Plasticity in dormancy behaviour of Calanoides acutus in Antarctic coastal waters
Plasticity in dormancy behaviour of Calanoides acutus in Antarctic coastal waters
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DOI：
10.1093/icesjms/fsaa042
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发表时间：
2020-09-01
影响因子：
3.3
通讯作者：
Pond, David W.
中科院分区：
文献类型：
--
作者：
Biggs, Tristan E. G.;Brussaard, Corina P. D.;Pond, David W.
进入休眠状态的桡足类动物，如尖吻甲藻，是南大洋食物网的主要消费者，它们将季节性浮游植物生物量的一部分转化为蜡酯(WE)储备的长期能量和生理资源。我们研究了南极半岛西部地区尖吻鳗成虫和成体的季节丰度和脂类分布与浮游植物动态的关系。休眠开始时，我们的不饱和度相对较高，叶绿素a(Chla)浓度，主要归因于硅藻，正在下降。冬季WE不饱和度的下降可能是一种休眠计时机制，随着Chla浓度的增加，可能会促进沉积，从而导致表层和深水之间的遥相关导致上升。夏末的硅藻水华与雌性的提前休眠终止和第二次产卵事件有关。如果受到两个主要产卵事件的限制，高生物量浮游植物水华的频率和持续时间可能会影响尖吻鳗雌成虫的寿命(1年或2年)。夏末，由第二次产卵活动产生的新成员可能受益于较低的捕食量和较高的浮游植物食物可获得性。根据自下而上和自上而下的条件，桡足类灵活地调整其生命周期策略，使个体能够在南大洋非常多变的环境中优化其繁殖成功的可能性。
Copepods that enter dormancy, such as Calanoides acutus, are key primary consumers in Southern Ocean food webs where they convert a portion of the seasonal phytoplankton biomass into a longer-term energetic and physiological resource as wax ester (WE) reserves. We studied the seasonal abundance and lipid profiles of pre-adult and adult C. acutus in relation to phytoplankton dynamics on the Western Antarctic Peninsula. Initiation of dormancy occurred when WE unsaturation was relatively high, and chlorophyll a (Chl a) concentrations, predominantly attributable to diatoms, were reducing. Declines in WE unsaturation during the winter may act as a dormancy timing mechanism with increased Chl a concentrations likely to promote sedimentation that results in a teleconnection between the surface and deep water inducing ascent. A late summer diatom bloom was linked to early dormancy termination of females and a second spawning event. The frequency and duration of high biomass phytoplankton blooms may have consequences for the lifespan of the iteroparous C. acutus females (either 1 or 2 years) if limited by a total of two main spawning events. Late summer recruits, generated by a second spawning event, likely benefitted from lower predation and high phytoplankton food availability. The flexibility of copepods to modulate their life-cycle strategy in response to bottom-up and top-down conditions enables individuals to optimize their probability of reproductive success in the very variable environment prevalent in the Southern Ocean.