The Edwards lab, in collaboration with the Dinsdale lab, recently headed to the USC Wrigley Institute for Environmental Sciences on Catalina Island for a week of intensive research and SCUBA diving. The goals of this trip were to 1) test and become proficient at deploying benthic chambers (in preparation for Alaska!), 2) use the chambers to assess the amount of photosynthesis occurring in communities invaded with Sargassum horneri, and 3) investigate the microbial communities associated with S. horneri and compare it to communities commonly found on the native giant kelp (Dinsdale Lab).
During the trip we deployed benthic production chambers (Figure 1) which we like to describe as underwater greenhouses. These chambers are equipped with oxygen and light sensors that allow us to track photosynthesis of algae communities over the course of the incubation.
Take a look at a video (below) that shows how we set the chambers up underwater!
The underwater incubations usually last for 4 hours. If the incubation last longer than 4 hours, the chamber creates an unnatural environment because the water becomes oxygen rich (photosynthesis is happening!) and there is not enough carbon present for photosynthesis to occur. We stop the incubations before this occurs and flush the chamber to start a new incubations, Using a series of short incubations we can model the amount of photosynthesis occurring in a community over longer time periods!
These chambers will be used along the California coast and in the Aleutian Islands and can help us answer many research questions such as:
- How has the large scale loss of kelp forests in the Aleutian Islands altered the net photosynthesis occurring in the region? (Dr. Matt Edwards and Dr. Brenda Konar)
- What is the net primary production occurring in seagrass (Zostera marina) beds? (Melissa Ward)
-How has the invasion of Sargassum horneri in southern California influenced the primary production of these habitats? (Genoa Sullaway)
-What is the difference in kelp forest net photosynthesis between Northern and Southern California? (Pike Spector)
Thank you to Melissa Ward for the video. Thank you to the staff at the USC Wrigley Institute for the assistance during our stay. Additionally, thank you to the National Science Foundation for the funding that has allowed us to construct and use these chambers in Catalina and in the Aleutian Islands!