1. Global Drivers of Phytoplankton Phenology Trends
关键词Tags: phytoplankton phytoplankton
摘要：浮游植物是全球初级生产的关键贡献者，也是海洋生态系统变化的敏感指标。浮游植物物候的变化，特别是其生长期的开始、终止和持续时间，对于以它们为食的更高营养水平具有重要影响。几项当地研究提供了将物候变化与气候变化联系起来的证据。然而，迄今为止，全球分析依赖于不到二十年的表面叶绿素时间序列观测，因此很难将趋势与变异性区分开来，并在全球层面建立潜在驱动因素的一致性。在这里，我们使用跨卫星传感器协调的 OC-CCIv5 卫星观测数据和 NEMO-PlankTOM12 全球海洋生物地球化学模型来重新审视浮游植物物候学的最新趋势，并确定 1998-2020 年期间的全球驱动因素。通过统计分析来分离和控制潜在驱动因素之间的协方差，我们发现海温变暖趋势明显与浮游植物生长季节的较早开始、较晚终止和较长持续时间相关。相反，MLD、海温变异性和叶绿素的变化与同一方向的起始和终止变化相关，因此两个边界平行移动，部分抵消了它们对持续时间的影响。 PlankTOM12 模型成功地再现了大多数观察到的物候模式及其与潜在驱动因素的关联，提供了机械关系的证据，并帮助确定驱动因素的全球重要性。 我们的研究结果表明，浮游植物生长期开始较早、终止较晚和持续时间较长的趋势可能与气候变化有关，因此在全球持续变暖的情况下，浮游植物生长期可能在不久的将来持续存在。
Abstract: Phytoplankton are key contributors to global primary production and serve as sensitive indicators of changes in marine ecosystems. Changes in phytoplankton phenology, and in particular the onset, termination, and duration of their growing period, have important implications for higher trophic levels that feed on them. Several local studies have provided evidence linking phenological shifts to climate change. However, global analyses have so far relied on time‐series observations of surface chlorophyll covering less than two decades, making it difficult to separate trends from variability and establish the coherence of underlying drivers at the global level. Here we use the OC‐CCIv5 satellite‐derived observations harmonised across satellite sensors and the NEMO‐PlankTOM12 global ocean biogeochemical model to revisit recent trends in phytoplankton phenology and identify their global drivers during the 1998–2020 period. Using statistical analysis to separate and control for covariance among underlying drivers, we show that SST warming trends are clearly associated with earlier initiation, later termination, and longer duration of the phytoplankton growing season. In contrast, changes in MLD, SST variability, and chlorophyll are associated with shifts in initiation and termination in the same direction, such that both boundaries move in parallel, partly cancelling their effect on duration. The PlankTOM12 model successfully reproduces most of the observed patterns in phenology and their association with the underlying drivers, providing evidence of the mechanistic relationships, and helping to ascertain the global significance of the drivers. Our findings suggest that trends towards earlier initiation, later termination, and longer duration of phytoplankton growing periods are likely associated with climate change, and may therefore persist in the near future under continued global warming.