Making the Ocean Accessible Through Sound
“Scientists are finding that people can sometimes pick up more information from their ears than the eyes can see. And ears can perceive patterns in the data that the eyes can’t see,” said Amy Bower, a Senior Scientist at Woods Hole Oceanographic Institution and Principal Investigator for the Accessible Oceans project. “Adding sound to science allows more people to experience science, follow their curiosity, and make science more accessible to all. “
Bower joined forces with a multidisciplinary team to explore ways sound could be used to visualize data. Funded by the National Science Foundation’s Advancing Informal STEM Learning Program, Bower and her team have been working for nearly two years on Accessible Oceans: Exploring Ocean Data through Sound. Their goal is to inclusively design and pilot auditory displays of real ocean data. They are implementing a process called sonification, assigning sound to data points. Each member brings expertise to the task at hand. Principal Investigator Bower is an oceanographer. Dr. Jon Bellona is a sound designer with specialization in data sonification at the University of Oregon. Dr. Jessica Roberts and graduate student Huaigu Li, both at Georgia Tech, are Learning Sciences and human-computer interaction experts. Dr. Leslie Smith, an oceanographer and specialist in ocean science education and communication at Your Ocean Consulting, Inc., rounds out the team. Bower is a blind scientist, who lends a crucial perspective in the research and overall execution of the project.
To begin, the team chose to use datasets collected by the Ocean Observatories Initiative (OOI) that had previously been transformed into classroom-ready use by Smith and the Ocean Data Labs. The team is working first on three of these curated datasets: the 2015 eruption of Axial Seamount, the vertical migration of zooplankton during an eclipse event, and carbon dioxide exchange between the ocean and the atmosphere.
“Data is made of numbers. Sonification is basically just translating numbers into sound,” Bower explained. “So instead of seeing numbers go up and down on a graph, for example, you can hear them go up and down.”
To ensure an inclusive final product, the team has undertaken a co-design process in which a variety of stakeholders have been engaged for input throughout the process. The team interviewed both subject matter experts and teachers of the blind and visually impaired to ensure that both scientific and pedagogical needs were being met. They then explored the integration of various auditory display techniques and ended up with a mix of data sonification, narration, and environmental sounds. The team put together a sample of five to six sonification examples for each data set, then surveyed a group of blind, visually impaired and sighted adults and students with science and non-science backgrounds. The survey’s purpose was to ask which sounds and which approaches might work best for both sighted and visually impaired listeners.
“We asked, for example, which of these sounds do you think best represents gases coming in and out of the ocean. The feedback was overwhelmingly in favor of a breathing sound,” said Bower. “As listeners will hear in the first example below that deals with carbon dioxide exchange between the ocean and the atmosphere, the breathing sound, with narration explaining what to expect, really brings the data to life.”
Accessible Oceans is a pilot and feasibility study for a museum exhibit that would introduce the broader public to what it’s like to experience ocean data through sound. At the end of this two-year project, the team intends to submit another proposal to design and build an exhibit that make ocean data come alive in a new and accessible way.
“As we’ve been working on this project, we’ve come to realize that to engage more people in science, technology, engineering and math, we can appeal to their ears as well as their eyes,” added Bower. “And I’m determined to help make science as accessible as possible for everyone.”
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To hear more about Amy Bower’s work as an oceanographer and her exploration of sonification, tune into this episode of The Science of Ocean Sounds, Tumble Science Podcast for Kids.
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Canadian and OOI Gliders Meet in Pacific
In an important collaborative undertaking, the Ocean Observatories Initiative (OOI) Glider 363 and a Fisheries and Oceans Canada (DFO) Glider crossed paths along Line P, a transect line in the northeast Pacific. This modern day “intersection” provides an opportunity for scientists to have co-located science profiles to match up with sensor data, but also an efficient way to extend data about ocean conditions along Line P throughout the year.
Line P consists of 27 stations extending from Vancouver Island to Ocean Weather Station Papa (OWSP), also known as “Station Papa.” OSWP (located at 50°N, 145°W) has one of the oldest oceanic time series records dating from 1949-1981. This 32-year-old record is supplemented by data collected by shipboard measurements along Line P conducted by DFO three times/year. The US National Oceanic and Atmospheric Administration also has a surface mooring at Station Papa, which contributes year-round data to this important record. Beginning in 2014, OOI also enhanced Station Papa with an array of subsurface moorings and glider measurements.
