Recently, Li Qian's team, a researcher at the State Key Laboratory of Tropical Marine Environment (LTO), Institute of Oceanography, Chinese Academy of Sciences, revealed the response mechanism of phytoplankton in the northern South China Sea to atmospheric settlement in summer. The results were published in Limnology and Oceanography. Li Qian is the corresponding author of the paper, and doctoral student Zhou Weiwen is the first author of the paper.
Atmospheric sedimentation is an important source of marine nutrients, and on average, the nutrient flux of atmospheric sedimentation input into the nearshore ocean is equal to the flux of river input. Aerosol particles contain mineral nutrient salts and trace metals, as well as components influenced by human activities, which can affect the physiological level and community structure of marine phytoplankton, playing an important role in the marine carbon cycle and carbon neutralization. Accurately assessing the effects of atmospheric deposition on nearshore and shelf ecosystems is more challenging than in the open open ocean, but this sea area is an important part of global primary productivity and is critical to understanding the impact of atmospheric deposition on global marine biogeochemical processes.
The aerosol load in the northern south China Sea is increasing due to human activities, but the biological response mechanism of atmospheric sedimentation is still not fully elucidated. The study found that regardless of the previous type of nutrient salt restriction in phytoplankton communities, the addition of aerosols and rainwater significantly increased the size fraction of microphytegton. Plants have three different responses: positive, unaffected, and negative. The apparent inhibition of the Upwelling Zone in Qiongdong may be due to the poor tolerance of subsurface planktonic communities to trace metal physiology brought about by upwelling. Prochlorococcus growth was consistently inhibited by additives, but both positive and negative effects were observed for the remaining picospic plankton communities; the addition of aerosols and rainwater stimulated phosphorus-restricted polycoccals, while nitrogen-limiting polycoccals were inhibited. The results showed that the response of phytoplankton to atmospheric sedimentation in the shelf sea was jointly affected by the fertilization effect of nutrient salts in aerosols and the physiological toxicity of trace metals in aerosols.
This study deepens the understanding of the spatial distribution of phytoplankton biomass and community structures affected by atmospheric sedimentation in the northern shelf area of the South China Sea. The research work has been funded by the talent team of the Guangdong Provincial Laboratory of Marine Science and Engineering (Guangzhou) in the South China, the National Natural Science Foundation of China, and the Research Fund of the LTO Key Laboratory.
Figure 1.Survey section and ship-based culture experimental station in the continental shelf sea area of the northern South China Sea
Fig. 2.Response of typical station phytoplankton chlorophyll to restriction nutrient salt addition and atmospheric sedimentation addition in different sections
Source: South China Sea Institute of Oceanology, Chinese Academy of Sciences