After two weeks of quarantine at home where possible, Airbnbs, and deserted family vacation homes, the 12-member Endurance Array team will head to Newport, Oregon on July 1 to board the R/V Thomas G. Thompson. As part of COVID-19 precautions, all of the needed equipment to service the Endurance Array will have been transported to the pier by non-seagoing staff prior to their arrival. The seagoing staff will simply arrive at the dock, load the ship, and then go to sea.
Under normal circumstances, the array is serviced – that is moorings are recovered and new ones deployed to ensure that the collection and transmission of ocean data continues seamlessly – twice a year. The regularly scheduled expedition this spring was canceled due to the coronavirus epidemic, so the cruise this summer will combine the work of the spring and fall expeditions.
“We are pleased to be able to get to the arrays this summer and to work aboard the R/V Thomas G. Thompson. This ship is large enough to give us all enough space to adequately social distance while onboard,” said Ed Dever, project scientist and principal investigator for the Endurance Array project. The ship will sail from its homeport in Seattle to meet the Endurance Array team in Newport, Oregon.
“With COVID-19 keeping some researchers on land, people are more interested than ever in the data that we collect remotely using the OOI. It’s important to have this opportunity to recover and replace the equipment at our Oregon and Washington lines,” Dever added.
The expedition will involve replacing seven moorings at six locations and the deployment of four gliders and four coastal surface piercing profilers. The team also will be measuring salinity, temperature, density, oxygen, and chlorophyll as a function of depth, during CTD casts before and after mooring recoveries. These onsite real-time data are publicly shared, as are all data continuously collected by the arrays throughout the year.
This expedition will involve three legs, traveling back and forth between different locations in the array and Newport to unload and pick up the huge coastal moorings. (Estimated weight of ~ 11 tons/per mooring). In total, the team will travel an estimated 1000 nautical miles during the expedition.
Dever’s OOI colleague Jon Fram at Oregon State University will be the chief scientist on this expedition. He remarked, “COVID-prevention has significantly changed operations onshore as well as while we are aboard the Thompson. Even for the seemingly simple task of ensuring that everyone had adequate masks for the duration, we tried out six different mask styles to find one that would be comfortable enough for everyone to wear for the duration of the journey. We also had to figure out how to achieve appropriate social distancing while onboard, which will change our normal operations.”
The Endurance Array team usually invites graduate students along on these expeditions to provide extra sets of hands, while offering mentoring opportunities and shipboard experiences for future potential marine scientists. During this summer expedition, only one graduate student will be onboard, who has previous experience on similar cruises.
Collaborative non-OOI scientific experiments, however, will take place. The Endurance Array team will gather the data rather than the non-OOI scientists involved, who would normally be onboard. Three different non-OOI experiments will occur. The first involves Linsey Haram of the Smithsonian, who collects fouling communities that grow on panels attached to OOI buoys. Ashley Burkett of Oklahoma State University is involved in the next, which entails collecting settling organisms on devices attached to the Seafloor Multi-Function Nodes (MFN) at the base of some surface moorings and act both as an anchor as well as a platform to affix instruments. The third, proposed by Taylor Chapple of Oregon State University, involves testing deployment of tagged fish acoustic monitors on the Near-Surface Instrument Frame (NSIF), a cage containing subsurface oceanographic instruments attached to multiple data concentrator logger computers.
Added Dever, “These three experiments are great examples of how scientists can become involved in the OOI and access the data they need. They demonstrate how scientists can have access to ocean data without ever having set foot aboard a ship.”
After the Endurance Team’s expedition, the Regional Cabled Array team will board the R/V Thomas G. Thompson on 30 July to begin a month-long expedition to service the RCA array, which provides power and equipment to a multitude of data gathering ocean equipment on the ocean floor.Read More
A team from Woods Hole Oceanographic Institution (WHOI) was onboard the R/V Neil Armstrong at the Pioneer Array, about 75 nautical miles south of Martha’s Vineyard in the Atlantic, deploying equipment and collecting data. Due to COVID-19 restrictions, the number of the science party onboard was limited. These limits prevented participation by the Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) team, whose members would have been onboard under normal circumstances.
