The catchment and climate regulation of pCO<sub>2</sub> in boreal lakes

Sobek, Sebastian; Algesten, Grete; Bergström, Ann‐Kristin; Jansson, Mats; Tranvik, Lars J.

doi:10.1046/j.1365-2486.2003.00619.x

Cited by 340 publications

(346 citation statements)

References 59 publications

(84 reference statements)

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“…In this study, significant correlations between DOC concentrations and this ratio were obtained only when the natural lakes were plotted with the wood harvested systems (Lake Bouleau excluded), suggesting that DOC concentrations are more closely linked to the additional inputs of allochthonous OM caused by increased erosion and OM leaching in the wood harvested systems rather than to natural OM inputs from a large watershed [Sobek et al, 2003].…”

Section: Using Water Chemistry and Bulk Analyses To Study Carbon Cyclmentioning

confidence: 65%

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

et al. 2012

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[1] Most natural freshwater lakes are net greenhouse gas (GHG) emitters. Compared to natural systems, human perturbations such as watershed wood harvesting and long-term reservoir impoundment lead to profound alterations of biogeochemical processes involved in the aquatic cycle of carbon (C). We exploited these anthropogenic alterations to describe the C dynamics in five lakes and two reservoirs from the boreal forest through the analysis of dissolved carbon dioxide (CO 2 ), methane (CH 4 ), oxygen (O 2 ), and organic carbon (DOC), as well as total nitrogen and phosphorus. Dissolved and particulate organic matter, forest soil/litter and leachates, as well as dissolved inorganic carbon were analyzed for elemental and stable isotopic compositions (atomic C:N ratios, d 13 C org , d 13 C inorg and d 15 N tot ). We found links between the export of terrestrial organic matter (OM) to these systems and the dissolved CO 2 and O 2 concentrations in the water column, as well as CO 2 fluxes to the atmosphere. All systems were GHG emitters, with greater emissions measured for systems with larger inputs of terrestrial OM. The differences in CO 2 concentrations and fluxes appear controlled by bacterial activity in the water column and the sediment. Although we clearly observed differences in the aquatic C cycle between natural and perturbed systems, more work on a larger number of water bodies and encompassing all four seasons should be undertaken to better understand the controls, rates, and spatial as well as temporal variability of GHG emissions, and to make quantitatively meaningful comparisons of GHG emissions (and other key variables) from natural and perturbed systems.

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Section: Using Water Chemistry and Bulk Analyses To Study Carbon Cyclmentioning

confidence: 65%

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

et al. 2012

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“…The first is that cells are transported from the drainage area to the lake and thereby influence the composition of the community by displacement of other cells. The second possible explanation is that the water flowing from the drainage area influences the character of the lake water, e.g., in the amount and character of the dissolved organic carbon (Sobek et al 2003), which in turn, being an important substrate for the bacteria, selects a certain composition of the bacterial community. Discriminant analysis was used as a means to investigate which environmental factors statistically best explain the lake categories we defined.…”

