seasonal changes in irradiance and temp
- Greater seasonal variability in rainfall
- River discharge
- Wind speed
What is the best way long-term patterns are recorded?
In sediments
What are 4 factors that cause large inter-annual and decade-long variation?
- Changes in predation pressures from fish or invertebrates
- Changes in zooplankton food supply related to nutrient supply and algal density
- Changes in spring – ice covered and algal growth in spring
- Competitive interactions among zooplankton species
What kind of relationship is between fish density and Daphina? (+ or -)
Negative relationship
What dramatic effects can manipulation of planktivorous fish stocks have? (3 things)
- Zooplankton abondance
- Biomass
- Community structure
What are 3 ways of removing zooplankton resulted from under ice anoxia?
- Netting
- Poisoning
- Naturally by winter kills
What does a high abundance of zooplankton do to abundances of large zooplankton ?
Reduces it
- Which they preferentially feed on
What does size distribution of macro-zoo-plankton in lakes provide?
A useful index of the structure of fish communities
What is water management most concerned with in the temperate zone?
The end result
- And not with the importance of the different mechanisms that determined the desired transparency
What are the first steps towards the development of models that better predict impacts on aquatic systems?
Identification and quantification of mechanisms
What type of macrozooplankton commonly plays a key role in reducing the phytoplankton biomass?
Filter feeding macrozooplanktons
What has biomanipulation of temperate lakes been proposed to do?
Acts as a management tool for increase in water clarity in eutrophic systems in which a sediment reduction in internal or external nutrient loading cannot be brought about
What 2 things does growth of a zooplankton population or community require?
- Enough food of sufficient quality
2. Appropriate size
What happens to organismal size when the filtering rate per unit biomass decreases over a wide body-sized range?
It increases
What 2 things does filtering and grazing rates depend on?
- Food concentration
2. Food quality
Haney In-Situ Grazing Chamber
- Was developed to gently trap zooplankton while automatically exposing the enclosed assemblage to trace amounts of radio-labelled food particles
- Uses radio-labelled cells food particles to attract zooplankton
- Once caught gets filtered out and measured
What happens to biomass as grazing rates decline?
Gradually declines and evens out (see graph in notes)
What happens to biomass as TP increases?
Increases
What is the most important correlation of production?
Population biomass
What happens to biomass as the weight of an individual increases?
Decreases
What 3 things increase with increase in temp?
- Egg development
- Growth rates
- Feeding rates
What 3 things do interaction between top down and bottom up define?
- Community structure
- Biomass
- Productivity
Cyclomorphosis
The pronounced died vertical migration (DVM) of macro-zoo-plankton and distinct seasonal changes in the morphology of successive generations
What do more fish present?
Stronger vertical migration
What does food dictate?
Where the zooplankton are in the water column
What are the 2 environmental cues that trigger migration?
- Light intensity
2. Release if info-chemicals by a variety of predators
What do chemical cues and alarm substances do?
Stimulate migration
Kairomones
Chemical cues provided by the excretory products of predators
Alarm substances
Cues provided by injury or partially eaten prey organisms of the same species
What does DHM stand for?
Diel Horizontal Migration
What is an important reason for migration?
Predator avoidance
What does full moon light reduce?
The extent of migration
- Extent of migration is a function of organismal size
