Research

Thousands of natural gas seeps have been discovered as streams of bubbles rising up from the seafloor just offshore from coastlines around the world. Extensive fields of seeps, largely releasing the same methane gas that we use to heat our homes, have recently been found about a hundred miles east of North Carolina?s Cape Hatteras at water depths as shallow as 300 feet. It is estimated that at least tens of thousands of these hydrocarbon-rich seeps occur on continental margins around the world. The seeps, usually seen as large rising plumes by sonar systems on research ships, inject huge, but poorly quantified, amounts of methane into overlying waters as they rise through the water column. A primary question is how much of the methane, a potent greenhouse gas, actually reaches the atmosphere. This question is the subject of much current research funded by several Federal research agencies including the National Science Foundation and the Department of Energy. Oceanographers believe that the methane (and other gases included in the bubble streams such as ethane and propane) are either transported away by ocean currents or consumed by microorganisms specially adapted to live with hydrocarbons as their main carbon source. This proposal seeks to determine the importance of microbial consumption in controlling methane distributions in the deep ocean and how the consumption rates depend on concentrations of methane, oxygen and other chemicals, as well as in situ pressures and temperatures. Previous studies in laboratories aboard research ship using samples returned to the surface suggest that microbial consumption of methane from the seeps may lag for a week after its injection into the water column and thus that physical dispersion by currents may dominate deepwater methane dynamics through dilution. However, other measurements suggest that there is no lag before aggressive microbial oxidation of injected methane begins. We have proposed to conduct in situ measurements of microbial methane consumption and related microbial community structure in bottom waters at several coastal and continental margin sites off the North Carolina coast and the northern Gulf of Mexico, where numerous natural seeps have also been observed. We will use new technologies developed after the release of massive quantities of methane during the Deepwater Horizon disaster in the Gulf. The sites offer varying concentrations of methane and other chemical and physical conditions such as oxygen concentrations and temperature that will allow us to test specific hypotheses about the role of microbial processes. Through performing the experiments with instruments right on the seafloor next to the seeps we can remove much of the uncertainty surrounding previous shipboard measurements. We will use newly developed seafloor landers equipped with advanced laser methane sensors that are capable of multi-week measurements while assaying dissolved oxygen, dissolved inorganic nitrogen and the microbial community for the presence of methane-consuming methanotrophs and their activity using advanced genomics techniques that can reveal the nature of methanotrophic responses to ambient methane concentrations. Successful collection of in situ methane consumption rate data and associated microbial community changes should prove important for modeling ocean methane dynamics over a range of oceanographic conditions including seep-enriched bottom waters and bottom waters impacted by accidental hydrocarbon releases. Graduate and undergraduate students supported by the project will gain critical skills in laboratory and field settings and will also benefit from frequent interactions with established researchers from diverse fields. Team members will participate in hands-on undergraduate education and training through developing individualized research projects leading to honors theses, presentations at national meetings and excellent graduate school placements. Graduate and undergraduates will also participate in K-12 science outreach efforts that help to attract and inform the next generation of oceanographers. The team will work with the University of North Carolina Morehead Planetarium and Science Center and participate directly in the North Carolina Science Festival. Through media contacts made from TED talks, exciting results will be broadly disseminated to the public. The project will have immediate relevance for understanding microbially mediated responses to hydrocarbon inputs from accidental releases along the Southeast Atlantic margin where oil and gas exploration are a constant topic of state and national policy discussions. Hundreds of recently discovered gas seeps along the continental margin offshore of Cape Hatteras, North Carolina plus thousands in the northern Gulf of Mexico, inject huge amounts of dissolved methane into overlying shelf and slope waters through dissolution of rising bubble plumes. The fate of the methane is largely controlled by a balance between microbial oxidation and advective transport away from seep sources. The efficacy of microbial oxidation likely depends on concentrations of methane, oxygen and ambient dissolved inorganic nitrogen (DIN), as well as in situ pressures and temperatures. Recent shipboard aerobic methane oxidation rate (AMOR) measurements suggest that microbial consumption of seep methane may lag for a week and thus physical dispersion could dominate deepwater methane dynamics through dilution. However, methane stable carbon isotopic measurements in bottom waters suggest that there is no lag before aggressive oxidation of injected methane begins. We propose to conduct in situ measurements of AMOR while simultaneously investigating its microbial drivers at representative North Carolina and Gulf of Mexico continental margin sites featuring numerous active bubble seeps. These sites offer varying concentrations of methane and DIN; performing the experiments in situ will remove much of the uncertainty of shipboard rates. We will conduct the measurements utilizing newly developed benthic lander systems equipped with advanced laser methane sensors that are capable of multi-week AMOR measurements while assaying dissolved oxygen, DIN and the microbial community for the presence of methanotrophs (through metagenomes) and their activity (through metatranscriptomes) that can reveal the nature of methanotrophic responses to ambient methane concentrations. The project will test key hypotheses about deep-sea methane dynamics including determining if there are significant lags in microbial responses after exposure to elevated methane concentrations, determining the relationships of AMOR to methane and DIN concentrations and investigating the response times and magnitude of methanotrophs to spatial and temporal variability in methane concentration. Successful collection of in situ AMOR and associated microbial community data will prove important for modeling ocean methane dynamics over a range of oceanographic conditions including seep-enriched bottom waters and accidental hydrocarbon releases. 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.

To carry out the recovery and redeployment of the NSF Ocean Observatories Initiative (OOI) Irminger Sea Array, servicing four moorings and up to five gliders in an area southeast of Greenland (38-41W, 58-61N). The platforms will carry multidisciplinary instrumentation and provide the capability for real time communication of data and control of sampling. A surface mooring will instrument the sea surface and upper ocean, capturing the surface forcing and upper ocean variability. A profiling mooring will measure through the water column. Two additional taut subsurface moorings and the gliders will complete the capabilities to obtain vertical profiles and sample the mesoscale (10s to 100 km) variability at the site. Shipboard data will be obtained to assess the performance of the instrumentation.