An important intersection
[media-caption path="/wp-content/uploads/2022/09/image012.png" link="#"]The OOI glider left from Newport, OR aboard the RV Zephyr and was deployed on July 3 in open ocean over the Juan de Fuca Ridge. The glider transited along Line P to the Papa Array starting from station P16. A DFO glider was traversing Line P at the same time, providing an opportunity for US and Canadian scientists to have co-located profiles to match up with sensor data. [/media-caption]The DFO glider was deployed in late May returning from OWSP. The OOI glider left from Newport, OR aboard the RV Zephyr and was deployed on July 3 at 46 N 130W in open ocean over the Juan de Fuca Ridge. The glider transited along Line P to OOI’s Global Station Papa Array starting from station P16, which is in international waters just outside the Canadian EEZ. A DFO glider was traversing Line P at the same time, providing an opportunity for US and Canadian scientists to have co-located profiles to match up with sensor data.
At the point of the cross-over the OOI glider had been at sea for about 40 days. Both OOI’s and DFO’s glider have very similar sensors onboard that measure temperature, salinity, pressure, oxygen, optical backscatter, chlorophyll, and colored dissolved organic matter. These measurements when compared to historical data provide insight into existing and possibly changing conditions in the water column.
“At a very basic level these deep-ocean rendezvous provide us with an opportunity to compare the sensor data mid-deployment, instead of just at the start or end of their respective deployments. This can help us look for any trends or offsets that might indicate sensor issues – such as aging, fouling, and other issues that may impede performance. This information helps people understand and be able to use data from these gliders,” explained Peter J. Brickley, OOI’s Glider Lead. “The other outcome is that our joint glider data can contribute extra sampling along Line P. While there are several cruises along this line every year, those efforts are spaced far apart in time (sometimes several months). Autonomous gliders can fill some of the gaps, are relatively inexpensive to operate, and can help better delineate conditions, including changing anomalies as they occur.”
Another contributing factor to making this initial glider cross-over a useful test case is that a scheduled DFO Line P cruise on the Canadian Coast Guard Ship John P. Tully was happening concurrently along Line P. The team aboard the Tully started sampling in early August and are scheduled to complete sampling by the month’s end. The ship collected some data in the vicinity of both gliders, offering another opportunity to compare and contrast data.
[media-caption path="/wp-content/uploads/2022/09/zephyr2.png" link="#"]The OOI glider deployed from the R/V Zephyr heading north to reach Line P in time to cross-over with DFO’s glider to share and contrast data collected. Credit: R/V Zephyr ©WHOI. [/media-caption]While the glider cross-over is an important first, it is emblematic of the ongoing cooperative effort between the Canadian DFO, NOAA, and OOI teams sampling in this important region. Communications occur regularly between OOI team members and the Chief Scientist conducting DFO shipboard sampling, as well as between OOI and NOAA personnel.
Added Brickley, “This recent excursion along Line P was planned, but also a serendipitous opportunity that could be leveraged quickly. Once we all have the chance to assess the data provided, we’ll be in a better position to explore making this a more regular occurrence. If it turns out that our sampling schemes are easily aligned, that could be another step to help advance understanding of ocean processes from coastal, eutrophic waters into the heart of the high nitrate, low chlorophyll area of the NE Pacific.”
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Scientists and Fishers Learning from One Another
At a recent meeting of the Cape Cod Commercial Fishermen’s Alliance, it was evident how much can be learned when scientists and fishers share information. An example was the shifting location of the Gulf Stream. Fred Mattera, President of Commercial Fisheries Research Foundation of Rhode Island, wondered why the temperature of the continental shelf was 72 degrees in December. He contacted Glen Gawarkiewicz, a Woods Hole Oceanographic Institution senior scientist, to share his observation. Gawarkiewicz used data from OOI’s Coastal Pioneer Array to confirm that the Gulf Stream, which carries warm and salty water, had shifted 120 miles north. Gawarkiewicz explained to the audience that he would have never identified this change if it hadn’t been for Mattera’s contact.
This is but one example of how those who use the ocean and those who study it can benefit by sharing information. To read more:
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Using Aircraft Expertise for Underwater Operations
Regional Cabled Array (RCA) Engineer Eric McRae came to the RCA Team with a 20+ year background keeping aircraft in the air, cars on the road, and medical devices safe. McRae worked on a Head-Up display and skid control and braking systems on some large commercial aircraft that are flying now. He also worked on a popular pacemaker/defibrillator for a medical instrument company. As a result of this experience, and long-term work in automotive engine control, McRae brought with him a mindset about correct behavior of control software to the RCA. He simply will not accept anything that is misbehaving. In the past, people’s lives were at stake, now it’s possible interruption of data collection or loss of scientific equipment.
