Copepods make up the largest zooplankton biomass in coastal areas and estuaries and are pivotal for the normal development of fish larva of countless species. During spring in neritic boreal waters, the copepod pelagic biomass increases rapidly from near absence during winter. In the calanoid species Acartia tonsa, a small fraction of eggs are dormant regardless of external conditions and this has been hypothesized to be crucial for sediment egg banks and for the rapid biomass increase during spring. Other eggs can enter a state of induced arrest called quiescence when external conditions are unfavourable. While temperature is known to be a pivotal factor in the transition from developing to resting eggs and back, the role of pH and free Oxygen in embryo development has not been systematically investigated. Here, we show in a laboratory setting that hypoxic conditions are necessary for resting eggs to maintain a near-intact rate of survival after several months of induced resting. We further investigate the influence of pH that is realistic for natural sediments on the viability of resting eggs and document the effect that eggs have on the pH of the surrounding environment. We find that resting eggs acidify their immediate surroundings and are able to survive in a wide range of pH. This is the first study to demonstrate the importance of hypoxia on the survival capabilities of A. tonsa resting eggs in a controlled laboratory setting, and the first to show that the large majority of quiescent eggs are able to tolerate prolonged resting. These findings have large implications for the understanding of the recruitment of copepods from sediment egg banks, which are considered the primary contributor of nauplii seeded to pelagic populations in nearshore habitats in late spring.

中文翻译：

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pe足纲car螨的卵需要低氧条件才能耐受长期的胚胎发育停滞

pe足类动物是沿海地区和河口最大的浮游动物生物量，对于无数种鱼幼虫的正常发育至关重要。春季在北半球水域中，co足类中上层生物量在冬季几乎没有缺水的情况下迅速增加。在Calanoid种类的Acartiatona中，无论外部条件如何，一小部分卵都处于休眠状态，这被认为对于沉积卵库和春季春季生物量的快速增长至关重要。当外部条件不利时，其他鸡蛋可能会进入诱导停滞状态，称为静止状态。尽管已知温度是从发育到静止卵再返回的关键因素，但尚未系统地研究过pH和游离氧在胚胎发育中的作用。这里，我们在实验室环境中显示，低氧条件对于静息卵在诱导静息几个月后维持接近完整的存活率是必要的。我们进一步研究了天然沉积物的实际pH值对静止卵的生存力的影响，并记录了卵对周围环境pH的影响。我们发现静息的鸡蛋会酸化其周围环境，并且能够在很宽的pH值范围内生存。这是第一个证明缺氧对在受控实验室环境中对扁桃体静息卵存活能力的重要性的研究，并且第一个表明大部分静态卵能够耐受长时间静息的研究。这些发现对于理解从沉积卵库募集co足类动物具有重要意义，