Field and laboratory studies reveal interacting effects of stream oxygenation and warming on aquatic ectotherms
Aquatic ecological responses to climatic warming are complicated by interactions between thermal effects and other environmental stressors such as organic pollution and hypoxia. Laboratory experiments have demonstrated how oxygen limitation can set heat tolerance for some aquatic ectotherms, but onl...
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Published in: | Global change biology Vol. 22; no. 5; pp. 1769 - 1778 |
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Main Authors: | , , , |
Format: | Journal Article |
Language: | English |
Published: |
England
Blackwell Science
01-05-2016
Blackwell Publishing Ltd John Wiley and Sons Inc |
Subjects: | |
Online Access: | Get full text |
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Summary: | Aquatic ecological responses to climatic warming are complicated by interactions between thermal effects and other environmental stressors such as organic pollution and hypoxia. Laboratory experiments have demonstrated how oxygen limitation can set heat tolerance for some aquatic ectotherms, but only at unrealistic lethal temperatures and without field data to assess whether oxygen shortages might also underlie sublethal warming effects. Here, we test whether oxygen availability affects both lethal and nonlethal impacts of warming on two widespread Eurasian mayflies, Ephemera danica, Müller 1764 and Serratella ignita (Poda 1761). Mayfly nymphs are often a dominant component of the invertebrate assemblage in streams, and play a vital role in aquatic and riparian food webs. In the laboratory, lethal impacts of warming were assessed under three oxygen conditions. In the field, effects of oxygen availability on nonlethal impacts of warming were assessed from mayfly occurrence in 42 293 UK stream samples where water temperature and biochemical oxygen demand were measured. Oxygen limitation affected both lethal and sublethal impacts of warming in each species. Hypoxia lowered lethal limits by 5.5 °C (±2.13) and 8.2 °C (±0.62) for E. danica and S. ignita respectively. Field data confirmed the importance of oxygen limitation in warmer waters; poor oxygenation drastically reduced site occupancy, and reductions were especially pronounced under warm water conditions. Consequently, poor oxygenation lowered optimal stream temperatures for both species. The broad concordance shown here between laboratory results and extensive field data suggests that oxygen limitation not only impairs survival at thermal extremes but also restricts species abundance in the field at temperatures well below upper lethal limits. Stream oxygenation could thus control the vulnerability of aquatic ectotherms to global warming. Improving water oxygenation and reducing pollution can provide key facets of climate change adaptation for running waters. |
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Bibliography: | http://dx.doi.org/10.1111/gcb.13240 EU MARS - No. 603378 ark:/67375/WNG-TGB80XL4-R NERC DURESS - No. NE/J014818/1 Marie Curie FP7 Integration Grant - No. 334048 istex:9B84432D34AB29D47C202024BEE916B80B952006 ArticleID:GCB13240 Data S1. Supporting analysis: investigating the link between dissolved oxygen and BOD. Figure S1. Relationship between dissolved oxygen (DO) and biochemical oxygen demand (BOD). Figure S2. Location of the 2632 sample sites divided over the eight EA regions distinguished. Figure S3. Projected model responses of Ephemera danica (left) and Serratella ignita (right) occupancy (proportion of samples where species was present at a given site) along a gradient of deteriorating oxygenation (increasing BOD-values). Table S1. Model summary for Ephemera danica (best fitted model in Table ). Table S2. Model summary for Serratella ignita (best fitted model in Table ). Table S3. Model summary for E. danica, excluding summer months (June, July, August). Table S4. Model summary for S. ignita, excluding summer months (June, July, August). ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1354-1013 1365-2486 |
DOI: | 10.1111/gcb.13240 |