McRae adopted his approach to help design and keep operational the Shallow Profilers on the RCA moorings which must work correctly for a year at a time in the cold, dynamic, and sometimes hostile, waters of the Pacific Ocean. The Shallow Profiler houses 10 scientific instruments and includes a winch that pays out power and communication cable allowing the science pod to rise through the water column to a depth below the surface determined by currents and wave conditions.
“I think that the Cabled Array Team is successful because many of us came from industries where it was not acceptable to produce something that could fail,” McRae explained. “We use this same mindset to figure out ways to make things work and keep them working even under the most difficult of circumstances.”
[media-caption path="/wp-content/uploads/2022/07/eric-selfie.png" link="#"]RCA Engineer Eric McRae stands with the components of one of the RCA Shallow Profilers that he programmed to successfully move up and down the water column in the Pacific since 2014. Photo: McRae.[/media-caption]From his first days at the RCA, Gary Harkins, his boss at the time, told McRae that his job was to make sure the Shallow Profiler was safe. “Safety was the top priority — not science, or anything else. Once we were sure the profiler could be operated safely, we could accomplish whatever the science mission wanted.” Initially, McRae worked with Dr. Doug Luther and Dr. Kendra Daly to understand how the science team wanted the profiler to run. Once he understood the science requirements, he worked with RCA’s mechanical designers to understand how they wanted to design the mechanical aspects of the system.
McRae then used his experience to influence the design and created a viable electronic control system that supports communications that keep the winch running and its science pod node traveling up towards the surface and back down nine times a day. A winched cable provides continuous power and communications to the science pod, allowing science and engineering data to flow to shore in real time. The mechanical design and control system have kept the Shallow Profiler operational since its launch in 2014.
[embed]https://vimeo.com/733359478[/embed]The control system continually “talks” to the winch and science pod to assess movement through the water. Near the bottom, the science pod doesn’t move very much, except for an occasional tilt caused by currents. As it gets close to the surface, however, surface waves can have a huge impact on how the profiler moves and how much tension is on the cable. The science pod weighs ~900 pounds in air so when it gets moving back and forth underneath waves, it could significantly stress the cable. To prevent this from happening, the science pod “reports” three times a second to the control system about the conditions it is experiencing. These reports include acceleration, rotation, proximity to the surface, wave length, and a slew of other variables so that needed adjustments can be made automatically to keep the winch and ultimately its valuable science pod “safe.” If conditions warrant, the control system has the capability of aborting a running profile and/or parking the science pod near the mooring to wait things out.
The Shallow Profiler is often on the move. Each of the nine daily profiles take between one and a half to two and a half hours, depending on the profile type and ocean conditions. There’s a gap of about 30 to 45 minutes between profiles, where the science pod is parked down near the mooring platform. During that time, the controller is constantly monitoring the waves on the surface. McRae developed an algorithm to look at the worst-case peak to trough wave pressure so that when the profiler starts up for a run towards the surface, it has already calculated what it thinks the worst wave height combination will be. The original requirements of the system were that the science pod can go no closer to the surface than five meters or three wave heights, whichever is greater, so when it starts up, it already knows the ceiling for the coming profile.
“As designed, the profiler is smarter than we are. It makes seven decisions three times a second to ensure that it is on the right path and has accounted for all predictable conditions” McRae said.
Of course, there are other hazards besides ocean conditions. In September of 2017, a trawler’s net hit the mooring line at the Oregon Offshore site and eventually the mooring platform itself, pulling the 14,000-pound mooring and its two huge anchors from the seafloor. The profiler was running at the time and recorded the action until the boat pulled hard enough that the seafloor cable came unplugged. There has also been a smattering of mechanical issues, but the system has matured nicely. Should something unexpected go wrong in the future, McRae has programmed the profiler to take “evasive” action, then notify him and his team on land. This performance record demonstrates that not only did McRae’s work help keep the profiler safe, it helped make it a reliable component of the RCA that scans through the water with ease. The three profilers have made >40,000 profiles since 2015, making unprecedented measurements of ocean parameters.
