Science Serving Maryland's Coasts

Emily Dougherty, Gwynedd Mercy University

Class Year: 

Project Title: 

Determining the Abundance of Bacteria on Marine Particles of Different Size Classes


Microbes that live in association with marine particles have significant involvement in the remineralization of particulate organic carbon in the deep ocean within the biological pump. To better understand this process of carbon movement, it is important to study these microbes and the types of particles on which they live. Diverse particle characteristics can influence the microbes that inhabit them. This study aimed to examine the relationship between the size of particles and the number of microbes living on them. Previous studies have found the relative microbial abundance on various sized particles, but this experiment calculated the total abundance of cells per particle, in order to better understand the preferred particle habitats of different microbial species. Particles were collected with different sized filters and DNA was extracted for quantitative PCR and sequencing. Though it was hypothesized that cell number would scale with particle size, this relationship was not found. Rather, the abundance of microbes on each particle size depended on the specific type of microbe.