Like volcanoes on land, the mid-ocean ridges that cross the ocean floor are not continuously erupting; however, the magmatic heat present just beneath the surface can continue to drive hot springs, just like the ones found within the crater of the "super volcano" at Yellowstone. In our recent work, we have shown that the chemicals released into the oceans from seafloor hot-springs can be dispersed all across the oceans. Now our interest has focused in on one element in particular, iron. This is one of the most abundant elements in every planetary body in the Universe yet it is vanishingly rare in Earth's oceans today. Set against that, it is essential to just about every form of life on Earth from the simplest and most ancient strains of microbes to the most complex animals including humans. In Earth's oceans, the lack of this "essential micro-nutrient" has been found to limit how much life can flourish near both the south and north poles in the Pacific Ocean in the sunlit surface ocean even though the supply of sunlight and other major nutrients (phosphorous, nitrogen) should be more than adequate. Our newest research suggests that iron released from hydrothermal plumes (where the concentrations coming from vents are more than 1 million times higher than normal ocean water) could play a major role. Despite undergoing massive dilution as hydrothermal solutions leave the vents and traverse thousands of kilometers through the oceans, we believe that at least some of the iron released from deep sea hot springs can survive this journey and make a significant impact on how much live exists in Earth's polar oceans and how much CO2 it draws down from the atmosphere. To investigate that idea, this project will study the fate of iron released from a hydrothermal vent over a length scale that hasn't been studied before - from the first 1km through the ocean out to 100km away from the vent-site. This will fill a gap in our knowledge between what happens right at a vent-site (as studied by research submarines) and what happens to ocean chemistry all across Earth's entire ocean basins (as studied by a huge international research project called GEOTRACES). Our work will use a 3D computational model to predict where the plume of material from a vent in the Northeast Pacific Ocean should escape to after it is erupted from some vents at a volcanic system called the Juan de Fuca Ridge. We will then use an advanced autonomous free-swimming robot to search out in the predicted plume area, first to test the accuracy of our predicted model and, second, to collect samples from the hydrothermal plume from where it first forms to as far out as we can follow it. The samples we collect will include both filtered seawater and the particulate material (whether mineralogical or microbiological) that we can extract from the filters. Together, this will allow us to track the fate of the iron and other key physical and geochemical tracers down-plume away from the vents, to work out where it ends up (in the water and in the sediments) and also how fast those processes happen. The work we do will also help plan how to conduct similar robotics-based exploration on future space missions beyond Earth where it has been hypothesized that seafloor events also exist (e.g. Saturn's moon Enceladus) and where, if we are really lucky, we may find that life is hosted based on the energy from seafloor volcanoes, just as happens here on Earth. We have a resident artist embedded in our program who has already begun experimenting with the use of air-flow and sound in her sculptures to help communicate the complex nature of these plumes. She will join our cruise, and work with our team post-cruise to design and hopefully build a sculpture that that could potentially result in a large and long-term outdoor installation. The international GEOTRACES program has revealed that iron (Fe) is released ubiquitously from submarine ridges to the deep ocean. Results from US GEOTRACES section GP16 showed that both dissolved and particulate (colloidal) Fe may persist so far as to be able to influence primary productivity in High-Nutrient/Low-Chlorophyll (HNLC) regions of the Southern Ocean. As a complement to these sectional studies, we propose a detailed process study to elucidate the mechanisms by which hydrothermally sourced Fe can persist across the oceans at the scale that GEOTRACES has revealed. Specifically, while the "persistent" Fe in a hydrothermal plume appears to behave quasi-conservatively from 100km to 4000km across the SE Pacific Ocean, it is also known that the majority of the Fe present at the Southern EPR on that US GEOTRACES GP16 cruise did not persist over the 100km separation between that station and the next deep ocean station beyond the ridge crest. To fill that gap, this project will conduct a coupled modelling and field study to investigate the fate of hydrothermally sourced Fe at ranges of 0-1, 1-10 and 10-100km down-plume away from a well established vent-source. To begin, we will use the detailed micro-bathymetry and the long-term current meter data available from the Main Endeavour Segment of the Juan de Fuca Ridge to implement a recently developed 3D theoretical plume dispersion model that can predict both the detailed 3D dispersion trajectory and the rate of flow within the hydrothermal plume away from two long-studied and well characterized Main Endeavour Field (MEF) vents. At sea, we will use that predictive model to guide Sentry autonomous underwater vehicle (AUV) surveys that will follow the plume "down-wind" and "across-plume" to compile a 3D survey using in-situ sensors [optical, redox, conductivity, temperature, depth (CTD)] that will allow us to (1) confirm (and better constrain) the predictive model, and to (2) map out the shape and trajectory of the plume to provide context for discrete water column samples that we will collect - both from the AUV and from a trace metal clean CTD-rosette. Sampling from the AUV will use the latest generation of SUPR samplers designed for the CLIO trace-metal-clean water sampler. This will suffice for samples of dissolved, colloidal and particulate trace metals and collection of filtered material for grain-by-grain mineralogical and biogeochemical analyses. That sampling program will be backed up by larger volume sampling down-plume using a CTD-rosette to augment our AUV-based program with helium isotope analyses (to track extents of physical plume dilution at increasing distances downwind and across plume) and for complementary ligand and organic compound analyses to investigate the role that organic complexation might play in protecting reduced species of Fe [and manganese (Mn), too] against oxidative precipitation and removal from the oceanic water column. Post cruise, our combination of biogeochemical measurements and improved 3D physical modelling will not only be able to provide new insights into the processes that control the fluxes of Fe and Mn to the oceans from hydrothermal venting but also the length scales over which those processes take effect. Finally, because our 3D theoretical model includes velocities, we also anticipate being able to deduce the rates at which these processes occur.

Two Sentry Engineering Dives for 2023 - requested on Chris German cruise

MATE Floats Marine Technology Summer Camp is an immersive week-long camp designed to give community college students and other under-represented groups in marine technology experience working with BGC-Argo data and other oceanographic data collection tools and resources. During this cruise, they will observe a CTD cast and learn how to take and process CTD samples for chlorophyll, oxygen, and nitrate. They will potentially take and analyze other samples as time allows.

