We congratulate our member and frequent symposium presenter, Lauren Hall, on successfully defending her PhD thesis at Rutgers University on Thursday, March 6, 2025! Lauren performed her research in the Haggblom and Kerkhof labs at Rutgers School of Environmental and Biological Sciences. Her thesis, “A Tale of Two Reefs: Organohalide Cycling in Marine Sponges,” offers new insights into how microbial communities function in marine sponges to transform compounds that contain halogens, particularly bromine, in their marine environment. Max Haggblom (advisor), Lee Kerkhof, Donna Fennell, and Mengyan Li (NJIT) were her committee members.
Marine sponges, being filter feeders, play a significant role in the marine ecosystem by influencing nutrient cycling and the health of surrounding habitats. Her research indicates that marine sponges harbor diverse microbial communities that participate in the biotransformation of organobromine. These microbes can utilize organobromines as terminal electron acceptors in anaerobic respiration, leading to their breakdown and cycling of bromine. This process is essential for understanding how pollutants, especially halogenated organic compounds, impact marine ecosystems and how these ecosystems respond to environmental changes. Through techniques including anaerobic culture, HPLC, ribosomal operon, and genomic sequencing, she was able to investigate the ecological roles of these microbial communities within sponges. This research sheds light on the dynamics of microbial interactions and highlights the sponges' contributions to biogeochemical cycles in the ocean. Overall, studying organohalide cycling in marine sponges is crucial for comprehending ecological functions, pollutant degradation, and the resilience of marine ecosystems to environmental stressors.
Marine sponges are ancient filter-feeding metazoans harboring rich microbiomes contributing to many biogeochemical cycles. Sponges produce a wide variety of brominated organic compounds thought to be anti-predatory metabolites. Industrial organobromines, such as flame retardants, also pollute the marine environment. Lauren’s work assessed Great Barrier Reef sponge microbiome host-specificity, particularly concerning dehalogenating bacteria. She found the sponges harbor diverse, host-specific microbiomes, especially at the strain level. Zeroing in on dehalogenation bacteria, she probed her various sponge juices and nearby Great Barrier Reef sand specifically for Desulfoluna spp. She found many Desulfoluna strains closely related to Desulfoluna spongiiphila using ribosomal DNA operon analysis. Still, they did not appear to be host-specific, having a cosmopolitan distribution on the reef. Expanding her sampling to Hawaii, she isolated and characterized three strains of a novel dehalogenating bacterial species she named Desulfoluna pacifica. D. pacifica was most closely related to D. butyratoxydans. Two of the new D. pacifica strains were from two different Great Barrier Reef sponges, and one of the strains was from a Hawaiian sponge. Examining their genomes, Lauren found each strain harbors three reductive dehalogenase genes (rdhABC) closely related to the three already described D. butyratoxydans reductive dehalogenase genes. She concluded that Desulfoluna pacifica plays an important role in natural organohalide cycling in Pacific Ocean marine sponges. Looking beyond Desulfoluna spp., she also isolated and characterized two more novel sponge-associated dehalogenating bacteria in both Great Barrier Reef and Hawaiian sponges: a Halodesulfovibrio sp. and an interesting isolate (NS4ri1) in the family Desulfuromonadaceae. NS4ri1 represents a new sponge-associated debrominating genus and species with not just three but eight rdhA homologs. She proposed the name Dehalogenimusa anaincola for the new isolate. The publication of Lauren’s work is currently in review.
Lauren has presented her research often, including:
· Rutgers University Fermentation Seminar Series, November 2024
· At the Sustainable Development Forum, Beijing, China. October 2024
· ASM Microbe 2024 in Atlanta, where her abstract was selected for a travel award
· ASM Microbe 2023 in Houston
· Rutgers School of Graduate Studies Research Café. December 2022
· International Symposium on Microbial Ecology, Lausanne, Switzerland 2022
· Invited speaker at the Theobald Smith Fall Symposium, Seton Hall University, 2022
· Gordon Research Conference, Environmental Sciences, Holderness, NH, June 2022.
· Rutgers University Microbiology Symposium 2022
Beyond her research, Lauren demonstrated exceptional leadership and dedication to community outreach. She served as President (2021-2022) and Vice President (2020-2021) of the Rutgers Student Chapter of ASM, where she organized seminars and fostered collaboration among peers. She also mentored undergraduate researchers, helping to inspire the next generation of microbiologists.
Lauren's hard work and dedication have earned her numerous accolades, including:
Student and Postdoctoral Travel Award to ASM Microbe 2024
Robert S. and Eileen A. Robison Scholarship Award for Excellence in Graduate Studies, Rutgers Department of Biochemistry and Microbiology
Hamo Hachnasarian Scholarship, Rutgers School of Environmental and Biological Sciences
Graduate School Excellence Fellowship, Rutgers School of Environmental and Biological Sciences
The Rutgers Aresty Undergraduate Research Award
Jilin University Summer Chemistry Fellowship, Changchun, China
· Van Dyke Award for Excellence in Chemistry Course Support, Rutgers Department of Chemistry and Chemical Biology
As Dr. Hall embarks on the next chapter of her career, we are excited to see how she will continue to push the boundaries of microbial ecology and inspire future scientists. Her innovative research and dedication to mentoring reflect the very best of the microbiology community.
Please join us in celebrating Dr. Lauren Hall and her remarkable achievement!
