Kuttippurath J, Maishal S, Anjaneyan P, Sunanda N, Chakraborty Kunal
CORAL, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Hyderabad 500090, India.
Heliyon. 2023 Jul 5;9(7):e17940. doi: 10.1016/j.heliyon.2023.e17940. eCollection 2023 Jul.
Global oceanic regions are rapidly changing in terms of their temperature, oxygen, heat content, salinity and biogeochemistry. Since the biogeochemistry of the oceans is important and pivotal for global food production, and a major part of the world population relies on marine resources for their daily life and livelihood, it is imperative to monitor and find the spatio-temporal changes in the primary productivity of oceans. Here, we estimate the changes in Chlorophyll-a (Chl-a) and Net Primary Productivity (NPP) in the north Indian Ocean (NIO) basins of Bay of Bengal and Arabian Sea for the period 1998-2019. We find a substantial reduction of NPP in NIO since 1998 (-0.048 mg m day yr) and the increase in sea surface temperature (SST) (+0.02 °C yr) is the primary driver of this change. Furthermore, there is a significant (10-20%) change in the air mass or dust transport to NIO from the period Decade 1 (1998-2008) to Decade 2 (2009-2019). This change in air mass trajectories has also altered NPP in both basins through the changes in nutrient input and associated biogeochemistry. Henceforth, this study cautions the changes in primary productivity of NIO, and suggests regular assessments and continuous monitoring of the physical and biological processes from a perspective of food security and ecosystem dynamics.
全球海洋区域在温度、氧气、热量含量、盐度和生物地球化学方面正在迅速变化。由于海洋的生物地球化学对全球粮食生产至关重要且具有关键作用，并且世界上很大一部分人口的日常生活和生计依赖海洋资源，因此监测并找出海洋初级生产力的时空变化势在必行。在此，我们估算了1998 - 2019年期间孟加拉湾和阿拉伯海的北印度洋（NIO）盆地中叶绿素a（Chl-a）和净初级生产力（NPP）的变化。我们发现自1998年以来北印度洋的净初级生产力大幅下降（-0.048毫克·米⁻²·天⁻¹·年⁻¹），而海面温度的升高（+0.02℃·年⁻¹）是这一变化的主要驱动因素。此外，从十年1（1998 - 2008年）到十年2（2009 - 2019年），输送到北印度洋的气团或沙尘传输发生了显著（10 - 20%）变化。气团轨迹的这种变化也通过营养物质输入和相关生物地球化学的变化改变了两个盆地的净初级生产力。因此，本研究警示了北印度洋初级生产力的变化，并建议从粮食安全和生态系统动态的角度对物理和生物过程进行定期评估和持续监测。
