Research

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.

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.

Launch a 3m buoy at near the current location of the old buoy, south for Port Fourchon Louisiana. Then recover the old buoy and anchor.

This ONR-TFO project continues work to improve the understanding and prediction of mid-frequency sound propagation in coastal environments. This will be accomplished via a collaborative effort between UW-APL Ocean Acoustics ( DJ Tang, T. Hefner ), UW-APL Ocean Physics ( R. Harcourt, J. Mickett ), Scripps Institution of Oceanography ( Y-T Lin, W.S. Hodgkiss ), and NRL Stennis (G. Jacobs, J. Osborne). The primary goals of the fieldwork component of this project are to: Quantify the dependence of the large high-frequency variability (scintillation, when under sampled) in transmission loss due to stratification and internal wave spectra along the acoustic path. Collect highly-resolved towed profiler measurements to allow a statistical representation of high-frequency internal waves to facilitate prediction of TL variability at O (10) minute timescales, and to enable a priori assessment of acoustic signal uncertainty. Collect coordiated oceanographic and acoustic measurements to better quantify the impact of nonlinear internal waves---energetic, ubiquitous and regular on the Washington shelf---on mid-frequency acoustic propagation. Both along and across-wavecrest studies will be carried out. Collect microstructure measurements along with towed profiler measurements to improve our understanding of how acoustic ducts are modified by turbulent mixing. Are ocean model lateral and vertical diffusivity levels realistic? Support APL and Scripps Acoustics field experiments by providing comprehensive moored and towed profiler measurements to resolve the dominant variability of the sound speed environment, allow interpretation of changes to this field, and enable post-experiment acoustic modeling.

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.

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.

Open ocean surface waters are natural sources of methane emissions to the atmosphere. As recently as a decade ago the source of this methane was enigmatic, for methane production was only known to occur in certain anaerobic environments. Production of methane in the aerobic marine water column was posed as a “methane paradox”. The discovery of several metabolic pathways that enable microbes to transform organic matter into methane under aerobic conditions has led to a reexamination of the marine methane paradox and a shift away from the anaerobic methanogenesis paradigm. In this project we propose that the pathway microbes use to make methane depends on the nutrient conditions that prevail in mid ocean surface waters. In the North Atlantic Ocean, phosphorus limits microbial production, and microbes produce methane as a by-product of organic phosphorus degradation. In contrast, nitrogen limits microbial production in the North Pacific Ocean, and we propose that in this ocean basin microbes produce methane as a by-product of organic nitrogen degradation. To test this hypothesis we propose to compare the results of geochemical and biological measurements we made in the Sargasso Sea with a parallel set of geochemical measurements we propose to make in the North Pacific Ocean. Specifically, we propose to measure methane and ethylene, the carbon stable isotope values of methane, the chemical composition of high molecular weight dissolved organic matter with respect to methylamine (MeA) and methylphosphonate (MPn) along with the carbon isotopic value MeA and MPn in high molecular weight dissolved organic matter. We will preform a suite of laboratory experiments with cultured marine microbes to test if they can make methane from methylamine, and conduct parallel sets of experiments in the field. We will bring into cultivation new methane producing microbes from water samples collected as part of our field program.