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Measurements Below the Surface
Strong winds and large waves in remote ocean locations don’t deter the Ocean Observatories Initiative (OOI) from collecting measurements in spite of such extreme conditions. By moving the moorings below the surface, the OOI is able to secure critically important observations at sites such as the Global Station Papa Array in the Gulf of Alaska, and the Global Irminger Sea Array, south of Greenland. These subsurface moorings avoid the wind and survive the waves, making it possible to collect data from remote ocean regions year-round, providing insights into these important hard-to-reach regions.
Instrumentation on the surface mooring in the Irminger Sea, however, has nowhere to hide and the measurements they provide are also often crucial for investigations, such as net heat flux estimates. Providing continuous information about wind and waves remains one of the most challenging aspects of OOI’s buoy deployments in the Irminger Sea. Fortunately, with each deployment, OOI is improving the survivability of the surface mooring so they continue to add to the valuable data collected in the region by their subsurface counterparts.
[media-caption path="/wp-content/uploads/2022/07/FLMB-9_DSC_0934.jpg" link="#"]The top sphere of a Flanking Mooring being deployed through the R/V Neil Armstrong’s A-Frame. Credit: Sawyer Newman©WHOI.[/media-caption]Below the surface in the Irminger Sea
A team of 15 OOI scientists and engineers spent the month of July in the Irminger Sea aboard the R/V Neil Armstrong, recovering and deploying three subsurface moorings there, along with other array components. The Irminger Sea is one of the windiest places in the global ocean and one of few places on Earth with deep-water formation that feeds the large-scale thermohaline circulation. Taking measurements in this area is critical to better understanding changes occurring in the ocean.
OOI’s Irminger Sea Array also provides data to an international sampling effort called OSNAP (Overturning in the Subpolar North Atlantic) that runs across the Labrador Sea (south of Greenland), to the Irminger and Iceland Basins, to the Rockall Trough, west of Wales. The OOI subsurface Flanking Moorings form a part of the OSNAP cross-basin mooring line with additional instruments in the lower water column. During this current expedition, the Irminger Team will be recovering and deploying OSNAP instruments that are included as part of the OOI Flanking moorings, in addition to turning several OSNAP moorings as well.
[media-caption path="/wp-content/uploads/2022/07/FLMB-9_DSC_0941.jpg" link="#"]The Flanking Mooring top float in the water during deployment. The sensors mounted in the sphere will measure conductivity, temperature, fluorescence, dissolved oxygen and pH at 30 m depth. Credit: Sawyer Newman©WHOI.[/media-caption]The triangular array of moorings in the Irminger Sea provide data that resolve horizontal variability, how much the physical aspects of the water (temperature, density, currents) and its chemical properties (salinity, pH, oxygen content) change over the distance between moorings. The individual moorings resolve vertical variability – the change in properties with depth. Three of these moorings are entirely underwater, with no buoy on the surface. They do have, however, multiple components that are buoyant to keep the moorings upright in the water column.
[media-caption path="/wp-content/uploads/2022/07/FLMB-9_DSC_0984.jpg" link="#"]The mid-water sphere holds an ADCP instrument which will measure a profile of water currents from 500 m depth to the sea surface. Photo Credit: Sawyer Newman©WHOI.[/media-caption]Each subsurface mooring has a top sphere at 30 m depth, a mid-water sphere at 500 m depth, and back-up buoyancy at the bottom to ensure that the mooring can be recovered if any of the other buoyant components fail. Instruments are mounted to the mooring wire to make measurements throughout the water column.
[media-caption path="/wp-content/uploads/2022/07/FLMB-9_IMG_5328.jpg" link="#"]Glass balls in protective “hard hats” provide extra flotation at the bottom of the mooring. Their tennis ball yellow color looks almost fluorescent in the brief (and much enjoyed) sunshine. Photo Credit: Sheri N. White©WHOI.[/media-caption] Read MoreUncovering Changing Life in the Water Column
Oregon State University Assistant Professor Jennifer Fehrenbacher needed a ship to carry out her National Science Foundation-funded research investigating the lives of foraminifera (single-celled organisms about the size of a grain of sand and smaller) in the northern Pacific. Her work, in collaboration with Dr. Claudia Benitez-Nelson at the University of South Carolina (UofSC), involves deploying bottom-moored sediment traps and collecting plankton tows while at sea, giving researchers the opportunity to explore foraminifera that live in lighted surface waters, and how these communities have changed over time in response to the surrounding ecosystem.
