Differences in the Effects of Storms on Dissolved Organic Carbon (DOC) in Boreal Lakes during an Early Summer Storm and an Autumn Storm

Kate A Warner,Rachel A Fowler,Jasmine E Saros

doi:10.3390/w12051452

Abstract

In boreal lakes, increased precipitation events have been linked to increased concentrations of dissolved organic carbon (DOC), however the effects of seasonal differences on DOC and how this may impact storm response remain unclear. We evaluated DOC concentration and a set of DOC quality metrics during an early summer storm and an autumn storm on a suite of six lakes in Acadia National Park in Maine, USA. to better understand differences in seasonal storm responses. Our results revealed differences in the response of DOC quality metrics to an early summer versus an autumn storm, with changes in DOC quality metrics varying by storm and lake features. During the early summer storm, we observed greater changes in various DOC quality metrics in deep lakes with longer residence times, whereas during the autumn storm, lakes with large watershed area to lake area ratios experienced the greatest changes. Land cover was highly correlated with changing DOC quality metrics in the early summer storm but did not play a significant role in the autumn storm response. Our research provides evidence of seasonal differences in the effects of storms on boreal lakes, which are ultimately mediated by a combination of lake and watershed characteristics as well as seasonal differences in climate such as solar radiation and antecedent weather conditions.

Highlights

Dissolved organic carbon (DOC) is an important regulator of ecosystem structure and function in lakes [1,2,3]
SUVA254, a*320, and a*380 decreased in response to the early summer storm, whereas they increased after the autumn storm (Figure 3)
Percent change in concentration was negatively percent change in DOC and percent change in DOC quality metrics appear stronger at P2 than at P1 correlated to percent changeand in SUVA

Summary

Introduction

Dissolved organic carbon (DOC) is an important regulator of ecosystem structure and function in lakes [1,2,3]. DOC quantity and quality in a lake are dependent on vegetation type, season, climate, hydrology, and disturbance to the surrounding watershed [11,12]. Widespread increases in DOC and color in lakes in the Northern Hemisphere have been attributed to a combination of factors including increases in air temperatures [14,15], changes in the intensity of the hydrological cycle [16,17], and reductions in acid deposition [18]. Lakes respond rapidly to external pressures, including changes in weather and climate as well as land use [19]. Since 1996, the northeastern U.S has received 53% more extreme precipitation events compared to 1901–1995 [30]

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