Department of Biological Sciences, University of Bergen, Bergen, Norway.
The Norwegian Institute for Water Research, Marine Biology Section, Bergen, Norway.
Glob Chang Biol. 2024 May;30(5):e17308. doi: 10.1111/gcb.17308.
At high latitudes, the suitable window for timing reproductive events is particularly narrow, promoting tight synchrony between trophic levels. Climate change may disrupt this synchrony due to diverging responses to temperature between, for example, the early life stages of higher trophic levels and their food resources. Evidence for this is equivocal, and the role of compensatory mechanisms is poorly understood. Here, we show how a combination of ocean warming and coastal water darkening drive long-term changes in phytoplankton spring bloom timing in Lofoten Norway, and how spawning time of Northeast Arctic cod responds in synchrony. Spring bloom timing was derived from hydrographical observations dating back to 1936, while cod spawning time was estimated from weekly fisheries catch and roe landing data since 1877. Our results suggest that land use change and freshwater run-off causing coastal water darkening has gradually delayed the spring bloom up to the late 1980s after which ocean warming has caused it to advance. The cod appear to track phytoplankton dynamics by timing gonadal development and spawning to maximize overlap between offspring hatch date and predicted resource availability. This finding emphasises the importance of land-ocean coupling for coastal ecosystem functioning, and the potential for fish to adapt through phenotypic plasticity.
在高纬度地区，适合生殖事件的窗口期特别窄，促进了营养层次之间的紧密同步。气候变化可能会破坏这种同步性，因为例如，较高营养层次的早期生命阶段及其食物资源对温度的反应不同。这方面的证据尚无定论，而且补偿机制的作用也知之甚少。在这里，我们展示了海洋变暖与沿海水体变暗是如何共同驱动挪威罗弗敦地区浮游植物春季繁殖时间的长期变化的，以及东北北极鳕鱼的产卵时间是如何同步响应的。春季繁殖时间源自可追溯至 1936 年的水文观测数据，而鳕鱼的产卵时间则是根据自 1877 年以来每周的渔业捕捞量和鱼卵上岸数据估算得出的。我们的研究结果表明，土地利用变化和淡水径流导致的沿海水体变暗，逐渐将春季繁殖期推迟到 20 世纪 80 年代后期，之后海洋变暖又导致其提前。鳕鱼似乎通过调整性腺发育和产卵时间来跟踪浮游植物的动态，以使后代孵化日期和预测资源可用性之间的重叠最大化。这一发现强调了陆海耦合对沿海生态系统功能的重要性，以及鱼类通过表型可塑性适应的潜力。
