Research

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.

Historical DDT data exists for the Palos Verdes Shelf sediments, which was long believed to be the primary source of DDT and its breakdown products to the marine food web in the Southern California Bight. Scientists will thoroughly characterize the relevant contaminant profiles water column and food web components at Dumpsite Two. They will use a targeted approach to quantify the major DDT-related compounds, while utilizing a broader approach to fingerprint the less well studied breakdown products of DDT. We will trace relevant contaminants into the local, deep food web near and around the dumpsite.

This project will renew the integrated observational program at Davis Strait, delivering data to the community and matching ongoing collections at Bering Strait, Utqiagvik, Alaska, and Fram Strait to extend the time series of concurrent measurements across the major Arctic Gateways. The extended timeseries will document changes in freshwater and heat fluxes, and will be combined with numerical modeling to investigate the processes that control variability in the strait and the potential impacts. The backbone system relies on the tested combination of moorings instrumented with sensors to measure ice thickness and motion, ocean currents, temperature and salinity, and biennial ship-based sampling of chemical and biological properties that have successfully delivered core measurements for the past decade. Bottom pressure sensors augment the system to quantify sea surface height gradients, which will support investigations of the primary forcing mechanisms. Integrated marine ecosystem observing includes biogeochemical and marine mammal passive acoustic measurements augmented with tracking of key fish species, and zooplankton and phytoplankton observations. These observations will launch the Davis Strait/Baffin Bay Distributed Biological Observatory (DBO) in Davis Strait, complementing the developing Atlantic DBO that includes transect lines in Fram Strait and Barents Sea, and the existing Pacific DBO in the northern Bering, Chukchi and Beaufort Seas.

Our objective is to understand and quantify sediment transport processes on continental shelves and slopes by internal solitary waves (ISW) using in-situ observations and physics-based modeling. We hypothesize that internal waves may generate strong near-bed flows that are capable of generating sediment transport to alter seafloor roughness and create bedforms across the continental shelf. Our long-term goal is to develop a new modeling capability to estimate sediment transport across continental shelf driven by ISW. We will use field observations and physics-based models to improve our understanding of sediment transport by shoaling ISW in continental shelf waters deeper than 50 m. Our study will be composed of 3 main tasks: 1) field experiment to collect in-situ observations of water-column and near-bed morphodynamics where ISW occur in continental shelf waters, 2) quantify ISW contribution to bottom stress (which drives sediment transport) from near-bed velocity, and 3) estimate near-bed velocities from thermocline oscillations of ISW. These tasks are structured to arrive at the project deliverable of a new modeling capability to estimate sediment transport across continental shelf driven by ISW.

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.

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.

Ship time dedicated to facilitate experiential learning for UGA and USG graduate and undergraduate students.

Deploy and recover oceanographic surface moorings, profilers and gliders for the Ocean Observatories Initiative (OOI) Coastal Endurance Array. Seven surface moorings will be deployed and recovered over the shelf and slope of central Oregon and central Washington. Up to four profiler moorings will be deployed and recovered over the shelf of central Oregon and central Washington. Up to six gliders will be deployed and recovered off the coasts of central Oregon and Washington. The moorings, profilers and gliders include multidisciplinary sensors taking multiyear time series as part of OOI. During the cruise, the ship will aslo acquire data for validation of these sensors (underway oceanographic and meteorological data, CTD and auxiliary sensor profile data and CTD rosette bottle samples.

The physical oceanography at the New England Seamounts (NESM) is dominated by the Gulf Stream. This surface-intensified current, which can reach speeds >4 knots (2 m/s), is a full-water column feature that spans more than 4000-m depth on its approach to the seamount chain. The location where the strongly meandering Gulf Stream crosses the seamount chain can vary by ~900 km. The crossing-location ranges from occasional crossings just north of the Bear Seamount (39°54’N, 67°23’ W) to an extreme southern occurrence near the Nashville Seamount (34°32’N, 57°W). This time-varying crossing-location is expected to have first order effects on: (1) local current-topography interactions at each seamount (e.g., mixing, lee wave generation, etc.) and (2) a range of environmental conditions at the seamounts—including impacts on thermocline depth, mode water thickness, and upper-ocean mixed-layer depth. The meandering current serves as a moving front between the Slope Sea (shallow thermocline and cool, fresh surface waters) to the north and the Sargasso Sea (deep thermocline and warm, salty surface waters) to the south. Since the environmental conditions vary so strongly across the Gulf Stream, just a small shift in Gulf Stream crossing-location at the NESM can be accompanied by a large change in the local environment at a given seamount. To help track the mesoscale variability around Atlantis II seamount, and to record higher frequency variability associated with internal tides, current and pressure sensor equipped inverted echo sounders (CPIESs) were deployed in April 2023 and will be recovered in fall 2024.

