Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
NIWA, Wellington, New Zealand.
Sci Rep. 2022 May 11;12(1):7740. doi: 10.1038/s41598-022-11908-z.
Marine heatwaves (MHWs) can cause dramatic changes to ecologically, culturally, and economically important coastal ecosystems. To date, MHW studies have focused on geographically isolated regions or broad-scale global oceanic analyses, without considering coastal biogeographical regions and seasons. However, to understand impacts from MHWs on diverse coastal communities, a combined biogeographical-seasonal approach is necessary, because (1) bioregions reflect community-wide temperature tolerances and (2) summer or winter heatwaves likely affect communities differently. We therefore carried out season-specific Theil-Sen robust linear regressions and Pettitt change point analyses from 1982 to 2021 on the number of events, number of MHW days, mean intensity, maximum intensity, and cumulative intensity of MHWs, for each of the world's 12 major coastal biogeographical realms. We found that 70% of 240 trend analyses increased significantly, 5% decreased and 25% were unaffected. There were clear differences between trends in metrics within biogeographical regions, and among seasons. For the significant increases, most change points occurred between 1998 and 2006. Regression slopes were generally positive across MHW metrics, seasons, and biogeographical realms as well as being highest after change point detection. Trends were highest for the Arctic, Northern Pacific, and Northern Atlantic realms in summer, and lowest for the Southern Ocean and several equatorial realms in other seasons. Our analysis highlights that future case studies should incorporate break point changes and seasonality in MHW analysis, to increase our understanding of how future, more frequent, and stronger MHWs will affect coastal ecosystems.
海洋热浪 (MHWs) 会给生态、文化和经济上具有重要意义的沿海生态系统带来巨大变化。迄今为止，海洋热浪的研究主要集中在地理位置孤立的地区或全球海洋的广泛分析，而没有考虑沿海生物地理区域和季节。然而，要了解海洋热浪对不同沿海社区的影响，需要采用综合的生物地理季节方法，因为 (1) 生物区反映了社区范围内的温度容忍度，以及 (2) 夏季或冬季的海洋热浪可能对社区产生不同的影响。因此，我们从 1982 年到 2021 年，针对世界上 12 个主要沿海生物地理区域中的每一个，进行了特定季节的 Theil-Sen 稳健线性回归和 Pettitt 变化点分析，分析了海洋热浪事件数量、海洋热浪天数、平均强度、最大强度和累积强度的季节性变化。我们发现，在 240 项趋势分析中，有 70%显著增加，5%减少，25%不受影响。在生物地理区域内的指标之间以及在季节之间，都存在明显的趋势差异。在显著增加的情况下，大多数变化点发生在 1998 年至 2006 年之间。回归斜率在海洋热浪指标、季节和生物地理区域中普遍为正，并且在检测到变化点后最高。在夏季，北极、北太平洋和北大西洋区域的趋势最高，而在其他季节，南大洋和几个赤道区域的趋势最低。我们的分析强调，未来的案例研究应该将断点变化和海洋热浪分析的季节性纳入其中，以增加我们对未来更频繁、更强的海洋热浪将如何影响沿海生态系统的理解。
