Northeastern mountain ponds as sentinels of change: Current and emerging research and monitoring in the context of shifting chemistry and climate interactions

Depth Moderates DOC Impact on Cold‐Water Refugia in Small, Northern Temperate Lakes

“…Although all lakes in the Northeast have been exposed to some degree of acidic deposition and climate change, trends in DOC are not uniform across the region (Figure 2). In Maine, coherent DOC trends in some regions suggests that anthropogenic stressors like climate change and recovery from acidification are driving forces of DOC dynamics (Gavin et al., 2018; Nelson et al., 2021; Strock et al., 2017). A lack of regional coherence in the population of lakes studied here suggests individual watershed and lake properties can contribute to multi‐decadal DOC trends and underscores the importance of quantifying watershed and lake characteristics that may confound the impact of regional clarity trends (Magnuson et al., 1990).…”

Climate-Driven Increases in Source Water Natural Organic Matter: Implications for the Sustainability of Drinking Water Treatment

“…For several decades, there have been increases in the concentration of natural organic matter (NOM) measured as dissolved organic carbon (DOC) or color in surface waters, a phenomenon sometimes referred to as brownification. − Brownification has been widespread throughout the northern hemisphere, with one of the most reported drivers being the reversal of atmospheric acid (e.g., SO 4 ) deposition, , which increases the solubility of NOM. ,, The authors have previously demonstrated brownification trends through the reversal of acid deposition in the context of surface waters and drinking water supplies in Atlantic Canada ,, and globally . More recently, the importance of climate change − and changing land use ,, have been highlighted as other drivers of increased NOM export to surface water, particularly as deposition stabilizes. However, the individual importance of these factors has been difficult to disentangle. ,,,, Many climate projections estimate that global temperature will continue to warm and that precipitation events will become more intense and frequent, which will undoubtedly promulgate these water quality trends.…”

Adapting direct filtration to increasing source water dissolved organic carbon using clarification and granular activated carbon

“…Collectively, these studies have identified relationships between increased DOC concentration and lower levels of atmospheric acid deposition. More recently, the importance of climate change (Finstad et al, 2016; Imtiazy et al, 2020; Kopáček et al, 2019; Lepistö et al, 2021; Marty et al, 2021; Meyer‐Jacob et al, 2020; Nelson et al, 2021; Riise et al, 2018) has been highlighted as a driver of increasing DOC concentration, particularly as acid deposition stabilizes.…”