UH Hilo marine scientists identify sources of pollution in coastal waters off West Hawai‘i

In the investigation, the research team discovered that troublesome nutrients found in coastal waters and coral reefs off West Hawai‘i are from human sources, like fertilizer run off. The study was published last month.

Group of people in beach setting sort through bottles of water samples.
UH Hilo students work with a collaborative group of UH Hilo marine science faculty and experts from The Nature Conservancy and the National Oceanic and Atmospheric Administration to document water quality at Kūki‘o Beach on the west side of Hawai‘i Island, 2017. At left is lead author of the study, Jazmine Panelo, and at right is a co-author Tracy Wiegner—both collaborated with multiple agencies on “Spatial distribution and sources of nutrients at two coastal developments in South Kohala, Hawai’i.” (UH Hilo Department of Marine Science)

By Jordan Hemmerly.

A group of University of Hawai‘i at Hilo researchers, their students, and community partners have published information that is imperative to improving overall water quality on Hawai‘i Island.

The study documents distribution of nutrient pollution within coastal waters with coral reefs in proximity to two developments on the west side of the island, and identifies the sources of those nutrients. The group sampled a variety of public beaches, the Waikoloa and Hualali watersheds, and resort development areas including the Mauna Lani and the Kūki‘o in order to identify distribution patterns and sources of excess nutrients found in groundwater, anchialine ponds, as well as ocean surface waters and water surrounding coral reefs.

Steve Colbert
Steve Colbert
Tracy Wiegner
Tracy Wiegner

Lead author of the study is research assistant and UH Hilo alumna Jazmine Panelo.

Heading the research team were co-authors and marine scientists Tracy Wiegner and Steve Colbert from the Department of Marine Science at UH Hilo.

The findings were published in the Marine Pollution Bulletin last month.

In the investigation, the team discovered the overabundance of troublesome nutrients found in coastal waters and coral reefs are from human sources, like fertilizer run off. Coral reefs impacted by this type of nutrient pollution are less resilient to disease and ocean warming. The researchers discovered the nutrient concentrations tend to decrease as they move downhill toward the ocean.

At both Pau‘oa and Kūki‘o, the researchers found higher concentrations of most nutrients in groundwater than in ocean water. Some anchialine ponds and shoreline seeps near landscaped areas, including golf courses, had elevated nutrient concentrations.

Along with Panelo, Wiegner, and Colbert, co-authors of the study include UH Hilo alumna Leilani Abaya, alongside Courtney Couch of the Hawai‘i Institute of Marine Biology and Cooperative Institute for Marine and Atmospheric Research at UH Mānoa.

Eric Conklin, Kimberly Falinski, and Chad Wiggins from The Nature Conservancy, and Stuart Goldberg, Jamison Gove and Lani Watson from the National Oceanic and Atmospheric Administration (NOAA) are also co-authors.

Wiegner says it took a village to conduct the sampling. UH Hilo summer interns from the Pacific Internship Programs for Exploring Science collected data along with volunteer undergraduates, graduate students in the tropical conservation biology and environmental science program, and visiting students from out-of-state universities.

“We had some people swimming out to collect water samples, and another team on the shoreline processing the samples,” says Wiegner. “It was really great to see.”

Map of study area on the West Hawaii coastline.
Location of stations sampled May to August 2017 at Pau’oa (A) and Kūki’o (B) Bays, Hawai’i. Different shapes represent different water types or nitrogen sources. Location of nitrogen source stations (fresh groundwater, fertilized soil, and wastewater treatment plant) sampled are shown in the top right inset map for each development. Fresh groundwater is defined as salinity <1. Bottom right inset map shows location of developments on Hawai’i Island relative to the state of Hawai’i. (Image from study)

In the ocean, one person at flotation device and another heads to shore with water sample.
An undergraduate volunteer works with a scientist from The Nature Conservancy to collect offshore seaweed and water samples to document nutrient sources and patterns at Kūki‘o, Hawai‘i Island, 2017. (Department of Marine Science, UH Hilo)

The research was initiated through NOAA’s Habitat Blueprint program, which addresses the growing challenge of coastal and marine habitat loss and degradation. The federal program is designed to respond to the needs of individual communities looking to protect the environment. The goal is to help the communities better manage their natural resources.

The research group worked closely with members of West Hawai‘i communities who expressed interest in the collected data.

“[Our research partners] have close contact with these local communities and their community association leaders,” explains Wiegner. “We were able to learn from them which community associations were interested in the kinds of information we were collecting.”

Two women stand on a platform at water treatment plant. One holds bottles for sampling.
UH Hilo then-graduate student Jazmine Panelo (right), now a research assistant and lead author of the study, collaborated with staff from the Hawai‘i Water Supply Company to collect wastewater samples from the Waikoloa Village treatment plant in effort to document nutrient pollution sources in Pau‘oa Bay, West Hawai‘i, in 2017. (Department of Marine Science, UH Hilo)

Colbert says the data was shared with community members and associations in the area “as soon as we could.”

The goal is for the information to be useful in future community planning endeavors and further reef research. The researchers say the findings can be used to identify actions needed to improve the health of nearshore coral reefs.

By Jordan Hemmerly, who is earning her bachelor’s degree in marine science at UH Hilo.

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