Centre Oceanogràfic de les Balears, Instituto Español de Oceanografía (IEO, CSIC), Moll de Ponent s/n, 07015 Palma de Mallorca, Spain.
The Leatherback Trust, Goldring-Gund Marine Biology Station, Playa Grande, Costa Rica; Menéndez Pelayo International University (UIMP-CSIC), Isaac Peral 23, 28040 Madrid, Spain.
Sci Total Environ. 2024 Nov 20;952:175961. doi: 10.1016/j.scitotenv.2024.175961. Epub 2024 Sep 1.
Climate warming threatens sea turtles, among other effects, because high temperatures increase embryo mortality. However, not all species and populations are expected to respond the same way because they could have different thermal tolerances and capacities to adapt. We tested the effect of incubation temperature on egg mortality in a population of green turtles (Chelonia mydas) previously suggested to be less affected by extreme climatic events than others. We (1) assessed the relationship between temperature and hatching success, (2) defined an optimal range of temperatures that maximized hatching success and (3) assessed the variability in the response to temperature among clutches laid by different mothers, which could allow adaptation. Hatching success was consistently high in green turtle clutches with a skew toward high values, with 50 % of clutches having a success above 94 %. Yet, it was mildly affected by temperature, declining at both low and high temperatures. The optimal range of mean incubation temperatures was between ~30.5 °C and 32.5 °C. Current mean temperatures (31.3 °C) fall within the middle of the optimal range, indicating a potential resilience to further rises in mean nest temperature. Hatching success was best described by nest temperature and the interaction between female identity and temperature. This last predictor indicated a variability in thermal tolerance among clutches laid by different mothers and therefore, a capacity to adapt. The studied population of green turtles seems to be less vulnerable than others to climate warming. Understanding how different populations could respond to increasing temperatures could help complete the picture on the potential effects of climate change on sea turtles.
气候变化威胁到海龟等生物，因为高温会增加胚胎死亡率。然而，并非所有物种和种群都会以相同的方式做出反应，因为它们可能具有不同的耐热性和适应能力。我们测试了孵化温度对绿海龟（Chelonia mydas）卵死亡率的影响，此前有研究表明，该种群受极端气候事件的影响小于其他种群。我们（1）评估了温度与孵化成功率之间的关系，（2）确定了使孵化成功率最大化的最佳温度范围，（3）评估了不同海龟母亲产卵对温度的反应差异，这可能有助于适应。绿海龟卵的孵化成功率一直很高，且呈高值偏态分布，有 50%的卵成功率高于 94%。然而，温度对其孵化成功率有轻微影响，在低温和高温下都会下降。最佳平均孵化温度范围在~30.5°C 到 32.5°C 之间。当前的平均温度（31.3°C）处于最佳范围的中间，表明对未来平均巢温升高有一定的适应能力。孵化成功率最好由巢温以及雌海龟身份和温度之间的相互作用来描述。最后一个预测因子表明，不同海龟母亲产卵的卵对温度的耐受性存在差异，因此具有适应能力。研究中的绿海龟种群似乎比其他种群对气候变暖的脆弱性更低。了解不同种群如何应对温度升高，有助于全面了解气候变化对海龟的潜在影响。
