Paredes-Molina F J, Chaparro O R, Navarro J M, Cubillos V M, Paschke K, Márquez F, Averbuj A, Zabala M S, Bökenhans V, Pechenik J A
Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
Mar Environ Res. 2024 Jan;193:106270. doi: 10.1016/j.marenvres.2023.106270. Epub 2023 Nov 21.
Upwelling phenomena alter the physical and chemical parameters of the sea's subsurface waters, producing low levels of temperature, pH and dissolved oxygen, which can seriously impact the early developmental stages of marine organisms. To understand how upwelling can affect the encapsulated development of the gastropod Acanthina monodon, capsules containing embryos at different stages of development (initial, intermediate and advanced) were exposed to upwelling conditions (pH = 7.6; O = 3 mg L; T° = 9 °C) for a period of 7 days. Effects of treatment were determined by estimating parameters such as time to hatching, number of hatchlings per capsule, percentage of individuals with incomplete development, and shell parameters such as shell shape and size, shell strength, and the percentage of the organic/inorganic content. We found no significant impacts on hatching time, number of hatchlings per capsule, or percentage of incomplete development in either the presence or absence of upwelling, regardless of developmental stage. On the other hand, latent effects on encapsulated stages of A. monodon were detected in embryos that had been exposed to upwelling stress in the initial embryonic stage. The juveniles from this treatment hatched at smaller sizes and with higher organic content in their shells, resulting in a higher resistance to cracking 30 days after hatching, due to greater elasticity. Geometric morphometric analysis showed that exposure to upwelling condition induced a change in the morphology of shell growth in all post-hatching juveniles (0-30 days), regardless of embryonic developmental stage at the time of exposure. Thus, more elongated shells (siphonal canal and posterior region) and more globular shells were observed in newly hatched juveniles that had been exposed to the upwelling condition. The neutral or even positive upwelling exposure results suggests that exposure to upwelling events during the encapsulated embryonic phase of A. monodon development might not have major impacts on the future juvenile stages. However, this should be taken with caution in consideration of the increased frequency and intensity of upwelling events predicted for the coming decades.
上升流现象会改变海洋次表层水的物理和化学参数，导致温度、pH值和溶解氧水平降低，这可能会严重影响海洋生物的早期发育阶段。为了了解上升流如何影响腹足纲动物单齿刺棘螺的包囊发育，将含有不同发育阶段（初始、中期和晚期）胚胎的卵囊暴露于上升流条件下（pH = 7.6；O = 3毫克/升；T° = 9°C）7天。通过估计孵化时间、每个卵囊的孵化幼体数量、发育不完全个体的百分比以及壳参数（如壳的形状和大小、壳强度以及有机/无机含量百分比）等参数来确定处理效果。我们发现，无论发育阶段如何，在有或没有上升流的情况下，对孵化时间、每个卵囊的孵化幼体数量或发育不完全百分比均无显著影响。另一方面，在胚胎初始阶段暴露于上升流压力的胚胎中，检测到了对单齿刺棘螺包囊阶段的潜在影响。该处理组的幼体孵化时体型较小，壳中的有机含量较高，由于弹性更大，孵化30天后对破裂的抵抗力更强。几何形态测量分析表明，暴露于上升流条件会导致所有孵化后幼体（0 - 30天）的壳生长形态发生变化，无论暴露时的胚胎发育阶段如何。因此，在暴露于上升流条件的新孵化幼体中观察到壳更细长（水管和后部区域）且更呈球形。上升流暴露的中性甚至积极结果表明，在单齿刺棘螺发育的包囊胚胎阶段暴露于上升流事件可能对未来的幼体阶段没有重大影响。然而，考虑到预计在未来几十年上升流事件的频率和强度会增加，对此应谨慎对待。
