Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • BCO-DMO Processing Description
• Data Files
• Parameters
• Instruments
• Project Information
• Funding

Trials were conducted to test the hypothesis that carnivory increases with temperature. Eight aquariums were used as "cold treatment" (16 degrees Celsius) and the remaining as "warm treatment" (26 degrees Celsius). Each aquarium was divided in two using a plastic mesh. Randomly selected whelk (12­­ to 16 centimeters in length) were put in one half of the aquarium. Four to seven barnacles were previously glued to a small rock using epoxy (Splash zone compound A788 HG) and put in both sides of the aquarium. Each day the mesocosm room was visited two times (at 7:30 am and 7:30 pm) to assess predator position in each tank and to count the number of barnacles consumed. This experiment ran for 20 days.

Experiments were conducted in the Galapagos Science Center on San Cristobal Island in the Galapagos Archipelago. Whelks and barnacles were collected in La Barcaza, a rocky reef located on the North of the Island (coordinates: -0.67136 N, -89.2651E).

- Imported original file "PredationExperiment_WhelkBarnacles_2021_Updated.xlsx" into the BCO-DMO system.
- Created date-time fields in ISO8601 format (both Local and UTC); removed original date/time fields
- Saved final file as "894148_v1_whelk_barnacle_expts.csv".

NSF Award Abstract:
A well-known pattern in coastal marine systems is a positive association between the biomass of primary producers and the occurrence or intensity of upwelling. This is assumed to be caused by the increase in nutrient concentration associated with upwelling, enabling higher primary production and thus greater standing algal biomass. However, upwelling also causes large, rapid declines in water temperature. Because the metabolism of fish and invertebrate herbivores is temperature-dependent, cooler upwelled water could reduce consumer metabolism and grazing intensity. This could in turn lead to increased standing algal biomass. Thus upwelling could influence both bottom-up and top-down control of populations and communities of primary producers. The purpose of this study is to test the hypothesis that grazing intensity and algal biomass are, in part, regulated by temperature via the temperature-dependence of metabolic rates. Broader impacts include the training and retention of minority students through UNC's Course Based Undergraduate Research program, support of undergraduate research, teacher training, and various outreach activities.

The investigators will take advantage of the uniquely strong spatiotemporal variance in water temperature in the Galápagos Islands to compare grazing intensity and primary production across a natural temperature gradient. They will combine field monitoring, statistical modeling, grazing assays, populations-specific metabolic measurements, and in situ herbivore exclusion and nutrient addition to measure the effects of temperature on pattern and process in shallow subtidal communities. The researchers will also test the hypothesis that grazer populations at warmer sites and/or during warmer seasons are less thermally sensitive, potentially due to acclimatization or adaptation. Finally, the investigators will perform a series of mesocosm experiments to measure the effect of near-future temperatures on herbivores, algae, and herbivory. This work could change the way we view upwelling systems, particularly how primary production is regulated and the temperature-dependence of energy transfer across trophic levels.