Organism aggregation, resource patchiness, and layering have long been recognized as fundamental ecosystem properties, especially in dynamic marine pelagic systems. However, integrating fine-scale (1-10 m) water column structure into our understanding of the forces that regulate marine ecosystems has proved challenging. Specifically, an overwhelming majority of marine organisms (plankton) experience their environment at fine spatial scales, which are difficult to sample, yet most measurements of chemical and biological parameters that define the structure of food webs and the flow of energy are averaged over much larger portions of the water column. This mismatch hinders our ability to understand the trophic consequences of fine-scale variability. Addressing this challenge will help to resolve key, and potentially predictable, sequences of events that change community structure and have trophic consequences that propagate throughout the food web in productive continental shelf environments. The trophic consequences of layers and patches depends on the proliferation of the zooplankton groups that exploit them. Conversely, other groups may proliferate in environments lacking vertical structure. One key trophic link on continental shelves is occupied by grazers such as doliolids and copepods – the relative abundance of these groups can determine if carbon is vertically exported or recycled within the microbial loop. Our long-term goals are to understand the ecological role of doliolids and the conditions that favor their proliferation (compared to copepods and other crustaceans). Because doliolids aggregate on fine spatial scales in several ecosystems, biological measurements need to be made on similar spatial scales and through time. Obtaining these measurements within different oceanographic contexts can answer several fundamental questions. For example, what are the trophic consequences of fine scale structure? Do these structures favor particular zooplankton communities above and below, and over what temporal and spatial scales do these structures persist or extend? Answering these questions requires sampling with complementary techniques, and will advance the fundamental understanding of how ecosystems will respond to changes in oceanographic structure, placing seemingly chaotic zooplankton communities into a predictive framework. We propose an ambitious field campaign in two shelf ecosystems with similar zooplankton taxa yet contrasting oceanographic regimes where doliolids are known to form blooms. The sampling will encompass two seasons (summer and winter) with contrasting degrees of stratification. Innovative molecular and stable-isotope measurements will allow for a robust coupling to oceanographic features and zooplankton abundance and community composition, elucidating the trophic consequences of vertical structure, layering, and mixing. In addition to primary research cruises, the multi-cruise plan will also include cruises that will be focused on optimizing the use of novel and proto-type equipment (sea trials) and several education cruises for graduate students and K-12 educators.

The Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) technology is a transformative approach for ocean sensing, since it is capable of monitoring sound sources over instantaneous wide areas spanning 100 km or more in diameter. Ocean sound sources detected by POAWRS include biology such as sounds from marine mammals, fish and crustaceans; geophysical processes such as hurricanes and submarine volcanoes; and man-made activities such as ships and other ocean vehicles, seismic earthquake plate tectonic studies, offshore piling, wind farms, and hydrocarbon prospecting. The instantaneous continental-shelf scale environmental monitoring capability and temporal-spatial dynamics of sound sources revealed by POAWRS makes it an important technology that could become an indispensable tool in field operations, such as large-scale marine ecological studies, fisheries stock assessments and management, compliance-based ocean enviromental and marine mammal monitoring, as well as in studies of the effects of man-made sound on marine ecosystems. The Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) technology, comprising of a large-aperture coherent hydrophone array hardware and real-time array data processing and analysis software, provides automatic signal detection, classification and localization, enabling ocean discoveries to be made right at sea, with real-time feedback that allow the data collection procedure to be adapted and optimized on-the-fly. A towed large-aperture 160-element coherent hydrophone array system implementing the POAWRS approach was previously developed inhouse at Northeastern University. The objectives of the current proposal are to conduct (i) mechanical upgrades to the array subapertures, (ii) develop, enhance and optimize POAWRS real-time processing and analysis software for array data sampled at high frequencies of 100 kHz per element, including computational and archival hardware, and (iii) sea tests to verify system upgrades and overall system operational readiness to support future ocean scientific research and studies.

This multi-cruise project request is for the major infrastructure deployment and recovery of the National Science Foundation (NSF) Ocean Observatories Initiative (OOI) Coastal Endurance Array (EA) ( https://www.oceanobservatories.org ). The Endurance Array includes fixed and mobile assets to observe cross-shelf and along-shelf variability in the coastal upwelling region of the Oregon and Washington coasts and provide synoptic, multi-scale observations of the eastern boundary current regime. Two lines of Endurance moorings run approximately east-west across the continental shelf north and south of the Columbia River outflow. Three different mooring types are used to capture surface meteorology along with near-surface, near-bottom and mid-water column ocean structure in the vicinity of the shelf break front. The mooring types are: Coastal Surface Mooring (SHSM, OSSM), Inshore Surface Mooring (ISSM), and Offshore Profiler Mooring (OSPM). Moorings are permitted under the United States Coast Guard (USCG) Private Aid to Navigation (PATON) program. The moored array is supplemented by gliders surveying the continental shelf and slope waters offshore of the moored array and coastal surface piercing profilers at the Oregon and Washington Inshore and Shelf sites. Like glider deployments and recoveries, CSPP deployments and recoveries can occur on mooring cruises or from small vessel cruises.

Replace buoy and mooring systems at the FRP2, CAP2 and CHR60 buoy sites.

