Sikuliaq

Arctic coastal zones are experiencing rapid changes in the annual duration of sea-ice cover, with implications for the duration of wave exposure and strength of wave energy reaching the coast each year. These effects have important implications for coastal stability and the character of seafloor habitats, with related impacts on nutrient transfer and ecosystem health. In the shallow shelf regions of the coastal Arctic, sea ice that is both attached to the land and grounded on the seafloor (known as landfast ice) has an outsized impact on regional sea ice, ocean, and sediment dynamics. Landfast ice has been trending towards later freeze-up, coinciding more closely with the stormier season with high sediment transport rates, and likely increasing the connection with the off-shelf forcing. The overarching aim is to understand the feedbacks between sea ice, upper ocean processes – particularly, surface waves – and sediment transport during the highly spatially and temporally heterogeneous landfast ice formation period. The field experiment will focus on ice formation within an approximately 75 km x 50 km region on the Alaskan Beaufort shelf, centered on the 150N line extending northwards from the coast at Oliktok Point near Prudhoe Bay. Our research will take a nested approach to capture the spatial and temporal variability of physical feedbacks during the freeze-up. The expected outcomes of this project include better predictions of the atmospheric and off-shelf conditions that lead to landfast ice formation, and improved understanding of the sediment pathways on the Beaufort Shelf during the period of high transport and ice formation.

Sea salt aerosols are particles that are formed from blowing winds and breaking waves over the ocean surface. These particles can act as the building blocks for cloud droplets and eventually precipitation. Very large particles, known as giant sea salt aerosols (GSSA) have been historically difficult to observe because most instrumentation has been designed for smaller particles. There remains considerable uncertainty regarding the production and vertical mixing of GSSA particles within the lowest part of the atmosphere above the ocean?s surface. This study will make measurements of GSSA using a specialized instrument and combine that with numerical modeling to address questions about how these particles move through the atmosphere. This award is for observational and modeling research that will address a critical gap in aerosol research relating to giant sea salt aerosol production and distribution. The research plan consists of a three-pronged approach. The researcher will use the mini-Giant Nuclei Impactor to make observations of GSSA during research cruises from Hawai'i. These data will be analyzed to construct a distribution of GSSA from the turbulent wave layer through the mixed layer of the atmosphere.

Ocean/atmosphere coupling influences atmospheric river (AR) track, timing, and intensity. Uncertainty in ocean conditions both far upstream and just prior to landfall – as well as inadequacies in the parameterizations of air-sea exchange in forecast models – can yield significant forecast uncertainty even on short time horizons (1-3 d). Similarly, it is not yet clear the extent to which ocean/atmosphere interactions impact the development of extreme AR events, for example from “stalling” fronts (e.g. Zou et al. 2023), or those that occur during conditions of anomalous ocean heat content (e.g. El Nino; Bartusek et al. 2021). Key to improving our understanding of the coupled ocean/atmosphere evolution during the formation and passage of an atmospheric river is the collection of in situ research-grade air/sea fluxes and ocean boundary layer response in high resolution and in real time. Under past ONR funding, we have collaboratively developed a system that provides this information at the sea-surface and continuously across the ocean boundary layer to depths of several hundred meters, utilizing a unique ocean wave-powered profiler and a relatively low-cost, easy-to-deploy buoy.

This NOPP Global Internal Wave (GIW) Study aims to deploy Internal Wave Resolving (IWR) Arrays globally to analyze the generation, propagation and dissipation of internal waves in the ocean using a combination of high vertical-resolution moorings and bottom mounted echo sounders to determine wave modal structures, speed, and direction of internal wave propagation. These internal-wave resolving (IWR) arrays consist of current- and pressure-sensor-equipped inverted echo sounders (CPIESs), current-sensor-equipped PIESs (CPIESs), and a densely instrumented, full-depth mooring. The observations are being used to enable seamless, skillful modeling and forecasts of these internal waves between the deep ocean and the shore. In fall 2024, a partial IWR Array comprising 6 CPIESs was deployed on a cruise of opportunity around one of the tall moorings deployed by the Mixing belOw Tropical Instability waVEs (MOTIVE) team in the Equatorial North Pacific. These CPIESs will be recovered as part of the MOTIVE recovery cruise.

