The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field observations
The impact of ocean acidification and warming on the skeletal mechanical properties of the sea urchin Paracentrotus lividus from laboratory and field observations
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DOI：
10.1093/icesjms/fsv018
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发表时间：
2016-02-01
影响因子：
3.3
通讯作者：
Dubois, Philippe
中科院分区：
文献类型：
--
作者：
Collard, Marie;Rastrick, Samuel P. S.;Dubois, Philippe
大气中二氧化碳浓度的增加导致了碳酸盐化学和海洋温度的变化。这些过程对海洋生物的影响将取决于它们应对这些变化的能力，特别是维持碳酸钙结构的能力。在这里，将实验室实验（长期暴露于pH值降低和温度升高的环境中）和从低pH值自然环境中收集的个体（潮间带池和二氧化碳渗漏周围的个体）结合起来，全面研究了近期pH和温度条件对拟硬海胆（Paracentrotus lividus）骨骼力学性能的影响。为了评估骨骼力学性能，我们对海胆测试板的断裂力、杨氏模量、第二面积矩、材料纳米硬度和特定杨氏模量进行了表征。在实验室实验中，这些参数都没有受到低pH值和/或温度升高的显著影响，只有长期暴露于二氧化碳渗漏导致的低pH值环境中的个体才受到低pH值的影响。在潮汐池中，来自岩石池的个体的破裂力更高，杨氏模量更低，其特征是pH变化最大，但也以钙化藻类为主，这可能解释了一些变化。因此，pH值降低到2100年的预期水平并没有直接改变lividus试验的机械性能。由于测试完整性的维持是海胆生存的问题，并且由于削弱测试会增加海胆被捕食的风险，我们的研究结果表明，预计在本世纪末海水pH值下降和海水温度升高不应该对海胆的脆弱性构成直接威胁。
Increased atmospheric CO2 concentration is leading to changes in the carbonate chemistry and the temperature of the ocean. The impact of these processes on marine organisms will depend on their ability to cope with those changes, particularly the maintenance of calcium carbonate structures. Both a laboratory experiment (long-term exposure to decreased pH and increased temperature) and collections of individuals from natural environments characterized by low pH levels (individuals from intertidal pools and around a CO2 seep) were here coupled to comprehensively study the impact of near-future conditions of pH and temperature on the mechanical properties of the skeleton of the euechinoid sea urchin Paracentrotus lividus. To assess skeletal mechanical properties, we characterized the fracture force, Young's modulus, second moment of area, material nanohardness, and specific Young's modulus of sea urchin test plates. None of these parameters were significantly affected by low pH and/or increased temperature in the laboratory experiment and by low pH only in the individuals chronically exposed to lowered pH from the CO2 seeps. In tidal pools, the fracture force was higher and the Young's modulus lower in ambital plates of individuals from the rock pool characterized by the largest pH variations but also a dominance of calcifying algae, which might explain some of the variation. Thus, decreases of pH to levels expected for 2100 did not directly alter the mechanical properties of the test of P. lividus. Since the maintenance of test integrity is a question of survival for sea urchins and since weakened tests would increase the sea urchins' risk of predation, our findings indicate that the decreasing seawater pH and increasing seawater temperature expected for the end of the century should not represent an immediate threat to sea urchins vulnerability.