A synthesis of ecosystem metabolism of China's major rivers and coastal zones (2000–2020)

Abstract

Ecosystem metabolism is a vital measurement for understanding the dynamics of aquatic environments. China has a range of aquatic resources and in the past two decades, there has been an increasing interest in ecosystem metabolism research. However, no studies have evaluated overall variation and environmental patterns which affect metabolism in China's vast range of aquatic systems. For this paper, we searched for articles with metabolism data for China's major rivers and coastal zones from 2000 to 2020. We identified 127 studies documenting ecosystem metabolism functions including primary production (PP), community respiration (CR) and net ecosystem production (NEP). Using path analysis, we documented relationships across a range of environmental parameters. Light availability affected riverine and coastal PP (<0.1-10.7 gC m À2 day À1 ), while riverine PP was also linked to precipitation, photosynthesis-related biomass, and land-use variables.Riverine and coastal CR ranged from 0.01 to 24.3 gC m À2 day À1 and was affected strongly by nutrient concentrations. Average NEP ranged from 2.9 to 9.2 gC m À2 day À1 , suggesting the potential of some of the evaluated ecosystems to be CO 2 sinks. Within this review, the large spatiotemporal range allows for a wideranging understanding of the variation of metabolic processes which contribute to CO 2 dynamics and the role of aquatic ecosystems in regional climate change. Additionally, by evaluating aquatic ecosystem metabolism across such a diverse range of environmental conditions this work provides a scientific basis for future assessments of ecological risks under the complex conditions of climate change.