Seasonal total nitrogen data was collected from 15 sites in Poyang Lake with the help of the Observation and Research Station for the Wetland Ecosystem of Lake Poyang, CAS. The data is collected in Jan, Apr, Jul and Oct every year. The field investigation was conducted according to the lake ecosystem survey guidance.（Protocol sharing）

The use statement is suggested to adopt the following method: the quarterly data of transparency of Poyang Lake region from 2009 to 2020 is from the national key research and development plan project "Research and Application Demonstration of Key Technologies for Ecological and Water Security in the Great Lakes Basin (2018YFE0206400)". The quotation method is suggested to be as follows: Xu Ligang Nanjing Institute of Geography and Lakes, Chinese Academy of Sciences Quarterly transparency data of Poyang Lake region from 2009 to 2020 2023。