Date of Award
2024
Degree Type
Thesis
Degree Name
Master of Science in Oceanography
Department
Oceanography
First Advisor
Roxanne A. Beinart
Abstract
In the oxygen-depleted environments of New England's coastal marine sediment, microbial communities engage in symbiotic interactions to overcome energy deficiencies from oxygen limitation. Among these interactions, ciliates, known for their ability to form diverse symbiotic relationships, play a prominent role. The ciliated protozoa, Metopus sp. commonly form symbiotic relationships with bacteria and archaea that support their fermentative metabolism (Fenchel and Finlay, 1995), though the diversity of these partnerships, particularly in the ocean, is poorly known. To gain insights into the interactions between Metopus ciliate cultures and their microbial partners, we employed Fluorescence in Situ Hybridization (FISH) with species-specific probes. We used taxonomic-specific probes EUB338, DELTA495, and DSBAC357, each labeled with a CY3 dye, to distinguish bacterial prey from symbionts using FISH. Additionally, we utilized DSB986 in combination with DSB1030 to target Desulfobacter sp., a vital group within the symbiotic community. Moreover, we employed the ESTC3 probe labeled with a CY5 dye to visualize the presence of TC1, a novel bacterial endosymbiont that has been studied in other ciliates but not previously identified in Metopus sp. All probes successfully hybridized with our Metopus ciliate cultures, enabling us to differentiate between bacterial prey and symbiotic partners. This innovative method has provided us with a deeper understanding of the complex microbial interactions in New England's coastal marine sediment. The discovery of TC1 as an endosymbiont within Metopus sp. expands our knowledge of ciliate symbiosis in challenging environmental conditions. Understanding bacterial symbiosis is vital for maintaining ecosystem stability and comprehending the complex relationships among microorganisms. The discovery of TC1 as an endosymbiont within Metopus sp. represents a significant advancement in our understanding of ciliate symbiosis, shedding light on how microorganisms coexist and support each other in challenging environmental conditions. Similarly, the identification of Desulfobacter sp. as ectosymbionts on the surface of the Metopus sp. provides valuable insights into potential ecological implications. Studying bacterial symbiosis unravels the delicate balance that allows life to thrive in intricate ecosystems, impacting nutrient cycling, biogeochemical processes, and ecological conservation.
Recommended Citation
Gutiérrez, Raúl A., "PROBING THE ANOXIC WORLD OF COASTAL MARINE SEDIMENTS IN NEW ENGLAND: UNDERSTANDING THE NOVEL PARTNERSHIP BETWEEN PROTISTS AND THEIR BACTERIAL SYMBIONTS" (2024). Open Access Master's Theses. Paper 2517.
https://digitalcommons.uri.edu/theses/2517