Research ProjectHow Humans Move Marine Parasites

  • Dr. Katrina Lohan with water sample from Punta Culebra, a site at the Pacific entrance to the Panama Canal.

    Dr. Katrina Lohan with water sample from Punta Culebra, a site at the Pacific entrance to the Panama Canal. Photo Credit Kristina Hill-Spanik

  • Sediment sample from Fort Sherman, Panama

    Sediment sample collected at Fort Sherman, a site near the Caribbean entrance to the Panama Canal. Photo Credit Dr. Carmen Schlöder

  • Sampling microbial communities on the hulls of ships

    The aftermath of divers sampling microbial communities on the hulls of ships. Photo Credit Dr. Ian Davidson

Project Goal

We are examining the role of humans in spreading marine parasites and disease in marine systems, primarily focusing on marine shipping as the mechanism for transporting these organisms. We are also attempting to understand the characteristics associated with successful parasite invaders to better understand their invasion risk.


Marine shipping is a major contributor to the spread of marine organisms, allowing plants and animals to travel vast distances, which would otherwise be impossible. Though small microscopic organisms (aka microbes) are much more abundant in the marine environment and likely also spread through marine shipping, these organisms are much less conspicuous and have not been well-studied in invasion biology. Nevertheless, there are multiple examples of the devastating impacts that toxic and parasitic microbes can have when they are introduced and infect novel hosts in new geographic areas, including MSX disease in the Chesapeake Bay and crayfish plague in Europe.

Our research on parasite invasions involves understanding the role of humans in spreading marine parasites, assessing the characteristics that make parasites successful invaders, and examining the underlying mechanisms that allow for successful parasite invasions. We are examining the protistan communities, including parasites and toxic taxa, associated with ballast water of commercial ships entering ports across the US to assess the extent to which marine ships are dispersing these organisms, changing their global distributions and allowing for potential invasions. We are also assessing the microbes, including parasites, associated with the biofilms on the hulls of these ships. Additionally, we are testing the effectiveness of different treatment technologies in removing microbial taxa from ballast water. Due to the difficulty in finding and identifying these small organisms based on morphology*, we are using genetics, specifically metabarcoding*, to identify microbes in these samples. Finally, we are beginning to examine the characteristics and mechanisms that allow for successful parasite invasions using laboratory experiments to understand how parasites associated with ships can move from ships to hosts in the surrounding environment.

Feature Stories

What Parasites are Hitching a Ride to the Chesapeake Bay in Ballast Water? By Katrina Lohan. February 3, 2014


Dr. Katrina Lohan

Term Definition 
Morphology the branch of biology that deals with the form of living things and the relationships between their structures
Biogeography The branch of biology that studies the geographical distribution of species, traits, and ecosystems

A DNA-based method for rapidly identifying the community of organisms in a particular sample using a combination of PCR and high throughput DNA sequencing