News
Opportunity to Test OOI Data Lab Notebooks
The OOI Ocean Data Labs team is looking for instructors of introductory oceanography courses to “test drive” a collection of new online laboratories that focus on important oceanographic themes and topics using OOI data.
They are seeking a pilot implementation team of 14-16 faculty to implement two labs with students this Fall. They are offering a $750 stipend, which includes a training webinar, detailed feedback and evaluation, and a wrap-up session. The implementation must be completed by December 2020.
Beginning in January 2020, a team of faculty contributors compiled a sequence of OOI Data Labs into an online laboratory manual. It includes topics in biological, chemical, physical and geological oceanography for use in typical Introductory Oceanography courses. The manual is a collection of eight lab exercises, with built-in assessments, and accompanying instructor guides.
Applications are due Sunday 9 August 2020. Apply here.
Read MoreEight Weeks of Intensive Virtual Learning
Two weeks. That is the amount of time Janice McDonnell and Sage Lichtenwalner, Co-PIs of the OOI Ocean Data Lab Project, had to create an eight-week intensive, hands-on virtual program for Research Experience for Undergraduates (REU) students, who couldn’t attend their original programs due to COVID-19 restrictions. McDonnell and Lichtenwalner jumped in with both feet and successfully pulled together a program for 16 undergrads from 16 institutions that will wrap up on July 31st. Not only did they have to develop a curriculum in short order, they recruited 17 mentors, who provided one-on-one mentoring for each of the REU students.
In 14 days, McDonnell and Lichtenwalner, working with colleagues at the Rutgers RIOS REU, developed a curriculum, which included two two-hour workshop sessions on Zoom every day for the first two weeks. The workshop was followed by six weeks where students focused on a research project using oceanographic data to answer a scientific question. They were helped by REU leaders and mentors along the way.
The initial workshop focused on students using a “baby data set” before working on something as complex as an OOI dataset or other similarly large dataset. “Initially, we gave them mini research projects that could be done in two weeks. This allowed the students to be collaborative and interactive, while learning Python as a tool using data to answer questions about the ocean,” explained McDonnell.
The key to the program’s success was keeping it engaging. The curriculum mixed up content, approach, and activities to ensure students stay involved on and off the screen. The team used a tactical approach – starting where students are and building upon their level of understanding. They incorporated a lot of different approaches, including think-pair-shares and an activity from the Right Question Institute, another NSF-funded project, which guides people to ask better research questions.
“We were constantly looking for opportunities to be interactive, reflective, and to give students the opportunity to apply their knowledge,” added McDonnell.
Another technique used were Zoom breakout groups to supplement group interaction. These breakout sessions provided students with opportunities to work together, with mentors, and to get to know each other.
Breakout sessions were also used to meet members of a career panel in virtual personalized sessions.“The career panel for this REU cohort was much more diverse than it is typically. The virtual nature of the interaction made it possible for people from all over the country to join in and participate,” said Lichtenwalner. “We facilitated it in a nice round robin sort of way using Zoom’s breakout function. Students chose their top choices, then met with them either individually or with another student. This gave them an incredible opportunity to meet people in careers that they might not otherwise have access to.”
“I’m really proud of our REU,” said McDonnell. “It’s not easy to teach online but good learning can, and does, happen online and we were able to do that. And the collaboration that took place was really the secret sauce for making this all work. NSF program officer Lisa Rom and Science Assistant Rennie Meyers were committed to and worked really hard to find a solution to make the REU program happen in the middle of a pandemic. The students were great and so excited about the opportunity that we put together for them. And, the mentors went above and beyond the call of duty to help make this program work for the students.”
Each week, for example, one mentor, Dr. Jessica Carriere-Garwood, of Rutgers University introduced her students to people in her professional circle at lunch time each week, with the opportunity to talk about what the students are doing and their interests. “That doesn’t always happen in a regular REU. There are a lot of pluses and minuses of being virtual and this was certainly one of the pluses,” added McDonnell.
