Synchronous variation of dissolved organic carbon in Adirondack lakes at multiple timescales

Dissolved organic carbon (DOC) is a key component of aquatic ecosystems with complex effects on ecosystem function. While long-term increases in DOC termed brownification have received considerable attention, directional trends typically account for a minority of variance. DOC concentrations also fluctuate on seasonal to multiannual timescales, but the causes of such variations are less understood. We used a wavelet-based approach to study timescale-specific, spatially synchronous fluctuations in DOC across 49 lakes in the Adirondacks, New York, USA. DOC varies synchronously among lakes at within-season, annual, and interannual timescales, but relationships with external drivers and internal processes indicated by lake chemistry differed across timescales. External drivers explained 78% of spatial DOC synchrony at the annual time scale. Beyond positive trends related to regional recovery from acidification, variability in DOC is a consequence of fluctuations at several timescales that are common among Adirondack lakes in precipitation, solar radiation, and internal chemical concentrations.

Automated summary

Dissolved organic carbon (DOC) plays a crucial role in aquatic ecosystems and has complex effects on ecosystem function. The study examined fluctuations in DOC at different timescales across 49 lakes in the Adirondacks, New York, USA, and found that DOC varied synchronously among lakes at within-season, annual, and interannual timescales. The causes of these variations differed across timescales, with external drivers explaining 78% of spatial DOC synchrony at the annual timescale.