Research

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.

This research involves submersible-based (ROV or Alvin) sampling and geological mapping of the volcanic stratigraphy at various locations along the margin of the Platform along with a comprehensive shore-based geochemical study of sampled lavas and sampling and dating of deep-sea corals for paleoclimate research in collaboration with UK colleague Dr. Laura Robinson- U. Bristol. These studies will allow us to investigate the volcanic emplacement processes involved in construction of the Platform and geochemical relationships between the submarine platform lavas and adjacent/overlying volcanic islands. During the planned research cruise, we will conduct the most comprehensive and systematic in situ sampling of the volumetrically largest volcanic portion of the Galápagos Archipelago, the Galápagos Platform. The UK component of the research program will combine field work (sample collections from the Eastern Equatorial Pacific, EEP), geochemical analyses (precisely-dated, high-resolution carbon cycle records from deep-sea corals) and integrated modeling (intermediate complexity and GCM). These approaches will be used to provide specific tests of competing hypotheses, as well as a broad synthesis of the processes controlling the carbon cycle during the most pronounced warming period of recent Earth history. In order to conduct the mapping and sampling of lavas, deep-sea corals and associated biology required to meet our research objectives, we plan to carry out a 23 day field program on a Global class vessel with either ROV Jason or HOV Alvin at approximately 10 study sites distributed around and within the Galapagos Platform, and along the southern end of the Northern Volcanic Seamount Chain that extends to the NNW from the platform to the Galapagos Spreading Center.

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.

The cruise is designed to be a student-focused field course to give students experiences on a variety of oceanographic field techniques. We will carry out hydro graphic surveys with CTD rosette, net tows with PI-supplied nets, and benthic sampling (multi-core, box-core and gravity core) with OSU's coring facility equipment. Because of transport logistics and costs, the cruise is typically focused on the central-northern Oregon margin offshore form Newport. This is a required course for OSU ocean science students and the dates are critical because they correspond to the Spring Break for the university.

This is a relatively short cruise to recover five shelf hydrographic moorings that are to be deployed at the end of the primary WA Shelf Acoustics Cruise presently scheduled aboard the R/V Sally Ride from July 15-Aug. 15, 2022. This fieldwork is part of one component of three interdependent and collaborative research efforts that together have an overarching primary goal of significantly improving the prediction of SONAR signal excess and its uncertainty for a required duration (e.g., 72 hours) for a given operational area. The primary long-term goal of this specific component (APL-Ocean Physics) is to improve the predictive modeling of hydrographic features that control acoustic transmission of mid-range frequencies. This three year effort will parallel and integrate with the proposed APL-Acoustics and NRL work. This effort will heavily leverage ongoing UW modeling efforts (LiveOcean), a host of ongoing observational assets on the Washington shelf, and existing ocean measurement tools. Our specific program objectives are to: 1) quantify the space and time scales of the acoustic ducts. 2) identify the mechanisms controlling the formation and evolution of these ducts. 3) apply new knowledge to improve key processes and inputs in models to more accurately reproduce and predict these ducts. 4) provide comprehensive field observations to ground truth models and provide critical environmental data for the acoustics field experiment, allowing detailed acoustic modeling. 5) via modeling investigate these phenomena in other operationally-significant regions. The long-term moorings that will be recovered during this cruise will significantly add to the collection of hydrographic observations that will address objectives 1-4 above. In particular, the long-term moorings will help us to better understand the seasonal variation of the secondary acoustic ducts and the spatial structure of that seasonality.

Submarine canyons are ubiquitous along continental margins, and often thought of as key conduits for the transfer of terrestrial sediment, nutrients and organic material to the deep sea. During sea level highstands, most of this shelf to deep-sea transport occurs on an episodic basis, driven by seabed resuspension in and around the canyon head, associated with large storms, floods, earthquakes and other energetic events that are thought to induce gravity-driven, downslope sediment flows. However, the processes that control canyon flushing and sediment infilling remain poorly understood. To date, most of the direct monitoring of these processes has been focused on large submarine canyon and fjord systems that are highly active during the current sea level highstand. This proposed effort is a collaborative, interdisciplinary effort with the goal of understanding the origin of modern deep-water stratigraphy associated with submarine canyon dynamics. The observational component will deploy two instrumented arrays in canyons of differing morphology (Astoria Canyon and Quinault Canyon) to develop a spatially distributed minute-scale record of water and particulate transport processes over a complete annual cycle. This data would yield the timing and magnitude of canyon transport processes, and help constrain the sedimentary response to oceanographic disturbances. A seasonal seabed surface core survey in the region will examine annual depositional cycles, and allow for the direct testing of seafloor remobilization thresholds along canyon thalwegs. All of these data will then be used as model inputs, providing the constraints for locally-parameterized hydrodynamic modeling of sediment gravity-flow triggering and runout distances.

