OCB turns 20! Please share how OCB has impacted your career trajectory
Visit the OCB at booth 45 (exhibit hall map)
See list of OCB-relevant science sessions
Events & Workshops (full list) – includes lots of early career support!
SOLAS, OASIS, and CLIVAR Workshop FAIRSEAS: The Future of Internationally Coordinated Air-Sea Interactions Research – Feb. 21, 2026 (Edinburgh, Scotland – hybrid format) DETAILS
Agency Forums
Town Hall Meetings
Ocean Outcomes Sessions
Global overturning circulation is a planetary conveyor belt: dense waters sink around Antarctica, spread through the deep ocean for centuries, and eventually rise elsewhere, redistributing heat, nutrients, and carbon. But how does this slow, pervasive movement of water impact marine microbes?
To find out, researchers collected over 300 water samples spanning the full depth of the ocean along the GO-SHIP P18 line in the South Pacific. They found that microbial genomes cluster into six spatial cohorts that are not only delineated by depth, but also circulatory features, like Antarctic Bottom Water formation, and ventilation age. Distinct functional signatures also emerged across these circulation-driven zones. For example, genes for light harvesting and iron uptake dominate in surface waters, while adaptations for cold, high pressure, or anaerobic metabolism characterize deep and ancient waters. Antarctic Bottom Water communities also carry hallmarks of rapid genetic exchange, suggesting horizontal gene transfer may help microbes adapt as they sink into the deep ocean. Even in waters isolated from the atmosphere for over a thousand years, many microbial genomes have coverage patterns that imply active replication, demonstrating that long-isolated water masses still support active microbial populations. In considering patterns of microbial diversity, researchers also identified a pervasive “prokaryotic phylocline” in which richness spikes just below the surface mixed layer and remains high to full ocean depth, only dipping slightly in very old water.
These results demonstrate that physical circulation, not just temperature or nutrients, partitions the ocean into microbial biomes. Understanding this linkage is critical because microbes determine the amount of carbon that is recycled or stored long-term in the deep ocean. As climate change alters overturning circulation, the functioning of these hidden microbial ecosystems and their role in regulating atmospheric CO₂ may shift in unexpected ways.
Authors
Bethany C. Kolody (University of California San Diego; UC Berkeley; J. Craig Venter Institute)
Rohan Sachdeva (UC Berkeley)
Hong Zheng (J. Craig Venter Institute)
Zoltán Füssy (UC San Diego; J. Craig Venter Institute)
Eunice Tsang (UC Berkeley)
Rolf E. Sonnerup (University of Washington)
Sarah G. Purkey (UC San Diego)
Eric E. Allen (UC San Diego)
Jillian F. Banfield (UC Berkeley; Lawrence Berkeley National Laboratory; Monash University)
Andrew E. Allen (UC San Diego; JCVI)
Social media
Twitter/X: @science_doodles, @Scripps_Ocean, @JCVenterInst
Bluesky: @banfieldlab.bsky.social, @bethanykolody.bsky.social, @scrippsocean.bsky.social, @jcvi.org
https://www.science.org/doi/10.1126/science.adv6903
Overturning circulation structures the microbial functional seascape of the South Pacific
Science
A recent study in Nature Geosciences observed high concentrations of methane overlying permeable (sand) sand sediments in bays in Denmark and Australia. These environments are not one would expect to see methane because they are highly oxygenated and the high concentrations of sulfate in seawater typically inhibit methanogenesis. The authors showed that the methane was not being imported from local groundwater using geochemical methods. Using a combination of biogeochemical, microbial isolation, culturing and genomic approaches, revealed that methane was being produced by fast growing microbes resistant to oxygen exposure using plant produced substrates such as dimethylsulfide and amines. This work shows that where marine plants such as seaweed and seagrass grow and accumulate there may be high and sporadic production of methane. This has implications for how we account for the carbon sequestering capacity of coastal environments and the climate impact of increasing algal blooms such as coastal Ulva and the great sargassum bloom.
