Marine Heatwaves in China's Marginal Seas and Adjacent Offshore Waters: Past, Present, and Future

Abstract

Under the combined impacts of natural changes and human activities, the past, current, and future marine heatwaves (MHWs) in China's marginal seas and adjacent offshore waters (CMSOW) need a comprehensive understanding. This study provides a systematic analysis of the spatiotemporal variations using daily sea surface temperature data and simulates the future trend using 12 climate models. During 1982–2018, the mean annual total days, duration, frequency, and mean intensity of the MHWs in the CMSOW increased by 20–30 days/decade, 5–9 days/decade, 1–2 decade−1, and 0.1–0.3°C/decade, respectively (p <0.01). The maximum sea surface temperature anomalies in the Bohai Sea was over 6–8°C, and the MHW's frequency, duration, and mean intensity were higher than twice the global average, which could have impacted fishery resources and occurrence of harmful algal blooms. The variations of the MHWs in the CMSOW result from the robust ocean surface warming, which is caused by increased solar radiation due to reduced cloud cover, reduced ocean heat loss from weaker wind speed, weakening but warmer Kuroshio, and strong El Niño. In the future, the areas with longer total days and duration will increase; the spatial pattern of frequency has a negative relationship with that of duration while that of mean intensity is mostly unchanged. Year 2040 is a key node for the future changes of MHW under different Representative Concentration Pathways. The trend of total days increases from fast to slow, and frequency shows an opposite trend; the duration and mean intensity rise faster after 2040.

Variations in Summer Marine Heatwaves in the South China Sea

“…In addition, modes of climate variability also modulate the frequency, intensity, and duration of MHWs by changing the ocean temperature (Holbrook et al., 2019; Oliver, Perkins‐Kirkpatrick, et al., 2018; Scannell et al., 2016). As an example, the phases of ENSO are important in enhancing or suppressing MHWs in different regions worldwide (Benthuysen et al., 2018; Di Lorenzo & Mantua, 2016; Holbrook et al., 2019; Yao et al., 2020).…”

Development of metal adaptation in a tropical marine zooplankton

“…We revealed that the evolution of metal adaptation comes at the cost of reducing the capacity to deal with additional stressors; here we examined elevated temperature. This is important as increasing temperature, especially from marine heatwaves in this region 62 is predicted to seriously affect the structures, function, and ecological services of the coastal ecosystems 63 . Detangling the transgenerational plasticity and evolution of adaptations to one stressor (Cu) and the associated costs would be the point of departure for tackling more complex issues on how marine species may persist, thrive or collapse under multiple-stressor conditions 64 .…”

Classifications and Characteristics of Marine Heatwaves in the Northern South China Sea

“…However, the short-term extreme event-based research still lacks, and the short-term extreme events actually exert a more important influence on ecosystems due to substantially higher temperatures than normal temperature (Smith, 2011;Li et al, 2019), such as harmful algae blooms, which are closely related to extreme warm events or MHWs (Cai et al, 2016(Cai et al, , 2017. Under global warming, there is a long-term increase of MHWs in marginal seas in China (Yao et al, 2020).…”