Comma shrimp galore
Hi! My name is Victoria Vandersommen, and I like to look for crustaceans in mud. I’m a master’s student at the University of Alaska Anchorage in Dr. Sarah Gerken’s lab. We are particularly interested in a type of crustacean called a cumacean, which are also known as comma shrimp due to their body shape. These little critters (1-30 mm) are incredibly important to marine ecosystems by feeding larger animals such as whales, birds, and fish. They live in the surface layer of mud, feeding on dead organic material, which is then recycled to higher trophic layers; this where the fun begins with sampling. When you don’t have a ship with an epibenthic sled to collect sediment (2nd photo), you manually poke in the mud to make an impression that fills with water and little animals, and if you’re lucky, you’ll see cumaceans flicking around in the pool of water! Fortunately, the RV/IB Nathaniel B. Palmer has an amazing new epibenthic sled that has been a dream for collecting an abundance of cumaceans and other tiny invertebrates.
Cumaceans vary greatly in their appearance, ranging from white to multi-colored, smooth to spiny, eye lobes to none- all based on their species. For my research, I am aiming to determine the baseline biodiversity in the circum-Antarctic; currently, there are 100-150 species recorded. On a larger scale there are 1,900 species of cumaceans that have been described worldwide to-date! We have 515 animals from the West Antarctic from a 2020 cruise, are hard at work collecting samples here in the East Antarctic (over 1,000 animals collected to-date!), and will be traveling to the Ross Sea in 2025 to collect samples. This information will help us monitor changes to cumacean distribution with warming Antarctic regions, and also infer dispersal due to currents, as cumaceans are poor swimmers.
As an undergraduate, I studied in Dr. Gerken’s lab to determine if cumaceans contain gut microbes (spoiler alert: they do!). I collected the samples from the live-aboard M/V Discovery while working as a wilderness guide in Prince William Sound, AK. Without a microscope on board, I would preserve them without getting a good look at the animals until I was back at the lab. One of the most amazing parts of this incredible experience has been to see such colorful, lively cumaceans under a microscope. There’s a thrill with each petri dish you look at for first time, not knowing what animals you’ll encounter.
When I’m not hunting for cumaceans, I’m on deck looking for penguins and admiring the massive icebergs. We have been incredibly lucky to have two southern lights shows, Adele and Emperor penguin sightings, Minke whales, and gorgeous sunrises. Antarctica is a mesmerizing and grand place that I will never forget.
University of Alaska Anchorage
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