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Advances in the aquatic sciences
RESEARCH ARTICLE (Open Access)

Investigating the effects of increased salinity on leaf litter decomposition and mortality of an aquatic invertebrate detritivore (Caecidotea sp.)

Zachary B. Gordon https://orcid.org/0009-0008-7096-0038 A B * , Raymond P. Kidder II A , Craig Aumack A and J. Checo Colon-Gaud A
+ Author Affiliations
- Author Affiliations

A Georgia Southern University, Statesboro, GA, USA.

B Oglethorpe University, Brookhaven, GA, USA.

* Correspondence to: zachbgordon22@gmail.com

Handling Editor: Richard Marchant

Marine and Freshwater Research 76, MF25029 https://doi.org/10.1071/MF25029
Submitted: 8 February 2025  Accepted: 10 September 2025  Published: 7 October 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Context

Coastal freshwater wetlands and their associated communities are at an increased risk of salinity exposure because of a variety of contemporary and historical anthropogenic stressors. Salinization shifts the community structure of aquatic organisms, such as macroinvertebrates, leading to decreases in functional ecological integrity. These salinity-driven changes to communities have the potential to alter macroinvertebrate-mediated processes such as detrital decomposition.

Aims

Our study aimed to examine the relationship among salinity exposure, leaf decomposition and mortality of a common freshwater macroinvertebrate (isopod: genus Caecidotea).

Methods

Using an in-laboratory microcosm approach, we exposed tanks of isopods and detrital leaf material to varying salinity levels for 23 days, after which isopod mortality and decomposition of detrital material were measured.

Key results

We found that increases in salinity increased isopod mortality, but had no effect on leaf disc decomposition.

Conclusions

These findings demonstrated the negative effect of increased salinity on a common freshwater macroinvertebrate. Additional studies regarding the response of non-isopod decomposers, such as bacteria and fungi, are needed to provide a more complete understanding of the effects of salinity intrusion in at-risk freshwater habitats.

Implications

As we expect salinization to increase in the future, it is important to understand how organisms and the processes they contribute to and rely on will be affected. The detrital decomposition process and aquatic macroinvertebrates are key foundations of aquatic food webs, and significant bottom-up changes could have drastic implications for ecosystems.

Keywords: anthropogenic change, aquatic macroinvertebrates, Caecidotea, detrital decomposition, isopods, microcosms, salinity effects, salinity stress.

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