Experiments

At the heart of LIAT are experiments, experiments, and more experiments! Below are a selection of experiments that are done by students in the lab using LIAT. Most do not require extensive equipment to run or collected data from, and all can be optimized for the goals of the instructor and students.

All were designed by students as part of a Course-based Undergraduate Research Experience (CURE). Those experiment with videos were designed by students and executed by me during the Covid-19 pandemic. Others were designed and executed by first-year students in groups of 2-4 for their final CURE projects. Those that involve competition were conducted by students in upper-level ecology courses.

What are the effects of varying nitrogen to phosphorus ratio on algae population growth?

Conducted in 2020 for students during the Covid-19 pandemic.

Independent variable: N:P ratio

Dependent variable: cells/mL of Raphidocelis subcapitata

What are the effects of varying predation rate at the top of a 3-level food chain on algae and herbivore populations?

Conducted in 2020 for students during the Covid-19 pandemic

Independent variable: rate of predation on Daphnia magna (waterfleas)

Dependent variables: cells/mL of Raphidocelis subcapitata, abundance of waterfleas

What are the effects of adding nutrients to a 3-level food chain on algae and herbivore populations?

Conducted in 2020 for students during the Covid-19 pandemic

Independent variable: added nutrients

Dependent variables: cells/mL of Raphidocelis subcapitata, abundance of waterfleas

Does light intensity affect growth of algae populations?

Independent variable: light intensity (from grow lights)

Dependent variable: cells/mL of Raphidocelis subcapitata

Does temperature affect growth of algae populations?

Independent variable: ambient temperature (from environmental chambers)

Dependent variable: cells/mL of Raphidocelis subcapitata

Does waste from damselfly larvae affect the growth of algae populations?

Independent variable: volume of damselfly waste added

Dependent variable: cells/mL of Raphidocelis subcapitata

Does pH affect rates of algae and Daphnia population growth and survival?

Independent variable: pH

Dependent variables: cells/mL of Raphidocelis subcapitata, Daphnia magna population size (no. individuals/LIAT microcosm

Does photoperiod affect the growth of algae populations?

Independent variable: photoperiod (by grow lights on timers)

Dependent variable: cells/mL of Raphidocelis subcapitata

Does estrogen concentration affect the growth of algae populations?

Independent variable: estrogen concentration

Dependent variable: cells/mL of Raphidocelis subcapitata

Do different consumers affect the growth of algae populations differently?

Independent variable: Consumer identity (2 species of zooplankton)

Dependent variable: cells/mL of Raphidocelis subcapitata

Does water from different distances in the watershed from a lake affect the growth of algae populations differently?

Independent variable: distance from lake

Dependent variable: cells/mL of Raphidocelis subcapitata

Do pollutants (magnesium sulfate, sodium fluoride, and synthetic oil) affect the growth of algae populations?

Independent variable: pollutant type

Dependent variable: cells/mL of Raphidocelis subcapitata

Does nutrient concentration affect population growth rates of R. subcapitata and Daphnia magna?

Independent variable: nutrient concentration

Dependent variables: cells/mL of Raphidocelis subcapitata, D. magna population size

Do light filters of various colors affect population growth rates of R. subcapitata?

Independent variable: color of cellophane around LIAT microcosm

Dependent variable: cells/mL of Raphidocelis subcapitata

Does temperature affect competition between two phytoplankton species?

Independent variable: temperature (in environmental chambers)

Dependent variables: cells/mL of Raphidocelis subcapitata, and/or Microcystis aeruginosa, and/or Scenedesmus quadricauda

Does pH affect competition between two phytoplankton species?

Independent variable: pH

Dependent variables: cells/mL of Raphidocelis subcapitata, and/or Microcystis aeruginosa, and/or Scenedesmus quadricauda

Does photoperiod affect competition between two phytoplankton species?

Independent variable: photoperiod (grow-lights on timers)

Dependent variables: cells/mL of Raphidocelis subcapitata, and/or Microcystis aeruginosa, and/or Scenedesmus quadricauda

Does temperature affect competition between two zooplankton species?

Independent variable: temperature (in environmental chambers)

Dependent variables: population sizes of Daphnia magna and Ceriodaphnia dubia

Does pH affect competition between two zooplankton species?

Independent variable: pH

Dependent variables: population sizes of Daphnia magna and Ceriodaphnia dubia

Does photoperiod affect competition between two zooplankton species?

Independent variable: photoperiod (grow lights on timers)

Dependent variables: population sizes of Daphnia magna and Ceriodaphnia dubia

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