Pervasive aquatic vegetation organic carbon losses in China's lakes

One of the major global concerns is to mitigate carbon dioxide emissions to addressing the detrimental impacts of climate change. Aquatic vegetation, as a natural carbon pool, offers a potential solution to such problems. However, a crucial impediment is the absence of comprehensive estimates of its organic carbon storage. Here we used meta-analysis method to estimate aquatic vegetation organic carbon storage and analyze its dynamics in China's lakes based on literature-reviewed data, in situ measured data and aquatic vegetation area database. We built a database of aquatic vegetation survey data that contains 1145 samples collected since 1950, involving >174 lakes and reservoirs. All samples were formatted and a comprehensive dataset encompassing organic carbon storage of aquatic vegetation across 616 lakes was first generated. The results showed that the aquatic vegetation organic carbon storage had decreased 7.87 × 10⁵ t (a 58.52 % decrease, with the slope of -3.40 × 10⁴ t/yr) since 1986. Changes of the organic carbon storage experienced three periods dominated by emergent aquatic vegetation (EAV): sharp increase (1986-1995), decrease (1995-2010), and rapid decrease (2010-2020). Our analysis suggests that lacustrine aquatic vegetation ushered in a pervasive organic carbon losses period around 1995, especially that of EAV. This finding alerts for conservation of aquatic vegetation to ensure the continued success of these natural carbon guardians.