But through an innovative use of onboard technology, WHOI’s Shipboard Scientific Services Group made it possible for the NES-LTER team to receive data and images of phytoplankton and microzooplankton in near-real-time along the cruise track. The data were collected by Imaging FlowCytobots (IFCBs), which provide long term, high-resolution measurements of phytoplankton abundance and their cell properties. The data can be viewed here.
Said WHOI researcher Taylor Crockford from her research laboratory on land, who beta-tested the data transmission with the WHOI onboard team, “In this challenging time of the Coronavirus, we are thankful for this opportunity to continue long-term research into the productivity and food web on the Northeast U.S. Shelf while the cruise was underway.”
The Ocean Observatories Initiative is funded by the National Science Foundation.Read More
The first issue of Download, the OOI’s new newsletter, was released on 1 May. It provides a short, concise look at the OOI, with clickable links for digging deeper into specific topics. It covers the latest OOI developments, scientific advances being made using OOI data, and opportunities for you to participate in the OOI, through help with proposals, data use, workshops, and other events.
Sound is omnipresent in the ocean. Human-induced noise has the potential to affect marine life.
After the global recession in 2008, the ocean became quieter as shipping declined. Off the coast of Southern California, for example, scientists at Scripps Institution of Oceanography found that noise amplitudes measured from 2007-2010 were lowered by 70 percent with a reduction in one ship contributing about 10 percent.
A similar quieting of the ocean can be expected as global ship traffic continues its decline in response to the corona virus pandemic. This quieter ocean offers scientists ways to expand their ongoing research on ocean sound and its impact on marine life.[media type="image" path="https://oceanobservatories.org/wp-content/uploads/2020/04/Finhval_1.jpg" link="#" alt="Fin Whale"][/media]
“It takes time to document real change in the ocean, but University of Washington oceanographers have reported that over the past decade, fin whales have been communicating more softly in the Pacific,“ said Deborah Kelley, professor of oceanography at the University of Washington and director of the OOI’s Regional Cabled Array (RCA) component. “A quieter ocean allows us to hear more clearly life and other natural processes within the ocean.”
Years of listening to whales
John Ryan, a biological oceanographer at the Monterey Bay Aquarium Research Institute (MBARI), has been “listening in” on whales and other marine creatures since 2015 using a hydrophone on the Monterey Accelerated Research System (MARS), a cabled observatory, which was in part established as a test bed for the OOI Regional Cabled Array. Ryan and colleagues studied the occurrence of humpback whale (Megaptera novaeangliae) song in the northeast Pacific using three years of continuous recordings off the coast of central California.[media type="image" path="https://oceanobservatories.org/wp-content/uploads/2020/04/Humpback_Whale_underwater_shot.jpg" link="#" alt="Humpback Whale"][/media]
“We’ve been listening almost continuously since July 28, 2015, using a broadband, digital, omnidirectional hydrophone connected to MARS. Listening continuously for that long at such a high sample rate is not easy; only by being connected to the cable is this possible,” explained Ryan.
The researchers were able to discern whale songs from the busy ocean soundscape in Monterey Bay National Marine Sanctuary, which is a feeding and migratory habitat for humpback whales. The humpbacks’ song was detectable for nine months of the year (September–May) and peaked during the winter months of November through January. The study revealed strong relationships between year-to-year changes in the levels of song occurrence and ecosystem conditions that influence foraging ecology. The lowest song occurrence coincided with anomalous warm ocean temperatures, low abundances of krill – a primary food resource for humpback whales, and an extremely toxic harmful algal bloom that affected whales and other marine mammals in the region. Song occurrence increased with increasingly favorable foraging conditions in subsequent years.
Because the hydrophone is on the cabled observatory, its operation can be adjusted to achieve new goals. For example, the sampling rate of the hydrophone was doubled during an experiment that successfully detected very high frequency echolocation clicks of dwarf sperm whales (with Karlina Merkens, National Oceanic and Atmospheric Administration). “And that’s a beautiful aspect of being on the cable,” added Ryan. “Not only do we know that it is working, we catch any network glitches pretty quickly so we don’t lose data, and we can do real-time experiments like these.”
