The research group of Park Shilong of Chenghuan University published an article in Nature - Plants to reveal the dynamic changes and driving mechanisms of the seasonal peak time of photosynthesis in vegetation in the northern hemisphere

Vegetation growth is regulated by climatic factors and has obvious seasonal dynamics
.
In the Northern Hemisphere, the seasonal peak photosynthetic rate of vegetation (GPP_max) is closely related
to the interannual change of ecosystem carbon sink function.
In recent years, the dynamic change mechanism of vegetation GPP_max has become a new hotspot
in the field of carbon cycle research.
In terms of the size and occurrence time of vegetation GPP_max, climatic conditions and canopy structure have important influences
.
Whether the seasonal peak times of the two match or not is directly related to whether GPP_max can reach the potential maximum
.
Therefore, in order to more accurately understand the carbon sequestration potential of vegetation in the northern hemisphere, it is necessary to understand: in the current context of rapid climate change, how does the vegetation in the northern hemisphere adjust the canopy structure according to changes in environmental conditions, thereby affecting the occurrence time of GPP_max?

Based on multi-source remote sensing and flux observation data, combined with machine learning methods, the research group of Academician Park Shilong of the School of Urban and Environmental Sciences of Peking University quantitatively analyzed the difference between GPP_max time and normalized vegetation index (NDVI) seasonal peak time and its change mechanism
in the past 20 years in the northern hemisphere vegetation GPP max time and normalized vegetation index (NDVI, which characterizes vegetation canopy structure).
It is found that compared with the GPP_max time of vegetation, the seasonal peak time of vegetation canopy structure lags by an average of 8 days, mainly due to climate and nutrient constraints (as shown in the figure below).

In the past 20 years, the increase of atmospheric_CO2 concentration has led to the advance of vegetation GPP_max time, which is relatively stable due to climatic and nutrient conditions, so that the time difference between the two is increasing
.
The study points out that the current ecosystem model has not accurately depicted the temporal and spatial dynamics of vegetation GPP_max and canopy structure peak time, and it is urgent to improve the expression
of related mechanisms.
This study provides new insights
into the dynamic mechanism of vegetation growing seasons in the Northern Hemisphere.

Temporal differences between photosynthesis and seasonal peaks of canopy structure in vegetation in the northern hemisphere (a, green indicates the first peak of photosynthesis and yellow indicates the first peak of canopy structure) and the relative contribution of different factors to spatial variation of temporal differences (b)

The results were published in the journal Nature Plants (doi:10.
1038/s41477-022-01278-9) under the title "Seasonal peak photosynthesis is hindered by late canopy development in northern ecosystems
.
" 。 Zhao Qian, a 2020 doctoral student at the School of Urban and Environmental Sciences of Peking University, is the first author, and Shilong Park and Zhu Zaichun, a researcher at the Shenzhen Graduate School of Peking University, are co-corresponding authors
.