Science Highlights
Identifying Impacts of Ocean Acidification and Hypoxia
Ocean acidification has emerged as a leading threat to marine ecosystems, and the fisheries and shellfish growers that depend on a productive and vibrant ocean. The Coastal Endurance Array in the Pacific Northwest array is situated in an epicenter for early impacts from the co-occurrence of ocean acidification and hypoxia.
Read MoreDrivers of Ocean Overturning Circulation Revealed
rminger Surface Mooring data were used to identify a new mechanism by which the atmosphere controls ocean heat loss leading to dense water formation. The results are particularly important as the connection between air-sea exchanges and the ocean circulation is still poorly understood, hindering attempts to understand the climate change induced slowdown of the Atlantic circulation.
Read MoreSouthern Ocean Air-Sea Interaction
The Southern Ocean is an important region in the global ocean uptake of heat and carbon. Data collected by OOI’s Global Southern Ocean Surface Mooring helped identify extreme heat loss events driven by cold Antarctic winds in driving the seasonal mixed layer deepening in the region and dramatic year-to-year variations.
Read MoreInternal Tide Impacts on Ocean Circulation
Internal tides (ITs) have critical roles in determining the meridional overturning circulation and oceanic heat budget. The Regional Cabled and Coastal Endurance Arrays data are making it possible to identify the impacts of changes associated with the ITs.
Read MoreMarine Heatwaves
The Coastal Endurance, the Regional Cabled, and the Global Station Papa Arrays were key in identifying and monitoring the approach of a marine heatwave known as the “Blob” and its links to multiple ecosystem impacts on the US west coast.
Read MoreAccelerating Marine Ecological Research
Mid-trophic level organisms, such as zooplankton and forage fish, play a critical role in mediating energy transfer from primary production to top predators in the marine ecosystem. Using Coastal Endurance Array echosounders, scientists are observing long-term changes in the distribution and abundance of this important part of the marine food web.
Read MoreNew View of Biological Carbon Pump
The ocean’s biological carbon pump plays an important role in the global carbon cycle. Using OOI data from the Global Irminger Sea Array, researchers discovered that much of the organic carbon exported from the surface is ventilated back to the atmosphere, rather than being sequestered long-term as had been previously thought.
Read MoreSlope and Shelf Flow Anomalies Off Oregon
Slope and Shelf Flow Anomalies Off Oregon Influenced by the El Niño Remote Oceanic Mechanism in 2014–2016
Adapted and condensed by OOI from Kurapov et al., 2022, doi.org/10.1029/2022JC018604.
[media-caption path="/wp-content/uploads/2023/01/Endurance-science-highlight-fixed.png" link="#"]Time series of the daily averaged meridional current component at the Oregon shelf location, averaged in the vertical between 60 and 70 m below the surface: (red) ADCP data and (black) model. Data from before 2015 come from various moorings maintained at the NH-10 site. Data after 2015 come from the OOI Oregon shelf site. The model reproduces the observed variability over the entire 10-year period very well, except for episodes in Dec 2010 and Oct 2013. Overall, no systematic biases or trends are found. See Fig. 7 Kurapov et al. (2022).[/media-caption]Kurapov et al. analyze outputs of a regional ocean circulation model to demonstrate the measurable impact of the El Niño remote oceanic forcing mechanism along the US West Coast during the major heat wave period of 2014–2016. The 2-km horizontal resolution model, based on the Regional Ocean Modeling System (ROMS), was run for the period of 2009–2018. Though the model does not assimilate observations, it performs well by comparison with time series data (including OOI data, Figure above) explaining observed variability on temporal scales from several days to seasonal and interannual.
The El Niño-related oceanic anomalies provided by a global state estimate are introduced in the regional model at the southern boundary at 24N. These propagate alongshore with coastally trapped waves (CTWs) and influence the variability off Oregon (41°–46°N). In particular, CTWs are evident in the subsurface along-slope current, vs, and in the depth of the 26.5 kg m3 isopycnal surface over the slope, z26.5. In summer 2014 and 2015, vs anomalies are positive (northward) and z26.5 anomalies are negative (deeper) along the US West Coast. In addition to the CTW patterns, z26.5 anomalies also exhibit slow-moving features associated with undercurrent widening, separation, and subsurface eddy variability. Over the Oregon shelf, El Niño conditions contributed to the sharp weakening of the southward alongshore current throughout the water column in July 2014 and 2015, despite the near-average southward, upwelling-favorable winds.
Kurapov, A. L., Rudnick, D. L., Cervantes, B. T., & Risien, C. M. (2022). Slope and shelf flow anomalies off Oregon influenced by the El Niño remote oceanic mechanism in 2014–2016. J. Geophys. Res.: Oceans, 127, e2022JC018604. doi.org/10.1029/2022JC018604.
