Inside the GO-BGC Array Project to Monitor Ocean Health

Stephen Riser has been a Professor of Oceanography at the University of Washington for about 35 years, with a focus on large-scale ocean circulation, and more recently, studying its chemical via marine instrumentation. “I've been a part of the Argo program since its beginning in 1999,” said Riser in a recent interview with Marine Technology TV, “and my group has produced and deployed about 2,500 Argo floats during that time.”

In late October 2020, the National Science Foundation approved a $53 million grant to a consortium leading ocean-research institutions – including Monterey Bay Aquarium Research Institute (MBARI), Woods Hole Oceanographic Institution (WHOI), University of Washington, Scripps Institution of Oceanography, and Princeton University – to build a global network of chemical and biological sensors that will monitor ocean health – to build and deploy 500 robotic ocean-monitoring floats around the globe.

According to Riser, this project is “taking it to a new level” as the new network of floats, called the GO-BGC Array will collect observations of ocean chemistry and biology between the surface and a depth of 2,000 meters (6,562 feet). Data streaming from the float array is then made freely available within a day of being collected to be used by researchers, educators, and policy makers globally.

“So GO-BGC is going to build on top of Argo, which has been around since 1999 and is a global array of nearly 4,000 floats that profile in the ocean between the surface and 2,000 meters every 10 days,” said Riser. “It has been a major addition to our knowledge, (and to date more than) 4,000 scientific papers have been written using the data. The data are available in real time, within 24 hours of being collected to anyone in the world. There's nothing proprietary about it.”

GO-BGC or Go Home

GO-BGC is an extension of Argo, adding new sensors and new measurements. “So we're starting to measure things like dissolved oxygen, pH, nitrate, chlorophyll, other things that will enhance the array,” said Riser. “in addition to being a tool that mostly physicists can use, now biologists and chemists are going to get a lot out of this as well.”

While the consortium tasked to build and deploy the GO-BGC array is diverse, University of Washington has the largest ‘slice of the funding pie’ premised on its unmatched experience. “The University of Washington's piece is about $23 million of that $53 million,” said Riser. “We have the most experience at with these biogen chemical floats, and in the beginning, most of the floats deployed will be ones that come from here.”

Predictably the project includes a long list of technology partners to bring the array to fruition, let by Teledyne Marine and Sea-Bird Electronics. “We will be building, and when I say ‘building’ I mean putting together here at UW things that are already fabricated by Teledyne, Sea-Bird Electronics, and various sensor manufacturers,” said Riser. “Once we put these together, we do a lot of tests and we arrange for the deployments in the world ocean. Of the 500 floats in GO-BGC, I think something like 320 of them are planned to come from UW.”

The key technology is the profiling float, “which Teledyne was one of the very first to produce those and has been doing that very well for the last 20 years,” said Riser. “Each of these floats (essentially) has three pieces to it: the buoyancy engine; the sensors; and the software.” Clara Hulburt, APEX Product Line Manager, Slocum Glider Commercial Sales Manager, Teledyne Webb Research, discussed the project from Teledyne’s point of view.

“We have been partnering with the University of Washington for almost the entire time we've been building APEX profiling floats, since 1995, and we have delivered (approximately) 9,800 floats now,” said Hulburt. “About eight years ago we developed the biogeochemical float, where we're able to integrate up to six sensors, which is the Argo-recommended BGC suite in our floats.”

Typically Teledyne delivers the floats as a complete product, but the relationship with UW is unique, as Hulburt explains. “We have a unique partnership with the University of Washington where we deliver a kit of parts, and they finish the fabrication on their end to their specifications.”

“De-Bugged”: Proven Technology; New Possibilities

The original Argo floats have only temperature and salinity measurements on them, said Riser, while the new floats include temperature and salinity, “but they also measure biogeochemical properties, such as nitrate, oxygen, pH, fluorometry and particulate backscatters. So that's what makes them distinct. But the floats look very similar. And even though we're just starting GO-BGC, this float has been around for a while. We're not starting this in a vacuum. There are already a couple of hundred of these in the water in various places going back a number of years.” In fact, maturity of a proven technology platform was a key plank in the NSF awarding the $53 million, said Riser. With funding in hand and work underway, Riser and his colleagues a moving toward activation of the array to help expand the amounts of information coming from the ocean.

“Certainly the design of Argo, in the beginning, was to look at climate-related things,” said Riser, noting that the bulk of the heat that comes in from the sun is stored in the ocean. “Over 90% of the incoming heat from the sun ends up stored in the ocean, but when you think about a climate, there's more than just heat,” said Riser.

The carbon cycle is another part of it, and these floats will allow us to start to assess the ocean's role in the carbon cycle, said Riser, noting that while it is not well understood today, “we should be able to get that out of this after a few years (as well as) a number of other things involved with the carbon cycle and biogeochemical cycling in general.”

Although the project was formally announced only a few month ago, work is already underway. “We have placed orders for equipment, and we hope to have the first (12) floats on a cruise on the research vessel, Thomas G. Thompson out of Woods Hole in March of 2021,” followed by a voyage across the Pacific Ocean from Tokyo to Seattle during the summer of 2021.