Comma shrimp, otherwise known as cumaceans

We are on the RVIB Nathaniel B. Palmer, heading south for the Ross Sea! I am Professor Sarah Gerken from the University of Alaska Anchorage, here to study cumaceans. Cumaceans are small brooding crustaceans that live in bottom sediments. Brooding doesn’t mean they have emotional angst, it means the females carry their offspring in a pouch until the offspring come out as small copies of the adults, lacking only their final pair of legs. The lack of a larval stage and the generally poor swimming capabilities of cumaceans means they probably don’t move very far during their lives. Thus, it is likely that each area of the Antarctic has different species, even if they look quite similar to each other, a phenomenon known as cryptic speciation.

This is our third expedition to the Antarctic. In 2020, we went to the West Antarctic Peninsula and Weddel Sea. In 2023 we went to the East Antarctic, and now we are going to the Ross Sea, so we’ll have samples from all around the Antarctic. These samples will allow us to the test the validity of reported circumantarctic cumacean species distributions, among other things.

I did my BA and MS at the University of California, Santa Cruz, and a PhD in Oceanography at the University of Maine Orono, and I am currently a Professor of Biological Sciences at the University of Alaska Anchorage. My biological research that brings me to Antarctica is exploring cumaceans as a model system to explore invertebrate adaptations to the changing Antarctic. This project will leverage integrative taxonomy, functional, comparative and evolutionary genomics, and phylogenetic comparative methods to understand the true diversity of Cumacea in the Antarctic, identify genes and gene families experiencing expansions, selection, or significant differential expression, generate a broadly sampled and robust phylogenetic framework for Cumacea based on transcriptomes and genomes, and explore rates and timing of diversification in Antarctic cumaceans. The project will contribute to understanding of gene gain/loss, positive selection, and differential gene expression as a function of adaptation of organisms to Antarctic habitats. Phylogenomic analyses will provide a robust phylogenetic framework for Southern Ocean Cumacea.

Dr. Sarah Gerken
University of Alaska Anchorage