Rosenberg Institute Seminar Series - Sam Bedgood

Sam Bedgood, Postdoctoral Scholar, Oregon State University

Symbiosis in flux: Algal endosymbiont contributions are shaped by sea anemone diet and size

Sea anemones in the genus Anthopleura along the California Coast can host millions of algal symbionts intracellularly within an individual. These nutritional partners provide carbon to the host anemone via photosynthesis while the anemone provides high concentrations of nitrogen and a safe place for the algae to reproduce. This appears to be the ideal nutritional partnership, but the benefits from each partner are dependent on fluctuations in the environment and physiological constraints. Our research aimed to implicate this symbiosis in niche differentiation of three congeneric anemone species that coexist in the rocky intertidal zone. We found that anemones up-or down-regulate symbiont densities in response to changes in diet, altering the balance of dietary carbon from captured prey and photosynthesizing algae. However, physiological constraints of surface-area-to-volume ratios in the host anemone also play a role in nutrition; growing large comes at a cost of losing algae and its nutritional benefits.

Sam is a postdoctoral scholar in the Weis Lab at Oregon State University where he studies symbiosis in cnidarians that partner with intracellular algae, including coral and sea anemones. He is currently interested in symbiosis establishment, nutrition, and maintenance during cnidarian development. He received his Ph.D. from the University of California Irvine where he focused on physiological and nutritional trade-offs between sea anemones in the genus Anthopleura and their symbiotic dinoflagellate algae. Sam’s research background is broad and includes community ecology, isotopic diet analysis, behavioral ecology, physiology, and cellular biology.