Puget Sound, the largest estuary by volume in the continental United States, has recently 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. Multibeam and single-beam sonar data from cruises conducted in years 2011, 2018, 2019, 2020 and 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 Cascadia Subduction Zone 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.

SQUID (Sampling Quantitative Internal-wave Distributions) is part of the NOPP "Global Multi-agency Experiment on Internal Wave Energy, Mixing, and Interactions in the Ocean and Their Representation in Global Ocean Models and Operational Forecasts." The principal field activity of SQUID is to deploy 50 velocity and microstructure profiling floats (EM-APEX) from multiple cruises of opportunity over the 3-year program (2023-2025). UNOLS cruises will be sought out in suitable locations and times to launch 5-10 floats over the course of each cruise. Although we do have the ability to send personnel on a few of these, it is anticipated that ship or science party personnel will be able to accomplish these launches. We are also happy to provide training to personnel beforehand. Overall, we are looking to collect profiling float internal wave measurements over a range of values of the following parameters: (a) latitude, (b) topographic roughness, (c) internal tide amplitude, (d) high-frequency wind variability, (e) mean current speed, (f) mesoscale eddy kinetic energy, and (g) proximity to the coast. Each float will operate for somewhat over a year, drifting at depth and collecting bursts of 4-6 profiles every 5-10 days. Several of these deployments will be from GO-SHIP cruises, which are ideal for EM-APEX launches in SQUID because they tend to span a large geographical (and, hence, internal wave parameter) range. This request (squid2) is for the second SQUID cruise entered into the MFP portal and describes deployment of 2 floats from a planned transit on the R/V Armstrong which will pass through the East Coast diamond of the SWOT satellite fast-repeat phase.

Collaborative Research: Unraveling the habitat and dynamics of slow slip events through integrated borehole observations in the northern Hikurangi subduction margin Not yet available from the NSF awards site.

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.

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.

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.

The purpose of this collaborative project is to advance understanding of the role of marine planktonic animals (or zooplankton) in the biological pump, or transport of carbon from surface to deeper ocean waters. This movement of carbon from surface to deep ocean water can ultimately affect carbon dioxide in the atmosphere, with implications for global climate. Many marine zooplankton, including species of copepods and krill, play a direct role in the biological pump both because they are abundant and because they can migrate from surface waters at night, where they feed, to depths of more than 500 m at night. At the same time, some organisms called flux feeders will remain at depth and do not migrate. Instead, they rely on particles produced by other zooplankton feeding in surface waters. In this project, the investigators are focusing on populations of flux feeders in the deeper ocean waters of the Sargasso Sea. They are leveraging an ongoing long-term research program, conducting field collections using specialized nets and particle traps, as well lab experiments, as a way to understand how these organisms modify the particles around them. This project is supporting a postdoctoral scientist and providing research experiences for undergraduates at two institutions. An education specialist is creating lesson plans for an award-winning Ask-A-Biologist website, designed for public and K-12 audiences. Images of zooplankton will be disseminated to the public and scientific community via EcoTaxa (a web platform devoted to plankton biodiversity, with images and taxonomic annotation) and physical samples will be archived as part of a teaching library. The oceanic biological carbon pump refers to the export of dissolved and particulate organic carbon to the deep ocean, and it is a significant driver of atmospheric carbon uptake by the oceans. Evidence from long-term research carried out at the Bermuda Atlantic Time-series Study (BATS) site suggests that the spectrum of particles collected by gel-traps below the euphotic zone changes drastically below 150 m, which is attributed to resident populations of zooplankton that feed on vertically migrating zooplankton as well as sinking particles. The goals of this study are to investigate the role of different zooplankton taxa on both particle aggregate formation and in particle transformation, and to compare and characterize the particles generated by the zooplankton communities with those collected by particle traps. The investigators are combining field collections with experiments onboard ship and in environmental chambers. They are collecting samples over two years, with three cruises a year to capture distinct seasons. They are assessing high-resolution vertical distribution of zooplankton in the upper 600 m using Multiple Opening-Closing Net and Environmental Sensing System (MOCNESS) tows during day- and night-time, to distinguish diel vertical migrators from resident populations and to quantify contributions to particulate organic carbon flux via fecal pellet production. On each cruise, sinking particles are being collected using gel trap tubes attached to the particle traps deployed monthly at BATS. In addition, roller tank experiments are determining how individual zooplankton mediate aggregate formation. Particle types and fecal pellets are being characterized using image analysis and DNA-based analysis of microbial communities. Finally, ongoing data collection from the long-term BATS program is providing invaluable environmental context and will ensure results from this study contribute to ongoing community efforts to observe and predict the fate of carbon in our global system.