Fehrenbacher found her ship. She will be joining forces with the Endurance Array Team aboard the R/V Sikuliaq during its bi-yearly expedition to recover and deploy ocean observing equipment at its array in the northeast pacific off the coast of Oregon. Fehrenbacher and her team of four researchers will join the Endurance Array 16 team in early April for the second of its two-leg expedition. This will be a continuation of her research project that began in September 2021.
Last September, Fehrenbacher’s team put in place two tandem sediment traps that are located close to the OOI Slope base node. One was deployed at about 600 meters water depth, the other slightly above the sea floor. The last sediment trap study in this region was conducted around 30 years ago, and the foraminiferal species have likely changed since then, as have ocean conditions.
[media-caption path="/wp-content/uploads/2022/03/IMG_5185-copy.jpg" link="#"]Fehrenbacher’s team will be retrieving two tandem sediment traps that are located close to the OOI Regional Cabled Array slope base node. Credit: Jennifer Fehrenbacher, OSU.[/media-caption]
The sediment traps have been collecting material in place for the past six months and will be recovered along with the Endurance 16 team’s recovery and deployment work. Once the traps are back onboard, the collecting cups will be taken off, emptied, replaced, and the traps redeployed for another six-month period. The researchers will package the collected materials for analysis at OSU and UofSC.
The team also will be examining live specimens from night-time plankton tows, taking advantage of quiet night-time hours to conduct the plankton tows when the Endurance team is unable to work safely moving large, bulky, and unwieldy equipment in and out of the ocean. “This arrangement is a win-win for everyone,” said Endurance Array Chief Scientist Ed Dever. “It maximizes the use of ship time, while helping to provide data to answer some questions about how ocean conditions are changing.”
Fehrenbacher’s team will be conducting a series of discrete new tows from the surface to about 500 meters. “While I don’t anticipate a ton of critters in the really deep water, net tows haven’t been done extensively in these waters at these depths. The last one was 30 years ago by oceanographer Alan Mix and his graduate student Joseph Ortiz, so this new work will give us insight into how life in the water column may have changed over time, “ said Fehrenbacher.
Fehrenbacher’s team will be conducting experiments with live foraminifera in a portable travel lab they will bring onboard. A number of different experiments are planned:
PhD candidate Kelsey Lane will be collecting foraminifera (shortened version “forams”) to study their genetics and their microbial communities, other species living with forams.
Graduate student Grace Meyer will be striving to measure carbon and oxygen isotopes in individual forams. She will be collecting empty shells from both the water column and sediment trap material and compare what is found in both, providing information about water column processes that could alter shells’ composition.
Postdoctoral researcher Brittany Hupp will be collecting both live forams and empty shells to study the chemistry of different types of forams, looking at their isotopes and trace metals content.
Researcher Eric Tappa, a sediment trap expert from the UofSC, will be deploying and recovering the sediment trap equipment. Tappa has been working with sediment trap moorings for decades and have proven critical in providing longer time-series records of processes occurring in overlying waters.
As lead scientist Fehrenbacher will be participating in these onboard experiments. She also will be growing forams under controlled conditions and watching them to learn how temperature modulates their shells or their behaviors during the day-night cycle, and will continue her work with recovered forams once she returns to her home lab. There she will be measuring the trace element concentrations in foram shells so results can help inform the Paleo record. . She explained, “Foram shells are used basically as proxies for environmental conditions. So when we measure trace elements in their shells, this gives us information about the pH, temperature, nutrient content, and even the salinity of the ocean in the past.” The onboard experiments help scientists under how forams incorporate these elements into their shells when they are alive, which they can use in assessing past records.
[media-caption path="/wp-content/uploads/2022/03/IMG_5196-copy.jpg" link="#"]An anchor weighing ~2500 pounds is deployed to keep a sediment trap in place for six months until it is recovered with a treasure trove of marine life and particulates for investigation. Credit: Jennifer Fehrenbacher, OSU.[/media-caption]
Challenges of studying small living things
Studying single-celled organisms is difficult on dry land, but is compounded by a moving ship in rolling seas. Fehrenbacher’s team will be taking onboard multiple microscopes, including an inverted microscope to see their subjects, water circulators to keep them at constant conditions while they are alive, and a pH meter. High-powered microscopes are critical for the work because forams range in size from smaller than a grain of sand—about 100 microns— to up to about a millimeter.
“We look at forams in a petri dish under the microscope,” explained Fehrenbacher. “This is challenging as the ship moves back and forth so does the water in the petri dish so you’re looking back and forth as the ship moves.” The researchers have come up with the solution of holding the petri dish at an angle so the water and foram stay in one place and helps prevent researchers’ sea sickness.