William Wilcock of the University of Washington and his students have compiled a decade worth of data on fin whales in the northern Pacific. Fin whales call at about 20 HZ, which is too low of a frequency for humans to hear, but perfect for seismometers to record. The researchers aggregated ten years of data from both temporary recorders and now permanent RCA hydrophones and seismic sensors and looked at the frequency of the calls and calling intervals. The researchers found both have changed over time.
The fin whales call seasonally and the frequency of the calls has gone down with time.[audio mp3="https://oceanobservatories.org/wp-content/uploads/2020/04/Fin_whale_10x.mp3"][/audio]
Calls peak in late fall, early winter in relation to mating season. Gradually through the season the frequency decreases. At the start of the next season, the call frequency jumps up again, but not quite to where it was the year before. Over ten years, the frequency has gone down about 2 HZ, and scientists are puzzled as to why this is occurring. It is unlikely to be due to increasing ship noise, because this lower sound frequency is getting closer to the range of the noise level of container ship propellers, about 6-10 HZ.
In some settings, ship noise is known to affect whale behavior and the permanent network of hydrophones operated by the OOI and Ocean Networks Canada will provide an opportunity to study whether whales are avoiding the shipping lanes to Asia.
Volcanoes also rumble in the deep
Whale sounds are but one of many acoustic signals being recorded and monitored using hydrophones and broadband seismometers. The OOI’s RCA off the Oregon Coast includes 900 kilometers (~560 miles) of submarine fiber-optic cables that provide unprecedented power, bandwidth, and communication to seafloor instrumentation and profiler moorings that span water depths of 2900 m to 5 m beneath the ocean surface. Using a suite of instruments connected to the cable, which continuously stream data in real time, scientists are listening in on the sounds of submarine volcanism, which accounts for more than 80 percent of all volcanism on Earth.
More than 300 miles off the Oregon coast in 1500 meters of water, 20+ cabled seafloor instruments are located at the summit of Axial Seamount, the most active volcano on the Juan de Fuca Ridge, including hydrophones and seismometers, which can also record sounds in the ocean.
“Scientists were able to hear(as acoustic noises traveling through the crust) >8000 earthquakes that marked the start of the Axial eruption in 2015. Coincident with this seismic crisis bottom pressure tilt instruments showed that the seafloor fell about 2.4 meters (~8 feet).[video width="670" height="384" m4v="https://oceanobservatories.org/wp-content/uploads/2020/04/Axial-seamount-audio-.m4v"][/video]
It was a remarkable collaborative event with scientists from across the country witnessing the eruption unfold live,” added Kelley. Such real-time documenting of an eruption in process was possible because of how Axial is wired. It is the only place in the oceans where numerous processes taking place prior to, during, and following a submarine eruption are captured live through data streaming 24/7. William Wilcock, University of Washington, and Scott Nooner, University of North Carolina, Wilmington, and colleagues reported these findings in Science, 2016.
Data collected from the hydrophones at the seamount’s base supported another discovery about Axial, indicating that it explosively erupted in 2015. Hydrophones recorded long-duration diffusive signals traveling through the ocean water consistent with explosion of gas-rich lavas, similar to Hawaiian style fissure eruptions. Follow-on cruises documented ash on some RCA instruments, again indicating the likelihood of explosive events during the 2015 eruption.
“Having the opportunity to listen in while a submarine volcano is active offers a really interesting window into things,” said Jackie Caplan-Auerbach, associate dean at Western Washington University and lead author of a G-cubed article that reported the possible eruptive findings. “While we cannot say with utter certainty that there were explosions at Axial, there’s a lot of evidence that supports this. We know from having listened to other eruptions that this was the same type of sound. It’s distinct, like the hissing sound of a garden hose on at top speed. We also found these really fine particulates, which could only have resulted from an eruption, had collected on one of the instruments at the site.”[audio wav="https://oceanobservatories.org/wp-content/uploads/2020/04/axial_explosive.wav"][/audio]
Added Caplan-Auerbach, “My favorite part of having OOI is it offers an ability for pure discovery. Its real time nature makes it possible to observe and see what happens. And sometimes the planet just hands you a gift that you didn’t expect. Not always being hypothesis driven is a very valuable aspect of science that I hope does not get lost. I’m very appreciative of projects like this that open our eyes into signals that we didn’t know were there.”
