People: Margarita Brandt and John Bruno
The goal of this project is to determine if the intensity of herbivory and algal biomass are, in part, regulated by temperature fluctuations related to different outcropping regimes. We will determine the genetic structure of two species of damselfish (Stegastes arcifrons and Stegastes beebei) to infer patterns of connectivity in the Galapagos Marine Reserve. First, we will focus on the genetic component of the project, by extracting DNA from the tissue samples. By using SNIPs (Single Nucleotide Polymorphisms) markers, we hope to be able to determine the genetic composition of the different populations.
Specific objectives:
- Use counts of fish and sea urchins at different depths on multiple islands in the Galapagos Marine Reserve to determine their diversity and abundance and to describe their behavior,
- Determine the impact of herbivorous fish on communities and benthic assemblages,
- Prove that decreases in temperature associated with outcrops reduce herbivory and increase the total biomass of macroalgae,
- Prove that herbivore populations are less sensitive to changes in temperature in warmer sites and/or during warmer seasons due to acclimatization or adaptation,
- Measure the relative importance of nutrient supply, herbivory, and temperature by monitoring the existing macroalgae biomass,
- Predict the effect of ocean warming (caused by greenhouse gas emissions) on species interactions and the structure of subtidal communities in Galapagos, and
- Determine the relative importance of top-down and bottom-up controls in sponge communities