Off-campus Michigan Tech users: To download campus access theses or dissertations, please use the following button to log in with your Michigan Tech ID and password: log in to proxy server

Non-Michigan Tech users: Please talk to your librarian about requesting this thesis or dissertation through interlibrary loan.

Date of Award


Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Stephen Techtmann

Committee Member 1

Amy Marcarelli

Committee Member 2

Jennifer Becker


Each year, hundreds of thousands of boats travel across the globe carrying over 80% of the world’s cargo. With all of these boats traveling all over the world, it is important to understand the organisms which live in and on the boats. This study looks at the extent to which bacteria can colonize ships. The potential for microbes from the water to colonize boats is an understudied, yet important topic which affects ecosystems and human health. Because of increasingly affordable metagenomic tools, it is now possible to characterize microbial communities in more detail than has been affordable and or practical in the past. Ballast water is intentionally taken onto a ship to increase stability and safety, and it has been shown to be a key vector in the spread of some non-native species. Because bacteria are ubiquitous in most environments, they have potential to be transported on ships in additional ways. Bilge water collects at the bottom of all boats and is another potential vector for the spread of non-native species. Additionally, bacteria frequently colonize underwater surfaces, making the outside surfaces of a boat another likely location for colonization by water microbes. Using a large data set collected from 20 ports in five regions of the world (Asia, Europe, east and west coasts U.S.A. and Great Lakes U.S.A.) we explore how the boat microbial community is similar to the water. We do this with microbial diversity analysis and source tracking software. The results from the source tracking software showed on average 40% of the bilge bacterial community and 52% of the hull bacterial community were sourced from the water. This suggests that microbes from the port water colonize a boat and have potential to travel with that boat. Source tracking analysis attributed an average of 60% of the bilge bacterial community and 48% of the hull bacterial community to unknown sources. To further quantify these unknown sources, we investigated air and dock as potential sources to the boat microbiome. After analysis with source tracking software, we showed that air contributed minimally to the boat microbiome (

11152019-Thesis-Final-LGS.pdf (2690 kB)
A global comparison of the bacterial communities of bilge water, boat surfaces and external port water

11152019-Thesis-Final-LGS.pdf (2690 kB)
11202019-Thesis-Final-LGS.pdf (2681 kB)