Abstract

Anaerobic metabolism is an important response to stress in many organisms. Intertidal species often face heat stress during low tide. Balanus glandula (Darwin, 1854) is a high-shore intertidal barnacle common to the Pacific that experiences prolonged low-tide air exposure. It is not known whether B. glandula uses anaerobic metabolism during emersion, or if its use varies by latitude. We measured low tide D-lactate production in two US west coast populations of B. glandula separated by 14 degrees of latitude. We exposed barnacles to seven low-tide air temperatures (10, 15, 20, 25, 30, 35, and 38 °C) for which aerobic respiration has been previously measured. Our northern population of B. glandula increased D-lactate production at high air temperatures where aerobic metabolic depression is known to occur, indicating sublethal stress. In contrast, our southern population showed little increase in D-lactate over the same temperature range, coincident with high aerobic respiration across those temperatures. In a second experiment, we quantified D-lactate at 1, 2, and 6 hours post-emersion for northern B. glandula exposed to either a 10 or 38 °C low tide, to measure their potential lactate usage. While D-lactate was elevated at 38 °C compared to the 10 °C control immediately following low tide exposure, it dropped to control levels, and was likely excreted, within 1 hour of re-immersion. Our results suggest that the low latitude population of B. glandula may be more resilient to climate change than its high latitude counterpart in the absence of adaptation, which has strong implications for species distribution.

中文翻译：

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萌芽胁迫下橡子藤壶Balanus glandula（Darwin，1854）（Cirripedia：Balanidae）中的D-乳酸产生

摘要

无氧代谢是许多生物体对压力的重要反应。潮间带物种经常在退潮时面临热应激。Balanus glandula（达尔文，1854年）是太平洋地区常见的高岸潮间带藤壶，长期处于低潮空气暴露状态。尚不知道芽孢杆菌在出苗期间是否使用厌氧代谢，或者其使用随纬度而变化。我们在美国西海岸的两个B. glandula种群中，相隔14个纬度测量了低潮D-乳酸的产生。我们将藤壶暴露于七个低潮空气温度（10、15、20、25、30、35和38°C），这些温度先前已测量过有氧呼吸。我们北方的甘蓝型种群在已知发生有氧代谢抑制的高空气温度下，D-乳酸的产生增加，表明亚致死压力。相反，我们的南部人口在相同温度范围内的D-乳酸含量几乎没有增加，同时在这些温度范围内有氧呼吸旺盛。在第二个实验中，我们对暴露于10或38°C低潮的北部B. glandula出苗后1、2和6小时的D-乳酸进行了定量，以测量其潜在的乳酸使用量。低潮汐暴露后，D-乳酸盐在10°C的对照下在38°C升高，但在重新浸入后1小时内，D-乳酸下降至对照水平，并有可能排泄。我们的结果表明，低纬人群的甘蓝 在没有适应的情况下，与高纬度气候变化相比，它对气候变化的适应力可能更大，这对物种分布具有重要影响。