Researchers from NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) in Miami, FL, conduct regular bimonthly hydrographic surveys at 27N in the Florida Straits to monitor the transport and water-mass properties of the Florida Current. The Florida Current is part of the Gulf Stream system, which is the upper limb of the western boundary current system in the North Atlantic Ocean. These cruises are a part of the laboratory’s long-running Western Boundary Time Series (WBTS) project and directly measure the Florida Current at nine locations across the Straits of Florida at 27N, between Jupiter, Florida, and the Little Bahama Bank in the Bahamas. WBTS 27N hydrographic sections, conducted bimonthly throughout the year, are critical to improving our understanding of the North Atlantic Subtropical Gyre circulation and the Atlantic Meridional Overturning Circulation (AMOC). Importantly, data collected during these cruises and others are also used to calibrate the 27N submarine cable system which publicly provides daily transport estimates of the Florida Current . The AMOC is a significant factor in climate change, oceanic carbon sequestration, and sustainable fisheries. In addition to the direct ship-based measurements conducted during WBTS 27N cruises, these surveys also support and service project moored instrumentation, located on either side of the Straits, which provide key times series data. These monitoring efforts are necessary for quantifying AMOC and gyre variability over time and for identifying decadal changes in the large-scale circulation, water-mass properties, and heat transport. The WBTS project is part of an international collaboration which partners include AOML’s WBTS, the University of Miami’s Rosenstiel School of Marine and Atmospheric Science (UM/RSMAS) Meridional Overturning Circulation and Heat-flux Array (MOCHA) Program, and the UK National Oceanography Centre’s Rapid Climate Change (RAPID) Program.

UW Oceanography Dept. Ocean 492 Research Apprentices Student Cruise for Fall Quarter 2024.

Topside service and maintenance for a Fugro Wavescan Buoy. Buoys measure wind, waves, and currents. Data is transmitted to erddap and distributed.

We will deploy the Flying Sea Glider over the side (no flying for these tests) at which point it will act as a conventional underwater glider. We will track and follow it with the ship for a 2-day mission. We will recover the glider at the end of the test.

STEMSEAS aims to provide ship-based, 6-10 day exploratory experiences for undergraduates from diverse backgrounds aboard NSF-funded research vessels. Students will sail with experienced faculty and graduate student near-peer mentors, and engage in geoscience and oceanography activities.

Sediment trap studies help scientists better understand the environmental factors (e.g., temperature, salinity, ocean circulation, nutrient supply, etc.) that control the chemical composition, ecology, and life history of planktonic organisms living in the water column. These planktonic organisms, preserved in ocean sediments as microfossils or molecular fossils, can be used to reconstruct oceanographic conditions in the Gulf of Mexico over the past few centuries to the past few millions of years. Scientists at the USGS are using a long-running sediment trap (2008-2018+) in the northern Gulf of Mexico to calibrate foraminifera, biomarker, and other micropaleontological proxies for use in climate reconstructions. The sediment trap mooring has been deployed in the Gulf of Mexico (27.5 ºN, 90.3 ºW) at 700 meters water depth from 2008-2018. It is programmed to rotate every 7-14 days throughout the year, resulting in a weekly to bi-weekly resolution time series of sinking particle flux. Samples are recovered from the sediment trap once every 9-12 months. On these cruises water is collected via the CTD for isotopic and trace metal analysis, as well as to measure parameters of the carbonate system (dissolved inorganic carbon, total alkalinity, pH). Sometimes live foraminifera are collected with a plankton net for additional geochemical and genetic analyses.

The full extent of injury to mesophotic and deep benthic communities (MDBC) from the Deepwater Horizon (DWH) oil spill remains unknown. The MDBC portfolio is a suite of four projects selected by the OO TIG to restore MDBC injured by the 2010 DWH oil spill in the Gulf of Mexico. The four projects are: Mapping, Ground-truthing, and Predictive Habitat Modeling (MGM), Habitat Assessment and Evaluation (HAE), Coral Propagation Technique Development (CPT), and Active Management and Protection (AMP). One goal of this 18-day experiment is to provide us with data that we can add to the Threats Database and use in the Science to Management portion of the AMP project as well. The experiment will also allow us to monitor a recent threat reduction action (installation of a deep mooring buoy to prevent anchoring) to help begin to meet AMP MAM goals. Then, the data we receive from the experiment and how the experiment goes generally will help inform future methods of monitoring vessel activity and visitor use in the Sanctuary/managed areas, which can then further contribute to Science to Management.