On Earth there are three fundamental ways in which volcanoes form. This study will examine how two of these styles behave in proximity. The Galapagos archipelago is a well-known example of hotspot volcanism, fed by a rising plume of hot mantle, and this system is interacting with the Galapagos Spreading Center (GSC) where volcanism occurs in response to seafloor spreading at the boundary between two tectonic plates moving apart. Scientists have studied the Galapagos hotspot-GSC system for several decades and have long puzzled over persistent discrepancies between geophysical and geochemical observations and physical models for how the pair work together. This study will image how mass and temperature are transported, as well as how magma is generated beneath the Galapagos system, using a technique called seismic tomography. A network of instruments spanning a large area of the islands and adjacent seafloor will be deployed. These seismometers will record seismic waves traveling from distant earthquakes and ambient ground displacement over a period of 15 months. As the seismic waves pass beneath the study area, they respond to differences in mantle composition, temperature, deformation, and the presence of magma. Imaging these properties will allow many unanswered questions particular to the Galapagos system to be addressed. The study will also address the fundamental processes occurring in the shallow part of the mantle that is hot and weak and the interactions with the the cool, stiff overlying part that forms Earth's tectonic plates. This program will train three graduate students in marine geophysics. In addition, an Apply-to-Sail program will allow graduate students and early career scientists from other institutions and community college instructors to participate on the research cruises to gain sea-going training. Lastly, Ecuadorian scientists and graduate students will also participate on the cruises, bolstering science education and international research collaboration. To produce the first mantle seismic view of how mantle plume-ridge interaction really works, an open-access seismic dataset will be collected around the Galapagos system. The experiment and subsequent analyses are designed to address three main scientific questions: (i) At what depths, in what geographic pattern, and by what mechanism does mantle plume material flow northward to the Galapagos Spreading Center and disperse along the ridge? (ii) Do the scale and nature of heterogeneity indicate small-scale, sub-lithospheric convection? and (iii) What is the spatial distribution of melting and volatile release, as well as the associated heterogeneity in composition and rheology due to plume-ridge interaction? The Galapagos system is exceptionally well-suited for such a study given the history of previous investigations of the surface manifestations, the evidence from mantle tomography below the Galapagos Archipelago, and the favorable azimuthal distribution of seismic sources. A large number (53) ocean-bottom, broadband seismometers will be deployed for 15 months in an array spanning the area between the Galapagos Islands and the Western Galapagos Spreading Center. Data from 7 broadband stations on the islands also will be used. The data will undergo initial processing, including ambient noise cross-correlation, and be archived in the IRIS-DMC for immediate public use. Tomography models of isotropic velocity will be produced from body waves, isotropic velocity from the combination of surface waves and ambient noise, as well as radial and azimuthal anisotropy from surface waves. Receiver functions will be analyzed to identify discontinuities related to the lithosphere and melting and shear wave splitting will be used to map anisotropy. Geodynamic models of plume-ridge interaction will be used for hypothesis testing by comparing modeled and observed seismic waveforms, and by using the geodynamic models as a priori information for the tomographic inversions. The project will also substantially advance a broad understanding of mantle plume processes, the asthenosphere, and their interactions with oceanic lithosphere; specifically, the deployment will function as a unit array within the Pacific Array Initiative.

Cruise intent is to replace meteorological/oceanographic buoys along the coast of South Carolina and North Carolina. FRP2, CHR60, CAP2 and SUN2.

This SME is for the transit from Suva, Fiji to Wellington, New Zealand.

