Has lake brownification ceased? Stabilization, re-browning, and other factors associated with dissolved organic matter trends in eastern Canadian lakes

作者：Md Noim Imtiazy, Andrew M. Paterson, Scott N. Higgins, Huaxia Yao, Daniel Houle, Jeff J. Hudson · 发表于：Water Research · 年份：2024 · DOI：10.1016/j.watres.2024.122814 · 被引用次数：13 · 研究领域：Marine and coastal ecosystems、Aquatic Ecosystems and Phytoplankton Dynamics、Soil and Water Nutrient Dynamics

• The rise in DOC has ceased at some sites, but a renewed increase was also observed. • DOC and DON may be linked to distinct factors, resulting in asynchronous trends. • Climate change is becoming more influential on DOC than acid deposition. • New trends may emerge in the future due to the dynamic nature of their drivers. The increase in dissolved organic carbon (DOC) concentrations in freshwater systems has received considerable attention due to its implications for drinking water treatment and numerous limnological processes. While past studies have documented the influence of recovery from acidification and climate change on long-term DOC trends, the emerging importance of these explanatory factors remains less understood. In addition, few studies have followed up on recent trends in sites that have undergone increases in DOC. Using a dataset from 1980 to 2020, we investigated interannual variations in DOC and dissolved organic nitrogen (DON) in 49 lakes across four eastern Canadian regions with a history of increases in DOC. We identified recent shifts in DOC patterns using LOESS smoothing and piecewise regression. We observed a stabilizing pattern or even a decrease (p < 0.001) in high acidification regions (Dorset and Nova Scotia), where increases in DOC were previously documented. At the low acid deposition region, IISD-Experimental Lakes Area, an increasing pattern in DOC stabilized in the early 2000s; however, DOC appears to be increasing again in recent years (p =...