Microbial Ecology Laboratory

Clam Cancer

Softshell clams (Mya arenaria) are susceptible to a form of transmissible cancer known as Bivalve Transmissible Neoplasia (BTN). This disease, which was first recognized as transmissible by Metzger et al. (2015), is thought to be passed from clam to clam through the environment and may contribute to clam mortality, while carrying no known risk to consumers of diseased clams. Our role in this project is to conduct time-series analysis of clams in Maine to estimate the prevalence of this disease in both clams and environmental water samples and to map these prevalence values to temperature and salinity. Previous work by Giersch et al. (2022) demonstrated that cancerous clam cells survived better at lower temperatures and higher salinities. Diagnosis of BTN in clams can be accomplished by microscopy when clams are carrying a high load of cancerous cells. However, a DNA-based approach (qPCR) developed by Giersch et al. (2022) has greater sensitivity than microscopy at moderate to low levels of cancer. Additionally, this qPCR method provides a means of sampling the disease in environmental DNA (eDNA) samples. This work is a collaboration with colleagues at Pacific Northwest Research Institute (PNRI), Gloucester Marine Genomics Institute (GMGI) and Bigelow Laboratory for Ocean Sciences (BLOS).

North Atlantic Right Whale Diet

North Atlantic Right Whales (NARW) are a threatened whale species, whose ranges may be shifting in response to environmental pressures and shifting distributions of their prey – minute crustaceans known as copepods. Given their size, rarity, and endangered status, studying the diets of NARW is a difficult task. However, DNA-based methods such as quantitative PCR (qPCR) and DNA metabarcode sequencing can reveal the diets of these whales by analysis of NARW fecal samples. Archived NARW fecal samples from the New England Aquarium serve as the source material for this project, with a primary focus on testing for the ecologically important copepod, Calanus finmarchicus. We have developed a qPCR assay for C. finmarchicus and have applied it to two NARW fecal samples (to date), with one sample testing positive and the other testing negative. In addition to C. finmarchicus, we will test samples for several additional species of lipid-rich copepods. The relative proportions of the different prey species will help to inform modeling efforts that seek to predict the distributions of NARW at certain times of the year. This work is a collaboration with colleagues at the University of South Carolina (USC), the New England Aquarium (NEAQ), and Bigelow Laboratory for Ocean Sciences (BLOS).