Research

DMS students help mapping sediments and fauna in Long Island Sound

Posted on May 22, 2025May 22, 2025 by Hannes Baumann

Carlee Dunn and Riley Pena, DMS graduate students in the Matassa Lab, worked alongside researchers from the University of Connecticut, University of New Haven, and US Geological Survey aboard the R/V Connecticut to map benthic habitats in western Long Island Sound. The cruise used USGS’s Seabed Observation and Sampling System (SEABOSS) to capture video and sample seafloor sediments and benthic organisms, such as brittle stars.

The team’s research is part of the Long Island Sound Habitat Mapping Initiative, which aims to characterize the regions seafloor habitats. You can see more of the action on the teams facebook page!

DMS researchers test novel underwater “presenter” helmet

Posted on May 22, 2025 by Hannes Baumann

Helmet_Auster_2 — Prof. emer. Peter Auster during the test dive of the new presenter helmet

21 May 2025
Research Professor Emeritus Peter Auster led a development project to demonstrate the utility of a "presenter helmet" and integrated oxygen rebreather to engage audiences with video recorded directly from environments of interest. The novel helmet allows an expressive human face and voice rich in excitement, in contrast to standard helmets and full-face masks.

The field test was conducted from the RV Weicker in a shallow seagrass meadow off Avery Point. The project was funded by CT SeaGrant with vessel support from the CT National Estuarine Research Reserve. Mike Lombardi from Lombardi Undersea LLC designed and built the helmet, rebreather, and submersible video "studio" complete with voice from the helmet. Associate Professor Jason Krumholz from the CT Reserve also dove the helmet and collected multiple video segments for posting over the web. The potential for “live dives” with a host on the seafloor is a possibility in the future.

Celebrating Student Research at the 15th Biennial Feng Colloquium

Posted on May 19, 2025May 19, 2025 by Hannes Baumann

By Samantha Rush.

On May 15, 2025, the Department of Marine Sciences hosted the 15^th Biennial Feng Graduate Research Colloquium. Named in honor of the first department head, Dr. Sung Y. Feng, the colloquium serves as a professional development event for our departments graduate students, who hone their skills in abstract writing, posters presentations and research talks. This year’s program featured 18 talks and 22 posters showcasing the breadth of multidisciplinary work across the department.

Started by Dr. Hans Dam in 1996, the 2025 Feng Steering Committee included Dr. Julie Granger, Emily Watling, Yifan Zhu, and Anne Gilewski. This year’s event also featured artwork by Matthew Leason and was made possible with the support of DMS staff, particularly Deb Schuler and Todd Fake. The event continues to be a valuable platform for students to hone their scientific communication skills, receive feedback, and share their work across the department.

Check out the talks, posters, and their abstracts here!

Check out a few more impressions from the day below!

Graduate Students Bring Ocean Science to Life at Sip ‘n Science Event

Posted on May 12, 2025May 16, 2025 by Hannes Baumann

By Samantha Rush.

Last Friday, DMS graduate students hosted the annual Sip ‘n Science event at Beer’d Brewing Co. in Stonington, featuring interactive science demonstrations for the local community. Despite a torrential downpour outside, the event was well attended and highlighted meaningful engagement between students, faculty, and the public. Students designed demonstrations of oceanographic principles or their own research, showcasing the breadth of work at the Marine Sciences department while also gaining valuable experience in communicating complex scientific concepts to a general audience.

This year’s demonstrations covered a wide range of topics, including microfossils, mercury, marshes, ocean waves, isotopes, ocean acidification, the Coriolis force, sea ice brine, Black Sea Bass gut contents, planktonic species, and coastal snails and crabs. Students were nothing short of creative - designing wave tank races, ranking games for mercury-impacted species, isotope explanations using the Hungry Hungry Hippos game, visual displays of acidification effects on seashells, rotating table experiments with dye to show ocean forces, larger than life-sized sea bass cutouts, and salty ice cubes to simulate polar sea ice processes.

Well done, everyone! The department is truly proud of its graduate students!

“Just keep swimming: challenges in PhD research”

Posted on March 8, 2025March 11, 2025 by Hannes Baumann

The ole adage holds true for DMS graduate student Emma Siegfried’s first experiments on a new species of sand lance

By Samantha Rush and Hannes Baumann

In 1984, the late Alphonse Smigielski and colleagues published a research paper that showed how American sand lance (Ammodytes americanus) could be successfully spawned and reared in the laboratory. Now, DMS PhD student Emma Siegfried is working to continue experimental research on this species, finding that revisiting the 40 year old study is not without challenges.

Sand lances are so called forage fish, meaning that their role in the ecosystem is to eat tiny planktonic organisms while being important food themselves for higher trophic animals such as other fish, seabirds, and marine mammals. Despite their importance, there is insufficient information about how this species will cope to climate change, particularly during the most sensitive larval and embryo stages. To fill this knowledge gap, Emma’s work focuses on exploring how increasing water temperatures and carbon dioxide (CO₂) levels affect sand lance embryos and larvae.

Previous research conducted in Prof. Hannes Baumann’s Evolutionary Fish Ecology lab discovered that embryos of the closely related Northern sand lance (Ammodytes dubius) are extremely sensitive to elevated CO₂ levels, as they are projected to occur in future oceans. However, whether American sand lance are equally CO₂ sensitive is not known.

Emma’s thesis research began in 2024 by first trying to find a reliable and easy to access location, where the species could be found and collected. In the harbor of the Wells National Estuarine Research Reserve in Wells, Maine, she found what she needed, because her fish occurred in high numbers there and could be sampled at low tide easily via beach seine. Now Emma’s goal was to catch the fish as close as possible prior to their spawning season, which in the case of sand lance starts with the beginning of winter.