This project supports an oceanographic field campaign in the tropical Pacific to make high temporal and spatial resolution measurements from moorings and ship of the oceanic velocity, density, and microstructure. Observations will be made of westward propagating oceanic fronts in the presence of Tropical Instability Waves (TIW) to better understand their influence on mixing and modulation of oceanic internal waves. The proposed work has important implications for understanding the El Nino Southern Oscillation (ENSO) and the role of the tropical oceans in climate. Education and outreach for this project will include mentoring a graduate student and postdoc, science presentations at local high schools, mentorship for Research Experience for Undergraduates (REU) interns, and participation in the Ocean Discovery Institute homework assistance program. This project addresses the dynamic processes that govern the observed modulation of internal waves, and turbulent mixing, by TIWs in the equatorial Pacific and the potential effects on heat regulation and ENSO predictability. Mechanisms to be studied include radiation of downward propagating internal waves from TIWs, modulation of the internal wave field by TIWs, and the fate of the internal waves in the presence of critical layers. The observational campaign will employ moorings, ship-mounted acoustics, ship-based profiling systems including a rapid profiling CTD (fastCTD) and a turbulence profiler (Epsilometer), and three autonomous drifting wave-powered profilers (WireWalkers). Three moorings will be deployed for a year north of the operational 140°W Tropical Atmosphere Ocean (TAO) mooring to target the seasonal cycle in the TIW modulation of internal waves and mixing.

Despite considerable research, debate persists about the relative importance of potential causes of the Cretaceous-Paleogene (K-Pg) mass extinction (66.0 Ma). The Coring Seymour Island project will focus on developing a more rigorous description of extinction patterns and depositional conditions during the K-Pg interval from a high paleolatitude location to better understand the nature of the K-Pg mass extinction. Macrofossils from this site are well-preserved and consequently well-studied, but sedimentary structures, geochemistry, and microfossils have all been significantly affected by recent surface oxidative and freeze-thaw weathering, and have received significantly less research. Surficial chemical and physical alteration has complicated interpretation of Seymour Island deposits, which represent the only high southern latitude K-Pg outcrop section. To move past the weathering horizon and collect more pristine material, drilling (supported by IDP) will recover sedimentary cores from high priority stratigraphic intervals. These cores will permit sampling at a much higher stratigraphic resolution and with much greater geochemical fidelity when compared with previous work attempted from surface samples. As contingency plan for any coring difficulties, rock samples from hand trenches will be recovered from previously identified areas with high erosion rates to try to access the least altered material possible.

This project comprehensively evaluates sea ice characteristics in the Weddell Sea, and parses the effects of sea ice melt on biological systems and carbon export through a dual approach involving environmental observations and replicated factorial incubation experiments. Snow pits and ice cores will be used to characterize physical (snow density, hardness, temperature, and grain size and shape) and chemical parameters (δ¹⁸O, nitrate + nitrite, and Fe concentrations) of sea ice. Physical characteristics will be used to better calibrate satellite observations and improve future remote sensing. Chemical parameters will help determine how much meltwater is sea-ice derived and will further constrain the impact of sea ice melt on macro and micro nutrient availability in the surface mixed layer. The spatial evolution of sea ice melt across the Weddell Sea continental shelf will be quantified through conductivity, temperature, and depth transects extending from Seymour Island to the shelf break. These transects will also include seawater sampling, zooplankton tows, and deployment of an in situ particle imager to characterize microbial, phytoplankton, and zooplankton communities and calculate particle flux. Experimental incubations will constrain the impacts of changing salinity, light, and nutrient regimes associated with ice melt on biological productivity, particle formation, and export potential.

This project will investigate a new Antarctic marine partnership between the ascidian (“sea squirt”) Synoicum adareanum and its microbiome, which includes a specific relationship with the bacterium Candidatus Synoicihabitans palmerolidicus. This bacterium produces the natural product palmerolide A (palA), an in vitro inhibitor of the enzyme V-type H+-ATPase (VHA). The objectives include: (i) Determining the microbiome composition, metabolome complexity, palA levels, and mitochondrial DNA sequence of S. adareanum morphotypes at sites in the Antarctic Peninsula and in McMurdo Sound, (ii) Characterizing the Synoicum microbiome using a multiomics strategy, and (iii) Assessing the potential for co-occurrence of Ca. S. palmerolidicus-palAVHA in host tissues and exploring the role of palA in modulating VHA activity in vivo and its effects on ascidian-microbe ecophysiology. Through a coupled study of palA-producing and non-producing S. adareanum specimens, we will characterize structural and functional features of the ascidian microbiome metagenome to better understand the relationship between predicted secondary metabolite pathways and whether they are expressed in situ using a paired metatranscriptome sequencing and secondary metabolite detection strategy. Combined with tissue co-localization results, functional ecophysiological assays aim to determine the roles that the natural product plays in the host ecology in its native Antarctic seafloor habitat.