Fehrenbacher predicts that the amount of material collected on the Endurance Array 16 cruise will keep she and her graduate students busy for at least the next two years and beyond. She added, “There’s really just nothing quite like the type of information you can get from sediment trap studies. While going out to sea for two weeks a year and doing plankton tows are helpful, we only get information about what’s in the water column at the exact moment of collection. But sediment traps provide months’ worth of data at really high resolution that we can compare with other OOI data and get a detailed picture of ocean conditions and how those conditions affect marine life.
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Distributed Acoustic Sensing Lays Groundwork for Earthquake, Tsunami Warnings, and More
Researchers using the OOI Regional Cabled Array are at the forefront of testing Distributed Acoustic Sensing (DAS) along the seafloor through funding from the National Science Foundation. Ocean-bottom DAS using submarine fiber optic cables promises to advance what we know about marine geology, offshore earthquakes, ocean currents, ocean waves, sediment transport, marine mammals, and a host of other activities that now can be measured by this revolutionary technique.
Taking advantage of a rare temporary shutdown of RCA’s submarine fiber optic cables during a shore station maintenance period, University of Washington Researcher William Wilcock and California Institute of Technology (Caltech) Graduate Student in Geophysics Ethan Williams were part of a team of scientists who installed DAS interrogators on RCA’s “dark cables” to test and collect data for a community experiment. The experiment was designed to determine the potential of submarine DAS to observe seismic, oceanographic, acoustic and geodetic processes. Each interrogator transmitted laser pulses down the fiber optic cable from RCA’s shore station and across the offshore Cascadia Margin and recorded the echoes that came back. This backscatter remains constant until some movement on the bottom or in the water column perturbs the fibers in the cable, changing the pattern of backscattered light. By rapidly probing the cable hundreds of times per second, DAS allows researchers to monitor what’s happening in the cable environment.
“Using DAS, the fiber optic cable acts, in effect, like a line of seismometers that can measure the stretching and contracting of the ground, “explained Wilcock. “It’s an amazing technology, similar to going out in the field and putting a seismic instrument every 10 meters for a stretch of 100 kilometers. So it’s just astounding in terms of what it can potentially measure,” said Wilcock.
The DAS system also has the capability of measuring other oceanographic signals. “It turns out that ocean bottom acoustic sensing on these fiber optic cables is as sensitive to the water layer above as it is to the solid Earth below. This sensitivity provides all sorts of really interesting signals that you would normally observe using an ocean bottom pressure sensor. DAS is opening up the door for lots of interesting research opportunities,” said Williams, who has been working with DAS systems for years under the supervision of Zhongwen Zhan at Caltech, one of the world’s foremost experts in the field.
Among the many potential ways DAS data might be used include advancing earthquake and tsunami early warning systems, and understanding wave and current action, sediment transport, and ocean-generated seismic noise, as well as providing biological information. In Wilcock’s case, he’s excited about using DAS to gain access to fin whale calls that were picked up by this DAS experiment.
The National Science Foundation funded this experiment in the hopes of developing protocols that can support the use of DAS for science and hazards mitigation in the Northeast Pacific while meeting national security requirements. The U.S. Navy conducted a preliminary review of the data and subsequently released the data for public use. The data are being stored on RCA servers at the University of Washington. Researchers will have ftp access to the data at this link. But because the full data set is 26 terabytes, researchers can also email ooicable@uw.edu to arrange to provide disks that will be returned with data they are interested in.
Four days of continuous measurements in this dynamic offshore environment also offer a potential treasure trove of data. Graduate student Williams is turning his attention to exploring these datasets and calibrating them against conventional measurements to better understand what some of the potential applications may be. “I’m very excited about the potential DAS brings to understanding what’s happening on the seafloor. Having, in essence, so many seismometers on the ocean floor means that we can apply all sorts of array-based processing so we’re not only averaging in time, we’re combining information in space. And this allows a lot of really innovative things that we weren’t able to do before.”
“But the real value of these datasets comes from being an open dataset. It will be a great facilitator for learning with the potential to expand general knowledge about how to use DAS in the marine geology and marine geophysics world, which is great,” Williams added.
Both Wilcock and Williams were excited about the potential for DAS to open up understanding of the processes involved in this deep-sea world. They both mentioned a dream of having DAS sensors integrated into future SMART cable technology to expand DAS use on land and in the sea.