Jessica Fitzsimmons, James Moffett, and Nicholas Hawco propose to collect four large volume (1000 L) seawater samples to develop an archive of consensus materials for trace metal analysis. Samples will be collected from the surface and 1000m at the Station ALOHA, and from two stations in the Gulf of Mexico influenced by the Mississippi River outflow. Samples will be collected and filtered using trace metal clean techniques into large-volume tanks, homogenized, and then dispensed into 500mL bottles for archiving and distribution to the community. Samples will be analyzed by groups worldwide for a suite of dissolved trace metals. Their data will be analyzed in collaboration with Antonio Possolo, of the National Institute of Standards and Technology (NIST). Consensus values derived from this synthesis for each element will be reported on the US GEOTRACES Web Site and in a peer-reviewed publication. The majority of samples will be archived for distribution, replacing the exhausted archives of previous intercomparison projects. The last two decades have seen great advances in our knowledge about the distribution and biogeochemical cycles of trace elements in the ocean. This was possible because laboratories worldwide had confidence that their analyses were producing consistent results. The establishment and distribution of consensus standards, from the SAFe (2004) and GEOTRACES (2008-2009) programs, were critical in this development. We propose to collect samples from Station ALOHA, where water chemistry will be very similar to the valuable samples collected in those former consensus-building programs. Those earlier efforts also revealed that there were some intercalibration issues that need to be addressed. For example, copper displays surprising variability in reported values that did not appear to arise from contamination, but could reflect artifacts arising from Cu complexation by organic matter for specific protocols. Cobalt shows similar issues, while vanishingly low surface oligotrophic concentrations of cadmium, zinc, and iron can prevent strong consensus against significant blanks at the picomolar level. These issues and others will be explored by Fitzsimmons, Moffett, Hawco, and other participants in the course of consensus building. Recent field campaigns in margins and estuaries have underscored the importance of a consensus standard in waters containing high concentrations of dissolved organic matter, which may create analytical artifacts for copper and other metals. It also needs to be determined what the constraints on long term storage are for such samples. This is the rationale for collecting a high-organics, lower salinity sample in the Gulf of Mexico.

Oceans, estuaries and coastal habitats are changing quickly, driven by both natural processes and human activities. The Washington Ocean Acidification Center (WOAC) was established by the state legislature to advance research and monitoring of ocean acidification and its biological effects in Washington waters. One facet of that research is the WOAC cruises. We go out three times a year, April, July, and September, to monitor ocean acidification and its affect on biology. These cruises are part of a long term time Ocean Acidification time series.

Puget Sound has been observed to host large fields of active methane venting from the seafloor. Although present throughout the Sound, the majority of gas emission sites are co-located over three major fault zones that fracture the entire forearc crust of the Cascadia Subduction Zone (CSZ). Multibeam and single-beam sonar data from cruises conducted between 2011- 2021 identified the acoustic signature of over 350 individual bubble plumes. Fluid samples from adjacent terrestrial hot springs and deep-water wells surrounding the estuary contain a helium-3 isotope signature, suggesting a deep fluid source arising from the underlying CSZ plate interface. However, limited data from our previous pilot study suggests that Puget Sound emission sites appear to lack similar helium isotope signatures expected from a deep plate-interface reservoir. As an alternative hypothesis, a shallow reservoir beneath the Holocene sediments that cover Puget Sound Eocene basement, with horizontal transfer to the thinly-sedimented Alki Point and Kingston Arch anticlines, is also possible. The origin of vigorous marine methane plumes arising from areas of thin sediment cover and associated with deeply-penetrating forearc fault zones but still presenting no thermal or chemical anomalies found in other similar forearc environments, remains an important unresolved scientific paradox.

Recent work has pointed to lakemounts as potentially critical features in large lake ecosystems, which, like seamounts in ocean environments, appear to be 'hot spots' that play a disproportionately large role in supporting ecosystem biodiversity and production. Further, commercially and recreationally important populations of fish on lakemounts (specifically, the lake trout Salvelinus namaycush) are highly abundant, despite the lack of stocking intervention in these regions which was the primary recovery strategy implemented after the collapse of the Great Lakes fishery in the 1950's and 1960's. As such, lake trout (and perhaps other fishes) at lakemounts may be a refugia for genetically-intact historic strains present prior to fisheries collapse in the Great Lakes, compared to coastal populations of stocked origin. Several mechanistic processes have been reviewed and proposed to be important at lakemounts in driving greater regional production. These processes include upwelling of deep, nutrient-rich hypolimnetic waters against the abupt topographies of lakemounts, both from large-scale currents and internal seiche events during stratification. Lakemounts also provide substrate for benthic organisms in an otherwise pelagic environment. Advective forces due to large-scale currents can also lead to deposition of algae and zooplankton through leeward eddy retention, and the trapping of vertically migrating organisms, making them vulnerable to predation by resident consumers.