Read MorePythias Oasis: The First-of-Its-Kind Seep in the Oceans
Adapted and condensed by OOI from Philip, et al., 2023, doi: 10.1126/sciadv.add6688.
[media-caption path="/wp-content/uploads/2023/01/Screen-Shot-2023-01-26-at-10.21.55-AM.png" link="#"] a) A multibeam sonar image of the methane bubble plumes at Pythias Oasis in 2015. b) Pythias orifice in 2015 showing the fluid-dominated, sediment-rich plume, as first visualized on the discovery dive by the ROV ROPOS. The main orifice has been continuously active since 2015. c) Pythias’ orifice in 2021 with increased biological communities and a small Fe-rich chimney. d) The edge of a large collapse-blowout zone – coring across this area in 2019 recovered substantial methane hydrate. e) A Neptunea snail nursery between the orifice site and the blowout zone.[/media-caption]Pythias Oasis is the first-of-its-kind seep in the oceans, providing a window into controls on megathrust events along the Cascadia Margin. Pythias Oasis, discovered during the 2015 Regional Cabled Array (RCA) Operations and Maintenance Cruise, utilizing the hull-mounted sonar on the R/V Thompson, is unlike any seep site yet described along active margins with unprecedented fluid chemistries (Figure above). It hosts an intense fluid-dominated venting system issuing low-salinity, hydrocarbon-bearing fluids carrying low concentrations of suspended particles from a discrete orifice that has been continuously active since 2015. Detailed sampling, as part of an NSF OCE-funded expedition in 2019 (OCE 16582901), and another dive in 2021 (added onto the RCA 2021 cruise) show that the fresh, warm fluids (four times background temperatures) are venting at the highest discharge rates yet measured within the Cascadia Subduction Zone (CSZ) and that the fluids are extremely enriched in boron lithium and iron.
Pythias Oasis provides a rare window into processes acting deep in the margin with fluid chemistries indicating that the fluids are sourced near the plate boundary in the Central CSZ at minimum temperatures of 150-250°C. The high discharge rates are thought to reflect draining of fluids along an over-pressurized reservoir associated with the subduction zone-perpendicular Alvin Canyon strike slip fault, suggesting that the faults regulate pore fluid pressure and megathrust slip behavior along the Central CSZ.
Results from this work are presented in Philip, B.T., E.A. Solomon, D.S. Kelley, A.M. Tréhu, T.L. Whorley, E. Roland, M. Tominaga, and R.W. Collier (2023) Fluid sources and overpressures within the central Cascadia Subduction Zone revealed by a warm, high-flux seafloor seep. Science Advances (9), doi: 10.1126/sciadv.add6688.
Read MoreAn Overview of Ambient Sound Using OOI Hydrophones
Adapted and condensed by OOI from Ragland, et al., 2022, doi.org/10.1121/10.0009836.
[media-caption path="/wp-content/uploads/2022/11/RCA-highlight.png" link="#"]Figure 1: Highlights of acoustic features from the five low frequency (Fs=200Hz) and six broadband (Fs = 64 kHz) hydrophones on the RCA.[/media-caption]Ragland et al., (2022) provides a wonderful overview of the unique opportunities for data and experimentally driven advancements in acoustics that are provided by (long-term) ambient sound recordings streamed live from hydrophones on the Regional Cabled Array. Figure 1, above (after Figure 5, Ragland et al., 2022), highlights acoustic features from the five low frequency (Fs=200Hz) and six broadband (Fs = 64 kHz) hydrophones on the RCA. Areas of research span the rare ability to conduct offshore monitoring of Fin whale migration, and the seasonal fluctuations and decade-long evolution of their calls, in situ offshore meteorological measurements with high temporal resolution to study wind and rain noise in the NE Pacific, the sound from commercial ships with impacts on the oceanic environment and marine life, ambient noise interferometry, volcanic eruptions, and both local and far-field earthquakes. As the authors note, the RCA-OOI data also provide significant opportunities for the development of machine learning tools for ocean acoustics. This work was supported by an award from the Office of Navy Research. The authors developed a public Python package (OOIPy) to access and explore the hydrophone data more easily (Schwock et al., 2021). OOIPy is also accessible through the OOI website tab Community Tools and Datasets.
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Ragland, J., F. Schwock, M. Munson, and S. Abadi (2022) Journal of the Acoustic Society of America, 151, 2085-2100, https://doi.org/10.1121/10.0009836.
Schwock, F., J. Ragland, L. Setiawan, M. Munson, D. Volodin, and S., Abadi (2021). OOIPY v1.1.3: A Python toolbox designed to aid in the scientific analysis of Ocean Observatories Initiative data, https://doi.org/10.5281/zenodo.5889288.
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