Intrinsic and Environmental Properties Govern the Homogenization of Dissolved Organic Matter Across Different Inland Waters During Winter–Spring Season

Abstract The stability of dissolved organic matter (DOM) significantly influences the regional and global carbon budget balances. However, current studies on DOM have largely overlooked the winter–spring season in temperate inland waters of the Northern Hemisphere, a critical transitional period characterized by low biological productivity, low temperatures. Here, we selected three representative inland aquatic ecosystems in China, rivers, lakes and ponds, to elucidate the driving mechanisms of environmental and intrinsic properties on the biodegradability (BDOC) of DOM. Results indicated that dissolved organic carbon (DOC) concentrations in rivers, lakes and ponds did not differ significantly with means of 7.52, 8.21 and 10.71 mg L −1 , respectively. BDOC was highest in rivers (44.53%), followed by lakes (37.58%), and lowest in ponds (33.71%). We first observed that the physicochemical and DOM properties of rivers, lakes and ponds exhibited homogeneity during winter–spring season. Humic‐like substances were identified as the primary components of DOM in these aquatic ecosystems during this period. DOC and BDOC were strongly influenced by oxidation reduction potential, electrical conductivity, total nitrogen, total phosphorus, ammonium nitrogen, chlorophyll a, spectral slope, specific ultraviolet absorbance at 254 nm, and humification index. Although geographical (longitude and latitude), climatic (temperature and precipitation), and anthropogenic factors (population and gross domestic product) also exerted effects on DOC and BDOC, their influence was relatively weak. Environmental and intrinsic properties jointly determined the homogenization of DOM in inland waters during winter–spring season. These findings have important implications for understanding the effects of both environmental and intrinsic properties on DOM at a geoclimatic scale.