Wildfires along the California coast pose a significant threat to marine ecosystems, with researchers collecting valuable data on the effects of the Palisades and Eaton fires on the Pacific Ocean. As ash particles and pollutants spread far beyond the fires’ reach, scientists warn of unprecedented environmental consequences.
The California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has been conducting quarterly research voyages to study the Pacific Ocean since 1949. This year’s winter mission, which took place from January to April, coincided with the Palisades and Eaton fires in the Los Angeles area. The researchers on board were able to collect valuable data on the effects of these wildfires on the ocean.
As ‘the flames raged,’ scientists urged the researchers at sea to collect additional samples beyond their planned scope. Using nets and other tools available on board, they gathered ash and extra water samples to study the toxins that may have seeped into the Pacific. The amount of human-made materials set ablaze, including batteries, cars, plastics, and building materials, means that the LA fires may affect the environment in unprecedented ways compared with other wildfires.
Wildfires release massive amounts of carbon dioxide and other greenhouse gases, exacerbating climate change.
They also destroy habitats, causing loss of biodiversity.
In addition, wildfires contaminate soil and water sources with toxic chemicals from burned vegetation and debris.
The impact is not limited to immediate areas; smoke particles can travel long distances, affecting air quality globally.
The size of the ash pieces collected by the researchers has been a significant discovery. Some as long as a thumb have been found, which is larger than expected. The strong winds that spread the fires also blew smaller bits as far as 160 kilometers offshore. Current models of aerosol movement during fires do not account for hunks of burnt materials, so this discovery may lead to revisions in the models.
Wildfire ash particles vary in size, typically ranging from 1-500 micrometers.
These fine particles can be easily airborne, contributing to long-distance dispersal.
Research suggests that smaller PM2.5 are more likely to travel far due to their increased mobility.
Studies have shown that wildfire ash can reach distant regions through atmospheric circulation patterns, affecting local air quality and ecosystems.
Marine biologist Julie Dinasquet is worried about pollutants driven into the water by the fires and debris flows from heavy rains that followed. ‘The ocean is already so stressed,’ she says. ‘Fires add another layer of complexity to increasing temperatures and longtime pollutants.’ She questions how resilient the ecosystem will be, especially if this kind of stress is increasing in the future.
Scientists who board CalCOFI cruises plan to continue gathering data on the LA fires’ effects for the remainder of this year, depending on funding. Marine biologist Nicolas Concha Saiz notes that during the spring 2025 trip, no ash or smoke was visible to the naked eye, and the water and air looked completely normal. However, they will have to wait and see what their new collected samples reveal.
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