ABSTRACT

Global warming is causing changes in the food web structure and seasonal plankton dynamics. The Baltic Sea is one of the fastest-warming sea areas and warming consequently affects the timing and magnitude of phytoplankton blooms. Based on available Chlorophyll a data from nine years between 1979 and 2018, from the entrance to the Gulf of Finland, we studied the timing of the phytoplankton spring bloom in relation to spring seawater temperature. We found the peak of the bloom to occur earlier in years with higher spring seawater temperature. In warmer years, there was also a shorter time lag between phytoplankton and zooplankton biomass peaks. In addition, it seems as the spring bloom total biomass has decreased with time, with more extensive summer blooms during later years, in line with the general trend observed in the Baltic Sea. The spring bloom has traditionally been considered the most important part of the season, but we argue that the whole growth season should be investigated since summer blooms appear to increase with warming.

摘要

全球变暖正在引起食物网结构和季节性浮游生物动态的变化。波罗的海是增速最快的海域之一，变暖因此影响浮游植物绽放的时间和幅度。基于可用的叶绿素a从1979年至2018年的9年中的数据，从芬兰湾的入口开始，我们研究了浮游植物春季开花与春季海水温度相关的时间。我们发现，随着春季海水温度升高，水华高峰出现在较早的年份。在温暖的年份，浮游植物和浮游生物量高峰之间的时间间隔也较短。此外，似乎春季开花的总生物量随时间而减少，随后几年的夏季开花更为广泛，这与波罗的海的总体趋势一致。传统上，春季开花被认为是该季节中最重要的部分，但是我们认为，应该对整个生长季节进行调查，因为夏季开花似乎会随着变暖而增加。