Linkages between weather, dissolved organic carbon, and cold-water habitat in a Boreal Shield lake recovering from acidification

2005 ◽  
Vol 62 (2) ◽  
pp. 341-347 ◽  
Author(s):  
W. (Bill) Keller ◽  
Jocelyne Heneberry ◽  
Julie Leduc
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Cold Water ◽  
Thermal Structure ◽  
Late Summer ◽  
Multiple Regression Model ◽  
Interannual Variations ◽  
Doc Concentration ◽  
Boreal Shield

To investigate potential effects of climate change on lake thermal structure, we examined relationships between the amount of cold-water habitat in late summer (defined as the 10 °C depth), summer weather, and dissolved organic carbon (DOC) concentration over a two-decade period (1981–2002) in a small Boreal Shield lake recovering from acidification. DOC concentration, wind-days (the product of mean daily wind speed and the number of days between ice-out and late-summer stratification), and mean daily temperature were significant predictors of the 10 °C depth in a multiple-regression model. A similar model using simply the number of ice-free days instead of wind-days was almost as effective. The models were quite successful in explaining interannual variations in the 10 °C depth when tested on a chemically and morphometrically similar nearby lake. While factors related to summer weather were important in explaining interannual variations in the amount of late-summer cold-water habitat, increased DOC concentration over the study period largely explained observed long-term decreases in the 10 °C depth (increases in cold-water habitat). DOC concentration was positively correlated with pH. In acidified regions, increases in DOC that accompany the recovery of acidified lakes will need to be considered in assessments of potential climate-change effects on lake thermal structure.

scholarly journals Stable Water Isotope Assessment of Tundra Wetland Hydrology as a Potential Source of Arctic Riverine Dissolved Organic Carbon in the Indigirka River Lowland, Northeastern Siberia

2021 ◽  
Vol 9 ◽  
Author(s):  
Shinya Takano ◽  
Youhei Yamashita ◽  
Shunsuke Tei ◽  
Maochang Liang ◽  
Ryo Shingubara ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Late Summer ◽  
Wetland Hydrology ◽  
Temporal Variations ◽  
The Arctic ◽  
Stable Water Isotopes ◽  
River Level ◽  
Northeastern Siberia ◽  
Doc Concentration

Arctic tundra wetlands may be an important source of dissolved organic carbon (DOC) in Arctic rivers and the Arctic Ocean under global warming. We investigated stable water isotopes and DOC concentration in wetlands, tributaries, and the mainstream at the lower reaches of the Indigirka River in northeastern Siberia during the summers of 2010–2014 to assess the complex hydrology and role of wetlands as sources of riverine DOC. The wetlands had higher values of δ18O and DOC concentration than the tributaries and mainstream of the Indigirka River. A relationship between the two parameters was observed in the wetlands, tributaries, and mainstream, suggesting the wetlands can be a source of DOC for the mainstream through the tributaries. The combined temporal variations in riverine δ18O and DOC concentration indicate the mainstream water flowed into the tributaries during relatively high river-level periods in summer, whereas high DOC water in the downstream wetlands could be discharged to the mainstream through the tributaries during the low river-level periods. A minor fraction (7–13%) of riverine and wetland DOC was degraded during 40 days of dark incubation. Overall, the downstream wetlands potentially provide relatively less biodegradable DOC to the Arctic river and costal ecosystem during the low river-level periods—from late summer to autumn.

scholarly journals First pan-Arctic assessment of dissolved organic carbon in lakes of the permafrost region

2021 ◽  
Vol 18 (12) ◽  
pp. 3917-3936
Author(s):  
Lydia Stolpmann ◽  
Caroline Coch ◽  
Anne Morgenstern ◽  
Julia Boike ◽  
Michael Fritz ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Cycle ◽  
Dissolved Organic Carbon ◽  
Significant Relationship ◽  
Global Carbon Cycle ◽  
Doc Concentration ◽  
Global Carbon ◽  
Permafrost Regions

