Firth Britney L, Craig Paul M, Drake D Andrew R, Power Michael
Department of Biology, University of Waterloo, Waterloo, ON, Canada.
Department of Biology, University of Waterloo, Waterloo, ON, Canada. Electronic address: https://twitter.com/pcraig77.
Comp Biochem Physiol A Mol Integr Physiol. 2024 May;291:111589. doi: 10.1016/j.cbpa.2024.111589. Epub 2024 Jan 20.
Fish gills are complex organs that have direct contact with the environment and perform numerous functions including gas exchange and ion regulation. Determining if gill morphometry can change under different environmental conditions to maintain and/or improve gas exchange and ion regulation is important for understanding if gill plasticity can improve survival with increasing environmental change. We assessed gill morphology (gas exchange and ion regulation metrics), hematocrit and gill Na/K ATPase activity of wild-captured blackside darter (Percina maculata), greenside darter (Etheostoma blennioides), and johnny darter (Etheostoma nigrum) at two temperatures (10 and 25 °C) and turbidity levels (8 and 94 NTU). Samples were collected August and October 2020 in the Grand River to assess temperature differences, and August 2020 in the Thames River to assess turbidity differences. Significant effects of temperature and/or turbidity only impacted ionocyte number, lamellae width, and hematocrit. An increase in temperature decreased ionocyte number while an increase in turbidity increased lamellae width. Hematocrit had a species-specific response for both temperature and turbidity. Findings suggest that the three darter species have limited plasticity in gill morphology, with no observed compensatory changes in hematocrit or Na/K ATPase activity to maintain homeostasis under the different environmental conditions.
鱼鳃是复杂的器官，与环境直接接触并执行多种功能，包括气体交换和离子调节。确定鳃形态测量在不同环境条件下是否会发生变化以维持和/或改善气体交换和离子调节，对于理解鳃的可塑性是否能随着环境变化加剧而提高生存能力至关重要。我们评估了野生捕获的黑斑镖鲈（Percina maculata）、绿边镖鲈（Etheostoma blennioides）和乔氏镖鲈（Etheostoma nigrum）在两种温度（10和25°C）和浊度水平（8和94 NTU）下的鳃形态（气体交换和离子调节指标）、血细胞比容和鳃钠钾ATP酶活性。2020年8月和10月在大河采集样本以评估温度差异，2020年8月在泰晤士河采集样本以评估浊度差异。温度和/或浊度的显著影响仅影响离子细胞数量、鳃小片宽度和血细胞比容。温度升高会减少离子细胞数量，而浊度增加会增加鳃小片宽度。血细胞比容对温度和浊度都有物种特异性反应。研究结果表明，这三种镖鲈在鳃形态方面的可塑性有限，在不同环境条件下未观察到血细胞比容或钠钾ATP酶活性的代偿性变化以维持体内平衡。
