Moderate reductions in dissolved oxygen may compromise performance in an ecologically-important estuarine invertebrate

Collins, Michael; Tills, Oliver; Turner, Lucy M.; Clark, Melody S. ORCID: https://orcid.org/0000-0002-3442-3824; Spicer, John I.; Truebano, Manuela. 2019 Moderate reductions in dissolved oxygen may compromise performance in an ecologically-important estuarine invertebrate. Science of the Total Environment, 693 (133444). https://doi.org/10.1016/j.scitotenv.2019.07.250

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Abstract/Summary

Coastal ecosystems, including estuaries, are increasingly pressured by expanding hypoxic regions as a result of human activities such as increased release of nutrients and global warming. Hypoxia is often defined as oxygen concentrations below 2 mL O2 L−1. However, taxa vary markedly in their sensitivity to hypoxia and can be affected by a broad spectrum of low oxygen levels. To better understand how reduced oxygen availability impacts physiological and molecular processes in invertebrates, we investigated responses of an estuarine amphipod to an ecologically-relevant level of moderate hypoxia (~2.6 mL O2 L−1) or severe hypoxia (~1.3 mL O2 L−1). Moderate hypoxia elicited a reduction in aerobic scope, and widespread changes to gene expression, including upregulation of metabolic genes and stress proteins. Under severe hypoxia, a marked hyperventilatory response associated with maintenance of aerobic performance was accompanied by a muted transcriptional response. This included a return of metabolic genes to baseline levels of expression and downregulation of transcripts involved in protein synthesis, most of which indicate recourse to hypometabolism and/or physiological impairment. We conclude that adverse ecological effects may occur under moderate hypoxia through compromised individual performance and, therefore, even modest declines in future oxygen levels may pose a significant challenge to coastal ecosystems.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.scitotenv.2019.07.250
ISSN:	0048-9697
Additional Keywords:	hypoxia, estuary, integrative, ecophysiology, Crustacea
Date made live:	24 Jul 2019 09:43 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/524474

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