Section: Materials and Methods-study Sites And Samplingmentioning

confidence: 99%

External control of bacterial community structure in lakes

et al. 2006

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Abstract-We investigated the importance of a regional factor for bacterial communities in lakes. External factors dominated the control of community structures in lakes with retention times up to 200 d, most likely as a result of bacterial import. Because these lakes are numerous in the boreal zone, regional processes can be of great importance for bacterial communities in general. Consequently, we propose that lakes function more like flow through systems, as opposed to the classical ''lake as microcosm '' concept. During the last decade, our knowledge about the diversity of bacteria in nature has increased enormously; however, little is understood about which factors are shaping bacterial communities (DeLong and Pace 2001;Zwart et al. 2002). Central to understanding patterns in community structure is knowledge about the relative importance of local versus regional processes (Chase 2003;Cottenie and De Meester 2004). It can be assumed that the degree of isolation, and thereby the rate of exchange of cells and genes between communities, should have consequences for which forces shape local microbial communities (Curtis and Sloan 2004;Papke and Ward 2004). In nature, a gradient in isolation of communities should exist from endosymbionts to those exhibiting a cosmopolitan distribution (Papke and Ward 2004).Early on, lakes and their ecosystems were assigned as isolated units in the ''lake as microcosm '' concept (Forbes 1887). This view of the lake was later revised, for instance, because of the discovery of the importance of allochthonous carbon for lake ecosystem function (Hessen and Tranvik 1998;Pace et al. 2004). Thus, lakes today are more often ecologically regarded as a part of a larger unit, i.e., the drainage basin (Soranno et al. 1999). Still, efforts in lake microbial ecology and diversity have largely focused on within-lake selective forces, rather than external influences on community structure and diversity, although it has been shown that lake (Crump et al. 2003;Masin et al. 2003; Lindström and Bergström 2004) and estuarine (Crump et al. 2004) community compositions can be largely influenced by inflowing bacteria. It can be assumed that the degree of isolation a lake bacterioplankton community experiences, and thereby the degree of influence by inflowing bacteria on local community structure, depends on the hydrological retention time of the lakes. Therefore, we used a range of lakes of different hydrological retention times to determine the magnitude of external influence on bacterial community structure in lakes. Our hypothesis was that lakes with short hydrological retention time should have bacterial communities that are more similar to those of the inflowing water than lakes with longer hydrological retention times because of the larger amount of imported bacteria to the former type of lake. Twelve relatively unproductive Swedish lakes with different hydrological retention times were studied (Table 1). We used denaturing gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified...

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“…Consideration of lakes as an important component of the terrestrial carbon (C) cycle has focused primarily on their processing of externally derived dissolved organic carbon (DOC) [1][2][3]. At high DOC loading, lakes are often heterotrophic (net ecosystem respiration is greater than primary productivity), which results in a net efflux of CO 2 to the atmosphere [4].…”

Section: Introductionmentioning

confidence: 99%

Land-use change, not climate, controls organic carbon burial in lakes

2013

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Lakes are a central component of the carbon cycle, both mineralizing terrestrially derived organic matter and storing substantial amounts of organic carbon (OC) in their sediments. However, the rates and controls on OC burial by lakes remain uncertain, as do the possible effects of future global change processes. To address these issues, we derived OC burial rates in 210 Pb-dated sediment cores from 116 small Minnesota lakes that cover major climate and land-use gradients. Rates for individual lakes presently range from 7 to 127 g C m -2 yr -1 and have increased by up to a factor of 8 since Euro-American settlement (mean increase: 2.8Â). Mean pre-disturbance OC burial rates were similar (14-22 g C m -2 yr -1 ) across all land-cover categories ( prairie, mixed deciduous and boreal forest), indicating minimal effect of the regional temperature gradient (approx. 48C) on background carbon burial. The relationship between modern OC burial rates and temperature was also not significant after removal of the effect of total phosphorus. Contemporary burial rates were strongly correlated with lake-water nutrients and the extent of agricultural land cover in the catchment. Increased OC burial, documented even in relatively undisturbed boreal lake ecosystems, indicates a possible role for atmospheric nitrogen deposition. Our results suggest that globally, future land-cover change, intensification of agriculture and associated nutrient loading together with atmospheric N-deposition will enhance OC sequestration by lakes.

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The catchment and climate regulation of pCO₂ in boreal lakes

Cited by 340 publications

References 59 publications

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

External control of bacterial community structure in lakes

Land-use change, not climate, controls organic carbon burial in lakes

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The catchment and climate regulation of pCO2 in boreal lakes

Cited by 340 publications

References 59 publications

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

Assessing carbon dynamics in natural and perturbed boreal aquatic systems

External control of bacterial community structure in lakes

Land-use change, not climate, controls organic carbon burial in lakes

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The catchment and climate regulation of pCO₂ in boreal lakes