Authors
Perran Cook (Monash University)
Ning Hall (University of free spirit)
IIOSC – 2025, International Indian Ocean Science Conference – 2025: Celebrating 10 years of the Second International Indian Ocean Expedition
1-5 December 2025 at INCOIS, Hyderabad, India
Website: https://iiosc2025.incois.gov.in/
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We are pleased to announce that applications are now open for new core committee members of the Early Career Scientists Network (ECSN) of the Second International Indian Ocean Expedition (IIOE-2). The ECSN provides a platform for early career researchers working on Indian Ocean science to connect, collaborate, and contribute to the broader goals of the IIOE-2. Eligibility criteria: 1. Applicants should be either a PhD student, postdoctoral researcher, or scientist with less than 10 years since obtaining their PhD or under the age of 40 (whichever comes first). 2. Applicants must be actively engaged in Indian Ocean research. If you are interested, please complete the application form attached to this e-mail and send it to ecsn.iioe@gmail.com. The deadline for submission is 24 October 2025. We encourage motivated early career scientists to apply, and kindly ask you to re-distribute this call within your network so it can reach as many eligible colleagues as possible.
When wildfire smoke drifts over the ocean, what happens beneath the waves? As wildfires change in nature and become more frequent, it’s increasingly important to understand how ash deposition affects the ocean’s smallest, yet most essential, inhabitants.
Figure 1. Conceptual illustration of coastal wildfires. Coarse-mode smoke including ash, rich in organic matter and low in minerals, is likely to settle near the fire source. Fine-mode smoke, with lower organic content and higher mineral composition, disperses farther. Wildfire smoke deposition can introduce both fertilizing nutrients, such as inorganic nitrogen and iron, and more toxic compounds, including dissolved organic matter (DOM) species like aromatic hydrocarbons, affecting marine trophic levels. Additionally, wildfire smoke on the ocean surface may alter sunlight penetration, impacting phytoplankton photosynthesis.
In a recent study, the authors investigated how wildfire ash leachate influences coastal microbial communities. Through field incubations along the California coast, we found that ash-derived dissolved organic matter (DOM) increased bacterioplankton specific growth rates and organic matter remineralization, while leaving bacterial growth efficiency unchanged. This suggests that the added DOM was primarily used to fuel basic cellular functions rather than biomass production. Meanwhile, microzooplankton grazing declined, even as phytoplankton division rates remained stable, hinting at a decoupling of predator-prey dynamics that could promote phytoplankton accumulation.
Pre-existing phytoplankton biomass had a greater influence on microbial responses than the chemical composition of the ash itself. In low-biomass waters, bacteria more readily consumed the ash-derived DOM. In contrast, in high-biomass waters, the leachate was less bioavailable, potentially allowing more refractory ash-derived carbon to accumulate. These baseline differences appeared to influence phytoplankton size structure: smaller cells increased in high-biomass settings, while larger cells became more prevalent in low-biomass waters. These shifts may have implications for nutrient cycling, food web structure, and carbon export pathways, depending on how microbial activity and community composition respond in situ.
Authors
Nicholas Baetge (Oregon State University)
Kimberly Halsey (Oregon State University)
Erin Hanan (University of Nevada, Reno)
Michael Behrenfeld (Oregon State University)
Allen Milligan (Oregon State University)
Jason Graff (Oregon State University)
Parker Hansen (Oregon State University)
Craig Carlson (University of California, Santa Barbara)
Rene Boiteau (University of Minnesota)
Eleanor Arrington (University of California, Santa Barbara)
Jacqueline Comstock (University of California, Santa Barbara)
Elisa Halewood (University of California, Santa Barbara)
Elizabeth Harvey (University of New Hampshire)
Norm Nelson (University of California, Santa Barbara)
Keri Opalk (University of California, Santa Barbara)
Brian Ver Wey (Oregon State University)
The Lofoten Basin Eddy (LBE) is a unique and persistent anticyclonic feature of the Norwegian Sea that stirs the water column year-round. However, its impact on biogeochemical processes that influence region carbon storage, including carbon fixation, particle aggregation and fragmentation, and remineralization, has remained largely unknown.