Ed Dever, one of the mentors from Oregon State University, had this to say about his mentoring experience: “Janice and Sage did a remarkable job spinning this REU up on short notice. They mentored not just the students, but the mentors (well, at least this mentor!). Janice, Sage, and Christine Bean did an amazing job of building a virtual community of students and mentors on the fly. This virtual community provided a unique experience to the students in that the community was much broader than an in-person REU at a single institution. It took all of us out of our comfort zones and helped us grow. Throughout the whole process, Sage patiently guided REU students in technical aspects of using Python to access and analyze data.”
The REU cohort will finish their research projects and present on 30-31 July. Of the 16 students, eight are using data from the OOI.
Citing the success of this first virtual REU, the team’s National Science Foundation (NSF) program officer Rom pondered “Why don’t we do this all the time, even if there isn’t a pandemic?“
Based on the successful experience this summer, NSF’s Division of Ocean Sciences is encouraging REU proposals for virtual REU’s, and especially those that use OOI data. The deadline is August 26th this year. Apply here.
Read MoreEndurance Array 13 Expedition: Clear Skies, Smooth Operations
The Endurance Array 13 Team had remarkably fair weather, blue skies, and pleasant sailing conditions during their 13-day expedition to recover and deploy equipment at the Array in the northeast Pacific Ocean. The weather was remarkable in that the team is usually in the northern Pacific during the spring and the fall, when the seas are not so forgiving and even in summer strong northerly winds can restrict operations. Because of COVID-19 restrictions this year, the Endurance Array spring and fall cruises were combined into this July cruise.
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Cake made in honor of the Endurance Array 13 expedition. Credit: R/V Thomas G. Thompson[/caption]
According to Ed Dever, who leads the Coastal Endurance Array team, the only thing better than the weather was the excellent support from both the University of Washington’s R/V Thomas G. Thompson crew and the National Oceanic and Atmospheric Administration (NOAA) Marine Operations Center – Pacific (MOC-P) staff. “Their support started in April after the cancellation of the planned spring Endurance cruise. Over the course of the next two months, Project Manager and Chief Scientist Jon Fram worked with UW and NOAA to schedule and implement this cruise with very little advance notice and a constantly evolving COVID-19 situation. COVID-19 mitigation measures included testing and a 14-day quarantine for the crew and science party and socially distanced procedures for access to the NOAA MOC-P pier and for loading and unloading the ship. Thanks to the cooperative, can-do spirit of all involved, everything went well at the pier and at sea.”
The team left Newport, Oregon aboard the R/V Thomas G. Thompson on 3 July, returning to port twice to offload recovered equipment and to pick up equipment to be deployed. Thirty-four people were onboard the Thompson—11 from OOI, two marine technicians, and 21 members of the ship’s crew.
Like the good weather and smooth seas, the expedition went smoothly, with the exception of one profiler not being recovered and one glider that had to be recovered shortly after deployment. Over the course of the 13 days at sea, the team replaced eight moorings and deployed two additional nearshore profilers. These range in size from 400-pound profilers attached to 700-pound anchors to 8,000-pound buoys with 11,000-pound multi-function nodes, which are at the base of surface moorings, serving as anchors as well as platforms to affix instruments.
The team also successfully deployed three gliders that are collecting data throughout the water column as they transect across the continental shelf. The scientific party also conducted 14 CTD casts, which provide a number of useful measurements. The CTDs measure conductivity, temperature, and depth that can be used to calculate salinity and density. These CTD casts also included instruments that measure dissolved oxygen, chlorophyll, and suspended particle concentration. The CTD frame also had a rosette of collections bottles, which are used to sample water at the depths of the deployed instruments. The casts and bottle samples are then used to check the calibration of the deployed instruments.