Volcanic eruptions are one of the most important processes that shape the Earth?s surface. However, eruptions are difficult to study up close because they are so destructive. The deep seafloor provides an opportunity to collect detailed observations of eruptions immediately atop a volcano. Since 2014, the NSF Ocean Observatories Initiative has operated a cabled observatory in the southern half of the summit caldera of Axial Seamount, an active volcano located 300 miles off the coast of Oregon. In 2015, the volcano erupted and the records from cabled instruments provided many insights. Among these insights were improvements in forecasting eruptions. Axial Seamount is rapidly inflating, and another eruption is now predicted in a few years. This proposal will operate 15 remote seafloor instruments for earthquake detection. Over 2 years the project will seek to record the next eruption. These new observations will improve understanding of how magma and fractures interact in volcanoes. Such interactions create the pathways of magma to the seafloor. This experiment is part of a broader effort in the volcano science community to develop Community Experiments. These experiments include different kinds of eruptions. Through the comparison of the different eruptions scientists will improve the understanding of volcano hazards. The data from this project will be available to all of the public. Among the science community this data sharing will help scientists interpret geological, hydrothermal and biological observations from submarine volcanoes.

Ocean turbulence consists of chaotic and intermittent motions that enhance ocean mixing on length-scales ranging from millimeters to hundred kilometers. Due to technological, financial and logistical limitations, ocean mixing can't be measured directly on global scales. Yet, numerical models that simulate ocean and climate dynamics require us to specify ocean mixing strengths. Hence, we develop simplification method, i.e. parameterizations, to still include this mixing. Unfortunately, the results from climate models, are very sensitive to choices in these parameterisation, meaning that they need to be further constraints by means of observations. As observations are thus impossible to obtain and the required scales, we develop theories that provide indirect estimates of mixing, from variables that we can measure on global scales or at high frequencies. This cruise aims to provide observations that can calibrate two such methods that will provide ocean mixing estimates. With these methods calibrated, we can produce estimates of global, full-depth and time varying maps of mesoscale and small-scale mixing strengths. These maps will constrain and improve parameterisations and thus ocean and climate models. With this cruise we will collect observational data with which we will: Main Goal: Calibrating the Spiraling inverse method. Main Goal: Calibrating Mesoscale mixing parameterisations. This includes estimating inermittency of mesoscale mixing and studying topographic mixing suppression. Bonus 1: Study topographic Rossby Waves and cross-slope mixing. Bonus 2: Study influence of mesoscale mixing on Nitrate fluxes (with University of Liverpool). The first goal is to calibrate the Spiraling Inverse Method (SIM). For this method, a certain amount of spiralling of temperature-gradient along neutral surfaces is required. This region has these characteristics but is also known for having significant amount of both small-scale and mesoscale mixing. Hence, the chosen location has the required ingredients to be able to calibrate the SIM. The second goal is to calibrate a new mesoscale mixing parameterization that includes effects of mean-flow suppression and topographic suppression effects. The resulting parameterization is then used to study intermittency of mesoscale mixing. The latter is rarely studied but impacts heat and tracer fluxes and needs to be included in future parameterizations for numerical ocean models. Then there are two bonus topics. One of them is study characteristics of Topographic Rossby Waves in this region and understand how they suppress mixing and transport tracers. The second one is to understand the effect of mesoscale mixing on interior to surface transport of Nitrate. An important aspect of the carbon cycle. The latter is a collaboration with Universities in the UK. In the framework of this research 4 moorings have been deployed within the EEZ of Bermuda. The current application is for recovery of these moorings

In this project scientists will investigate the deep layers of sediments and bedrock offshore the southeastern United States to better understand how the Atlantic Ocean started opening approximately 190 million years ago. In early Jurassic times, the continental margins of the Carolina Trough and Blake Plateau separated from northwest Africa by mechanical stretching and/or excessive volcanism, before the Mid-Atlantic Ridge started to accommodate extension by seafloor spreading. Old fault lines and sutures of the Appalachian basement may have been reactivated during this continental stretching phase, and lava flows may have filled the early rift basin. Whether this episode of volcanism was a cause or consequence of the breakup between North America and Africa is not yet clear. This question can be addressed with new marine geophysical data. With seismic images of the deep sediments and basement, the scientists can determine the relationship between basement faults and lava flows on the Carolina Trough and Blake Plateau. These two sections of the Atlantic continental margin are of particular interest because the Blake Plateau is much wider than the Carolina Trough. Either the Blake Plateau forms a block of continental crust that did not stretch much during continental rifting, or it is a plateau that largely consists of volcanic rock that formed during rupture of the continents.

The Great Lakes hold about 20% of the freshwater on Earth and have been increasingly impacted by human activities in recent decades. Lake Erie suffers from large, annually recurring, toxic cyanobacterial blooms in summer, whereas Lake Superior experiences smaller, localized cyanobacterial blooms after storm events. Cyanobacterial blooms have harmful ecological, human health, and economic implications. These blooms are a global phenomenon, observed in lakes and oceans, and can lead to low oxygen conditions and the production of toxins, both of which can be harmful for ecosystems. Understanding how different types of cyanobacteria influence nutrient cycling remains a major knowledge gap. This project aims to provide a deeper understanding of the long-term state of the Great Lakes ecosystem. The research approach combines new and established methods. Project results and implications will be shared with local and regional water interests in partnership with the Pittsburgh Collaboratory for Water Research, Education, and Outreach, the Great Lakes Commission Harmful Algal Blooms Collaborative, and the Lake Erie Area Research Network. Education is a central part of this project and training opportunities target next generation of scientists, including postdoctoral, graduate, and undergraduate students. The students and postdoc will receive state-of-the-art training in the rapidly developing fields of biogeochemistry and geomicrobiology, while working with an interdisciplinary team of scientists.

Deep water instrument tests and experiments.

The University of Hawaii ROV team will be conducting system and operational test dives on Lu'ukai prior to conducting research operations.

The major goals of the project are: Maintain the ALOHA Cabled Observatory (ACO) in an operational mode, including the core set of measurements; Provide community and public access to the data and the system; Present results to the community and public via publications, conferences, seminars, etc.; and Attract other users to the site to take full advantage of the system and other science at Station ALOHA.

