It’s all about the fluxes: Temperature influences ion transport and toxicity in aquatic insects
It’s all about the fluxes: Temperature influences ion transport and toxicity in aquatic insects
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一切都与通量有关：温度影响水生昆虫的离子传输和毒性
DOI：
10.1016/j.aquatox.2020.105405
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发表时间：
2020
影响因子：
4.5
通讯作者：
Buchwalter, D
中科院分区：
文献类型：
--
作者：
Orr, S;Buchwalter, D
许多淡水生态系统正在变得更咸和/或更温暖，但我们对这些因素如何相互作用并影响大多数水生物种的生理和生活史结果的理解仍然未知。我们假设温度调节离子传输速率。由于离子运输是能量昂贵的，盐度和/或温度的增加可能会影响离子通量率，并最终影响生物体的性能。放射性示踪剂（22 Na+，35 SO 4 −2和45 Ca 2+）实验用实验室饲养的蜉蝣（N. triangulifer）和其他野外收集的昆虫的研究表明，温度升高通常会增加离子传输速率。例如，将温度从15 °C升高到25 °C，在石蛾（Hydropsychesparna）中，22 Na+的吸收率增加了两倍（p <0.0001），35 SO 4 - 2的吸收率增加了四倍（p < 0.0001）。在蜉蝣Isonychia sayi和Maccaffertiumsp.中观察到22 Na+和35 SO 4 − 2吸收率的较小变化，这表明在离子运输的热敏感性方面存在物种特异性差异。最后，通过96 h的生物测定，证明了温度对SO 4的毒性有显著的影响。在最咸的条件下（1500 mg L− 1 SO 4），蜉蝣的存活率在15 °C时为78%，但在25 °C时仅为44%（p < 0.0036）。可以想象的是，在较温暖、较咸的环境中，能量调节的能量成本可能会在某些淡水昆虫中引起显著的主要离子毒性。
Many freshwater ecosystems are becoming saltier and/or warmer, but our understanding of how these factors interact and affect the physiology and life history outcomes of most aquatic species remain unknown. We hypothesize that temperature modulates ion transport rates. Since ion transport is energetically expensive, increases in salinity and/or temperature may influence ion flux rates and ultimately, organismal performance. Radiotracer (22Na+,35SO4−2, and45Ca2+) experiments with lab-reared mayflies (N. triangulifer) and other field-collected insects showed that increasing temperature generally increased ion transport rates. For example, increasing temperature from 15 °C to 25 °C, increased22Na+uptake rates by two-fold (p < 0.0001) and35SO4−2uptake rates by four-fold (p < 0.0001) in the caddisfly,Hydropsychesparna. Smaller changes in22Na+and35SO4−2uptake rates were observed in the mayflies,Isonychia sayiandMaccaffertiumsp., suggesting species-specific differences in the thermal sensitivity of ion transport. Finally, we demonstrated that the toxicity of SO4was influenced by temperature profoundly in a 96-h bioassay. Under the saltiest conditions (1500 mg L−1SO4), mayfly survival was 78 % at 15 °C, but only 44 % at 25 °C (p < 0.0036). Conceivably, the energetic cost of osmoregulation in warmer, saltier environments may cause significant major ion toxicity in certain freshwater insects.