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Improving Remote System Response in Increasingly Hostile Oceans
Wind and Waves and Hydrogen, Oh My!
Improving remote system response in increasingly hostile oceans
This article is a continuation of a series about OOI Surface Moorings. In this article, OOI Integration Engineer Alexander Franks discusses the mooring software and details some of the challenges the buoy system controller code has been written to overcome.
Components of the OOI buoys working in concert make up a system that is designed for deployment in some of the most challenging areas of our world’s oceans. These systems collect valuable scientific data and send it back to Wood Hole Oceanographic Institution (WHOI) servers in near real time. Mechanical riser pieces (wire rope, and/or stretch hoses) moor the buoy to the bottom of the ocean. Foam flotation keeps the buoy above water in even the worst 100-year storm, while its masthead supports instrumentation and satellite radios that make possible the continuous relaying of data. The software controlling the system is just as important as the physical aspects that keep the system operating.
The system software has a variety of responsibilities, including setting instrument configurations and logging data, executing power schedules for instruments and parts of the mooring electronics, controlling the telemetry system, interfacing with lower-level systems including the power system controller, and distributing GPS and timing. The telemetry system is a two-way communication path, so the software controls data delivery from the buoy, but also provides operators with the ability to perform remote command and control.
[caption id="attachment_22938" align="alignnone" width="745"]
Software flow diagram created by OOI Integration Engineer Alex Franks[/caption]
The unforgiving environment and long duration deployments of OOI moorings lead to occasional system issues that require intervention. Huge storms, for example, can build waves so high that they threaten wind turbines on the moorings. At the Irminger Sea Array, ice can accumulate so much as to drastically increase the weight of the masthead, and with subsequent buoy motion, risk dunking the masthead and instruments. Other mooring functions require constant attention. The charging system must be monitored to ensure system voltages stay at safe levels and hydrogen generation within the buoy itself is kept within safe limits. Two-way satellite communication allows operators to handle decision making from shore using the most up-to-date information from the buoy.
“Since starting in 2015 and following multiple mooring builds and deployments, I’ve realized that issues can rapidly arise at any time of the day or night. I started thinking about what the buoys can do for themselves, using the data being collected onboard,” Franks said.
One of the game-changing upgrades implemented by Franks was to read environmental data and make automated buoy safety decisions in real-time that were previously performed by the team manually. For example, previously, the team would need to monitor weather forecasts and decide preemptively whether changes to buoy operations were advisable. With recent software changes, the system can now change its configuration based on a variety of sensor inputs. These variables include system voltage, ambient temperature, hydrogen levels inside the buoy well, wind speed, and buoy motion (for sea state approximation). In addition to the software updates, the engineering team redesigned the power system controller. They added charge control circuits and the ability to stop the wind turbines from spinning. The software and electrical upgrades now provide redundant automated safeguards against overcharging situations, hydrogen generation, and turbine damage, maximizing buoy operability in harsh environments.
[caption id="attachment_22946" align="alignleft" width="650"]
Onshore engineers are able to keep track of Irminger Sea buoys and instrumentation on this new new dashboard.[/caption]
With a largely independent system, operators also needed a way to easily monitor status of the buoys and instrumentation. The software team created a new shoreside dashboard that allows operators to set up custom alerts and alarms based on variables being collected and telemetered by the buoy. While the buoy systems can now operate autonomously, alerts and alarms maintain a human-in-the-loop component to ensure quality control.
As operations and management of the moorings have progressed, the operations team has found opportunities to fine tune how operators and the system handle edge cases of how the system responds to hardware failures and extreme weather. In the past, sometimes conditions changed faster than the data being transmitted back to shore. This new sophisticated software automates some of the buoy’s responses to changing conditions in real time, which helps to ensure their continued operation even under challenging conditions. The decreased response time to environmental and system events using an automated system, coupled with the ability to monitor and interact remotely, has increased the reliability and survivability of OOI moorings.
Read MoreTracking Fish with Acoustics
New RAFOS Ocean Acoustic Monitoring (ROAM) tags have recently been designed to allow geolocation of underwater assets, including pelagic fishes, over large areas in the ocean and even deep into the ocean’s twilight zone.
