ORCID

Abstract

To understand animal adaptations, we need accurate estimates of the ecological factors impacting organisms in nature. While temperature is a well-established driver of physiological performance, its effects in aquatic systems are closely linked to water oxygenation. Oxygen levels are expected to differ spatially and fluctuate temporally much more strongly in water than on land, but our understanding of variation in temperature and oxygen levels in freshwaters remains limited. It is essential that environmental variation is recorded at spatial and temporal resolutions relevant to the organism. Here, we analyse spatial and temporal variation in water temperature and oxygenation across running and standing waters, using both microscale spot measurements and continuous loggers collecting data from the water column. Our results reaffirm that small-scale thermal gradients are much less pronounced in water than on land due to the high thermal conductivity and heat capacity of water. Regional weather conditions can therefore reliably predict water temperature across scales. By contrast, oxygen levels are much harder to predict from large-scale data as they can fluctuate sharply over very small spatial scales and within a single day, particularly in standing waters, exposing aquatic organisms to steep oxygen gradients. Our findings underscore the importance of incorporating fine-scale oxygen dynamics when studying aquatic species distributions and ecological strategies.  This article is part of the theme issue 'Life in natural microcosms'.

Publication Date

2026-06-25

Publication Title

Philosophical Transactions of the Royal Society B: Biological Sciences

Volume

381

Issue

1953

ISSN

0962-8436

Acceptance Date

2025-10-15

Deposit Date

2026-02-04

Funding

W.C.E.P.V. acknowledges support from the European Research Council (Marie-Curie Fellowships FP7-PEOPLE-2009-IEF and FP7- PEOPLE-2012-CIG) and the Netherlands Organisation for Scientific Research (NWO-RUBICON fellowship no. 825.09.009).

Keywords

aquatic ecology, biogeography, microclimate, climate change, downscaling, refugia, species distribution model, ponds, rivers, hypoxia, species distribution models

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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