This SME is for the box/kasten/Shipek coring work in the regions of Astoria and Quinault Canyons Overview: Characterizing source areas for ocean-triggered turbidites: sediment cores and surface grabs Detail: All data will support the PhD thesis of Evan Lahr and provide multiple undergraduates from the Ogston and Keil lab with 1) oceanographic field experience and 2) the samples and data needed for training of students in laboratory processes, data analysis and interpretation of results.

C-Streams addresses a key knowledge gap regarding how carbon uptake over the North Atlantic is controlled by ocean circulation. We are all aware that the Gulf Stream is important for heat supply to northern latitudes, but here we investigate how this current is crucial for setting carbon dioxide uptake from the atmosphere. Working with US partners, we will measure the strength and variability of Gulf Stream property transports in Florida Straits. We will measure the downstream evolution of Gulf Stream nutrient and carbon concentrations over 2000 miles using targeted observations by autonomous instruments, novel analyses and model simulations. We will determine how the Gulf Stream provides a far field control of North Atlantic carbon uptake, providing an alternative paradigm to the prevailing view of control by stratification. We will then assess whether climate models provide the right response of the North Atlantic carbon sink to climate change and for the right reasons. We will deploy 3 moorings with biogeochemical instrumentation at 27 N in the Florida Straits - the same latitude as the NOAA WBTS repeat stations and the new NSF FOCUS array - to continuously measure property transports of the Gulf Stream over a two-year period. In particular, these moorings will resolve the nitrate and low-carbon transports of the relatively fresh deep waters in the Straits that originate in the southern hemisphere. It is hypothesized that northward advection of these waters fuels uptake of anthropogenic carbon in the North Atlantic. We will deploy gliders and Argo floats to quantify mixing and entrainment of these waters along their northward path in the Gulf Stream

Terrestrial organic matter (OM) concentrations have been increasing in coastal waters, such as the Gulf of Maine (GoM), over the past 30 years. The implications of this change on critical mechanisms controlling the levels of mercury (Hg), and its toxic form, methylmercury (MeHg), in marine waters and at the base of the food web, are not well understood. Given this lack of knowledge, this proposal will examine the effects of climate-driven increases in terrestrial OM concentrations in GoM waters on the complex and often competing processes influencing: 1) Hg cycling and distribution; 2) the formation of MeHg; and 3) MeHg uptake to microplankton. Our central hypothesis is that higher terrestrial OM inputs and concomitant shifts in coastal OM concentration and quality will cause increases in Hg inputs, MeHg production and bioaccumulation. Terrestrial OM is thought to be a conduit for transfer of Hg from watersheds to coastal and offshore waters and controls the formation of aqueous MeHg by providing a microenvironment that supports bacterial Hg methylation. Increasing dissolved OM concentrations have been associated with decreased bioaccumulation of MeHg into phytoplankton, the primary bioaccumulation step for uptake of MeHg into seafood. However, our preliminary results show this association is mediated by OM source more than concentration, as indicated by the sulfur content of the OM. Furthermore, mixotrophic microplankton can bioaccumulate MeHg complexed with OM while feeding heterotrophically. Mixotrophs can seasonally dominate phytoplantkon assemblages in coastal waters, and the impact of heterotrophic feeding modes on MeHg uptake at the base of the food web has not been explored. This proposal is focused on studying the effects of OM dynamics on Hg and MeHg cycling and bioaccumulation through 1) field surveys and shipboard experiments in the GOM, where significant increases in terrestrially-sourced OM have caused a “yellowing” effect, and 2) through laboratory microcosm experiments using autotrophic and mixotrophic microplankton taxa under contrasting carbon acquisition modes and OM characteristics and concentrations. This work builds on our prior and ongoing work studying Hg cycling and bioaccumulation in estuarine environments along the Northeastern U.S. and will apply novel Hg and MeHg-specific isotopic analyses and measures of OM quality to enhance understanding. This research will fill important gaps in predicting the effects of environmental perturbations on marine MeHg levels, providing critical information to mitigating Hg emissions and MeHg exposures.

The Great Lakes hold about 20% of the freshwater on Earth and have been increasingly impacted by human activities in recent decades. Lake Erie suffers from large, annually recurring, toxic cyanobacterial blooms in summer, whereas Lake Superior experiences smaller, localized cyanobacterial blooms after storm events. Cyanobacterial blooms have harmful ecological, human health, and economic implications. These blooms are a global phenomenon, observed in lakes and oceans, and can lead to low oxygen conditions and the production of toxins, both of which can be harmful for ecosystems. Understanding how different types of cyanobacteria influence nutrient cycling remains a major knowledge gap. This project aims to provide a deeper understanding of the long-term state of the Great Lakes ecosystem. The research approach combines new and established methods. Project results and implications will be shared with local and regional water interests in partnership with the Pittsburgh Collaboratory for Water Research, Education, and Outreach, the Great Lakes Commission Harmful Algal Blooms Collaborative, and the Lake Erie Area Research Network. Education is a central part of this project and training opportunities target next generation of scientists, including postdoctoral, graduate, and undergraduate students. The students and postdoc will receive state-of-the-art training in the rapidly developing fields of biogeochemistry and geomicrobiology, while working with an interdisciplinary team of scientists.

Axial Volcano is one of the most extensively studied sites on the global network of mid-ocean ridges. Three eruptions have been observed in 1998, 2011 and 2015 with a near continuous 20-year record of vertical geodesy from bottom pressure sensors in the caldera recording cycles of inflation and rapid syn-eruptive deflation. Axial volcano has also been the focus of several seismic imaging studies including a recent three-dimensional seismic reflection experiment that provide a remarkably detailed view of the magmatic system. In comparison, the geodetic models of inflation are limited in complexity and resolution by the small number of geodetic sites and the difficulty distinguishing distributed inflation from fault motion on the buried outward dipping ring faults using vertical geodesy alone. Here we propose to install a 10-year 4 station acoustic network at Axial that range between each pair of transponders and include a pressure gauge, temperature, salinity and velocimetry sensors. One station will be connected to the OOI Regional Cabled Array enabling real time acquisition of data. The primary scientific objective is to measure horizontal extension rates across and within the caldera that can be combined with the other geodetic observations to (1) discriminate between distributed inflation and motion on the buried outward dipping faults beneath the east and west caldera walls and thus, understand the pattern of seismic coupling on these faults throughout the eruptive cycle; (2) contribute data that can enable more complex models of inflation and (3) obtain measurement of the dike with for dikes that propagate across the acoustic baseline. A secondary objective is to provide an acoustic network that can support future efforts to demonstrate and optimize remote communication and navigation of autonomous underwater vehicles.