More opportunities to expand knowledge about sound and the sea are on the horizon. The US. Navy has funded Shima Abadi, University of Washington, Bothell, for a comprehensive study of sounds recorded by the OOI hydrophones. Stay tuned!
Image credits: Top fin whale: Wikipedia, Aqqa Rosing-Asvid – Visit Greenland. Second from top: humpback whale: Public domain, National Oceanic and Atmospheric Administration.
The University-National Oceanographic Laboratory System (UNOLS), which coordinates oceanographic ships’ schedules, recommended on 17 March 2020 that cruise activities be paused for 30 days due to the COVID-19 pandemic. On 30 March UNOLS extended its guidance to suspend research cruises to July 1 2020. This action is designed to protect the health and safety of the crews and scientific parties.
The planned spring operation and maintenance (O&M) cruise to the Endurance Array in March was affected by the original 30-day guidance. The upcoming O&M cruises for the Pioneer, Irminger, and Papa Arrays aboard R/V Neil Armstrong and R/V Sikuliaq are impacted by this latest guidance.
The OOI is working with UNOLS and ship operators to find potential opportunities to complete the scheduled cruises and conduct needed maintenance on the arrays. In the meantime, there’s been no interruption in OOI data. OOI data continue to be collected and made available for use by the scientific and educational communities.Read More
OOI data team members have developed a new toolbox for downloading data from the Machine-to-Machine (M2M) interface using MATLAB, making data access as easy as 1, 2, 3. The work expands on the existing tools available on OOI. This new toolbox covers data from moorings, gliders, and profilers in the OOI Coastal Arrays and can easily be extended to other research platforms. A video tutorial on how to use this new tool is provided above. (A pdf of the tutorial is provided below).
In three short steps – define the mooring, node, and instrument – users can easily and quickly access relevant OOI data. “This new approach eliminates some steps and makes it easy for anyone to find and access data they are looking for, “said Jonathan Fram, OOI Endurance Array Project Manager at Oregon State University (OSU). “We found this new approach really streamlined data access using the M2M interface and we are certain other OOI data users will find it similarly helpful.”
Developed by OOI OSU team members, Craig Risien and Russ Desiderio, these new tools are part of our ongoing effort to simplify access to OOI data to encourage its broader integration into scientific research and classroom content. A tutorial showing how to use MATLAB to access OOI data can be viewed here.
Other members of the OOI OSU team, Chris Wingard and Ian Black, are testing Python and R tools to explore OOI data, as well. Once the tools have been tested and vetted, they will be available along with other community-generated tools here.
This new tutorial adds to others that have been developed to help users integrate OOI data into their science.Read More
“Just like lightning,” in one-minute presentations, 15 scientists shared amazing ways they are using OOI data in scientific investigations and in the classroom. This round of lightning talks capped the Ocean Observatories Initiative Facility Board’s (OOIFB) Town Hall at the 2020 Ocean Sciences Meeting on 20 February, demonstrating the multiple and creative ways OOI data are being used to answer key science questions in a changing environment.
The presentations ranged from how students are using real-life and real-time OOI data to advance their understanding of scientific principles to how researchers are using OOI data to identify the presence of marine life by sound to how modelers are making OOI data more accessible and useable.
“We were simply thrilled by the depth, breadth, and range of applications of OOI data shown during this lightning round,” Kendra Daly, chair of the OOIFB. “We were pleased so many presenters were willing to accept the challenge. This enthusiastic response clearly shows that OOI data are being used to help answer important science questions.”
Brief summaries of the talks are presented below.
Isabela Le Bras, Scripps Institution of Oceanography, reported on a recent article in Geophysical Research Letters, where she and her colleagues describe how they used data from the Irminger Sea Array moorings (2014–2016) to identify two water masses formed by convection and showing that they have different rates of export in the western boundary current. Upper Irminger Sea Intermediate Water appears to form near the boundary current and is exported rapidly within three months of its formation. Deep Irminger Sea Intermediate Water forms in the basin interior and is exported on longer time scales. The subduction of these waters into the boundary current is consistent with an eddy transport mechanism. The eddy transport process is more effective for the waters cooled near the boundary current, implying that cooling near boundary currents may be more important for the climate than has been appreciated to date.
