Fertilization and early development are usually the most vulnerable stages in the life of marine animals, and the biological processes during this period are highly sensitive to the environment. In nature, sea urchin gametes are shed in seawater, where they undergo external fertilization and embryonic development. In a laboratory, it is possible to follow the exact morphological and biochemical changes taking place in the fertilized eggs and the developing embryos. Thus, observation of successful fertilization and the subsequent embryonic development of sea urchin eggs can be used as a convenient biosensor to assess the quality of the marine environment. In this paper, we have examined how salinity and pH changes affect the normal fertilization process and the following development of Paracentrotus lividus. The results of our studies using confocal microscopy, scanning and transmission electron microscopy, and time-lapse Ca2+ image recording indicated that both dilution and acidification of seawater have subtle but detrimental effects on many aspects of the fertilization process. They include Ca2+ signaling and coordinated actin cytoskeletal changes, leading to a significantly reduced rate of successful fertilization and, eventually, to abnormal or delayed embryonic development.

中文翻译：

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海水盐度和pH值对海胆Paracentrotus lividus繁殖的影响

受精和早期发育通常是海洋动物生命中最脆弱的阶段，这一时期的生物过程对环境高度敏感。在自然界中，海胆配子在海水中脱落，在那里进行外部受精和胚胎发育。在实验室中，可以跟踪受精卵和发育中的胚胎发生的确切形态和生化变化。因此，观察海胆卵的成功受精和随后的胚胎发育可以作为一种方便的生物传感器来评估海洋环境的质量。在本文中，我们研究了盐度和 pH 值变化如何影响正常受精过程以及 Paracentrotus lividus 的后续发育。我们使用共聚焦显微镜、扫描和透射电子显微镜以及延时 Ca2+ 图像记录的研究结果表明，海水的稀释和酸化对受精过程的许多方面都有微妙但有害的影响。它们包括 Ca2+ 信号传导和协调的肌动蛋白细胞骨架变化，导致成功受精率显着降低，并最终导致胚胎发育异常或延迟。