Abstract. Lakes in permafrost regions are dynamic landscape components and play an important role for climate change feedbacks. Lake processes such as mineralization and flocculation of dissolved organic carbon (DOC), one of the main carbon fractions in lakes, contribute to the greenhouse effect and are part of the global carbon cycle. These processes are in the focus of climate research, but studies so far are limited to specific study regions. In our synthesis, we analyzed 2167 water samples from 1833 lakes across the Arctic in permafrost regions of Alaska, Canada, Greenland, and Siberia to provide first pan-Arctic insights for linkages between DOC concentrations and the environment. Using published data and unpublished datasets from the author team, we report regional DOC differences linked to latitude, permafrost zones, ecoregions, geology, near-surface soil organic carbon contents, and ground ice classification of each lake region. The lake DOC concentrations in our dataset range from 0 to 1130 mg L−1 (10.8 mg L−1 median DOC concentration). Regarding the permafrost regions of our synthesis, we found median lake DOC concentrations of 12.4 mg L−1 (Siberia), 12.3 mg L−1 (Alaska), 10.3 mg L−1 (Greenland), and 4.5 mg L−1 (Canada). Our synthesis shows a significant relationship between lake DOC concentration and lake ecoregion. We found higher lake DOC concentrations at boreal permafrost sites compared to tundra sites. We found significantly higher DOC concentrations in lakes in regions with ice-rich syngenetic permafrost deposits (yedoma) compared to non-yedoma lakes and a weak but significant relationship between soil organic carbon content and lake DOC concentration as well as between ground ice content and lake DOC. Our pan-Arctic dataset shows that the DOC concentration of a lake depends on its environmental properties, especially on permafrost extent and ecoregion, as well as vegetation, which is the most important driver of lake DOC in this study. This new dataset will be fundamental to quantify a pan-Arctic lake DOC pool for estimations of the impact of lake DOC on the global carbon cycle and climate change.

A long-term simulation of the effects of acidic deposition and climate change on surface water dissolved organic carbon concentrations in a boreal catchment

2009 ◽  
Vol 40 (2-3) ◽  
pp. 291-305 ◽  
Author(s):  
M. N. Futter ◽  
M. Forsius ◽  
M. Holmberg ◽  
M. Starr
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Monitoring And Evaluation ◽  
Doc Concentration ◽  
Emissions Scenarios ◽  
Carbon Concentrations ◽  
Headwater Catchment

Concentrations of dissolved organic carbon (DOC) are increasing in many surface waters across Europe. Two of the main mechanisms proposed to explain this increase are declines in sulfate (SO42−) deposition and changes in climate. Many of the reductions in SO42− have already occurred; climate change related effects are occurring now and will continue in the future. This paper presents the first application of a new version of INCA-C, the Integrated Catchments model for Carbon, which simulates the effects of both climate and SO42− deposition on surface water DOC concentration ([DOC]). The model was applied to Valkea-Kotinen, a small headwater catchment in Finland, where it was able to simulate present-day (1990–2007) trends in [DOC] in the lake and catchment outflow as functions of observed climate and European Monitoring and Evaluation Programme (EMEP)-modelled SO42− deposition. Using a parameter set derived from a present-day calibration, the model was run with two climate scenarios from the Special Report on Emissions Scenarios (SRES) and three EMEP deposition scenarios to simulate surface water [DOC] between 1960 and 2100. The results show that much of the historical increase in [DOC] can be explained as a result of historical declines in SO42− deposition and that surface water [DOC] will continue to increase as climate changes.

scholarly journals First Pan-Arctic Assessment of Dissolved Organic Carbon in Permafrost-Region Lakes

2020 ◽  
Author(s):  
Lydia Stolpmann ◽  
Caroline Coch ◽  
Anne Morgenstern ◽  
Julia Boike ◽  
Michael Fritz ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Significant Relationship ◽  
Global Carbon Cycle ◽  
Doc Concentration ◽  
Relationship Of ◽  
Global Carbon ◽  
Permafrost Regions