Since 2017, Clare Reimers and Kristen Fogaren, Oregon State University, have been working to assess seasonal variability in benthic oxygen consumption and the contribution of benthic respiration to the development of hypoxic conditions in the northern California Current, using time series data from the OOI Endurance Array. Reimers and Fogaren measured benthic oxygen consumption rates using in situ eddy covariation techniques and ex situ core incubations, during a series of ten cruises that allowed sampling near the Endurance Oregon Shelf and Inshore stations, in all seasons. During these cruises, the researchers used real-time data provided by the Endurance Array to optimize the settings for their eddy covariance deployments. They are now examining property-relationships in discrete bottom water samples collected during the cruises and using data from OOI assets to help separate influences of mixing and biochemical processes in the water column and sediments. The researchers are also synthesizing benthic flux measurements and placing these rates in the context of cross-shelf glider measurements and benthic node time series.
Adrienne Silver, University of Massachusetts Dartmouth provided details about how she is using Pioneer Array data to learn more about the influence of warm core rings on Shelf break circulation. Results from a 40-year Warm Core Ring census show a regime shift in warm core ring formation at 2000, with the number of rings doubling from an average of 18 rings per year (during 1980-1999) to 33 rings per year (during 2000-2019). This regime shift creates a large increase in the amount of warm salty water being transported northward toward the shelf from the Gulf Stream. The preferred pathway of these rings, or the Ring Corridor seem to indicate their proximity to the shelf break and the Pioneer array during their lifetime. The goal of Silver’s project is to understand how these warm core rings affect the shelf break exchange while traveling along the shelf. A large focus of the study will be on the salinity intrusion events which might be sourced from these warm core rings.
Liz Ferguson, CEO and founder of Ocean Science Analytics, is using data from OOI’s Coastal Endurance and Regional Cabled Arrays to determine the variables that are most useful for assessing the ecosystem of this region and obtaining baseline information on marine mammal acoustic presence for use in monitoring. Using long term physical and biological data provided by these arrays, Ferguson is assessing long-standing shifts in the ecology of this coastal and offshore environment by associating physical oceanographic variables with the vocal presence of marine mammals using the broadband hydrophone data. Temporal changes in the occurrence of marine mammal species such as killer whales, sperm whales and dolphins can be used as an indicator of ecosystem shifts over time. She is analyzing passive acoustic data provided by the OOI arrays to determine the presence of vocally active marine mammal species, identify their spatial and temporal use of these sites, and combining this information with the physical oceanographic variables to assess the ecological characteristics associated with marine mammal occurrence.
Sam Urmy of the Monterey Bay Aquarium Research Institute (MBARI) also is using OOI acoustical data in his research. Using an upward-looking echosounder and a high-frequency hydrophone at MBARI’s Monterey Accelerated Research System, Urmy showed how small animals in the epipelagic and mesopelagic altered their behavior in response to predators. These responses included abrupt dives during bouts of foraging by dolphins, changes in depth to avoid predatory fish schools, and dramatic alterations to daily vertical migratory behavior. Continual observations of the mesopelagic with active and passive acoustics are revealing several dynamic predator-prey interactions in an ecosystem that is typically thought of as relatively slow and static.
Veronica Tamsitt of the University of New South Wales used the OOI’s Southern Ocean mooring and the Southern Ocean Flux Site (SOFS, in the Southeast Indian) to study the Sub Antarctic Mode water (SAMW) formation. Tamsitt’s and her colleagues findings were reported in the Journal of Climate in March 2020. Using data from the two mooring locations, the researchers were able to compare and contrast characteristics and variability of air-sea heat fluxes, mixed-layer depths, and SAMW formation. The researchers found that inter mixed-layer depth anomalies tended to be intermittent at the two moorings, where anomalously deep mixed layers were associated with anomalous advection of cold air from the south, and conversely shallow mixed layers correspond to warm air from the north. Both the winter heat flux and mixed-layer depth anomalies, however, showed a complex spatial pattern, with both positive and negative anomalies in both the Indian and Pacific basins that Tasmitt and colleagues relate to the leading modes of climate variability in the Southern Ocean.
