Seawater carbonate chemistry and behavioural lateralization, morphometry and biomarker of Atherina presbyter

Considered a major environmental concern, ocean acidification has induced a recent research boost into effects on marine biodiversity and possible ecological, physiological, and behavioural impacts. Although the majority of literature indicate negative effects of future acidification scenarios, most studies are conducted for just a few days or weeks, which may be insufficient to detect the capacity of an organism to adjust to environmental changes through phenotypic plasticity. Here, the effects and the capacity of sand smelt larvae Atherina presbyter to cope and recover (through a treatment combination strategy) from short (15 days) and long-term exposure (45 days) to increasing pCO2 levels (control: ~515 μatm, pH = 8.07; medium: ~940 μatm, pH = 7.84; high: ~1500 μatm, pH = 7.66) were measured, addressing larval development traits, behavioural lateralization, and biochemical biomarkers related with oxidative stress and damage, and energy metabolism and reserves. Although behavioural lateralization was not affected by high pCO2 exposure, morphometric changes, energetic costs, and oxidative stress damage were impacted differently through different exposures periods. Generally, short-time exposures led to different responses to either medium or high pCO2 levels (e.g. development, cellular metabolism, or damage), while on the long-term the response patterns tend to become similar between them, with both acidification scenarios inducing DNA damage and tending to lower growth rates. Additionally, when organisms were transferred to lower acidified condition, they were not able to recover from the mentioned DNA damage impacts.

海洋酸化作为备受关注的重大环境问题，近年来推动了大量围绕其对海洋生物多样性、潜在生态、生理及行为影响的研究。尽管多数研究文献指出未来酸化情景会产生负面影响，但大多数实验仅开展数天至数周，这可能不足以检测生物体通过表型可塑性适应环境变化的能力。本研究针对沙银汉鱼（Atherina presbyter）幼体，通过处理组合策略，检测其在短期（15天）与长期（45天）暴露于梯度升高的二氧化碳分压（pCO₂）环境下的应对与恢复能力，设置的环境梯度如下：对照组约515 μatm，pH=8.07；中等组约940 μatm，pH=7.84；高浓度组约1500 μatm，pH=7.66。研究指标涵盖幼体发育性状、行为侧化，以及与氧化应激、损伤、能量代谢和能量储备相关的生物化学标志物。尽管高浓度二氧化碳分压暴露并未影响行为侧化，但不同暴露时长对形态变化、能量消耗及氧化应激损伤的影响存在差异。总体而言，短期暴露下，中等与高浓度二氧化碳分压环境会引发不同的响应（如发育、细胞代谢或损伤层面）；而长期暴露下，二者的响应模式趋于一致，两种酸化情景均会诱导DNA损伤，并降低生长速率。此外，当生物体被转移至酸化程度更低的环境后，无法从上述DNA损伤影响中恢复。