Characterization of microbial and viral evolutionary dynamics in diffuse flow hydrothermal vent fluids at Axial Seamount. This work will consist of two ancillary science days for three years in a row as part of the Ocean Observatories Initiative (OOI) cruises that are scheduled annually to Axial Seamount on the Juan de Fuca Ridge off the coast of Oregon and Washington for maintenance of the cabled array. During these ancillary science days, a fluid sampler will be mounted on an ROV/HOV to collect filters and whole water from diffuse fluids at hydrothermal vents. Ideally, hydrothermal fluids will be collected from vents at the International District in Axial Seamount. These fluids will be preserved for cell counts, viral counts, and metagenomic analysis.

The movement of heat from inside the Earth into the ocean is a key factor influencing ocean dynamics, chemical exchange, and life in the oceans. However, until now, it has not been possible to monitor, in real time and over long periods of time, the fluids venting from seafloor hydrothermal vents even though these fluids carry a significant amount of internal geothermal heat from deep in the ocean crust to the seafloor. This project overcomes this problem by installing newly tested instrumentation, a Cabled Observatory Vent Imaging Sonar system, capable of long term monitoring of hydrothermal vent fluid fluxes, on the National Science Foundation's recently completed Ocean Observing Initiative's cabled observatory at the ASHES hydrothermal field in the caldera of Axial Volcano on the Juan de Fuca Ridge. This sonar system is designed for imaging hydrothermal discharge and the measuring heat transferred by that discharge into the ocean from the subseafloor. One goal of the work is to continue improving the system and developing it into a reliable tool for long-term repeated quantification of hydrothermal activity (fluid flow and heat transport) using acoustic sensing. The resulting heat transport measurements will enable investigation of the connections between the volcanic system, which supplies heat to the surrounding rock; subsurface fluid flow processes; and the biological systems that depend on the reduced chemical species that emanate from the hydrothermal system as a result of the leaching of metals and other compounds from water-rock interaction in the subsurface. This second deployment of the cabled sonar system will test its ability to measure and couple discharge rates and heat transport. Broader impacts of the work include increasing infrastructure for science and applications that extend to monitoring and measuring the discharge rates of methane at methane seeps and/or oil at oil-well head blowouts such as Deep Water Horizon. The work will also result in the training of undergraduates and the integration of education and research. Results will also be disseminated to the public via lectures and media outlets. One of the most important field measurements needed for the study of coupled geo-bio-hydrothermal systems is heat flux. This is a fundamental property of seafloor hydrothermal systems. It connects its driving force (i.e., sub-seafloor heat sources such as volcanic magma or serpentinization) to the systems it impacts, such as the flux of chemicals into the ocean. It also exerts controls on the subsurface and surface biosphere. Previous attempts to adequately measure seafloor hydrothermal heat flux have been unable to measure it with the combined spatial/temporal coverage and resolution necessary to resolve the dynamics of venting. The installation of the recently developed and tested sonar system that will be installed on the National Science Foundation's recently commissioned Ocean Observatory Initiative cabled array at the ASHES hydrothermal vent field on the Juan de Fuca Ridge will enable the monitoring and quantification of hydrothermal discharge and the heat transferred by it from rocks below the seafloor to the ocean. The sonar system is able to make synoptic measurements across a significant areal extent of the vent field and can collect and transmit data for periods of up to several years. This greatly reduces the need for extrapolation in the data. In addition to the monitoring, this research will exploit an innovative method for inversion of acoustic data to estimate the heat flux of diffuse-flow around the vents using a newly developed acoustic method. Deployment of the instrument will be for 4 years. It will be combined with ground-truth measurements to establish the accuracy of the acoustic results in terms of flow rates for focused and diffuse flow and for temperature/heat flux. The resulting time series for heat flux from focused and diffuse sources has a broad range of applicability. In particular, heat flux values and variations have implications for the dynamics of hydrothermal venting at ASHES and its connections with seismicity, magma supply, crustal cooling, and basalt-water interactions. It also exerts influence on heat and chemical changes in the ocean, energy and nutritive supplies to seafloor ecosystems; and the extent and nature of the subsurface biosphere.

This cruise is in support of the National Science Foundations Ocean Observatories Initiative Regional Cabled Array (RCA) annual operations and maintenance cruise and will require an ROV (either ROPOS of Jason). It is anticipated that over 100 instruments will be turned (recovered with refurbished instruments reinstalled). Operations will visit all of the RCA sites located west of Newport along the Cascadia Margin (80 m - 2900 m water depth) and ~300 miles off shore at Axial Seamount. It is likely that at least one Deep Profiler mooring will be turned. In addition 6 science pods on the three 2-legged vertical moorings located at the Slope Base, Axial Base, and Oregon Offshore sites will be turned. A medium lift winch will be required for turning of moorings. The field program will also turn multiple secondary junction boxes (maximum weight ~ 3200 lbs). The cruise will be hosted on the interactiveoceans website with live streaming of deck and ROV operations and will include the undergraduate students that participate in the UW at-sea experiential learning program VISIONS. Similar to past cruises, additional NSF and ONR-funded days as well as a day funded by MARUM, GERMANY will be added onto the RCA field program.