Editor’s note: The Southern Ocean Array was decommissioned in January 2020. Its data, however, are still available for use by researchers, students, and the public.
Bringing OOI data into the classroom
Sage Lichtenwalner, Department of Marine and Coastal Sciences at Rutgers, The State University of New Jersey reported on the progress of the Ocean Data Labs Project. This project is a Rutgers-led effort to build a “Community of Practice” to tap into the firehose of OOI ocean data to support undergraduate education. To date, the project has hosted four “development” workshops that introduced participants to the OOI, conducted data processing with Python notebooks, and shared effective teaching strategies, in addition to a series of introductory workshops and webinars. As part of the development workshops, 56 university, college, and community college faculty designed 19 new “Data Explorations,” featuring web-based interactive “widgets” that allow students to interact with pre-selected data from the OOI. The project also sponsors a series of webinars, a fellowship program, and is compiling a library of resources (including coding notebooks, datasets, and case studies in teaching) to help the community.
Cheryl Greengrove, University of Washington Tacoma, summarized an article in the March issue of Oceanography that she and colleagues from across the United States wrote detailing ways to integrate OOI data into the undergraduate curriculum. The wealth of freely-accessible data provided by OOI platforms, many of which can be viewed in real or near-real time, provides an opportunity to bring these authentic data into undergraduate classrooms. The TOS article highlights existing educational resources derived from OOI data that are ready for other educators to incorporate into their own classrooms, as well as presents opportunities for new resources to be developed by the community. Examples of undergraduate introductory oceanography OOI data-based lessons using existing interactive online data widgets with curated OOI data on primary productivity, salinity, and tectonics and seamounts are presented, as well as ways to use OOI data to engage students in undergraduate research. The authors provide a synthesis of existing tools and resources as a practical how-to guide to support new resource development and invite other educators to develop and implement new educational resources based on OOI data.
Matthew Iacchei, Hawaiʻi Pacific University, presented how he has been integrating OOI data explorations to supplement his upper division oceanography lecture and labs with real data from around the world. Last semester, he had students explore patterns of dissolved oxygen and impacts of anoxia at the coastal endurance array in Oregon and compare that data to dissolved oxygen data the students collected in Kāneʻohe Bay, Hawaiʻi. This semester, students are working through two exercises with OOI data as part of their primary productivity lab (perfect, as it is now online!). Students will compare vertical profiles from Hawaiʻi with seasonal variations across the world, and will compare latitudinal drivers of primary production using data from a time-series from the Southern Ocean Array.
Strengthening OOI data usability
Wu-Jung Lee, a senior oceanographer at the Applied Physics Laboratory, University of Washington, is using data collected by the OOI to develop new methodologies for analyzing long-term ocean sonar time series. In a project funded by the National Science Foundation, she and her colleagues show that unsupervised matrix decomposition techniques are effective in discovering dominant patterns from large volumes of data, which can be used to describe changes in the sonar observation. Their preliminary analysis also show that the summaries provided by these methods facilitate direct comparison and interpretation with other ocean environmental parameters concurrently recorded by the OOI. A parallel effort that spun out of this project is an open-source software package echopype, which was created to enable interoperable and scalable processing of biological information from ocean sonar data.
As part of the Rutgers Ocean Modeling Group, in conjunction with University of California Santa Cruz, John Wilkin and Elias Hunter are delivering a high-resolution data assimilative ocean model analysis of the environs of the Pioneer Coastal Array, including a systematic evaluation of the information content of different elements of the observing network. The project uses the Regional Ocean Modeling System with 4-Dimensional Variational data assimilation. To produce a comprehensive multi-year (2014-2018) analysis required them to assimilate all available Pioneer CTD data, with quality checks, in a rolling sequence of data assimilation analysis intervals. They used three days of data in each analysis, which required queries to with a time range constraint and relevant platform (i.e. glider, profiler, fixed sensor), migrating all Pioneer CTD data (wire following profilers, gliders, fixed sensors, plus ADCP velocity) to an ERDDAP server. The simple graphing capabilities in ERDDAP allow quick browsing of the data to trace quality control or availability issues, and ERDDAP provides a robust back-end to other web services to create more sophisticated graphical views, or time series analysis. Using the ERDDAP Slide Sorter tool, they operate a quick look Control Panel to monitor the data availability and quality.
