Intellectual Merit

Seafloor massive sulfide (SMS) deposits form along the ocean’s plate boundaries, the result of hydrothermal activity associated with the formation of new ocean crust SMS deposits are a significant reservoir of both metals and metabolic energy, yet an understanding of the impact of weathering on the long-term reactivity of SMS is lacking. This project aimed to learn the fate of these deposits by identifying the presence and activity of active metabolisms involved in the cycling of carbon, iron and sulfur and the progression between different pathways as these deposits age (weather). The role of microbial activity in this weathering, and the metabolisms supported by long-term weathering of SMS was investigated using a modern metagenomic approach alongside of a traditional bacteriology approach where we grew enrichments of microbial communities in the lab to learn about their growth characteristics. Inactive SMS samples we collected by the submersible Jason II along a 10-Mya transect from on axis toward the ridge flanks. Samples of deposits were processed at sea, and frozen for later analyses (genomic) or transported live in cooler for growth studies (bacteriology). The presence of major microbial groups were identified through sequencing of DNA and RNA extracted from weathered rinds.

Broader Impacts

This research project involved significant participation undergraduate researchers from Stonehill College, a predominantly undergraduate institution. Two undergraduates were able to participate in the research cruise including launching and operating the deep submersible Jason II. Additionally, four other undergraduate students and a recent graduate who was transitioning to graduate school were trained in molecular methods, culturing methods, and bioinformatic analyses during this project. Three visits to k-12 classrooms were made in the Mashpee, MA public school system to inspire and engage children in STEM fields. Twice, undergraduate researchers participated in Women in Science programs at the Waquoit Bay National Estuarine Research Reserve, where they taught and mentored school-age girls during a day-long summer science camp.

Summary of Outcomes

The Stonehill researchers’ efforts three conference poster presentations were delivered. Two of these presentation had undergraduate researchers as the first author. The third presentation included four undergraduates as co-authors with the Co-I as the lead author. All of the undergraduate researcher also presented their work to the broader College community each year. In total six undergraduates and one recent graduate were trained under this project. Out of the six undergraduates, four have continued their training in graduate school in disciplines ranging from pharmaceutical chemistry to engineering to marine biology. The Co-I and the undergraduates participated in several outreach events targeting school-age children in an effort to mentor and encourage these children to remain interested in STEM fields. Our field and laboratory efforts resulted in 11 metagenomic analyses across a 10-Mya transect of SMS deposits and highlighted the transition between sulfur-driven primary production to metal driven primary production that coincided with a transition carbon fixation strategies. There strategies were confirmed by quantifying the key gene in these pathways in enrichment cultures developed from deep-sea samples and maintained in the laboratory. In total 200 initial enrichments were started in the months following the cruise. Using traditional bacteriological techniques like serial dilution we were able to maintain 26 unique enrichment communities for characterization.

Last Modified: 12/04/2023
Modified by: Daniel Rogers