Soil organic carbon dynamics and controlling factors in typical ecosystems of the Qinghai-Tibet Platea critical zone

The interface of the Earth’s critical zone is the place where organic carbon is dramatically decomposed and transformed．The dynamics and fate of organic carbon serve as an important foundation to reveal the material transportation in the Qinghai-Tibet Platea critical zones. This research analyzed temperature, soil moisture and stable carbon isotope values (δ¹³C) of CO₂ in different soil layers, measure soil surface respiration using soil respiration measurement system (LI-8100) , and analyzed carbon storage , carbon dynamics and its controlling factors in critical zones in seven typical ecosystems of the Qinghai-Tibet Platea. The results found that the underground carbon content and its controlling factors were very different in different ecosystems on the Qinghai-Tibet Plateau. The main controlling factor of carbon changes was water in alpine steppe and desert ecosystem while it was temperature in alpine meadow. In the meanwhile, this research also measured the maximum carboxylation rate (V_cmax) of dominant plants in each ecosystem, trying to explore the different carbon inputs in different ecosystems. Understanding the impacts of environmental changes on the geochemical cycling of critical zone’s organic carbon in the Qinghai-Tibet Platea would benefit the optimization of carbon cycling model and climate change predictions．