ABSTRACT Axial Seamount is the most active volcano in the U.S. Pacific Northwest - it just happens to be located underwater, about 300 miles off the Oregon coast. It has erupted three times in the last 20 years, and we know it is building toward another eruption in the next few years. Consequently, it is an ideal site for long-term monitoring with the National Science Foundation's Ocean Observatory Initiative Cabled Array (OOI-CA) in the Northeast Pacific ocean, which is the world's most advanced underwater volcano observatory. Previous monitoring with the OOI-CA has shown that Axial Seamount has a very repeatable cycle of inflation and deflation that has been used to forecast eruptions. This project will deploy additional monitoring instruments at Axial Seamount over the next 5 years and these will allow us to better forecast the next eruption, will improve our models of magma is supplied and stored within the volcano, and will test ideas about the deep-sea marine environment is impacted by submarine eruptions. This research serves the national interest and society because it will improve our understanding of how volcanoes work and how eruptions can be better forecast (both on land and underwater). This project will fund modest, cost-effective, and timely enhancements to the instrumentation on the OOI Cable Array to address some deficiencies in the existing infrastructure. A key element will be deploying Conductivity, Temperature, Depth (CTD) instruments on the seafloor to measure changes in salinity to test the hypothesis that hydrothermal brines are released in the summit caldera during some eruptions. Specifically this project will: (1) keep one seafloor CTD that is already deployed operating on the OOI-CA for 5 more years, (2) add two additional seafloor CTDs at two other sites on the OOI-CA for expanded spatial coverage and needed redundancy, and (3) build eight Mini-BPR (bottom pressure recorder) sensors to replace other instruments that are part of the long-term geodetic monitoring that augments the observations from the OOI-CA. These enhancements to the monitoring effort at Axial Seamount will be available in time to be deployed during the next eruption at Axial Seamount (currently expected between 2020-2022), which will help to increase our understanding of the shallow magma supply and storage systems at active basaltic volcanoes, the processes that lead to and trigger eruptions, and the impacts of submarine eruptions on hydrothermal systems and chemosynthetic ecosystems.

This program, lead by Y. Marcon and G. Bohrmann (University of Bremen, is funded by the German Federal Ministry of Education and Research, under between the University of Bremen with a subcontract with the University of Washington. The program focuses on the real-time, systematic and continuous monitoring (location, number, intensity) of all active bubble plumes issuing from Southern Hydrate Ridge utilizing cabled instrumentation that includes two multibeam sonar systems, a CTD and 4K camera provided by the two PI’s (see Marcon et al., (2021). Variability of Natural Methane Bubble Release at Southern Hydrate Ridge, Geochemistry, Geophysics, Geosystems, https://doi. org/10.1029/2021GC009894). This is a multi-year effort.

The significance of doliolid microbial interactions: Do doliolids fundamentally alter the trophic structure and productivity of sub-tropical continental shelf food webs? The long-term goal of this project is to understand the ecological function of doliolids on subtropical continental shelves and their influence on microbial processes. In association with monthly oceanographic field expeditions on the mid-continental shelf at 31°N and two longer longitudinal expeditions complemented with experimental studies, the project investigates the relationship between doliolid abundance and life stage composition, their spatial relationships to marine snow aggregates and other zooplankton, water column microbial activity, bacterial production, and net system productivity. Utilizing a constellation of modern and classical approaches in microbial and zooplankton ecology, including deployment of an in situ zooplankton imaging system in the South Atlantic Bight, microbial metagenomics and transcriptomics, and stable isotope-based tracer experiments, these studies will allow the testing of three fundamental hypotheses. First, independent of total shelf productivity, the presence and abundance of doliolids is correlated with heterotrophy compared to periods when doliolids are not abundant. Second, doliolids predictably shape continental shelf microbial communities, activity, and function, and third, doliolids are detrital feeders benefiting nutritionally from the consumption of microbial enriched aggregated particles and fecal material - the pool to which they also contribute.

Long-term observations over several decades are a powerful tool for investigating ocean physics, biology, and chemistry, and the response of the oceans to environmental change. The Bermuda Atlantic Time-Series Study, known as BATS, has been running continuously since 1988. The research goals of the BATS program are: (1) to improve our understanding of the time-varying components of the ocean carbon cycle and the cycles of related nutrient elements such as nitrogen, phosphorus, and silicon; and, (2) to identify the relevant physical, chemical and ecosystem properties responsible for this variability. In addition, the BATS program has strong and diverse broader impacts, contributing to the field of ocean sciences by providing high quality ocean observations and data for seagoing scientists and modelers, and a framework through which researchers can conceive and test hypotheses. This award will support the operations of the BATS program for five more years. The primary BATS research themes are as follows: (1) Quantify the role of ocean-atmosphere coupling and climate variability on air-sea exchange of CO2, and carbon export to the ocean interior; (2) Document trends and the controls on the interannual to decadal scale variability in carbon and nutrient cycles to their coupling in the surface and deep ocean via the Redfield Ratio paradigm; (3) Quantify the response of planktonic community structure and function, and impact on biogeochemical cycles to variability in surface fluxes and dynamical processes; (4) Facilitate development, calibration and validation of next generation oceanographic sensors, tools and technologies; and, (5) Generate a dataset that can be utilized by empiricists, modelers and students. This research integrates ocean physics, chemistry and biology into a framework for understanding oceanic processes and ocean change in the North Atlantic subtropical gyre. The existing 29 years of BATS data provide robust constraints on seasonal and interannual variability, the response of the Sargasso Sea ecosystem to natural climate variability, and signal detection of potential ocean changes. This project would extend the BATS program through years 31-35 to address a series of ten interlinked questions through integrated research approaches and a multitude of collaborative efforts. In addition to the themes above, and embedded into the ten questions and approaches, the BATS team will focus on, for example, coupling of particle production and biogeochemistry; revisiting the complexities of the biological carbon pump; oxygen decline; and changes in the hydrography, physics, ocean carbon cycle and biogeochemistry of the Sargasso Sea. The highest quality data observation and collection will be maintained and used to address these questions. Importantly, a wide range of collaborations at the BATS site, spanning the physical and biogeochemical disciplines, will aid these broad goals. Strong links to community stakeholders, and close collaboration (including methods intercomparisons and personnel exchanges) with the Hawaii Ocean Time-series are proposed. This work will extend the research findings of the project into educational and training opportunities within and beyond the oceanographic community, including training and mentorship of both undergraduate and graduate students.

