Combating Climate Change on a Green-Sand Beach Team from Cal Poly visits Hawaii to study carbon capture

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Packing for a beach day in Hawaii for most means reef-safe sunscreen, swimming shoes and snorkel gear but not if that shoreline visit is part of a mission to reverse climate change.

In that case, one needs seven pallets of scientific research equipment.

An international team of experts from the environmental, geochemical and biological sciences — including a Cal Poly professor and two students — spent a month last summer at mobile research stations on Big Island beaches to study a green volcanic mineral known as olivine that reduces ocean acidity and captures the carbon dioxide driving climate change.

Early each morning, the group would load up trucks with sampling and analytical equipment, plus a boat, and head for South Point, the southernmost point of land in the U.S., where they would devote their day to diving, sampling and testing.

The team’s research will paint a clearer picture of the risks and impacts of radically accelerating the weathering of olivine by spreading copious amounts onto coastlines where it can dissolve in seawater, increasing the rate of carbon dioxide absorption by the ocean.

Natural weathering happens too slowly to balance human carbon emissions but, if done safely and effectively, hastening the process could capture billions of metric tons of carbon dioxide.

Environmental engineering emeritus Professor Yarrow Nelson said the race is on to reduce emissions after a climate report last year predicted more wildfires, floods, heat waves and water shortages over the next 30 years due to a rise in global temperatures that now calls for carbon sequestration to reverse.

“While we still have to reduce fossil fuels, that’s not enough anymore. We just aren’t cutting it,” said Nelson, who now believes sequestering carbon is essential to climate change mitigation.

The Team Forms

When Casper Pratt began studying environmental engineering at Cal Poly, the San Francisco resident discovered the website for Vesta, a public benefit corporation exploring how to harness the carbon-capturing power of the olivine crystals that form natural green beaches.

Pratt said Vesta’s area of research aligned with his own interests in biology, chemistry and physics, so he reached out to the head of research to join the effort.

Vesta put Pratt to work modeling the hydrology of a beach in the Dominican Republic, but the then-first-year student had yet to be trained in groundwater hydrology.

Pratt was not deterred, however, and enlisted help from Nelson and the Vesta team to guide his work.

Along the way, Vesta realized that Nelson’s expertise on toxic trace metals in aquatic environments could help Vesta decide how much olivine is safe to add to a beach given the mineral contains nickel, chromium and cobalt which could harm marine life.

Nelson received a $38,000 Vesta grant and needed a graduate student for the research, so he asked his students if any were inclined to follow in the footsteps of the father of climate change.

“I asked for anyone on the level of Svante Arrhenius who wanted to help on a climate change project,” Nelson recalled of the reference to the Swedish physicist and chemist who was the first to claim in 1896 that fossil fuel combustion may eventually result in enhanced global warming.

Bip Padrnos, then a senior in Nelson’s class, laughed upon recalling the request, knowing he couldn’t promise Arrheniusstyle results but that he loved the idea.

“This project is so important, and I wanted to be involved,” Padrnos said.

A Sea Cucumber on a Green-Sand Beach

Pratt, now in his third year, and Padrnos, who is in the blended master’s program, joined Vesta’s research team in Hawaii in July, where home base was an Airbnb and their workplace a beach.

The team set up their mobile research station at one of three sites — green-sand Papakolea, white-sand Kua Bay or black- sand Richardson Beach Park — for a full day of collecting and analyzing seawater and sediment samples, with an occasional surf break.

The setup always attracted tourists, and even a school class, sparking many conversations about climate change.

Padrnos, Pratt and Nelson conducted sampling in conjunction with the larger Vesta team, diving at various depths and locations using syringes, tubes and even buckets to gather materials.

“It was special to be at a beach in Hawaii collecting our own samples,” said Padrnos, who grew up in Waimea. “Being there gave us a full sense of what was going on as we knew each spot and condition under which a particular sample was collected.”

Padrnos recalled one particularly memorable day at Papakolea when the team sampled until 8:30 p.m., using truck headlights to illuminate their research station.

Pratt, who was born into a surfing family in San Francisco, said a highlight

What’s Next?

The research that began in Hawaii is progressing, as Professor Yarrow Nelson works with student researchers Bip Padrnos and Casper Pratt to develop their experimental designs and design specific experiments at Cal Poly.

Padrnos returned from the Big Island with 4 liters of sediment that he’s spiking with trace metals so the trio can ascertain how the metals will move into the ocean and impact marine ecosystems.

was driving the Zodiac inflatable boat to transport Vesta’s scuba dive team amid 10-foot waves, as researchers struggled to keep their test samples vertical.

The Vesta research intern also cut up his fair share of sea cucumbers.

“Since sea cucumbers are bottom feeders, they are good at showing what is in the rocks,” said Pratt, who explained contents of the digestive tract were dissolved in acid to measure the presence of trace metals.

The Cal Poly crew’s piece of the larger research puzzle will be critical in showing the movement and changes in the trace metals released at olivine-enriched beaches.

Sea cucumbers at Papakolea, for example, might have a higher level of trace metals than at Kua Bay or Richardson’s.

“These findings could be a limiting factor in how much olivine is safe to put on a beach,” Nelson explained. “Our canary in a coal mine actually is a sea cucumber on a green-sand beach.” ■

The samples are being tested on the College of Agriculture, Food and Environmental Science’s inductively coupled plasmaoptical emission spectroscopy instrument that can measure 80 elements from the periodic table using argon plasma.

Professor Chip Appel, who teaches soil and water chemistry, oversees the testing, while research associate Matt Arnold runs the instrument to record any nickel, chromium or cobalt.

Developing the methodology was challenging, according to Arnold, but is now resulting in data that Nelson’s team will analyze.

“This method of carbon capture seems promising because it involves harnessing what is already happening,” Appel said. “We need to explore all these avenues.” ■