The Indian Ocean, the third largest among the world’s oceans, is experiencing unprecedented changes in sea surface temperature (SST). We present temporal and spatial dynamics of phytoplankton and their response to warming in the Indian Ocean (∼25°N to 30°S) during 1998–2019 using remote sensing data. Our study revealed that the area of the Indian Ocean Warm Pool (IOWP), defined as waters with SST values >28 °C, is significantly expanding in most regions, particularly in the most recent decade. The increase in IOWP area was greatest (∼74%) in the south-central basin. Furthermore, SST increased significantly in most areas of the Indian Ocean (10 out of 11 regions explored) over the 22-year study period with the highest increase of 0.7 °C observed in the south-central regions. Most other regions showed an average increase in temperature of 0.4–0.5 °C. At the same time, net primary production (NPP) showed large interannual variability in northern and central regions of the Indian Ocean, with slightly decreasing trends in a few northern regions. Overall, years of the first decade (1998–2008) showed more often cooler temperatures and higher productivity, except for a few years, whereas years of the last decade (2009–2019) showed more often warmer temperature and lower productivity, except in very recent years (2017–2019) when productivity was high. Mean Chl a concentrations increased in the last decade during the northeast monsoon period in the northwestern regions, suggesting increased NPP in December to March period as a future scenario in this highly productive area of the Indian Ocean. We also observed increasing SST in several major upwelling areas during the study period, whereas Chl a showed high interannual variability with no marked significant trends in most areas. Results from this study corroborate the importance of the southwest monsoon as a key driver of seasonal patterns in Chl a in major upwelling areas of the Indian Ocean.

印度洋是世界第三大海洋，其海面温度 (SST) 正在经历前所未有的变化。我们使用遥感数据展示了 1998-2019 年期间浮游植物的时空动态及其对印度洋（~25°N 至 30°S）变暖的响应。我们的研究表明，印度洋暖池 (IOWP) 的面积（定义为 SST 值 >28 °C 的水域）在大多数地区都在显着扩大，特别是在最近十年。中南部盆地的 IOWP 面积增加最大（~74%）。此外，在 22 年的研究期间，印度洋大部分地区（已探索的 11 个区域中的 10 个）的海温显着增加，在中南部地区观察到的最高增幅为 0.7 °C。大多数其他地区的温度平均升高 0.4-0。5℃。同时，印度洋北部和中部地区的净初级生产（NPP）呈现出较大的年际变化，北部少数地区呈小幅下降趋势。总体而言，第一个十年（1998-2008 年）表现出更冷的温度和更高的生产力，除了几年，而最后一个十年（2009-2019）表现出更常变暖和更低的生产力，除了非常最近几年（2017-2019 年）生产力高。平均氯 而过去十年（2009-2019 年）的温度更高，生产力更低，但最近几年（2017-2019 年）生产力较高。平均氯 而过去十年（2009-2019 年）的温度更高，生产力更低，但最近几年（2017-2019 年）生产力较高。平均氯a浓度在过去十年中在西北地区的东北季风期间有所增加，这表明 12 月至 3 月期间 NPP 的增加是印度洋这一高产地区的未来情景。我们还在研究期间观察到几个主要上升流区域的 SST 增加，而 Chl a显示出很高的年际变化，大多数区域没有明显的显着趋势。这项研究的结果证实了西南季风作为印度洋主要上升流区域Chl a季节性模式的关键驱动因素的重要性。