Spatial distribution and sources of nutrients at two coastal developments in South Kohala, Hawai'i

Jazmine Panelo; Tracy N Wiegner; Steven L Colbert; Stuart Goldberg; Leilani M Abaya; Eric Conklin; Courtney Couch; Kimberly Falinski; Jamison Gove; Lani Watson; Chad Wiggins

doi:10.1016/j.marpolbul.2021.113143

Spatial distribution and sources of nutrients at two coastal developments in South Kohala, Hawai'i

Mar Pollut Bull. 2022 Jan:174:113143. doi: 10.1016/j.marpolbul.2021.113143. Epub 2021 Dec 28.

Authors

Affiliations

¹ Tropical Conservation and Environmental Science Graduate Program, University of Hawai'i at Hilo, 200 W. Kawili St., Hilo, HI 96720, United States of America.
² Marine Science Department, University of Hawai'i at Hilo, 200 W. Kawili St, Hilo, HI 96720, United States of America. Electronic address: wiegner@hawaii.edu.
³ Marine Science Department, University of Hawai'i at Hilo, 200 W. Kawili St, Hilo, HI 96720, United States of America.
⁴ Habitat Conservation Division, Pacific Islands Fisheries Science Center, National Oceanic and Atmospheric Administration Inouye Regional Office, 1845 Wasp Blvd, Honolulu, HI 96818, United States of America.
⁵ The Nature Conservancy, Hawai'i, 923 Nu'uanu Avenue, Honolulu, HI 96817, United States of America.
⁶ Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, 46-007 Lilipuna Road, Kāne'ohe, HI 96744, United States of America.
⁷ Ecosystem Sciences Division, Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1845 Wasp Blvd., Honolulu, HI 96818, United States of America.

PMID: 34971985
DOI: 10.1016/j.marpolbul.2021.113143

Abstract

Nutrient sources to coastal waters with coral reefs are not well-characterized. This study documented spatial distributions of nutrients within coastal waters along two developments with coral reefs, and identified nutrient sources through nutrient mixing plots, δ¹⁵N measurements in macroalgal tissue, and NO₃^- stable isotope mixing models. Nutrients decreased from fresh groundwaters to offshore waters, with some surface waters higher in concentrations than benthic ones. Conservative and non-conservative mixing between fresh and ocean waters occurred, the latter suggestive of local nutrient sources and biological removal. δ¹⁵N in macroalgal tissue and NO₃^- concurred that fresh groundwater, ocean water, and fertilizers were dominant nutrient sources. Benthic salinity and NO₃^- + NO₂^- concentrations illustrated that submarine groundwater discharge delivered nutrients to reefs in pulses ranging from minutes to days. Information generated from this study is imperative for developing management actions to improve water quality and make coral reefs more resilient to stressors.

Keywords: And stable isotopes; Coral reefs; Hawai'i; Macroalgae; Nitrogen; Nutrients.

MeSH terms

Coral Reefs*
Environmental Monitoring
Groundwater*
Hawaii
Nutrients
Water Quality