With the longer-than-normal time in the water, the recovered equipment was more bio-fouled than during previous expeditions. But, there was some good news here in that the team found that the ultraviolet anti-fouling lights on the spectral irradiance (SPKIR) and dissolved oxygen (DOSTA) sensors kept the sensors clear and functional after nine months in the water.
The northern Pacific was alive with life as the team labored aboard the Thompson. The team and crew sighted orcas, mola molas, humpback whales, sharks, Pacific white-sided dolphins and a large red plankton bloom. During the journey, the team also conducted a virtual tour of the ship for Oregon State University for students participating in this year’s virtual Research Experience for Undergraduate program and Chief Scientist Jonathan Fram was interviewed by AltaSea in front of a live audience.
The 13 days at sea turned out to be a lucky 13, as evidenced in the pictures below:
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After a three-month delay to respond to COVID-19, the OOI Endurance cruise prepares to leave Newport, OR, aboard the University of Washington’s R/V Thomas G. Thompson at the NOAA Marine Operations Center-Pacific. Two instrumented bottom landers (multifunction nodes in OOI speak) are visible under the Thompson‘s A-frame. To the stern of the Thompson is NOAA’s ship Oscar Dyson. Credit: Ed Dever, University of Oregon[/caption]
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Endurance 13 cruise Chief Scientist Jon Fram applies copper tape to instruments to protect them from biofouling. The two instruments shown measures carbon dioxide in air and at the surface just below the buoy (top) and salinity and temperature (bottom). Credit: Ed Dever, Oregon State University[/caption]
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It’s always something. OOI technician’s Kristin Politano and Marnie Jo Zirbel prep buoy well instruments for deployment during the Endurance 13 Operations and Management Cruise. Credit: Ed Dever, Oregon State University[/caption]
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Endurance 13 Chief Scientist Jon Fram was interviewed before a live audience by AltaSea when he was aboard the R/V Thomas G. Thompson. Credit: AtlaSea and Aimee Wlliams[/caption]
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The Endurance 13 Array team recovered this surface mooring during its expedition. The wind turbine on the left went missing in a January storm. The turbine on the right was missing two blades. The left solar panel was battered by sea lion. Yet, amazingly the buoy kept relaying data in spite of being battered by the elements! Credit: Jon Fram, Oregon State University[/caption]
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After 13 days at sea, the R/V Thomas G. Thompson returned to Newport, Oregon on 16 July. Only after the final equipment of the third leg was offloaded could the crew and scientific party disembark to be reunited with family and friends after nearly a month apart. Credit: Sue Zemliak, Otter Rock, Oregon[/caption]
Read More Fram Interviewed Live During Endurance 13
UV Anti-fouling Light Keeps Oxygen Sensors Clean
Biofouling is a real challenge to keeping equipment deployed in the ocean free functioning properly to deliver data to shore. The addition of UV light is helping to keep the oxygen optode sensors clear and recording data. Photo: Jon Fram, Oregon State University.[/caption]
Biofouling is a hazard of keeping equipment in the ocean for long periods of time, particularly when it is near the surface where photosynthesis occurs. For OOI’s arrays that remain in the water for six months or longer, this is a pressing issue because of the need to ensure sensors can continue to collect and transmit data back to shore. The OOI scientists and engineers are always investigating ways to keep biofouling at bay. They recently worked with Aanderaa, which provides OOI’s oxygen optode sensors, to implement a solution to keep oxygen sensors free of biofouling by installing ultra-violet (UV) lights that periodically shine on the instruments’ sensing foil.
