Shellfish as a bioremediation tool: A review and meta-analysis

Giulia Filippini; Katherine A Dafforn; Ana B Bugnot

doi:10.1016/j.envpol.2022.120614

Shellfish as a bioremediation tool: A review and meta-analysis

Environ Pollut. 2023 Jan 1;316(Pt 2):120614. doi: 10.1016/j.envpol.2022.120614. Epub 2022 Nov 7.

Authors

Giulia Filippini¹, Katherine A Dafforn², Ana B Bugnot³

Affiliations

¹ School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia. Electronic address: giulia.filippini@mq.edu.au.
² School of Natural Sciences, Macquarie University, North Ryde, NSW, 2109, Australia; Sydney Institute of Marine Science, Mosman, NSW, 2088, Australia.
³ School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia; Commonwealth Scientific and Industrial Research Organisation, Brisbane, QLD, 4001, Australia.

PMID: 36356885
DOI: 10.1016/j.envpol.2022.120614

Abstract

Over the last century, human activities have increased the amount of nutrients inputs to terrestrial and aquatic ecosystems. These activities have altered nitrogen (N) and phosphorus (P) cycling, causing substantial changes in ecosystem function such as provision of clean air and water. Strategies that reduce and remove excess nutrients are urgently needed to remediate impacted systems. Reef-forming shellfish (oysters and mussels) can play a crucial role in nutrient cycling, particularly in N removal from aquatic systems by providing substrate for microbial colonisation and enhancing microbial denitrification in the surrounding sediments. However, the potential for shellfish to enhance nutrient cycling (and denitrification) will likely vary spatially and in response to several environmental factors. Here, we used 1) a qualitative analysis to review nutrient processes occurring on shellfish; and 2) a meta-analysis to evaluate the influence of shellfish on benthic metabolism and nutrient cycling in surrounding sediments, and how that is influenced by environmental factors such as grain size, seasonality, water body type, and tidal position. Overall, we found that shellfish increased oxygen consumption, with consequent release of ammonia (NH_4⁺) and phosphate (PO₄³^-) from shellfish and their surrounding sediments. These parameters did not depend on grain size, water body type and tidal height, but the release of PO₄³^- was variable between seasons, being highest during summer and autumn. Shellfish presence also enhanced denitrification measured as dinitrogen gas (N₂) efflux on both reefs and sediments. Denitrification was highest in lagoons; in sandy sediments; and during the warmest season (summer). Thus, our findings highlight that environmental context can mediate the effects of shellfish reefs on sediment function. This information is important for managers seeking to use these animals as an effective bioremediation tool.

Keywords: Bioremediation; Denitrification; Environmental factors; Meta-analysis; Nutrient fluxes; Shellfish.

Publication types

Meta-Analysis
Review

MeSH terms

Animals
Biodegradation, Environmental
Ecosystem*
Geologic Sediments*
Nitrogen / analysis
Shellfish
Water

Substances

Nitrogen
Water