Water chemical changes along a latitudinal gradient in relation to climate and atmospheric deposition

Weyhenmeyer, Gesa A.

doi:10.1007/s10584-007-9331-7

Cited by 40 publications

(42 citation statements)

References 24 publications

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“…We used TN concentrations to account for atmospheric deposition variations along a latitudinal gradient, since nitrogen concentrations in Swedish lakes best reflect the pattern of atmospheric wet deposition (Weyhenmeyer et al 2007). Sulfate concentrations, which can also be used as a proxy for atmospheric deposition, explained only 1% of the variations in TOC concentrations (R 2 5 0.01, p , 0.0001, n 5 3123).…”

Section: Resultsmentioning

confidence: 99%

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Nonlinear response of dissolved organic carbon concentrations in boreal lakes to increasing temperatures

Weyhenmeyer

Karlsson

2009

Limnology & Oceanography

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Recent increases in concentrations of dissolved organic carbon (DOC) in lakes and rivers over large regions have been related to both changes in the climate and in atmospheric deposition chemistry. Using a data set of 1041 boreal lakes along a 13u latitudinal gradient, sampled in 1995, 2000, and 2005, and an additional data set of 90 lakes along a 1000-m altitudinal gradient at 68uN, we show that DOC concentrations increase in a nonlinear way along a latitudinal and altitudinal temperature gradient. The nonlinear relation of DOC to increasing temperatures was consistent over space and time. Out of 14 meteorological, catchment, morphometric, and atmospheric deposition variables tested, the variable best explaining this kind of nonlinear pattern was the number of days when air temperatures exceeded 0uC, i.e., the duration of the main growing and runoff season (D T.0 ). Using D T.0 as an input variable, we were able to predict the nonlinear temperature response of DOC concentrations, both spatially (R 2 5 0.90, p , 0.0001) and temporally (R 2 5 0.90, p , 0.0001). D T.0 has an advantage over other variables because it includes the time factor, which is decisive for the duration that biogeochemical processes can take place. We suggest that DOC concentrations in lakes are influenced by climate change and that present temperature increases over Sweden result in an accelerated DOC increase toward warmer geographical regions.In humic lakes, the pool of organic carbon is dominated by dissolved organic carbon (DOC) imported from terrestrial surroundings. Terrestrial DOC plays a key role in aquatic ecosystems because it affects lake productivity, community structure, and metabolic balances (Jones 1998;Jansson et al. 2000 Jansson et al. , 2007, the global carbon budget ), the availability of dissolved nutrients and metals (Franco and Heath 1983), and the thermal structure (Fee et al. 1996) and optical properties of water bodies (Morris et al. 1995). Recently, an increase in DOC concentrations over large regions in the Northern Hemisphere over the last decades has been observed (Monteith et al. 2007). Temporal changes in DOC concentrations have been attributed to changes in runoff (Andersson et al. 1991;Schindler et al. 1997;Erlandsson et al. 2008 (2003) proposed that concentrations and fluxes of DOC are more strongly related to climate and topography than to internal properties.Considering that the majority of the climate-related drivers for DOC concentrations in lakes, such as runoff and temperature, show large variations between seasons at northern latitudes, we were interested to see whether temporal and spatial differences in length of seasons might have an effect on DOC concentrations in lakes. We hypothesized that the length of the main growing season, when main runoff events also take place, is a significant predictor for DOC concentrations in lakes, both on a spatial and a temporal basis. To test the hypothesis, we used a data set of 1041 boreal lakes along a 13u latitudinal gradient from three lake invento...

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Section: Resultsmentioning

confidence: 99%

“…In addition to lake-specific air temperatures, we determined the lake-specific duration of the main growing and runoff season, i.e., the number of days when air temperatures exceed 0uC (D T.0 ), according to the formula described in Weyhenmeyer et al (2004):…”

Section: Methodsmentioning

confidence: 99%

Nonlinear response of dissolved organic carbon concentrations in boreal lakes to increasing temperatures

Weyhenmeyer

Karlsson

2009

Limnology & Oceanography

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141

103

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“…Chromophoric dissolved organic matter is usually dominated by brown-colored humic substances from terrestrial ecosystems (Thurman 1985), and frequently measured as absorbance of filtered water at a given wavelength, for example, 420 nm (a 420 ) (Kirk 2003). In Swedish boreal surface waters, a 420 is among the water chemical variables that showed fastest change during the past decades, implying that waters appear increasingly brownish (Weyhenmeyer 2008). Accelerated browning of freshwaters has been reported from most northern European countries as well as North America (reviewed by Monteith et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of freshwaters to browning in response to future climate change

et al. 2015

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Many boreal waters are currently becoming browner with effects on biodiversity, fish production, biogeochemical processes and drinking water quality. The question arises whether and at which speed this browning will continue under future climate change. To answer the question we predicted the absorbance (a 420 ) in 6347 lakes and streams of the boreal region under future climate change. For the prediction we modified a numerical model for a 420 spatial variation which we tested on a temporal scale by simulating a 420 inter-annual variation in 48 out of the 6347 Swedish waters. We observed that inter-annual a 420 variation is strongly driven by precipitation that controls the water flushing through the landscape. Using the predicted worst case climate scenario for Sweden until 2030, i.e., a 32 % precipitation increase, and assuming a 10 % increase in imports of colored substances into headwaters but no change in land-cover, we predict that a 420 in the 6347 lakes and streams will, in the worst case, increase by factors between 1.1 and 7.6 with a median of 1.3. This increase implies that a 420 will rise from the present 0.1-86 m −1 (median: 7.3 m ), which can cause problems for the preparation of drinking water in a variety of waters. Our model approach clearly demonstrates that a homogenous precipitation increase results in very heterogeneous a 420 changes, where lakes with a long-term mean landscape water retention time between 1 and 3 years are particularly vulnerable to climate change induced browning. Since these lake types are quite often used as drinking water resources, preparedness is needed for such waters.

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“…A study of 196 Swedish lakes along a latitudinal temperature gradient revealed that a 1 °C air temperature increase caused an up to 35 days earlier ice break-up in Sweden's warmest southern regions with annual mean air temperatures around 7 °C. It caused only about 5 days earlier break-up in Sweden's coldest northern regions where annual mean air temperatures are around − 2 °C (Weyhenmeyer et al, 2004;Weyhenmeyer, 2007). Ice break-up in Finland has also become significantly earlier from the late 19th century to the present time, except in the very north (Korhonen, 2006).…”

Section: Past Trendsmentioning

confidence: 99%