As early as 2016, a team of OOI engineers and technicians from Oregon State University, the University of Washington, and Woods Hole Oceanographic Institution began to tackle some of problems with the instruments selected by OOI and to improve the quality of instrument measurements. In October of 2016 AML Oceanographic showed OOI’s instrument group data from Ocean Networks Canada of a UV light used to mitigate biofouling on Aanderaa’s oxygen optodes. The following October, OOI deployed a side-by-side test of two oxygen optodes (one with a UV light pointed at it) at seven meters depth on the Oregon Shelf Surface Mooring. Data from the two sensors tracked each other for six weeks, and then the unprotected sensor fouled. Within weeks, there were daily afternoon spikes of up to twice the oxygen level of the protected sensor, with slightly lower measurements than the unprotected sensor at night due to respiration of the biofilm. The team found that the biofouling signal wasn’t always as dramatic, nor did it always develop in the same period of time after deployment. Physics has a hand in this, too. Sometimes the fouling signal disappeared after a storm cleaned off the sensor.
In summer 2018, OOI started deploying UV-protected oxygen optodes mounted shallower than 70 meters on Surface Moorings. By mid-209, once some initial hardware and deployment issues were resolved, OOI expanded deployment of UV-antifouling from moored dissolved oxygen sensors, to the dissolved oxygen sensors on the Coastal Surface Piercing Profilers, and then to uncabled digital still cameras moored at less than 70 meters depth.
Following the success of the UV-light test on dissolved oxygen sensors, UV antifouling was tested on a moored Pioneer Array spectral irradiance (SPKIR) sensor in 2018. Here too, the testing conducted with Sea Bird Scientific, the SPKIR vendor, confirmed that the UV light did not damage the instrument’s optics. As a result, in 2019, all subsurface OOI spectral irradiance sensors on Surface Moorings were outfitted with UV-antifouling mitigation, as well as the Coastal Surface Piercing Profilers and uncabled digital still cameras moored at less than 70 meters. The team has adjusted the cycle of the UV lights so that they prevent biofouling without damaging the sensors, interfering with measurements, or utilizing too much power.
“While the solution appears simple, it was a long journey to find the right mix of equipment and duration of use to resolve the issue of biofouling for each sensor at each location, “explained Jonathan Fram, project manager for the Coastal Endurance Array at Oregon State University. “An ongoing challenge is the intermittency of biofouling and the many forms it can take, which can make it difficult to properly diagnose the problem. Usually biofouling is a slimy film, but sometimes it can be a barnacle or another large creature.”
“The use of UV-lights for biofouling mitigation, although well-known, cannot often be used due to the power required,“ added Sheri White, senior engineer at Woods Hole Oceanographic Institution, who was instrumental in moving this solution forward on the Pioneer Array. “We have the advantage of generating our own power, so that we are able to implement it on a number of optical instruments on our Surface Moorings.”
OOI continues to measure the impact of the UV light on biofouling. While the results are clear that the UV lights increase measurement reliability and accuracy, the team is still trying to gauge the extent of the improvements. Data are annotated to indicate when UV-antifouling was used for each instrument deployment.
Read MoreReturn to Sea in the COVID-19 era
The R/V Neil Armstrong returned to its home port in Woods Hole, MA, on 16 June 2020, having completed a successful 10-day mission to service the Pioneer Array, 75 nautical miles south of Martha’s Vineyard. Its crew and nine-member science party from Woods Hole Oceanographic Institution proved that it is possible to work onboard while adhering to strict precautionary measures to prevent the spread of the coronavirus.
The expedition was the first science mission to have departed Woods Hole, MA following a “pause” in research expeditions imposed in March by UNOLS (University-National Oceanographic Laboratory System). UNOLS coordinates the U.S. academic research fleet ship schedules and has established guidelines for COVID prevention and mitigation aboard these ships.
“The preparation was arduous and comprehensive” said Al Plueddemann, Chief Scientist for the Pioneer Array expedition. “That preparation paid off with a cruise that completed everything we set out to do.” Plueddemann led the scientific team in a partial “turn” of the moored array, which means that equipment that had been deployed was recovered for refurbishment, and replaced with equipment that could undergo the rigors of being at sea, collecting, and recording data for the next six months. Over the 10 days, the team deployed five Coastal Profiler Moorings (CPMs) and recovered seven CPMs. In addition to the mooring turns, the expedition included many CTD casts (measuring Conductivity, Temperature and Depth) in the vicinity of the Pioneer Array, and the collection of shipboard meteorological and oceanographic data, both while on station next to the moorings, and while underway along specific track lines.