Mitchell Scott and colleagues Aaron Marburg and Bhuvan Malladihalli Shashidhara at the University of Washington, are studying how to segment macrofauna from the background environment using OOI data from the Regional Cabled Axial Seamount Array. Their long-term goal is to use an automated approach to study species variation over time, and against other environmental factors. Their initial step focuses specifically on scale worms, which are very camouflaged, making them difficult to detect. To address this, the researchers initially used a deep learning model, called U-Net, to detect and localize the scale worm locations within an image. To address the high rate of false positives using this model, they added an additional classifier (a VGG-16 model) to verify the presence of scaleworms. This combined, applied approach proved feasible for scale worm detection and localization. Yet because the environment of the Axial Seamount is so dynamic due to the growth and decay of chimneys at the site and resulting changes in bacteria and macrofauna present, they found the performance of the model decreased over time.
Weifeng (Gordon) Zhang of Woods Hole Oceanographic Institution has been using Pioneer Array data to understand the physical processes occurring at the Mid-Atlantic Bight shelf break, including the intrusion of Gulf Stream warm-core ring water onto the shelf and the ring-induced subduction of the biologically productive shelf water into the slope sea. His findings were reported in a Geophysical Research Letters paper where data from the Pioneer Array moorings and gliders demonstrated the anomalous intrusion of the warm and salty ring water onto the shelf and revealed the subsurface structure of the intrusion. Zhang also shared findings reported in the Journal of Geophysical Research: Oceans where data from the Pioneer Array showed a distinct pattern of relatively cold and fresh shelf water going underneath the intruding ring water. These results show the subduction of the shelf water into the slope sea and a pathway of shelf water exiting the shelf. In both instances, Zhang and his colleagues used computer modeling to study the dynamics of these water masses. These two studies together suggest that shelf break processes are complex and require more studies in the region.
Hilary Palevsky of Boston College presented results from an ongoing project funded by the National Science Foundation’s Chemical Oceanography program, using biogeochemical data from the OOI Irminger Sea Array. Analysis of dissolved oxygen data on OOI Irminger Sea gliders and moorings from 2014-2016 showed the importance of biogeochemical data collected over the full seasonal cycle and throughout the entire water column, due to the influence of subsurface respiration and deep winter convection on biological carbon sequestration. The OOI Irminger Sea array is the first source of such full-depth year-round data in the subpolar North Atlantic. To quantitatively evaluate the annual rate of carbon sequestration by the biological pump and the role of deep winter convection, Palevsky and colleague David Nicholson of the Woods Hole Oceanographic Institution collaborated with OOI to improve the calibration of oxygen data at the Irminger Sea array by modifying the configuration of glider oxygen sensors to enable calibration in air each time the glider surfaces, which improves the accuracy and utility of the data collected both from gliders and from moorings. Palevsky presented preliminary results demonstrating successful glider air calibration at the Irminger array in 2018-2019 as well as work by student Lucy Wanzer, Wellesley College, demonstrating the importance of well-calibrated oxygen time series data to determine interannual variability in rates of subsurface respiration and deep winter ventilation in the Irminger Sea.
The spring 2020 OOI Endurance Operations and Management (O&M) turn cruise has been canceled due to travel and personnel restrictions imposed to stem the spread of the virus COVID-19. The 16-day cruise was set to depart on 31 March from Newport, Oregon aboard the R/V Sikuliaq to service the array off the Oregon and Washington coasts.
Jonathan Fram, Program Manager of the Endurance Array, explains in this EOS article some of the possible implications of the cancellation, which may range from some of the moorings losing power, to the gliders running out of batteries, to possibly missing the recording data documenting the coastal ocean’s transition from winter to spring.
The fall 2020 Endurance turn cruise (currently scheduled for September) is expected to take place.Read More
Five years of data have made a significant difference in understanding of the complex processes occurring in the remote and hostile conditions of the Southern Ocean. In its five years of deployment, OOI’s Southern Ocean Array has provided critical data that enhanced weather modeling and forecasting, while providing means to study the mechanisms behind Southern Ocean warming and the storage of carbon at depth.