[caption id="attachment_22879" align="alignleft" width="350"]
The ROAM tag is small (30 mm x 10 mm) and light enough (8 gm in water) to be attached to an ocean glider with no adverse impacts on performance. Here are two ROAM tags attached to OOI test glider 363 before deployment from the R/V Armstrong during the Pioneer 17 cruise. Credit: ©WHOI, Diana Wickman.[/caption]
An opportunity to test the new ROAM tags arose in conjunction with the October 2021 Pioneer Array mooring service cruise. “We had recently deployed moored sound sources in deep water between Cape Cod and Bermuda,” said Simon Thorrold who, with University of Rhode Island colleagues Melissa Omand and Godi Fischer, is leading the ROAM fish tag development. “One of our goals was to determine whether tagged fish near the continental slope south of New England could be detected using these distant sources.” Thorrold reached out to the OOI team to see if there was potential for a short-term test at the Pioneer Array site, located 75 nautical miles south of Martha’s Vineyard at the shelf-slope interface.
OOI Project Scientist Al Plueddemann and the OOI glider team determined that a glider test planned during the mooring service cruise in late October would be happening at the right place and the right time to be useful for testing the acoustic tags. “This technology is something we would like to consider for OOI, and in particular for the Pioneer Array in its new southern Mid- Atlantic Bight location,” said Plueddemann, “so the potential for a test was of interest to us.”
The glider team determined that the small (30×10 mm), light (8 gm in water) tags would have no measurable impact on glider performance and could be safely accommodated on the test glider. The tags were mounted to the glider by fitting the tags into plastic loop clamps and then securing the loop clamps to existing threaded holes in the glider hull. During the three-day test deployment, the glider made one dive to 50m, one dive to 200m, three dives to 500m, and approximately 76 dives to 200m.
The glider data and acoustic tag data are being evaluated, and will provide information about fish tag performance and the potential for future use within the OOI arrays.
This article was written by Woods Hole Oceanographic Institution colleagues: Senior Scientist Simon Thorrold and Senior Engineering Assistant II Diana Wickman.
Read MoreNew Controller Latest in OOI Innovations
Having equipment in the water around the clock for six months at a time provides many challenges for the land-based OOI engineering team charged with keeping the equipment operational so there is a continual flow of data to shore. Maintaining consistent, reliable power for the ocean observing equipment is at the top of this list of challenges.
OOI’s data-collecting instruments attached to the moorings run on batteries charged by renewable wind and solar energy. OOI is in the process of replacing the current solar panels with new panels that are more efficient at generating energy, even when shaded. To supplement this upgrade, the OOI arrays are also being outfitted with a brand-new solar controller to manage the energy going into the batteries. Like with the new solar panels, OOI engineers looked for a controller that was available commercially for easier repair and replacement.
“What was important to us was finding a way to use these new solar panels in the best, most optimal way,” said Woods Hole Oceanographic Institution (WHOI) engineer Marshall Swartz. “We looked for a company that would help us specify and build a customized algorithm for a controller that would optimize the functionality of the panels by taking into account battery temperatures.”
[media-caption path="/wp-content/uploads/2021/12/DSC0486-2.jpeg" link="#"]Buoys get quite the workout when they are in the water for six months and more. Powered by wind, solar, and batteries, OOI has recently improved the way energy from the solar panels is managed with new controllers. Credit: ©WHOI, Darlene Trew Crist. [/media-caption]
Some larger, older controllers can consume up to 3-5% of the energy coming into the device, but the new controller is smaller and more efficient, helping to optimize the amount of energy harvested.
Temperature conditions play a big role in how effectively the energy is managed. Changing battery temperatures require the controller to adjust its charge settings to maintain battery life and capacity. The controllers used on OOI moorings sense battery temperature and automatically adjust to assure best conditions to assure reliable operation.
“It’s really essential for us to maintain the proper charge levels for existing temperature conditions,” said Swartz. The OOI buoys encounter a wide range of temperatures: from subfreezing temperatures up to 40°C (over 100°F) when a buoy is sitting in the parking lot before it is deployed. When the buoys are deployed, water temperatures can vary widely from -1 to 33°C (~30 to 91°F), depending on seasonal conditions.
The new controller automatically regulates the amount of electricity going into the battery under such varying temperature conditions. If the wind turbines are generating more energy than the battery needs, for example, the controllers direct excess power into an external load that dissipates heat and adds resistance to the spinning of the wind turbines, preventing the turbines from spinning too fast, possibly damaging their bearings.
“As parts of the OOI infrastructure need replacing or to be upgraded, this offers us the opportunity to find more efficient, and often times, off-the-shelf, less-expensive replacements that will help us keep the arrays functioning and data flowing,” Swartz said. “It’s a winning combination for all parts of the operation.”
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