On top of what would be accomplished under normal operating conditions, the team was able to provide data in real-time to scientists who would normally be onboard, but whose participation was limited due to COVID-19 restrictions. Through an innovative use of data telemetry from the ship, WHOI’s Shipboard Scientific Services Group made it possible for members of the Northeast U.S. Shelf Long-Term Ecological Research (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.
“Our ability to conduct a near-normal cruise in the midst of the COVID-19 pandemic is a testament to the commitment to preparation from UNOLS and WHOI, and a reflection of the strong team within OOI and on the Armstrong” said Plueddemann. “We were all excited to get back to sea”.
The following is a collection of images from this successful mission.
After 14 days of quarantine, a nine-person science team from Woods Hole Oceanographic Institution boarded the R/V Neil Armstrong on 5 June 2020 to prepare for a 10-day expedition to service the Pioneer Array, 75 nautical miles south of Martha’s Vineyard in the Atlantic Ocean.The expedition was the first science mission to depart Woods Hole, MA, with new COVID-19 precautions in place. Photo: © Woods Hole Oceanographic Institution, Rebecca Travis
Chief Scientist of the Pioneer 14 Expedition, Al Pluedemann, models the uniform de rigueur —mandatory mask-wearing for the duration of the 10-day cruise. It was one of many stringent precautions taken to address the coronavirus pandemic. Photo: © Woods Hole Oceanographic Institution, Darlene Trew Crist
WHOI technicians (from left) Dan Bogorff, Nico Llanos, Chris Basque and Eric Hutt work to ensure that all equipment is in place as they prepare to head to the Pioneer Array. Photo: © Woods Hole Oceanographic Institution, Rebecca Travis
WHOI technician Chris Basque (far left) runs the deck while Bos’n Pete Liarikos and WHOI technician Nico Llanos (behind the buoy) assist in deploying the OSPM profiling mooring at Pioneer Array. Photo: © Woods Hole Oceanographic Institution, Rebecca Travis
While this may look like Snuffleupagus on the back deck of the R/V Neil Armstrong, it is actually a profiler buoyancy sphere recovered on the Pioneer 14 cruise. The sphere is covered with marine growth after spending eight months in the water. Photo: © Woods Hole Oceanographic Institution, Rebecca Travis
The Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) team, whose members would have been onboard under normal circumstances, remained onshore due to COVID-19 restrictions. But through an innovative use of data telemetry, Wood Hole Oceanographic Institution’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. Photo: NES-LTER
One of the rewards of working at sea is the peacefulness and beauty at the end of a long day aboard the R/V Neil Armstrong. Here the Pioneer 14 team got its just rewards as they lowered a CTD rosette frame into the Atlantic at sunset. Photo: © Woods Hole Oceanographic Institution, Rebecca Travis
Read MoreReady-to-use Educational Datasets Available
A new website of curated OOI datasets, called Data Nuggets, has launched. It contains valuable resources ready for integration into educational activities. The nuggets explore various concepts common in upper-level high school and introductory college courses and are designed and packaged to be readily accessible to educators to integrate into their existing curricula. Datasets were selected based on their quality and alignment with a broader OOI Science Theme.
The nuggets were created as part of the National Science Foundation-funded OOI Synthesis & Education project, Ocean Data Lab, conducted by Rutgers University and led by the Consortium for Ocean Leadership.
For now, four data nuggets are available:
- 2015 Axial Seamount Eruption
- Seasonal Phytoplankton Blooms at High Latitudes
- Flux of CO2 Between Ocean and Atmosphere
- Seasonal Mixing of the Irminger Sea Water Column
The material provided in each nugget ranges from a description of scientific relevance to high resolution graphs to how use Python to pull and use OOI data in the classroom. The nuggets are designed to support educators as they design their own activities using OOI data.