Abstract. Lakes in permafrost regions are dynamic landscape components and play an important role for climate change feedbacks. Lake processes such as mineralization and flocculation of dissolved organic carbon (DOC), one of the main carbon fractions in lakes, contribute to the greenhouse effect and are part of the global carbon cycle. These processes are in focus of climate research but studies so far are limited to specific study regions. In our synthesis, we analysed 2,167 water samples from 1,833 lakes across the Arctic in permafrost regions of Alaska, Canada, Greenland, and Siberia to provide first pan-Arctic insights for linkages between DOC concentrations and the environment. Using published data and unpublished datasets from the author team we report regional DOC differences linked to latitude, permafrost zones, ecoregions, geology, near-surface soil organic carbon contents, and ground ice classification of each lake region. The lake DOC concentrations in our dataset range from 0 mg L−1 to 1,130 mg L−1 (10.8 mg L−1 median DOC concentration). Regarding the permafrost regions of our synthesis, we found median lake DOC concentrations of 12.4 mg L−1 (Siberia), 12.3 mg L−1 (Alaska), 10.3 mg L−1 (Greenland), and 4.5 mg L−1 (Canada). Our synthesis shows a significant relationship of lake DOC concentration and ecoregion of the lake. We found higher lake DOC concentrations in boreal permafrost sites compared to tundra sites. About 22 % of the lakes in our extensive dataset are located in regions with ice-rich syngenetic permafrost deposits (yedoma). Yedoma contains large amounts of easily erodible organic carbon and we found significantly higher DOC concentrations in yedoma lakes compared to non-yedoma lakes. Compared to previous studies we found a weak significant relationship of soil organic carbon content and lake DOC concentration as well as between ground-ice content and lake DOC. Our pan-Arctic dataset shows that the DOC concentration of a lake strongly depends on its environmental properties, especially on permafrost extent and ecoregion, as well as vegetation, which is the most important driver of lake DOC in this study. This new dataset will be fundamental to quantify a pan-Arctic lake DOC pool for estimations of the impact of lake DOC on the global carbon cycle and climate change.

Effect of pH and Dissolved Organic Carbon on the Toxicity of Copper to Larval Fathead Minnow (Pimephales promelas) in Natural Lake Waters of Low Alkalinity

1993 ◽  
Vol 50 (7) ◽  
pp. 1356-1362 ◽  
Author(s):  
P. G. Welsh ◽  
J. F. Skidmore ◽  
D. J. Spry ◽  
D. G. Dixon ◽  
P. V. Hodson ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Fathead Minnow ◽  
Pimephales Promelas ◽  
Multiple Regression Model ◽  
Aquatic Life ◽  
South Central ◽  
Doc Concentration ◽  
Current Water ◽  
Ph Range

The impacts of pH and dissolved organic carbon (DOC) on the acute toxicity of Cu to larval fathead minnow (Pimephales promelas) were determined using natural soft water from two Precambrian Shield lakes in south-central Ontario. By artificially manipulating the pH and DOC levels of the water, we demonstrated that both acidification and the removal of DOC increased the toxicity of Cu. The 96-h Cu LC50s were determined over a pH range from 5.4 to 7.3 and a DOC concentration range from 0.2 to 16 mg∙L−1. The LC50s ranged from a low of 2 μg∙L−1 (pH 5.6, DOC 0.2 mg∙L−1) to a high of 182 μg∙L−1 (pH 6.9, DOC 15.6 mg∙L−1). A multiple regression model (log1096-h Cu LC50 = −0.308 + 0.192 pH + 0.136 (pH∙log10DOC)) was used to describe the relationship between Cu toxicity, pH, and DOC. The model was significant (p < 0.00001) and explained 93% of the variability in the toxicity data. These results suggest that current water quality objectives for Cu, and possibly for other metals, may not be sufficiently protective of aquatic life in soft, moderately acidic water containing low levels of DOC.

Climate change effects on peatland decomposition and porewater dissolved organic carbon biogeochemistry

2016 ◽  
Vol 128 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Catherine M. Dieleman ◽  
Zoë Lindo ◽  
James W. McLaughlin ◽  
Aaron E. Craig ◽  
Brian A. Branfireun
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Climate Change Effects ◽  
Carbon Biogeochemistry

scholarly journals Three representative UK moorland soils show differences in decadal release of dissolved organic carbon in response to environmental change

2011 ◽  
Vol 8 (12) ◽  
pp. 3661-3675 ◽  
Author(s):  
M. I. Stutter ◽  
D. G. Lumsdon ◽  
A. P. Rowland
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Environmental Change ◽  
Soil Properties ◽  
Process Models ◽  
Environmental Drivers ◽  
Specific Response ◽  
Soil C ◽  
Doc Concentration ◽  
Mineral Soils

