Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • BCO-DMO Processing Description
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

For time series collected at Tiny Towers hydrothermal vent with the PPS instrument, hydrothermal fluid samples were collected remotely and filtered through 0.4 micrometer (μm) polycarbonate filters, then preserved in RNALater in the instrument at the seafloor until instrument recovery. Upon recovery, filters were preserved at -80 degrees Celsius (C).

Other samples were collected using the UFO fluid sampler mounted aboard ROV Jason. Hydrothermal fluid samples were pumped through 0.2 μm Sterivex filters or into sterile 10 liter (L) bags mounted to the vehicle. Upon ROV recovery, Sterivex filters were preserved at -80 degrees C. Fluid from bags was filtered through 0.2 μm Sterivex filters, which were later preserved at -80 degrees C, and the filtrate was treated with iron chloride to precipitate viral particles. Precipitated viral particles were filtered through 1.0 μm polycarbonate filters and preserved at 4 degrees C until processing.

DNA was extracted from all filters using the MasterPure Complete DNA and RNA Purification Kit. Sterivex filters were cracked open prior to processing. PPS filters were cut in half prior to processing, and the second half was archived.

For viral metagenomes, viruses were reconstituted through an ascorbic acid buffer and then extracted using the Qiagen UltraSens Virus spin kit.

All samples were sequenced at the Northwest Genomics Center. Library construction was automated in 96-well plate format. At least 25 nanograms (ng) of genomic DNA was subjected to enzymatic fragmentation and a series of library construction steps utilizing the KAPA HyperPlus kit. All library construction steps were automated on the Perkin Elmer Janus platform. Libraries were validated using the Biorad CFX384 Real-Time System and KAPA Library Quantification Kit. Barcoded genome libraries were pooled using liquid handling robotics prior to loading. Massively parallel sequencing-by-synthesis with fluorescently labeled, reversibly terminating nucleotides was carried out on the NovaSeq sequencer.

- Imported original file "SRA_metadata_CAREER_2025.txt" into the BCO-DMO system.
- Marked "NA" as a missing data value (missing data are empty/blank in the final CSV file).
- Renamed fields to comply with BCO-DMO naming conventions.
- Split the "lat_lon" column into two separate columns, "latitude" and "longitude".
- Converted all dates in the "collection_date" column to YYYY-MM-DD format.
- Split the original "collection_date" column into two, one for date and one for time.
- Saved the final file as "986882_v1_hydrothermal_vent_metagenomes.csv".

NSF Award Abstract:
Microbes and viruses living near deep-sea hydrothermal vents act as filters for carbon, sulfur, iron, and other essential elements that emerge from the seafloor and flow into the global oceans. However, due to the challenges associated with sampling the deep sea, most studies to date have captured only snapshots of these communities, leaving significant knowledge gaps about how microbes and viruses adapt, evolve, and respond to changes in this environment. The researchers use infrastructure from the Ocean Observatories Initiative to conduct high-resolution monitoring of genetic changes over five years to investigate microbial communities’ function, ecology, and evolution at hydrothermal vents, which are thought to be one of the most ancient habitats on Earth. Data from this project are expected to be a valuable scientific resource for these and other researchers to address future questions. For example, it will inform our understanding about the early evolution of life on Earth and how microbes and their viruses respond to anthropogenic disturbances like deep-sea mining and climate change. This project engages and trains undergraduate students as scientific partners at all stages of the research process, facilitating their entry into scientific networks. Additionally, a new course guides college students in examining science within its cultural, political, and social context. The project also includes a program with a local elementary school to increase science literacy among young students.

The main objective of this project is to understand the ecological and evolutionary forces that mold hydrothermal vent microbial and viral populations over time. This project uses instruments from the Ocean Observatories Initiative Regional Cabled Array (OOI RCA) at Axial Seamount in the Northeast Pacific Ocean to collect hydrothermal fluid and DNA samples at regular intervals, approximately every 10-20 days over five years, to yield a time series of microbial and viral abundances and metagenomes. The specific scientific aims of this project are to: 1) identify environmental drivers of microbial community composition and function through time-series analyses of 16S rRNA amplicon and metagenomic datasets combined with chemistry, pH, and temperature data; 2) use single nucleotide variant and gene content variation over time in metagenome-assembled genomes to investigate evolutionary dynamics of microbial populations; and 3) assess models of viral population dynamics by tracking microdiversity within viral and microbial metagenomes over time. Comparative samples and data collected from other vent sites are used to determine the generalization of the results.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This project is funded by the Biological Oceanography and the Ocean Education Programs (Division of Ocean Sciences) and the Systematics and Biodiversity Science Cluster (Division of Environmental Biology).