More nuggets will be continually added so check the website often.
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COVID-prevention, Quarantine, and Collaboration: Endurance Array 13 is Ready to Go
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 MoreShipboard Data Transmission to Onshore Partners in Real-time
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 MoreAltered Carbon: Improvement to CO2 Measurements Enhance OOI Data Quality
Global carbon dioxide (CO2) concentrations are increasing in the atmosphere, largely due to the use of fossil fuels. The oceans are absorbing about 25-30 percent of the atmospheric CO2, resulting in a shift in seawater acid-base chemistry and a decrease in ocean pH, making seawater more acidic. To help scientists assess this changing ocean chemistry, the Ocean Observatories Initiative (OOI) uses the Sunburst SAMI-CO2 instrument to measure the partial pressure of carbon dioxide (pCO2) from 150-700 microatmospheres (μatm) in the upper 200 meters of the water column.
The distribution of pCO2 in seawater is dependent on gas exchange with the atmosphere at the ocean surface, the breakdown of plant material by microbial processes, and removal by photosynthesis, calcium carbonate formation, and rising temperatures. Increases in pCO2 can also be caused by dissolution of calcium carbonate, which is of particular importance because calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms, such as oysters.
Using the SAMI-CO2 instrument, OOI researchers determine the partial pressure of CO2 by equilibrating a pH sensitive indicator solution (Bromothymol Blue) to sampled seawater. Aqueous carbon dioxide in seawater diffuses across a permeable silicone membrane equilibrator within the instrument, which changes the color of the indicator solution from blue to yellow. The equilibrated indicator solution is then pumped through a chamber where light passes through the liquid and into a receptor that uses the wavelength to determine the amount of color change, and thus the amount of CO2 dissolved in the water.
“The OOI system parses the raw data from the instrument, applies a ‘blank’ value to correct for instrument drift, and then delivers calibrated pCO2 data to users on demand,” explained Michael Vardaro, OOI Research Scientist at the University of Washington. “We recently created a fix to apply the correct ’blank’ values to the pCO2 data to improve data accessibility and data quality.”
Blank values (e.g., optical absorbance ratios in the pco2w_b_sami_data_record_cal data stream) are used to calculate the data product “pCO2 Seawater (µatm)” at a specific timestamp. Blank values, however, are recorded intermittently to correct for drift of the electro-optical system, about once a week, which is a longer interval than the instrument sampling rate of one sample per hour.
The recent correction will ensure that any pCO2 data request will use a linearly interpolated value from the closest blanks if no blank value is found within the requested time range. This means that for an hourly pCO2 measurement that falls between weekly blank values the system will calculate the appropriate drift correction to apply based on the surrounding blank values, instead of trying to find a specific blank value that might be outside the date range of the requested data. In addition to improving data quality, this fix prevents the system from returning fill values or empty datasets. Additional restrictions were put on data delivery to prevent interpolation across deployments, which could pull blanks from different instrument serial numbers, potentially creating bad data. These fixes apply to all OOI pCO2 data. Users who have pCO2 data products generated prior to 4 February 2020 are encouraged to re-request their data to ensure that the correct interpolation code is applied.
Any questions about this data fix, or any other OOI data issues, should be directed to help@oceanobservatories.org.
Images
Top: Alex Andronikides, a VISIONS’17 student from Queens College, New York helps clean a Regional Cabled Observatory Shallow Profiler Mooring science pod that was installed off the Washington-Oregon coast. Credit: M. Elend, University of Washington, V17.
Bottom: Pre-deployment photo of a Sunburst SAMI-CO2 sensor attached to the Oregon Offshore Cabled Shallow Profiler pod, which moves up and down in the water column between 200 meters and near the surface off the coast of Newport, OR. Credit: M. Elend, University of Washington, V19.
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