Sikuliaq's 2026 shipyard and drydock will affect most of the transducers on the ship. The EM710 array will be entirely removed. A new centerboard shoe, including an entirely new multibeam system, an EM2042, will be installed. This will require patch testing of the EM2042. The EM304, our primary multibeam, will also have the fasteners for the ice windows replaced which will require re-leveling the transducer arrays. A SAT test would be appropriate after doing this. One of the EK80 transducers will be replaced, and all of them will be moved, either onto the new shoe, or to a new "Ice Can" on the sonar flat. The Beaufort sea shelf, Bering sea and Chukchi seas are all relatively shallow with very little being mapped at the resolution that the EM2042 will offer. Every year we have multiple funded cruises working in these areas. This calibration cruise would ensure the new multibeam system is fully functional after installation. We're requesting 3 days for the most important tests on the two multibeam systems. This is the minimum amount of time needed for QAT testing, per discussions with the MAC.

In support of the National Oceanographic and Atmospheric Administration (NOAA) Ocean Acidification (OA) Program, this mission will OA processes along the continental shelf off the Pacific coast of North America. The West Coast Ocean Acidification Cruise is part of the North Atlantic Ocean, East and Gulf Coast ocean acidification observing network. The legislative driver for this effort is the Federal Ocean Acidification Research and Monitoring Act of 2009 (FOARAM) act. NOAA is tasked with establishing a long-term monitoring program of ocean acidification utilizing existing global and national ocean observing assets. The main cruise objectives are: 1) Characterize the status of OA; 2) Carry out calibration measurements in proximity to OA observatories, in particular buoys equipped with OA sensors; 3) Generate calibration data necessary to develop predictive models of aragonite saturation status, pH, and other important OA indicators across the entire extent of the California Current system; 4) Carry out biological measurements (plankton) in conjunction with physical and chemical measurements of OA; 5) Possibly deploy Biochemical Argo Floats in deep waters (more than 2000m deep); and 6) Provide scientific information on the conditions of OA to support decision making and the best management of natural resources

NSF Directorate for Geosciences Office of Integrative Activities

We will investigate the role of stratification in governing the quality of organic particles and particulate flux to the seafloor, as a potential control on benthic-pelagic coupling and the supply of food resources for lower trophic-level consumers. We hypothesize that stratification influences nutrient cycling and distribution, contributing to differences in composition of plankton communities among water masses, which in turn affect the biochemical composition of organic particles. Our project will quantify biogeochemical processes in distinct water masses of the NBS, characterizing structure of plankton communities, sinking rates and quality of organic particles they produce, and the fate of these particles at the seafloor as they are processed by the benthic community. A coordinated field effort will involve both vessel- and mooring-based physical, chemical, biological and biogeochemical measurements designed to capture mechanistic links between water-column stratification and the nature and fate of organic material. Ship-based surveys and moored instrumentation will be used to characterize stratification in the NBS during the summer months, and to sample plankton communities and particles in discrete water masses on either side of density interfaces, e.g. the Bering Sea cold pool and the overlying surface water.

Characterizing Arctic ocean-ice-atmosphere variability and predicting the system’s evolution on synoptic to seasonal timescales requires observations that span a broad range of spatial and temporal scales. Forecast quality depends on observations for initialization, assimilation, and for informing how the simulations represent unresolved physics. Data intended for use in nowcast/forecast efforts must be delivered in a timely fashion - a challenging requirement for polar regions where ice blocks access to satellite services. To support Navy missions in the ice-covered Arctic, this effort builds on technologies developed during the Arctic Mobile Observing Innovative Naval Prototype (AMOS INP) to maintain a multi-year, persistent presence in the central Arctic to investigate the pathways through which incoming Pacific waters make their way into the central Arctic, and broader questions of the mechanisms responsible for the transfer of heat and momentum in upper ocean. Efforts will also focus on extending the technologies and approaches that allow long-term, persistent autonomous observing, including infrastructure that supports geolocation, platform networking and data exfiltration.

Field work will include water sampling by CTDs and sediment sampling using piston cores, multicores, and trawls.