In December, 2017 the Thomas wildfire was tearing through parts of Ventura and Santa Barbara Counties. It charred more than 280,000 acres of land, directly caused two deaths, and destroyed more than a thousand structures.
Debris and ash created issues for many of the region’s waterways. The first instinct is that it might also be a major form of toxic pollution for the ocean. But, researchers say they’ve discovered ash could actually be beneficial.
"There were metals, which can be good or bad, toxic or beneficial for organisms, and then there were a bunch of nutrients that phytoplankton use to grow," said Tanika Ladd.
Ladd was a UC Santa Barbara graduate student at the time of the Thomas Fire. As the ash from the fire was coming down, she and some of her colleagues had an idea. The were supposed to go on a previously scheduled research cruise, but decided they should pivot to look at the impacts of the ash on the ocean.
"It was a bunch of different groups that kind of took different aspects of understanding wildfire ash on the ocean," said Ladd. "Our little group decided to do some experiments while we were out there, looking at the microbial communities."
She said they looked at existing research. It showed while ash can heavily impact fresh water systems, little had been done to study effects on the ocean.
So, Ladd and some fellow UCSB researchers developed a testing plan.
"We took some ash deposited on car windshields," said Ladd. "We knew it was on soil on the ground. We took some of the ash, and dissolved it in sea water. It started leaching chemicals into the sea water."
She said they found metals, and nutrients.
Ladd is the lead author on a research paper on the ash study. So, was the ash concentrated enough to make a significant difference in the sea life off our coast? Did it in effect act as ocean fertilizer. Ladd admits those are hard questions to answer.
"We tried to do some calculations of how much biomass was burned, and how much ash was created, and how much made it to the ocean," said Ladd. "We did think it added enough to make a small difference."
Ladd points out that all wildfire ash isn’t the same, so the ocean impacts could be different.
The researcher said the findings suggest large wildfires could be important sources of nutrients like nitrogen to coastal marine systems. In effect, the leaching of nutrients could act as food for various types of microbial life.
She thinks this study opens the door for more research. Their research paper on the impacts of ash was just published in the scientific journal Proceedings Of The Royal Society.