We have in the Gulf an array of moored Current and Pressure Recording Inverted Echo Sounders (CPIES) and Sonardyne Origin-65's, which combine bottom-mounted upward-looking Acoustic Doppler Current Profilers (ADCP) and PIES. The array is located to intercept and detect the probable trajectories followed by pulses of strong deep currents associated with Topographic Rossby Waves (TRWs). The currents-pulses are enroute to Sigsbee Escarpment, where they pose an unseen hazard to industry operations, not reliably detectable from surface observations. The observations and data from this bottom instrumentation has been harvested by Uncrewed Surface Vessels, at dates that can be adaptively chosen to produce useful warnings that a burst of strong currents will arrive along Sigsbee Escarpment. Because the Sonardyne batteries are being depleted faster than originally expected, the entire array needs to be recovered in September, 2025.

The project involves deployment of OBS instruments across two branches and the center of the Galapagos triple junction in the eastern central Pacific Ocean. The approximate geographic bounds of the deployment region are 1°S to 6°N, and 105°W to 98°W. The goal is to deploy two arrays of stations over a 3.5-year field season (i.e., one array of 44 stations deployed & recovered together in Y1-Y2 and another array of 38 stations in Y3-Y4). Nominal station deployment durations will be 12-15 months, contingent on ship time and available instrumentation. Fieldwork will also include multibeam mapping and gravimetry in the vicinity of the arrays.

We will investigate how ocean mixing can be generated by a diverse range of processes across the California Continental Margin. This proposal aims to support the student-led ocean mixing summer school at Scripps Institution of Oceanography (SIO) taking place in August/September 2025 under the guidance of Prof. Jennifer MacKinnon. Our goal is to address the science and assumptions behind turbulence measurements, with a practical at-sea component so participants can learn to collect and analyse data with a critical eye. We aim to understand how different sources of mixing affect the region around the Point Loma Wastwater Treatmant Plant, which is a source of public health concern for the Southern California Bight. Our experiment targets this problem to educate the summer school participants on the intersections between turbulence theory and observational measurements.We will use our local San Diego area to answer questions about the shelf and its impacts on waves, wind and mixing. Specific science questions include: How do internal waves drive mixing across the shelf? What are the relative roles of wind, buoyancy forcing and Langmuir circulation in driving turbulence in the boundary layer? How does the amount of turbulence affect the equilibrium depth and thickness of the wastewater plume?

This cruise is part of a multi-year effort to use the R/V “NEIL ARMSTRONG” to acquire SBP29 data over sites off the East Coast. In 2025 we will concentrate on areas from South Carolina to Massachusetts, including the Blake Ridge Diapir, known gas seep sites on the outer shelf and upper slope, Hudson Canyon, and offshore Massachusetts.

We will deploy profiling packages, scientific echosounders, plankton nets, and will collect water from the CTD rosette Niskin bottles for on-deck incubation, and analysis both on board and for shipping back to our labs. Profiling and sampling will occur around-the-clock, but with emphasis on dawn and dusk.

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, the Hawaii Ocean Time-series (HOT) program, near Hawaii was established. For over 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.

Overall, this study is designed to detect if hydrothermal circulation is present within oceanic crust just prior to entering the Cascadia subduction zone, offshore Oregon and Washington. The project will collect seismic reflection data and temperature data in seafloor sediments offshore Washington and Oregon, map the distribution of those sediments, to understand the controls on temperatures in the system and improve estimates of subduction zone temperatures. The results of this research have direct societal benefit, by informing earthquake hazard estimates. In addition, the proposed project will enhance education at New Mexico Tech, a STEM-focused Hispanic-serving institution. Two graduate students will be trained in geophysics and hydrogeology. Results of the project will be incorporated into classroom studies improving hands-on experience in undergraduate courses.