Figure caption: (a) Map of the Lofoten Basin Eddy study region including locations of 1886 profiles from 22 Biogeochemical-Argo floats (2010–2022) and a heatmap showing the relative extent of the LBE influence zone over the timeseries. (b–d) Mean monthly profiles and the difference (Δ) determined as inside minus outside the LBE influence zone of the mass concentration of particulate organic carbon in small particles (POCs). Arrows indicate key mechanisms regulating the regional biological carbon.
Using 12 years of data from Biogeochemical-Argo floats and satellite altimetry to track eddy movements, Koestner et al. (2025) examined how the LBE influences the seasonal transport of organic carbon from surface waters to the deep ocean. While the LBE can enhance carbon export during certain months, like during spring shoaling and late autumn subduction, it generally reduces the efficiency of the biological carbon pump. Inside the eddy, warmer subsurface waters and slower-sinking particles often lead to more respiration and remineralization, meaning less carbon reached the deep sea.
The LBE’s persistent influence on organic carbon cycling could affect regional climate feedbacks and marine ecosystems, including key fisheries in Norway. Understanding how features like the LBE modulate carbon sequestration is vital for improving climate models and managing ocean resources in a warming Arctic.
Authors
Daniel Koestner (University of Bergen)
Sophie Clayton (National Oceanography Centre)
Paul Lerner (Columbia University)
Alexandra E. Jones-Kellett (MIT & WHOI)
Stevie L. Walker (University of Washington)
Proposal info webinar September 23, 3-4pm
This webinar featured recent successful OCB activities and their PIs, Q&A with Project Office staff on community building and what makes a successful OCB proposal and activity.
The Ocean Carbon and Biogeochemistry (OCB) Program is soliciting proposals for OCB activities that will take place or begin during the 2026 calendar year. We seek proposals for OCB-relevant workshops and activities as follows:
The Surface Ocean CO2 Observing Network (SOCONET), an emerging observing network of the Global Ocean Observing System (GOOS), is looking for applications to join our Steering Committee (SOCONET SC) for term beginning on 1 December 2025. Please share the attached call document with your networks.
The newly selected SC members will join those currently acting as interim SC (list in the attached SOCONET Terms of Reference) to develop and deliver a comprehensive and effective set of coordination activities for SOCONET. These activities will include:
SC members serve for a period of four years, with the potential of renewing for an additional 4-year term. SC members are assisted by the Network Coordinator (currently provided by IOCCP) and Technical Coordinator employed at OceanOPS. SOCONET SC will meet once a year in-person, and up to monthly remotely. The expected time commitment for SOCONET activities is on average 1-3 days per month, which might occasionally accumulate around specific activities.
In this call we seek to fill several SOCONET SC positions hoping to be able to fill the expertise, geographic, career stage and other gaps identified by the iSC members. We seek individuals who are familiar with the ongoing community initiatives and needs. Ideally candidates would have some research experience on an international level and a working overview of the global landscape of surface ocean carbon observations. We encourage applications from individuals with strong leadership skills and past experience in providing strategic guidance, e.g. through international working groups or steering committees participation.
To make inquiries and/or to submit your applications, please contact the IOCCP Project Office (ioccp@ioccp.org) by 24 October 2025. Please provide the following information in your application:
NSF Ocean Sciences Office Hours
September 30, 3-4:30 PM (ET)
Staff and division leadership will share information and updates on preparing proposals, address commonly asked questions, and answer yours. These office hours webinars will not be recorded.
Register https://nsf.zoomgov.com/webinar/register/WN_yu5jE4EWQl2FyUZ1x2LEAw?utm_medium=email&utm_source=govdelivery#/registration
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Funding for the Ocean Carbon & Biogeochemistry Project Office is provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA). The OCB Project Office is housed at the Woods Hole Oceanographic Institution.