This project will determine how marine sediments exposed to large riverine discharge affect ocean acidification from the increasing uptake of atmospheric carbon dioxide (CO2) in coastal waters. Although ocean acidification in coastal oceans affects marine life and commercial fisheries, little is known on the feedback from the underlying sediment on water column acidification processes. The role of large deposits from rivers in these processes has also never been investigated. The Mississippi River will be used as example of a river that plays an important economic role along the southern coast of the United States and provides a high sediment load to the nearby continental shelf in the Gulf of Mexico. The geochemical and microbiological processes responsible for the transformation of particles deposited on the seafloor will be characterized near the Mississippi River mouth and along the nearby continental slope. The release of acids (CO2) and bases (alkalinity) from the sediment will be quantified using autonomous instruments deployed on the seafloor to determine whether sediments contribute to the acidity of the surrounding water column or instead provide bases to buffer the water column from atmospheric CO2 inputs. As the Mississippi River discharge during the later Winter and Spring provides much more sediment to the coastal zone compared to the rest of the year, research cruises will be taken twice a year to determine how seasonal variations in riverine discharge affect the release of acids and bases into the water column.

The primary objective of this cruise is to survey the unique gradient zone into the ETNP OMZ in an efficient and comprehensive manner, optimizing coverage and utilizing transit time to maximize the amount of data via several student led projects. This ship time proposal fulfills the category of research by graduate students and postdoctoral fellows. The science party is largely comprises SIO graduate students for whom data collection in this area will enable dissertation completion; additionally, berths have been reserved for an open call to additional student projects if funded. The transit time to and from the OMZ boundary will be utilized for phytoplankton imagery, cetacean and seabird surveys, and physical water mass analysis. Critically, winter in the ETNP hosts gray whale ( Eschrichtius robustus ) breeding and birthing en masse, allowing meaningful visual cetacean surveys. The transit will also serve physical oceanographers interested in the intersecting water masses which form the OMZ; shipboard ADCP will be used to measure velocity profiles to associate large-scale current features in the region, which includes the equatorial California Current and poleward California Undercurrent. Phytoplankton communities will also be continuously imaged through deployment of an Imaging Flow CytoBot (IFCB). If funded, the tangible outcomes of this cruise will include myriad dissertation chapters and publications discussed in the sections detailing the various projects below. Several participants are in the later stages of their PhD research, and need specific biological, physical, and chemical data from this extreme region in order to publish a chapter and begin their dissertations. Several other students are in their first or second years of PhD study or postdoctoral appointment, and are enthusiastic about learning how to work at sea while generating datasets from which to publish their first papers and inspire their proposals. These academic products will advance the careers of developing scientists while contributing to the limited body of work characterizing the expanding ETNP OMZ. This cruise is intentionally designed for early career scientists in diverse disciplines, fostering independence and creativity in designing and executing experiments in the field while providing a unique opportunity for cross-disciplinary work. Oxygen minimum zones are uniquely shaped by forces representing all fields of oceanography, and cruises surveying these areas are usually based in one of these fields, making data intercalibration impossible. In terms of broader impacts, this cruise will produce uniquely interdisciplinary comparable datasets which will provide new insights into the ETNP OMZ, while serving to train early career scientists and strengthen their networks outside of their disciplines.

Cruise 1: January 9, 2023 from Pensacola, FL or Mobile, AL to deploy 8 ASIS buoys off Santa Rosa Island, FL in northern part of Gulf of Mexico. Cruise 3: March 20, 2023 recover all 8 ASIS buoys off Santa Rosa Island, FL in northern part of Gulf of Mexico. Multiple transects between buoy locations and Pensacola, FL or Mobile, AL or Miami, FL will be needed. Per conversation with Hans Graber 7/21/2022 The intermediate cruise will not longer be necessary. Only deployment and recovery cruise. eb

Adding a single day to an OOI cruise for the recovery and redeployment of our sediment traps.

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.

