Biogenic elements-informed assessment of the impact of human activities on river ecosystems.

River ecosystems, acting as pivotal conduits linking terrestrial, marine, and atmospheric realms, have faced significant disturbances due to human exploitation of their resources. Recent years have witnessed a heightened intensification of human activities, adversely affecting the equilibrium of water ecosystems. To systematically study the various factors that affect river ecosystems under human activities, we introduce a universally applicable approach that considers the diversity of watersheds, biogenic elements, and human activities. Using this method, this application uncovers the sensitive human activity types, biogenic factors, and species significantly influencing river biodiversity within the study area. Incorporating statistical modelling, sensitivity screening, and advanced correlation analyses within a random forest regression framework, Sensitive biogenic elements and biological types affected by human activities were identified in typical watersheds, and the stability of different aquatic ecosystems was evaluated. Suggestions for watershed management measures were proposed When human activities affect the degree of water resource development and utilization, the forms of sensitive biogenic elements include DIC and Tsi; When human activities affect the discharge of pollutants into rivers, the forms of sensitive biogenic elements include TP, PP, and DEP, and the ratio composition includes TC: TN, TC: TP, TP: TSi, and TN: TP, This study pioneers a novel method for assessing human impacts on river ecosystems and successfully applies this approach to inform management decisions for river segments and tributaries in the middle and upper reaches of the Yangtze River basin. thereby enhancing our understanding of the consequences of human-induced impacts on biodiversity.

Cyanobacteria bloom hazard function and preliminary application in lake taihu, China.

In recent years, due to the intensification of human activities, water ecological problems are gradually increasing. As the third largest freshwater lake in China, Lake Taihu is an important drinking water source for several densely populated cities in China. The prominent water ecological problem in this area is mainly Cyanobacteria Bloom. Cyanobacterial blooms have been erupting which have affected local residents' drinking water and caused losses to the national economy. Based on the interpretation results of MODIS data in the Lake Taihu region from 2004 to 2014, this paper analyzes the main driving factors of cyanobacterial bloom are phosphorus and potassium through the correlation analysis of nitrogen, phosphorus, potassium and cyanobacteria area, normalizes nutrient, and identifies that the water level of Lake Taihu is the influencing factor of cyanobacterial bloom. A Lake Taihu cyanobacteria bloom hazard function is constructed to quantitatively assess the losses (economic losses) caused by cyanobacterial blooms from 2001 to 2012, supporting for cyanobacteria control management in Lake Taihu.