One of the longest open-ocean hydrographic stations in the world is maintained at the Hydrostation S site (formerly known as the Panulirus site) located ~25 km southeast of Bermuda in the North Atlantic Ocean. This program of repeat biweekly hydrographic observations began in 1954 (by Hank Stommel) and now, in its seventh decade, has proved to be the catalyst for numerous studies of ocean physics, biological processes and biogeochemistry. Hydrostation S continues to be recognized as one of the most important sustained ocean time–series. The renewal of the Hydrostation S program is proposed herein, extending this invaluable time–series of ocean hydrography to almost 70 years. The upper ocean warming trend has strengthened (about +1.4° C since the 1970's; ~+0.8°C in last decade) with significant salinification (+0.16). Deeper waters such as the Labrador Sea Water has cooled by a few tenths of a degree and freshened with a marked decadal oscillation. The signature of deoxygenation has been observed at Hydrostation S in the upper ocean (about 4 µmoles kg -1 decade -1 decrease in dissolved oxygen) as well as the oxygen minimum zone (~2.5 µmoles kg -1 decade -1 ). Hydrostation S also supports the longest global ocean CO 2 and acidification time-series (from 1983 to present) The major objective of the proposal is to continue Hydrostation S into the eighth decade with numerous questions related to warming and cooling, salinification and freshening, deoxygenation and insights on biogeochemical changes over time. This program constitutes frequent water column sampling of temperature, salinity, and dissolved oxygen (and indirectly, sampling of important ocean carbon time–series) of the North Atlantic subtropical gyre at the Hydrostation S site. Such work is complementary to other sustained observations such as the Bermuda Atlantic Time–series Study (BATS) and Ocean Flux Program (OFP). We propose to carry out a similar sampling format that has been followed for the past 68 years. As for the past ten years, we would continue to conduct two CTD profiles to better capture the deep–water variability while maintaining all the previous discrete depths. The first CTD cast will profile to full ocean depth (3,300–3,500 m) while the second CTD cast will profile to 500 m (to allow for instrumentation not rated for full ocean depth such as a PAR sensor). One indirect objective will be to continue to collaboratively evaluate a BIOS-based glider program with Hydrostation S data as critically important ground truthing data. The existing glider program has challenging issue, and the aim of this effort is to use robust and highly accurate Hydrostation S data to test the capability of emerging technologies over the next five to ten years.

ALVIN engineering dive during the Laura Lapham cruise in August 2023

This study will investigate the production, flux and reactivity of methane-derived dissolved organic carbon (DOC) from methane (CH4) seeps at Hydrate Ridge, Offshore Oregon. The study will address four fundamental questions to determine the significance of CH4-derived DOC within the ocean carbon cycle: (1) How much CH4-derived fossil DOC do seeps contribute to the oceans? (2) To what extent is CH4-derived C incorporated into DOC during anaerobic oxidation of CH4? (3) Is seep DOC bioavailable or recalcitrant when released into the deep ocean? (4) How does the flux of DOC to the water column vary over time? We will employ an interdisciplinary strategy that includes in situ sampling, laboratory incubations, and a comprehensive analytical geochemistry program. Data from the Ocean Observatories Initiative Regional Cabled Array at Southern Hydrate Ridge will be used to provide context for field and experimental data. The composition and abundance of organic and inorganic chemical species along with the stable and radiocarbon isotope composition of pore water, bulk sediment, and water column C pools will be used to identify DOC sources and quantify fluxes from cold seeps characterized by a range of advection rates. The centerpiece of the investigation will be a 7-day research cruise to Hydrate Ridge to collect sediments, pore fluids, and water column samples, and deploy OsmoSamplers for continuous time series fluid sampling. The results will form the foundation for estimating the contribution of CH4-derived DOC to the oceanic DOC pool.

Within the Cascadia Margin (CM) located off the OR and WA coast at water depths of 500m and less, methane continuously bubbles out of the seafloor at sites known as seeps. As the bubbles rise toward the sea surface, they release methane to the water column where it is consumed by bacteria, but some methane is released, either directly or indirectly, to the atmosphere where it acts as a potent greenhouse gas. Although thousands of seeps have been identified n the CM by their characteristic 'acoustic flare' on ship's sonar, little is known about the regional impact these seeps have on water column biogeochemistry and even the estimates of total methane flux are highly uncertain due to difficulty in empirically relating shipboard acoustic backscatter intensity measured at the sea surface to methane fluxed at the sea floor. To solve both of these problems, we propose to use a small fleet of two-person-portable Autonomous Underwater Vehicles (AUVs) equipped with a combination of dissolved methane sensors and high resolution imaging sonars and current meters to quantify methane fluxes all the way to the source at the sea floor. The AUVs will use advanced algorithms to autonomously search for a seep an then efficiently sample it.

The overarching goal of the proposed research initiative is to provide an independent estimate of GAJ abundance in the US Gulf GoM and SA in waters out to 150 m in depth. The independent estimate of abundance derived from the proposed research will be compared with the estimates derived from the stock assessment models used by NOAA Fisheries (Stock Synthesis, Beaufort Assessment Model), allowing validation, calibration, and further refinement of the model. To accomplish this ambitious task, we have assembled a well integrated multidisciplinary team that includes leading fisheries and statistical experts from across the GoM and SA. These scientists have extensive experience with reef fish research along with some of the most robust datasets, ongoing research programs/teams, sampling expertise, and analytical skills available. Our specific objectives are: (1) to synthesize bottom habitat observations and construct a spatially explicit habitat model throughout the study area (SA and GoM), (2) to synthesize existing fisheries data and stakeholder knowledge regarding regional, habitat-specific abundance of GAJ across the study area, (3) to design and conduct a comprehensive study to estimate, within a reasonable margin of uncertainty, the regional, habitat-specific absolute abundance of GAJ using a combination of video observations (towed, ROV mounted, and stationary) and hydroacoustics, (4) to determine movement behavior and connectivity of GAJ at local and regional scales using a combination of acoustic telemetry, conventional tagging and genetic markers, (5) to assess the efficacy of environmental DNA (eDNA) methods in conjunction with visual and acoustic approaches to determine presence/absence and/or relative abundance of GAJ as well as closely related species, (6) to update biological information for GAJ across the study region (age-length) and (7) to engage with stakeholder groups and collaborate with existing outreach teams to facilitate stakeholder input and to communicate the results of the project.