In late August of 2022, an unidentified multi-species acute tissue loss disease with signs and species susceptibility characteristics reminiscent of SCTLD and/or white plague was documented at East and West Bank in the Flower Garden Banks National Marine Sanctuary (FGBNMS, northwest GoM) by NOAA divers. Regardless of its etiology, the recent surveys performed at FGBNMS by NOAA staff identified what is the initial incidence area of a disease that will likely have significant impacts and possibly become widespread across the GoM. This offers an unprecedented opportunity to test hypotheses about the influence of coral community composition and pathogen dispersal on disease spread during the early stages of an outbreak that could profoundly change the diversity of GoM reefs. Given the isolation and high coral density of northwest GoM reefs, studying this outbreak in early stages will enable parsing of the impacts of reef-scale community composition versus seascape-scale dispersal in disease transmission and persistence. We hypothesize that 1) the abundance of highly susceptible species will dictate the initial spread of disease within reef sites. 2) We can determine the minimum pathogenic period of dispersing infectious material, if it is assumed these remote reefs were infected through disease dispersal via hydrodynamics. Furthermore, 3) filamentous viruses that infect Symbiodiniaceae are associated with disease-affected corals, as well as near-reef water (within 1m of reef bottom) on disease-affected reefs and the waste products of a coral predator (the fireworm, Hermodice carunculata), and 4) filamentous virus infections are detectable in Symbiodiniaceae within the genera Breviolum, Cladocopium and Durusdinium. To test these hypotheses, we will 1) identify strategic reef locations for disease surveillance on West and/or East Bank and contribute to the collection and generation of photomosaics in sampling areas to facilitate fate tracking. The abundance of high, moderate and low susceptibility species at West and/or East Bank will be extracted from these photomosaics and used to inform 2) a model we are building for disease spread. This model for FGB will be additionally informed by models of pelagic larval and material dispersal in the GoM and a model of SCTLD spread for USVI shallow and deep reefs. We will additionally aim to 3) and 4) sample Pseudodiploria strigosa, Orbicella franksi, and Porites astreoides (species with high, moderate, and low susceptibility, respectively, to SCTLD, n = 8 colony pairs per species). For each colony pair, we will sample disease lesion (DL) and apparently healthy tissue on a diseased colony (DH), as well as tissue from an apparently healthy colony (HH, n = 3 samples per colony pair) at two time points. Microbial communities from near-reef water, sediments and fireworms will be sampled when possible, with a goal of at least n = 8 per sample type. In culmination, our study will contribute to understanding the etiology of the disease and to a generalizable model that can predict the impact of disease spread and treatment on reefs based on coral species assemblages and seascape connectivity. This work will additionally clarify the role of viruses in coral disease on a high coral cover reef.

Model studies and satellite data suggest that Agulhas leakage -- the flux of Indian Ocean waters into the South Atlantic -- is increasing with climate change and that the associated trend in salt flux into the Atlantic may help stabilize the Atlantic meridional overturning circulation. Agulhas leakage also impacts the adjacent Benguela upwelling system, with increasing eddy kinetic energy expected to flush more nutrients and organisms offshore, causing a reduction in the productivity of this important fishery. So far, the turbulent nature of leakage has confounded observational evidence for these trends and influences. Here we propose an entirely novel approach to this important problem, using an eddy flux framework. Along the way we will be the first to characterize stirring and mixing in the unique eddy-dominated flow regime of the Cape Basin. The objectives of our project are to: (1) Observe and characterize submesoscale features generated by the mesoscale eddy strain field within the Cape Cauldron for the first time. (2) Make novel estimates of Agulhas leakage fluxes with these new observations, using theoretical eddy diffusivity and eddy flux frameworks. (3) Relate diffusivity and fluxes to new and existing satellite altimeter observations to infer variability in Agulhas leakage. To achieve these objectives we will collect new observations within the Cape Basin, targeting several dynamical regimes -- e.g. filamentation, eddy-eddy interaction -- to measure the related submesoscale features and estimate diffusivities. From these measurements we will quantify eddy heat and salt fluxes, similar to the way poleward heat flux has been successfully estimated in the Southern Ocean. We will use both Eulerian and Lagrangian instrumentation, including moorings, an undulating CTD system, gliders, drifters, profiling floats, and microstructure turbulence profilers, capturing time and space scales from hours to seasons and from 1 to 100 km. Our new observations will be synthesized and analyzed alongside other datasets, including measurements from the SWOT crossover in the Cape Basin and output from a 1/60 degree simulation, in order to generate a proxy for decadal leakage variability that can constrain climate projections.

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

AOML SFP regional surveys over the southwest Florida shelf and the Florida Keys reef tract have been routinely performed via the University of Miami's R/V F. G. Walton Smith on a bimonthly basis. Sampling methodologies similar to those utilized on AOML SFP bay surveys (discrete sampling and flow-through measurements) have been employed on these regional research cruises.

The 2023 XR05 Cruise is a NOAA funded cruise. The project lead is Xinping Hu (TAMUCC) and Chief Scientist; S. Mahmud (TAMU/GERG) is ship-board and autonomous vehicles operations lead and will serve as co-Chief Scientist.

In this 3-quarter long series of courses (OCEAN 443, 444 and 445), students are closely mentored by a faculty team to design, execute and communicate an original research project on a topic of their own choosing. This option usually included senior cruise on our research vessel, the R/V Thompson somewhere in the world's ocean. The Bachelor's of Science requires these courses. The Bachelor's of Arts does not.