Behind the scenes of UTRGV’s first-of-its-kind study on the carbon capture capacity of artificial reefs like the RGV Reef
American radio personality Paul Harvey was known for the phrase, “Now you know the rest of the story.” Taking a page from Harvey, in this blog, we share the backstory of the University of Texas Rio Grande Valley’s (UTRGV) carbon sequestration study.
For years, scientists around the globe have studied reefs and photographed the incredible marine life teeming around them.
Given ongoing concerns over greenhouse gas emissions and emergent discussions around decarbonization in recent years, though, one question remained unanswered—can artificial reefs capture carbon? If so, in what amounts—and what species do it best?
Many have pondered the question. But until Dr. Richard Kline and his two UTRGV graduate students in Brownsville took action, no one really knew the answer. Until now.
The UTRGV research team chose the largest nearshore artificial reef in the U.S. Gulf Coast—the RGV Reef, off South Padre Island in the Gulf of Mexico—becoming the first scientists in the world to do so on this scale.
Friends of RGV Reef volunteers sink and deploy in February 2025 the largest vessel ever introduced to the reef—a 110-foot-long ship that will serve as a thriving habitat for marine life.
“Being first is not what this was all about,” says Dr. Kline, who is leading the research. “We are trying to determine if artificial reefs can be part of the solution to help fight climate change.”
‘An exciting step forward for both climate and reef science’
Over a two-year period, Kline and his students dove on and around RGV Reef and used advanced sonar equipment on their boat to collect data and specimens to be tested for their ability to capture carbon. They analyzed the amount of carbon in fish inhabiting the reef, as well as crustaceans attached to the reef.
The UTRGV study was limited to measuring carbon over the reef’s surface. The team’s initial results netted seven metric tons of captured carbon—and these scientists believe that the two-and-a-half-mile-wide reef is actually capturing much more carbon, up to 10 times that amount.
Seventy tons of carbon, they believe, are being captured in the reef’s sediments. That’s equivalent to preventing 257 metric tons of CO₂ from entering the atmosphere.
"This is an exciting step forward for both climate and reef science,” said graduate student Allison White. “Fish and artificial reefs have been largely overlooked when it comes to carbon storage. Our research shows they may play a bigger role than we thought. This opens the door to exploring new, nature-based ways to help tackle climate change around the world."
An exploration of the power and resiliency of our oceans
The 1,650-acre RGV Reef—the largest artificial fish habitat off the Texas Gulf Coast—was created by non-profit group Friends of RGV Reef in 2017, using 4,000 tons of highway dividers, box culverts and other concrete materials; 67,000 cinder blocks; 47 reefing pyramids; and a pair of cleaned steel-hull vessels to begin with. An estimated 250,000 fish took up immediate residence after just one season’s worth of reef construction in 2017.
With over 11,500 tons of materials, the Friends of RGV Reef in 2021 created 58 low-relief nursery patches, each weighing 200 tons and spanning a combined 132 acres.
Presently the RGV Reef, built predominately from cinder blocks and concrete railroad ties, includes 43 types of structures and 510 reef patches consisting of either one structure type or multiple grouped structure types.
The reef has attracted more than 75 species of fish—including snapper, groupers, grunts, drums and sardines—with the structures providing food, protection from predators, and a space to conserve their energy from strong ocean currents. A growing number of marine organisms, such as soft corals, sponges, barnacles and biofilms, have also made a home at the reef.
The carbon sequestration study was announced in May 2022 by the Friends of RGV Reef and UTRGV. The study was funded through a $250,000 Fueling Futures grant from Enbridge.
According to the Friends of RGV Reef:
- Artificial reefs contribute to a 50% increase in species richness compared to non-reef areas.
- The presence of artificial reefs has been associated with a 30% rise in fish biomass, indicating healthier and more abundant marine populations.
- Studies show artificial reefs can support fish densities up to 20 times higher than surrounding sandy areas, providing essential habitats for various species.
The research conducted in South Texas should open eyes.
“The experience of conducting this research study gave me an insight into truly how powerful and resilient our oceans are,” said graduate student Michelle King.
“Not only can reef species that typically exist on natural reefs settle on these habitats, creating a biodiverse ecosystem, but they also accumulate carbon in their tissues and long-lived body structures. The further exploration of the benefits artificial reefs provide to our changing oceans is vital for our environment's future.”
‘Wherever there is a coastline, we can have artificial reefs capturing carbon’
What’s ahead? This summer, UTRGV research and findings will be made public through the team’s thesis work. They expect their findings will be published in academic journals by winter 2025.
What does the UTRGV team feel about reefs being part of the climate change solution?
“Our findings show that it can be a valuable tool. In building the artificial reef, new marine habitat was created, and fish came back in large numbers. That was win number one. Win number two is that yes, reefs do collect carbon. We now know that beyond a shadow of a doubt—that will definitely help in the battle against climate change,” continued Kline.
“The importance of this study is wherever there is a coastline in the world, we can have artificial reefs capturing carbon. The possibilities are enormous.”
The UTRGV scientists believe the greatest amounts of carbon being captured can be found in the ocean floor, in the reef’s sediments.
Could another study be on the way? Stay tuned, says Dr. Kline.
And now, you know the rest of the story.
