Beach in Southampton, New York Treated with Olivine Sand
Cheyenne Morrow
Initial studies of adding crushed olivine to ocean waters for atmospheric carbon dioxide absorption showed no adverse effects on the seafloor ecosystem during the first year.
While the New York State trial offers promising findings for this innovative carbon removal technology, researchers advise caution, as it may not encapsulate all potential negative impacts.
Emilia Jankowska from Hourglass Climate, the nonprofit organization conducting the study, stated that while the addition of olivine to the ocean should be regulated, “there are methods to minimize effects while maintaining effectiveness.”
The UN climate change agency highlights the necessity for carbon removal strategies, including reforestation and advanced carbon filtration methods, to achieve net-zero greenhouse gas emissions. With rising emissions, the aspiration to limit global warming to 1.5 degrees Celsius remains a challenge.
Olivine, a magnesium iron silicate mineral, is often found within the Earth’s mantle and reacts with CO2 when reaching the surface, forming stable compounds that can sequester carbon in the ocean for millennia.
A recent study indicated that spreading crushed olivine and similar silicates on crops could enhance this process, potentially removing up to 1.1 billion tons of CO2 annually. U.S. startup Vesta aims to introduce olivine directly into ocean waters, facilitating increased carbon absorption through bicarbonate formation.
However, olivine may contain trace amounts of heavy metals. Research has detected elevated nickel and chromium levels in crustaceans and mollusks exposed to olivine. There are concerns about sand potentially suffocating benthic organisms, such as crustaceans and worms.
In 2022, Vesta distributed 650 tons of olivine sand along Long Island’s coast, overlaying it with 13,500 tons of regular sand for shore reinforcement. However, as storms intensified, tides washed away much of the olivine.
Researchers collected sediment samples from shallow waters up to 160 meters offshore before and after adding olivine, and a year later. They compared these to samples from areas where only regular sand or no sand was added.
Among numerous species, only a minor decline was observed in the fringe bloodworm within the olivine-treated area, with overall benthic species’ abundance and diversity rebounding within two months. Species composition shifted similarly in regions where only regular sand was used, indicating common beach aquaculture practices.
Crucially, nickel, chromium, cobalt, and manganese concentrations in organisms remained low. “Natural systems are highly dynamic, causing dissolved elements to dilute rapidly,” Jankowska remarked.
While Vesta oversaw environmental monitoring for these trials, the analyses conducted by Hourglass were independently funded by the Grantham Foundation.
Olivine’s dissolution in ocean waters may lead to calcium carbonate precipitating from seawater, potentially trapping trace metals, as noted by Christopher Pierce at the UK National Marine Centre. Nevertheless, this might limit the additional CO2 absorption capacity of seawater.
This significant research transitions understanding from laboratory settings to real-world applications. Further investigation remains essential to comprehend varying biological responses and infection rates associated with CO2 ingestion.
Nonetheless, the study’s assertion of no negative effects may overstate the findings, according to James Kelly of Ocean Care. He notes that fluctuations in olivine concentrations could imply limited exposure, questioning the notion that olivine is inherently safe.
Hourglass Climate is currently tracking the results from a large-scale trial with Vesta. In 2024, 8,200 tons of olivine were identified 450 meters offshore from Duck, North Carolina. Preliminary insights suggest recovery in species richness and diversity, although metal accumulation analysis is ongoing.
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Source: www.newscientist.com
