Anderson Thomas R, Hessen Dag O, Gentleman Wendy C, Yool Andrew, Mayor Daniel J
Marine Systems Modelling, National Oceanography Centre, Southampton SO14 3ZH, UK.
Centre of Biogeochemistry in the Anthropocene, Department of Bioscience, University of Oslo, Oslo 0316, Norway.
J Plankton Res. 2024 Jun 7;46(4):439-451. doi: 10.1093/plankt/fbae028. eCollection 2024 Jul-Aug.
Respiration of lipids by copepods during diapause (overwintering dormancy) contributes to ocean carbon sequestration via the seasonal lipid pump (SLP). Parameterizing this flux in predictive models requires a mechanistic understanding of how life history adaptation in copepods shapes their timing of exit from diapause. We investigate the optimal phenology of in the Norwegian Sea using an individual-based model in which diapause exit is represented as a trait characterized by phenotypic mean and variance. Without interannual variability, optimal exit correlated with the onset of the spring phytoplankton bloom and phenotypic variance was of no benefit. In contrast, copepods endured reduced fitness and adopted bet-hedging strategies when exposed to interannual variability in bloom timing and predation: later exit from diapause and phenotypic variance maintained adult numbers in anomalous late-bloom years. Exit nevertheless remained well before the peak of the bloom which is a favorable strategy when low predation early in the year enhances survival of eggs and early developmental stages. Our work highlights the complex interactions between and its environment and the need for improved understanding of bet-hedging strategies and the cues of diapause exit to progress the representation of the SLP in global biogeochemical models.
在滞育（越冬休眠）期间，桡足类动物对脂质的呼吸作用通过季节性脂质泵（SLP）促进了海洋碳固存。在预测模型中对这种通量进行参数化，需要对桡足类动物的生活史适应如何塑造它们从滞育中退出的时间有一个机制性的理解。我们使用一个基于个体的模型来研究挪威海中桡足类动物的最优物候，在这个模型中，滞育退出被表示为一个由表型均值和方差表征的性状。在没有年际变化的情况下，最优退出与春季浮游植物水华的开始相关，表型方差没有益处。相比之下，当桡足类动物在水华时间和捕食存在年际变化的情况下，它们的适合度会降低，并采取风险对冲策略：滞育退出时间推迟，表型方差在异常晚水华年份维持了成年个体数量。然而，退出时间仍然远早于水华高峰期，当年初低捕食率提高了卵和早期发育阶段的存活率时，这是一个有利的策略。我们的工作强调了桡足类动物与其环境之间复杂的相互作用，以及需要更好地理解风险对冲策略和滞育退出线索，以便在全球生物地球化学模型中改进对季节性脂质泵的表征。
