Part 2: Algae & Brine Shrimp Populations

2. Part 2: Algae & Brine Shrimp Populations • The field ecologist who study the Mono Lake ecosystem observe that the populations vary a lot over the course of a year. Sometimes, for instance, there are almost no brine shrimp in the lake, and at other times there are trillions. They reasoned that there must be some limiting factors that result in small populations sometimes and huge populations at other times.

3. Part 2: Algae & Brine Shrimp Populations • The scientists know that the survival of the whole Mono Lake ecosystem depends on the algae. If the algae population (the producers) is large, the ecosystem will have the capacity to support large populations of primary consumers. • The scientists wanted to understand the factors that limit the populations of two important organisms in Mono Lake, the planktonic algae and the brine shrimp. They set up a yearlong laboratory experiment.

4. Part 2: Algae & Brine Shrimp Populations • Read the experimental setup and procedures described on Algae & Brine Shrimp Experiments. • Note the following pieces of information: • Eight experimental aquariums were set up and maintained. • Each aquarium had only one variable that changed over the course of the experiment. • The populations were sampled every month for 1 whole year.

5. Part 2: Algae & Brine Shrimp Populations • Think about the following as you work: • Which experiments were maintained at a consistently cold temperature all year? Which were maintained at a consistently warm temperature? • Which experimental aquariums were maintained at the same temperature as Mono Lake throughout the year? • What would a graph of time versus temperature look like for the aquariums maintained at the same temperature as Mono Lake throughout the year? • Analyze the data and record answers to the three questions on the analysis sheet, page 37.