Ecological Indicators (Jun 2023)
Projection of future long-term Aurelia coerulea biomass variability by regional moderate-temperature-duration approach in the Bohai and Yellow Seas
Abstract
As temperature is regarded as a significant environmental factor affecting the intensity and frequency of jellyfish blooms, the projection of jellyfish peak biomass variation under global warming becomes essential for disaster prevention and mitigation on long-term time scales. The jellyfish Aurelia coerulea is distributed in worldwide oceans, particularly in the Bohai and Yellow Seas (BYSs), which are productive regions with substantial economic and climatic significance and have been suffered from A. coerulea blooms. Based on the theory of how A. coerulea reacts to various experimental temperature circumstances, recent studies have been proposed to determine the qualitative trends of A. coerulea blooms in response to climate change. However, the quantitative study of future A. coerulea biomass variability is a challenging task due to the uncertainty in the numerical relation between temperature and the biomasses of A. coerulea and the difficulty in determining the biomass considering the high mobility of jellyfishes. In this paper, we develop a moderate-temperature-duration approach to solve these two problems. The temperature suitability for all key life stages of A. coerulea during pelagic and benthic processes is involved in this approach, and we identify the major life stage that determines the peak biomass variation. The projection of future peak biomass of A. coerulea in BYSs is performed based on this approach and utilizing the long-term projection results of temperature changes by 2100 using the MPI-ESM-MR model from phase 5 of the Coupled Model Intercomparison Project (CMIP5) under the RCP4.5 scenario. The results indicate that global warming can certainly lead to the increase in A. coerulea biomass in some degree. The steady state of the highest peak biomass will be achieved during 2075∼2080, with an increase of 8.4%, 5.0%, and 11.5% in the Bohai Sea, the North Yellow Sea, and the South Yellow Sea, respectively, compared to the first steady state starting in 2020 detected by the regime shift. However, the result also shows that global warming cannot consistently lead to the increase of A. coerulea peak biomass. As the temperature rises to a large extent, the duration of moderate temperature ranges for strobilation and growth may be reduced, and thus resulting in the decrease of peak biomass instead.
