Eat or Sleep: Availability of Winter Prey Explains Mid-Winter and Spring Activity in an Arctic Calanus Population
Eat or Sleep: Availability of Winter Prey Explains Mid-Winter and Spring Activity in an Arctic Calanus Population
复制标题
DOI：
10.3389/fmars.2020.541564
复制
发表时间：
2020-09-25
影响因子：
3.7
通讯作者：
Daase, Malin
中科院分区：
文献类型：
--
作者：
Hobbs, Laura;Banas, Neil S.;Daase, Malin
哲水蚤属的桡足类已经适应了高水平的季节性猎物的可用性，进入一个时期的冬眠在冬季称为滞育，但反复观察活跃的哲水蚤种。已在1月在高纬度峡湾这表明可塑性越冬策略。在过去的十年中，极夜期间在北极得到了深入的研究。一个活跃的微生物食物网的持续存在表明，在整个黑暗时期，低水平的替代桡足类猎物（如微型浮游动物）的流行。在这里，我们提供了进一步的证据，仲冬浮游动物活动的停泊声学从斯瓦尔巴群岛Kongsfjorden的十年记录。我们应用一个基于个人的生活史模型，调查健身后果的一系列越冬策略（滞育时间和持续时间）下的各种猎物可用性的情况。在没有冬季猎物可用性（P-win = 0 μ g C L-1）的情况下，最佳的时间退出滞育是在3月。然而，作为P-win增加（高达40亩C L-1），有一点健身差异桡足类退出滞育1月相比，3月。由此，我们认为哲水蚤能够（在能量方面）i）提前退出滞育以应对春季开花时间的不确定性，或者ii）如果滞育不可能（即，环境不够深，或没有足够的脂质储备建立了在前一个夏天）。可行的越冬策略的范围随着P-win的增加而增加，这表明哲水蚤有更大的灵活性。在非零P-win情况下。
Copepods of the genus Calanus have adapted to high levels of seasonality in prey availability by entering a period of hibernation during winter known as diapause, but repeated observations of active Calanus spp. have been made in January in high latitude fjords which suggests plasticity in over-wintering strategies. During the last decade, the period of Polar Night has been studied intensively in the Arctic. A continuous presence of an active microbial food web suggests the prevalence of low-level alternative copepod prey (such as microzooplankton) throughout this period of darkness. Here we provide further evidence of mid-winter zooplankton activity using a decadal record of moored acoustics from Kongsfjorden, Svalbard. We apply an individual based life-history model to investigate the fitness consequences of a range of over-wintering strategies (in terms of diapause timing and duration) under a variety of prey availability scenarios. In scenarios of no winter prey availability (P-win = 0 mu g C L-1), the optimal time to exit diapause is in March. However, as P-win increases (up to 40 mu g C L-1), there is little fitness difference in copepods exiting diapause in January compared to March. From this, we suggest that Calanus are able (in energetic terms) to either i) exit diapause early to deal with uncertainty in spring bloom timing, or ii) remain active throughout winter if diapause is not possible (i.e., environment not deep enough, or not enough lipid reserves built up over the previous summer). The range of viable overwintering strategies increases with increasing P-win, suggesting that there is more flexibility for Calanus spp. in a scenario of non-zero P-win.