Tracking the impacts of nutrient inputs on estuary ecosystem function

Alessandra L Suzzi; Troy F Gaston; Louise McKenzie; Debashish Mazumder; Megan J Huggett

doi:10.1016/j.scitotenv.2021.152405

Tracking the impacts of nutrient inputs on estuary ecosystem function

Sci Total Environ. 2022 Mar 10:811:152405. doi: 10.1016/j.scitotenv.2021.152405. Epub 2021 Dec 16.

Authors

Alessandra L Suzzi¹, Troy F Gaston², Louise McKenzie³, Debashish Mazumder⁴, Megan J Huggett⁵

Affiliations

¹ College of Engineering, Science and Environment, University of Newcastle, Ourimbah, NSW, Australia. Electronic address: alessandra.suzzi@uon.edu.au.
² College of Engineering, Science and Environment, University of Newcastle, Ourimbah, NSW, Australia.
³ College of Engineering, Science and Environment, University of Newcastle, Ourimbah, NSW, Australia; Hunter Water Corporation, Newcastle, NSW, Australia.
⁴ Australian Nuclear Science and Technology Organisation (ANSTO), Sydney, NSW, Australia.
⁵ College of Engineering, Science and Environment, University of Newcastle, Ourimbah, NSW, Australia; Centre for Marine Ecosystems Research, School of Science, Edith Cowan University, Joondalup, WA, Australia.

PMID: 34923003
DOI: 10.1016/j.scitotenv.2021.152405

Abstract

Estuaries are one of the most impacted coastal environments globally, subjected to multiple stressors from urban, industry and coastal development. With increasing anthropogenic activity surrounding estuarine systems, sewage inputs have become a common concern. Stable isotope analysis provides a well-established tool to investigate the incorporation of nitrogen into marine organisms and identify major nutrient sources. Benthic macroinvertebrate communities are often used as bioindicators in ecological studies as they typically display predictable responses to anthropogenic pressures, however have a suite of limitations and costs associated with their use. 16S rDNA amplicon sequencing techniques allow for investigation of the microbial communities inhabiting complex environmental samples, with potential as a tool in the ecological assessment of pollution. These communities have not yet been adequately considered for ecological studies and biomonitoring, with a need to better understand interactions with environmental stressors and implications for ecosystem function. This study used a combination of stable isotope analysis to trace the uptake of anthropogenic nitrogen in biota, traditional assessment of benthic macroinvertebrate communities, and 16S rDNA genotyping of benthic microbial communities. Stable isotope analysis of seagrass and epiphytes identified multiple treated and untreated sewage inputs, ranges of 5.2-7.2‰ and 1.9-4.0‰ for δ¹⁵N respectively, as the dominant nitrogen source at specific locations. The benthic macroinvertebrate community reflected these inputs with shifts in dominant taxa and high abundances of polychaetes at some sites. Microbial communities provided a sensitive indication of impact with a breadth of information not available using traditional techniques. Composition and predicted function reflected sewage inputs, particularly within sediments, with the relative abundance of specific taxa and putative pathogens linked to these inputs. This research supports the growing body of evidence that benthic microbial communities respond rapidly to anthropogenic stressors and have potential as a monitoring tool in urban estuarine systems.

Keywords: Anthropogenic impacts; Biomonitoring; Coastal management; Next-generation sequencing; Stable isotope analysis; Wastewater.

MeSH terms

Anthropogenic Effects
Ecosystem*
Environmental Monitoring
Estuaries*
Nutrients