Dr. Lisa A Waidner

AAP bacteria are photoheterotrophic which means they can obtain energy from light and organic molecules. The pufM gene (Figure 1) is one of many that gives these bacteria the ability to use light as an energy source (Figure 1). Like other heterotrophic bacteria, AAPs contribute to the microbial loop (Figure 2) which plays a mojor role in recycling organic matter 9OM) and may change our understanding of the oceans ability to sequester CO2. Harvesting light energy allows AAP to grow larger and cycle OM at a faster rate (1).
The percentage of AAPs contributing to the microbial loop is not well known. If AAPs make up anywhere between 5-10% of the community, their light harvesting capabilities can change our view of the impact the microbial loop has on OM recycling. One biological factor that influences the abundance of AAP is grazing. Larger bacteria such as AAPs are more susceptible to grazing than smaller bacteria (2,3). For my research I am enumerating total AAPs, Roseobacter (Rsb.)-like AAP, Rhodobacter (Rba)-like, AAP and a novel Gulf of Mexico strain, called denovo0-like AAP. I sampled surface waters in Fall 2020 and again in Spring at Shoreline Park, and performed manipulation experiments to study grazing impacts on these specific groups. My question is: are total AAP bacteria equally grazed upon as total bacteria.