Four OOI moorings were deployed in February 2015 in a very sparsely sampled area in the Southern Ocean (55 degrees South, 90 degrees W) with the goal of helping modelers, forecasters and scientists understand this dynamic and volatile environment. One mooring was decommissioned in 2017. Two bottom halves remained in place through 2018 and a single surface mooring remained in place through January 2020. Collectively, these deployments provided a continual treasure trove of data to scientists, modelers, and forecasters.
This data stream is particularly important because the Southern Ocean is not only warming faster than other parts of the world ocean, it has also been implicated as the major region for ocean uptake of carbon dioxide.
“Collecting continuous data in this sparsely sampled region has provided a groundtruth point to help refine climate models and weather forecasts, and better understand complex processes occurring in the Southern Ocean,” said Dr. Sheri N. White, lead systems engineer for the Coastal Global Scale Nodes of OOI at Woods Hole Oceanographic Institution and chief scientist on the 2018 and 2020 OOI expeditions that recovered the Southern Array.
The benefits of deployment were evident. When the moorings were first deployed in 2015, data were not initially integrated into the World Meteorological Organization’s Global Telecommunication System (GTS). In August 2017, when the data were added to the GTS, making them more easily accessible for weather forecasters and modelers, they had an almost immediate impact on forecasting by the European Centre for Medium-Range Weather Forecasts (ECMWF). In August 2017, for example, OOI’s Surface Buoy picked up a low-pressure system moving through the area. Integrating these data into forecast models, researchers filled in some key spatial gaps in their observational coverage, reducing the error in 24-hour forecasts. With improved data, ECMWF was better able to forecast the next huge Southern Ocean storm with a central pressure around 955 mb that had simultaneous major impacts on southern South America, Drake Passage, and the Antarctic Peninsula.
The Southern Ocean Array also provided a platform for interagency and interdisciplinary collaborations. The National Science Foundation and its UK counterpart, the National Environmental Research Council joined forces to support two expeditions in 2018 and 2020. The 2018 expedition recovered the bottom halves of the moorings, while outfitting the surface mooring with equipment to measure silicate and nitrate using “lab-on-a-chip” technology (miniaturized analytical devices that integrate laboratory operations into a single chip on a very small scale.) This work was an investigation undertaken by Dr. Adrian Martin of the UK’s National Oceanography Centre and an investigator for CUSTARD (Carbon Uptake and Seasonal Traits in Antarctic Remineralisation Depth). The sensors and the surface mooring were recovered during the 2020 expedition.
“CUSTARD focuses on how interactions between marine organisms, nutrients in the water and the ocean circulation control the storage of carbon at depth. To do so requires information through the year because of the boom and bust seasonal cycle of phytoplankton,” explained Martin. “The mooring gave us both a variety of important data as well as a platform to deploy some of our own sensors year-round in the challenging environment of the Southern Ocean. The CUSTARD project benefited immensely from our collaboration with OOI. “
The OOI moorings also provided scientists with a means to study the mechanisms behind Southern Ocean warming. In a study led by Sarah Ogle of Scripps Institution of Oceanography, scientists found that just a few extreme storm events drive most of the mixed-layer deepening, suggesting that air-sea heat exchange is a highly episodic process.
“Only the largest storm events each year are able to mix the upper ocean enough to influence the ocean interior,” said Dr. Sarah Gille, also of Scripps and a member of OOI’s Facility Board. “With the removal of OOI, we’ve lost one window into these big events, but from the OOI data, we’ve gained some perspective on what types of measurements need to be collected to understand air-sea exchange in the region. In the future, I hope that we’ll be able to make use of newer autonomous systems to continue the research started in the Southern Ocean with OOI.”[media-caption type="vimeo" path="https://vimeo.com/398932101" link="#"] Crew members recover the last Southern Array Surface Mooring (9000+ lbs) aboard the RRS Discovery, operated by the Natural Environment Research Council.Video courtesy of Dr. Adrian P. Martin, National Oceanography Centre [/media-caption] Read More