Anchialine pool shrimp (Halocaridina rubra) as an indicator of sewage in coastal groundwater ecosystems on the island of Hawaiʻi

• Published in: PloS one 2023-08, Vol.18 (8), p.e0290658-e0290658
• Main Authors: Marrack, Lisa C., Beavers, Sallie C.
• Format: Article
• Language: English
• Subjects: Algae; Bioindicators; Biology and Life Sciences; Coastal ecosystems; Coasts; Consumers; Contaminants; Contamination; Coral reefs; Diet; Ecology and Environmental Sciences; Ecosystems; Endemic species; Engineering and Technology; Groundwater; Groundwater discharge; Halocaridina rubra; Indicator species; Isotopes; Marine ecosystems; Marine environment; Marine pollution; Medicine and Health Sciences; Metabolism; Monitoring; Monitoring methods; National parks; Nitrogen; Nitrogen isotopes; Nutrients; Parameters; Phosphorus; Physical Sciences; Pollutants; Research and Analysis Methods; Seaweeds; Sewage; Sewage disposal; Shellfish; Shrimps; Stable isotopes; Temporal variability; Tissues; Wastewater; Water quality
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0290658

Groundwater is a primary pathway for wastewater and other pollutants to enter coastal ecosystems worldwide. Sewage associated pathogens, pharmaceuticals, and other emerging contaminants pose potential risks to marine life and human health. Anchialine pool ecosystems and the endemic species they support are at risk and provide an opportunity to sample for presence of contaminants prior to diffusion in the marine environment. In this study, we tested the potential use of nitrogen isotopes in the tissues of a dominant anchialine pool grazing shrimp ( Halocaridina rubra) , as a bioindicator for sewage in groundwater flowing through their habitats. Water quality parameters and shrimp tissue isotopes (N and C) were collected from pools exposed to a range of sewage contamination along the West Hawai‘i coastal corridor from 2015 to 2017. Data were used to test for spatial and temporal variability both within and among pools and to examine the relationship between stable isotopes and water quality parameters. Within 22 pools, mean δ 15 N from whole tissue samples ranged between 2.74‰ and 22.46‰. Variability of isotope values was low within individual pools and within pool clusters. However, δ 15 N differed significantly between areas and indicated that sewage is entering groundwater in some of the sampled locations. The significant positive relationship between δ 15 N and dissolved nitrogen (p