In late August and early October 2024, Emma and her lab mates successfully collected sand lance and transported them live to the Rankin Seawater at Avery Point. There, however, sand lance proved challenging to care for, as they prefer spending days to weeks burrowed in sand (hence their name), making it difficult to monitor their health and development. Subsequent sampling efforts in November and early December brought a new set back, because the previously accessible population in Wells Harbor had evidently moved into slightly deeper waters and thereby out of reach for the beach seine. Unfazed, Emma proceeded to rear the fish she already had in the lab, hoping that they would ripen and eventually produce embryos for a CO₂-sensitivity experiment.

At first, this looked like another failure. Sand lance use the declining temperature as a cue to ripen, but the waters of eastern Long Island Sound that flow through the Rankin lab remained unseasonably warm well into December. Eventually, however, on 23 December 2024, water temperatures crossed the critical 7°C threshold, and 3 days later, Emma and her lab mates indeed succeeded in strip-spawning a few ripened up females! The fertilized embryos were then placed in the Automatic Larval Fish Rearing System (ALFiRiS) that allows computer-controlled exposure of organisms to different temperature and CO₂ conditions.

Unfortunately, more experimental setbacks followed. Less than 1% of the embryos actually developed to hatch, the CO₂-induced acidification did not produce the desired target pH levels, and a system malfunction remained undetected long enough to raise water temperatures to unnatural levels. Emma remains positive, however, and looks at her trials and tribulations as well as the preliminary data as a valuable exercise in gathering experience with this new, non-model species.

“Even though it didn’t go the way we expected, [we] still learned a lot.” she says.

She added that science is by definition challenging, but she is eager to apply what she has learned and move forward. More generally, her thesis research aims to answer the question whether CO₂-sensitivity is a shared trait among sand lance species. To that end, she is applying for a grant to collaborate with researchers in Bergen, Norway who have experience with another, closely related sand lance species (Lesser sand eel, Ammodytes marinus). She hopes to secure funding to travel and conduct research there from December 2025 through March 2026.

DMS sophomore to study if tiny algae grow calcium carbonate crystals

Posted on February 12, 2025February 12, 2025 by Hannes Baumann

Evelyn Lewis glances at the well plates full of colorful slime in Prof. Visscher’s lab and smiles. The life thriving in there is invisible to the naked eye, but she knows how to keep the microscopic critters happy. For almost a year now, she has helped taking care of them, and this has helped others in the lab with their research projects.

But now, Evelyn is starting a project of her own. Her soft voice betrays the nascent excitement, as she examines a well plate full of what looks like crusty, white dust.

“These are calcium carbonate crystals, and they look so beautiful under the microscope”, she says.

Thanks to a new supply grant from UConn’s Office for Undergraduate research, she will now have the opportunity to look at many more of these crystals. Evelyn’s research will focus on some of the smallest photosynthetic organisms in world, cyanobacteria. When they bloom they often coat themselves in slime that they can chemically manipulate. The conditions in this extracellular slime might then become favorable to bind carbon dioxide (CO₂) in form of calcium carbonate (CaCO₃), ultimately removing it from the atmosphere. In other words, cyanobacteria may be tiny but mighty as a natural tool for combating the increase of heat-trapping CO2 in the atmosphere.

“These natural options of using microbial slime for CO₂ removal remain surprisingly underexplored”, explains Visscher. “The slime binds calcium and when it sinks to the bottom, it supports CaCO₃ formation in sediments for thousands of years. This recently discovered mechanism provides novel insights into the global carbon cycle.”

So over the course of the next months, Evelyn will culture cyanobacteria again – but this time for her project. In small well plates, she will measure their CaCO₃ production for about two weeks in relation to differing amounts of calcium. Yet the arguably coolest part will come after that, when the collected crystals will be examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).

Ultimately, the gathered data will allow testing the overarching hypothesis that the presence of cyanobacteria increases CaCO₃ precipitation.

At DMS phytoplankton are now on IFCB-TV

Posted on February 5, 2025February 6, 2025 by Hannes Baumann

The team of DMS researchers Dr. Zofia Baumann, Dr. Kate Randolph and Hazel Levine are happy to share that a major new instrument has begun its long anticipated work. The Imaging Flow Cytobot - or IFCB for short - is for now installed in the Rankin Seawater lab, after being purchased with a UConn-CLAS shared equipment grant nearly two years ago (Dierssen, Baumann et al.).

The instrument has the capacity to monitor and display in real time the breath-taking diversity of microscopic life in the ocean. Our IFCB focuses on the smaller size classes 5 - 150 um, which mostly represent single cell algae and small mixotrophs.

Leveraging additional NSF support, we were able to overcome challenges with operating the IFCB on a routine basis. The IFCB now accesses the intake line of the Rankin Lab (a very small fraction of it) and then photographs any particles and characteristic shapes. The compilation below shows a given size range to illustrate some of the diversity. The IFCB now records these images and displays them on a public-facing online Dashboard, which can be mesmerizing to watch.

Plankton-composite — The composition of some of the larger phytoplankton as captured by the IFCB on February 6th 2025.

The implementation of the IFCB in Rankin Lab was led by Kate Randolph and greatly supported by Hazel Levine, Bob Dziomba, Charlie Woods, Todd Fake, and Chris Mills! Thank you.

The next step is to develop an AI-based classification system for automatic species identification. This will still take time, but we are collaborating with other IFCB users, including its inventors, and are optimistic about the progress ahead.

Marine Sciences