Deformation of the seafloor is an important tectonic process, which can best be studied with marine geodetic techniques. The GNSS-Acoustic method is the technique chosen by a community workshop to investigate the following processes in Cascadia and Alaska: 1. Along-strike changes in coupling and relation to onshore deformation. A strong and widely spaced geodetic backbone offshore of existing on-land geodetic infrastructure, in regions not constrained by land stations could serve as the greatest return on investment for scientific and hazards understanding of megathrust subduction behavior. 2. Near-trench coupling and relation to tsunami earthquake(s) and down-dip behavior. While Alaska is the only of the two locales that has the known occurrence of a damaging tsunami earthquake (characterized by its outsized tsunami wave amplitude for earthquake magnitude) in 1946, it is understood that due to depth restrictions particularly in the 1946 rupture patch, much more of the near-trench environment off Cascadia can be evaluated using current instrument pool transponders. 3. Occurrence of shallow aseismic slip and its relation to earthquakes. The Cascadia subduction zone has clearly observable and large down-dip slow slip events, and an overall large near-trench exposure capable of observation with the geodetic instrument pool. 4. Postseismic time-dependent variations in coupling, including transients, afterslip, viscous relaxation, and recoupling. This was viewed as much more important in Alaska where recent large earthquakes allow for much greater potential for capturing discernable time-dependent variations in coupling behavior.

Seafloor geodesy is an important tool for assessing geophysical hazards and driving forces in the offshore environment where approximately 90% of plate boundaries exist. Long-term deformation data from such observations can aid in identifying submarine magmatic processes, off-shore loading of faults that lead to large to giant earthquakes and tsunamis, submarine landslides, and hydrocarbon movement driven by anthropogenic activity. Currently, such long-term observations can be prohibitively expensive for many needed studies, and only limited measurements are made due to costs. Similarly, because of the relative sparsity of measurements, particularly with new autonomous Wave Gliders, only optimal submarine conditions have been significantly explored, limiting the potential environments that are deemed feasible for application. This design experiment directly addresses these concerns to enable wide utilization of these tools. A three-year design experiment is planned for lower cost capabilities for dense seafloor deformation measurements, including operation in higher seafloor gradients, particularly in deep environments. The project will deploy a mesh-geometry of 10 transponders ranging between 4 and 6 km depth along a segment of the Aleutian trench in 2024, combining ship-activities with an ongoing community seafloor geodetic experiment. For GNSS ranging and acoustic interrogation of the transponders from the sea surface, a green-powered autonomous Wave Glider will be used. The deployed sites will be measured frequently through the summers of 2024 and 2025 to evaluate the repeatability of observations across the mesh geometry. The transponders will be at depths and gradients not previously tested using a Wave Glider and the planned interrogation method. To improve recovery at greater depths, ranged lower frequency acoustics will be used (14-19.5 kHz) than are used for operations in shallower water (19-34 kHz), requiring a Wave Glider with a dedicated GNSS-Acoustic unit and lower frequency acoustic transducer. The mesh-network design allows for a substantial increase in observation points over a traditional geometry that requires three transponders. While the mesh design geometry will dictate the ultimate transponder efficiency for observation, an example network may have between 4 and 10 times the number of observations may be possible, substantially reducing instrument costs, and facilitating high-density observations of seafloor deformation that can be used to discriminate shallowly seated sources including submarine magmatism, near-trench deformation, hydrocarbon withdrawal, and submarine landslides.

Oceanographic and geologic criteria indicate that abyssal manganese nodules may occur in the abyssal regions of the southeastern portion of the Exclusive Economic Zone of Hawaii, which has been largely unmapped and unexplored. The goals of this research project are to ground truth the occurrence of abyssal manganese nodules, determine what water column, seafloor, and sub-seafloor features exist in these abyssal regions, observe nodule distribution and abundance as well as the concomitant fauna, and collect physical samples of nodules, sediments, and biology. These data will help characterize the geological and biological environment in this prospective abyssal nodule region and inform critical mineral and ecosystem resource potential.

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.

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.

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.