Abstract. Moorland carbon reserves in organo-mineral soils may be crucial to predicting landscape-scale variability in soil carbon losses, an important component of which is dissolved organic carbon (DOC). Surface water DOC trends are subject to a range of scaling, transport and biotic processes that disconnect them from signals in the catchment's soils. Long-term soil datasets are vital to identify changes in DOC release at source and soil C depletion. Here we show, that moorland soil solution DOC concentrations at three key UK Environmental Change Network sites increased between 1993–2007 in both surface- and sub- soil of a freely-draining Podzol (48 % and 215 % increases in O and Bs horizons, respectively), declined in a gleyed Podzol and showed no change in a Peat. Our principal findings were that: (1) considerable heterogeneity in DOC response appears to exist between different soils that is not apparent from the more consistent observed trends for streamwaters, and (2) freely-draining organo-mineral Podzol showed increasing DOC concentrations, countering the current scientific focus on soil C destabilization in peats. We discuss how the key solubility controls on DOC associated with coupled physico-chemical factors of ionic strength, acid deposition recovery, soil hydrology and temperature cannot readily be separated. Yet, despite evidence that all sites are recovering from acidification the soil-specific responses to environmental change have caused divergence in soil DOC concentration trends. The study shows that the properties of soils govern their specific response to an approximately common set of broad environmental drivers. Key soil properties are indicated to be drainage, sulphate and DOC sorption capacity. Soil properties need representation in process-models to understand and predict the role of soils in catchment to global C budgets. Catchment hydrological (i.e. transport) controls may, at present, be governing the more ubiquitous rises in river DOC concentration trends, but soil (i.e. source) controls provide the key to prediction of future C loss to waters and the atmosphere.

scholarly journals The effect of dissolved organic carbon on pelagial and near-sediment water traits in lakes

2011 ◽  
Vol 74 (2) ◽  
pp. 133-139 ◽  
Author(s):  
Krzysztof Banaś
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Redox Potential ◽  
Environmental Conditions ◽  
Calcium Concentration ◽  
Total Hardness ◽  
Sediment Layer ◽  
Ph Values ◽  
Doc Concentration ◽  
Good Transparency

The effect of dissolved organic carbon (DOC) on the environmental conditions of macrophytes has been studied in 35 lakes divided into soft- and hardwater: oligohumic (&lt;4.0 mg C dm<sup>-3</sup>), α-mesohumic (4.0-8.0 mg C dm<sup>-3</sup>), β-mesohumic (8.1-16.0 mg C dm<sup>-3</sup>) and polihumic (&gt;16.0 mg C dm<sup>-3</sup>). The optimum environmental conditions for macrophytes have been found in oligohumic lakes, characterised by low water colour and its good transparency. In soft- and hardwater lakes increasing concentration of DOC is accompanied with an increase in the colour (r=0.95), while the visibility decreases. With increasing DOC in the near-sediment layer the pH values decrease while the concentration of nitrogen increases and the concentration of phosphorus slightly increases. In hardwater lakes with increasing DOC concentration, the redox potential, conductivity, total hardness and calcium concentration in the near-sediment water decrease, whereas the content of CO<sup>2</sup> remains at a very low level.

Humic Colloid Generation of Transuranic Elements in Groundwater and Their Migration Behaviour

1986 ◽  
Vol 84 ◽  
Author(s):  
J.I. Kim ◽  
G. Buckau ◽  
W. Zhuang
Keyword(s):  
Heavy Metal ◽  
Humic Acid ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Metal Ions ◽  
Fulvic Acid ◽  
Photoacoustic Spectroscopy ◽  
Heavy Metal Ions ◽  
Colloidal Form ◽  
Doc Concentration

AbstractThe generation of humic colloids of Am(III) has been investigated in Gorleben groundwaters containing different amounts of humic substances. Dissolved organic carbon (DOC) in these groundwaters consists mainly of humic acid and fulvic acid, which is present in a colloidal form through aggregation with trace heavy metal ions of groundwater constituents. Concentrations of these heavy metal ions are proportional to the DOC concentration. The generation of Am(III) pseudocolloids through geochemical interactions with humic colloids in different groundwaters is quantified by ultrafiltration as well as ultracentrifugation by the aid of radiometric concentration measurements. The speciation of dissolved Am(III) species in groundwaters is carried out by laser induced photoacoustic spectroscopy (LPAS).

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