Marine plankton form the base of most ocean food webs that support valuable fisheries. This highly diverse and complex community is composed of organisms that drift with ocean currents. Planktonic organisms remain understudied: they are difficult to sample given that their sizes span more than six orders of magnitude from less than one micron to meters. Yet, understanding how these communities will respond to climate change, and ultimately how these responses affect valuable fisheries, and therefore food security, is critical. Because many ecological and physiological processes are dictated by relative size, the theory of size spectra (i.e., the relationship between size and organism abundance as it drives ecosystem properties such as food webs) provides a valuable framework for forecasting climate change impacts on marine ecosystems. A deeper understanding of the scope and nature of variability in size spectra under contrasting environmental conditions is needed. The dynamic, highly productive northern California Current off Oregon and Washington in summer and winter seasons produce a patchwork of oceanographic conditions including those associated with hypoxia and ocean acidification. This study is sampling the plankton communities in this region to investigate how gradients of temperature, nutrients, dissolved oxygen, and pH conditions impact size spectra. The coupling of in situ plankton imagery and morphometric data allows quantifying scales of variation in plankton size spectra as well as testing predictions of how changes in environmental conditions (notably, temperature, nutrients, O 2 , pH) correlate with shifts in size spectra and revealing functional consequences to the food web. Plankton size spectra are being compared across environmental conditions by sampling in a habitat with steep environmental gradients and during two contrasting seasons. Planktonic organisms spanning 10 orders of magnitude in biomass are sampled using two complementary high-resolution imaging systems: the In Situ Ichthyoplankton Imaging System (ISIIS) and the Laser In-Situ Scattering and Transmissometry (LISST) particle imager. High-throughput image analysis software is used to generate size distributions together with taxonomic classification. Depth-discrete meso-zooplankton samples are collected in parallel to examine community shifts in carbon and for the calibration of length-to-carbon conversions based on images for use in normalized biomass size spectra. These plankton collections are also being analyzed for diet and reproductive status of gelatinous zooplankton, and diet and daily growth rate of representative larval fishes. These two groups have been historically understudied yet play central roles in ecosystem function. These data are adding to the understanding of how these important organisms at the base of the marine food web are affected by environmental conditions, and how they affect plankton size spectra. This study is foundational to the understanding of marine ecosystems within the context of climate change.

Systematic long-term (greater than a few decades in length) time-series observations of aquatic and terrestrial environments have led to a more comprehensive understanding of the natural ecosystem variability and have enabled an assessment of human impacts on ecosystem dynamics. Because of their ability to store and transport large amounts of heat and to absorb carbon dioxide from the atmosphere, the world's oceans play a critical role in modulating environmental conditions for the sustained well-being of both land-based and marine organisms including humans. Despite their recognized scientific and societal importance, long-term records of key ocean processes are rare. In 1988, two ocean time-series programs were established: one in the North Atlantic near Bermuda and the other, the Hawaii Ocean Time-series (HOT) program, near Hawaii. For the past three decades, teams of scientists based at the University of Hawaii have made critical measurements of the 'state of our sea.' These long-term observations have established a baseline against which future states can be compared. The ship-based HOT program complements other diverse ocean observation programs including remote-sensing via satellites, moored buoys, profiling floats, and autonomous underwater vehicles. All HOT program data are publicly available and are frequently used by researchers and policy makers around the world.

These cruises utilize funding provided by the University of Minnesota. Chief Scientists will be completing seed research cruises or using their ship time to take graduate and undergraduate students on the research vessel Blue Heron.

FOCUS will investigate the relationship between sea-level changes in coastal Florida and variations in Gulf Stream transport of water and heat through Florida Straits. To address this goal, the project will use in-situ measurements of velocity, pressure and sound signals along a cross-section between Florida and The Bahamas. These measurements will lead to a better understanding of how 'sunny-day' flooding events in South Florida are linked to oceanic conditions offshore. Results will also illuminate links between variations in different components of Gulf Stream transport and the gyre and overturning circulation and heat content at basin scale. Investigators will interact closely with resilience program managers of a county in southeast Florida that is affected by increasingly frequent flooding from the ocean.

The northwest Atlantic is renowned for productive fisheries that depend upon a complex food web of planktonic organisms that provide them energy. In these waters -- as in coastal waters around the globe -- human activities, environmental variability, and decadal-scale change intersect to have diverse effects on the planktonic food web. It is crucial to understand the structure of this web, how it functions, and how it responds to seasonal environmental change, in order to respond appropriately to long-term trends that are accelerating in this region. Our understanding, however, has been limited by a lack of systematic and detailed measurements over a sufficient length of time so that we can observe the responses of these webs to environmental perturbations and uncover the underlying causes and implications. The Northeast US Shelf (NES) Long-Term Ecological Research (LTER) project will provide such observations, analyze them with a variety of models, and improve our ability to predict how planktonic food webs change through space and time, and how those changes impact the productivity of higher trophic levels including commercially important fish. In addition, the NES-LTER project will have multifaceted broader impacts, including collaboration with the National Oceanic and Atmospheric Administration's (NOAA), Northeast Fisheries Science Center to support multispecies, ecosystem-based management on the NES. The project includes an education plan that will provide opportunities to a broad range of learners and a far-reaching public outreach component will be developed through NOAA's international Science-On-a-Sphere network. While patterns of ecosystem change over seasons to decades have already been documented in this region, the key mechanisms linking changes in the physical environment, planktonic food webs, and higher trophic levels remain poorly understood. For this reason, predictive capability is limited and management strategies are largely reactive. To address these needs, the NES-LTER strategy combines observations that provide regional-scale context, process cruises along a high gradient cross-shelf transect, high-frequency time series at inner- and outer-shelf locations, coupled biological-physical food web models, and targeted population models. The research plan is guided by an overarching science question: How is long-term environmental change impacting the pelagic NES ecosystem and, in particular, affecting the relationship between compositional (e.g., species diversity and size structure) and aggregate (e.g., rates of primary production, and transfer of energy to important forage fish species) variability? By capitalizing on high levels of seasonal and interannual variability in the NES, the research will study short-term responses to change in the environment to a) characterize low and high export food webs, b) understand the linkages and transfer of energy from the phytoplankton to pelagic fish, and c) identify the mechanisms that underlie shifts between high and low export communities. Ultimately, mechanistic knowledge will be scaled up to understand and predict the impacts and feedbacks associated with trends in decadal-scale forcing in the ecosystem.