The project started as a text chain last week between University of Hawaiʻi researchers Sara Kahanamoku, Nyssa Silbiger and Andrea Kealoha. As the state reeled from heavy rains, the group wondered how the resulting runoff of floodwaters into the ocean might affect Hawaiʻi’s reefs.
“The coral reefs are incredibly important to the people here in Hawaiʻi, not just as a beautiful place to snorkel, but because they protect our coastlines. They provide us with food and sustenance, and the water quality has a direct impact on it,” said Silbiger, an associate professor in the UH Department of Oceanography.
She and her colleagues had the tools and expertise to assess water quality in Hawaiʻi’s nearshore ecosystems. But in order to make use of those resources, they needed water samples — ideally, lots of them.
That’s where the community came in. Silbiger and her colleagues put out a call last Thursday for volunteers who would be willing to collect water samples along Hawaiʻi coasts.
Silbiger said the response was overwhelming. Within 48 hours, more than 100 people had signed up.
“I had nurses from Kaiser come in and stop by. I've had students come and stop by. I've had all sorts of community members reach out that want to help. And it just made me so filled with emotion to think about how much the community cares and wants to understand what's going on,” Silbiger said.
The volunteers were given clean bottles to collect samples of ocean water over the weekend. For each sample collected, the volunteer filled out a Google form that included a geographic pin of where the sample was taken.
Over the course of the weekend, Silbiger said forms with new sample sites filled her inbox.
Silbiger marked each one on a map. More than 700 pins dotted the coastlines of Maui, Molokaʻi and Oʻahu.
In addition to popular surf and fishing spots, volunteers trekked to remote places, including Kalaupapa on Molokaʻi.
Silbiger said she even got pins from participants on boats miles offshore.
“When I showed that to someone, they're like, ‘Oh, someone put their GPS point in incorrectly,’” she said. “I was like, ‘No, no. That person literally went out to sea and collected those samples and took bottles and brought them back.’”
All those samples will be returned to Andrea Keahola’s lab at the University of Hawaiʻi, where the water will first be tested for nutrient levels.
“If we see high nutrients, we know that there's probably a lot of stress on the reef,” Kealoha said.
Nutrients, like nitrogen and phosphorus found in fertilizers or sewage, can promote harmful algae blooms along reef systems. Kealoha suspects that places with less wave energy, like South Maui’s reefs, may be harder hit.
“My concern is areas that aren't being flushed out are going to see the impacts of this event for much longer,” she said.
Silbiger and Kealoha plan to share their samples with two other UH labs, which will test for organic matter levels and toxins, like pesticides.
Microbial oceanographer Craig Nelson is part of the team that will process the samples to understand what sort of contaminants, like heavy metals, may have washed into the ocean during the storms.
Nelson has previously investigated the coastal water impacts of other major events, including the Red Hill fuel spill and the Lahaina fire.
“Lahaina was a similar situation. We had a huge disaster that nobody predicted. And one of the first questions for all of the community members was, can we fish? Can our keiki go in the water?” he said. “Those questions are the exact same questions here. And that's essentially why we're tackling this.”
Once these researchers establish a robust dataset on how the flooding from recent storms is affecting Hawaiʻi’s reefs, Sara Kahanamoku will work to put their findings in a historical context.
They plan to take sediment cores from reef systems to understand how past floods compare to what Hawaiʻi has experienced in the last month.
“Essentially, we can use this modern information to then say, ‘OK, do we see similar things in the past? And does it tell us something about whether or not events like this were common, 100 years or 200 years ago, or maybe 1,000 years ago?’” they said.
Kahanamoku said that the volunteers played a key role in shaping these forthcoming studies.
The researchers didn’t dictate where the volunteers should collect samples. Instead, they encouraged the volunteers to collect samples at the places that matter to them most.
“The point is to try to use the tools that we have here at the university and the information we can get from scientific methods to support what our communities want,” Kahanamoku said.
A website that will make the results of the samples publicly available is in the works.
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