Simple Models to Estimate Historical and Recent Changes of Total Organic Carbon Concentrations in Lakes

Valinia, Salar; Bishop, Kevin; Cosby, B. J.; Rosén, Peter; Fölster, Jens

doi:10.1021/es503170r

Cited by 19 publications

(17 citation statements)

References 57 publications

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“…What are the historic pre-industrial pristine conditions we are referring to? As an example, Valinia et al (2015) show that most Swedish lakes are now recovered to the same TOC concentrations as in 1860. However, Meyer-Jacob et al (2015) point out that decreasing concentrations of organic carbon in Swedish lakes started already in the years 1450-1600 as a response to land use changes and thus present concentrations are far away from pristine conditions.…”

Section: Discussionmentioning

confidence: 91%

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Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions

Musolff

Selle

Büttner

et al. 2016

Global Change Biology

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Reductions in emissions have successfully led to a regional decline in atmospheric nitrogen depositions over the past 20 years. By analyzing long-term data from 110 mountainous streams draining into German drinking water reservoirs, nitrate concentrations indeed declined in the majority of catchments. Furthermore, our meta-analysis indicates that the declining nitrate levels are linked to the release of dissolved iron to streams likely due to a reductive dissolution of iron(III) minerals in riparian wetland soils. This dissolution process mobilized adsorbed compounds, such as phosphate, dissolved organic carbon and arsenic, resulting in concentration increases in the streams and higher inputs to receiving drinking water reservoirs. Reductive mobilization was most significant in catchments with stream nitrate concentrations <6 mg L . Here, nitrate, as a competing electron acceptor, was too low in concentration to inhibit microbial iron(III) reduction. Consequently, observed trends were strongest in forested catchments, where nitrate concentrations were unaffected by agricultural and urban sources and which were therefore sensitive to reductions of atmospheric nitrogen depositions. We conclude that there is strong evidence that the decline in nitrogen deposition toward pre-industrial conditions lowers the redox buffer in riparian soils, destabilizing formerly fixed problematic compounds, and results in serious implications for water quality.

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Section: Discussionmentioning

confidence: 91%

“…As an example, Valinia et al . () show that most Swedish lakes are now recovered to the same TOC concentrations as in 1860. However, Meyer‐Jacob et al .…”

Section: Resultsmentioning

confidence: 99%

Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions

Musolff

Selle

Büttner

et al. 2016

Global Change Biology

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“…Other studies suggest that declining rates of acid deposition may be the key driver behind the observed OC increase in surface waters. Decreasing sulfur deposition rates allow catchment soils to recover from acidification, where the resulting decrease in acidity and/or ionic strength of the soil solution may increase the solubility of soil organic matter (OM) and consequently OC leaching (4,16,17). Some studies have linked the OC rise to recent changes in land-use practices, such as the drainage and burning of peatlands (18, 19), or to changes in land cover (20).…”

mentioning

confidence: 99%

Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring

Meyer-Jacob

Tolu

Bigler

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Organic carbon concentrations have increased in surface waters across parts of Europe and North America during the past decades, but the main drivers causing this phenomenon are still debated. A lack of observations beyond the last few decades inhibits a better mechanistic understanding of this process and thus a reliable prediction of future changes. Here we present past lake-water organic carbon trends inferred from sediment records across central Sweden that allow us to assess the observed increase on a centennial to millennial time scale. Our data show the recent increase in lake-water carbon but also that this increase was preceded by a landscape-wide, long-term decrease beginning already A.D. 1450-1600. Geochemical and biological proxies reveal that these dynamics coincided with an intensification of human catchment disturbance that decreased over the past century. Catchment disturbance was driven by the expansion and later cessation of widespread summer forest grazing and farming across central Scandinavia. Our findings demonstrate that early land use strongly affected past organic carbon dynamics and suggest that the influence of historical landscape utilization on contemporary changes in lake-water carbon levels has thus far been underestimated. We propose that past changes in land use are also a strong contributing factor in ongoing organic carbon trends in other regions that underwent similar comprehensive changes due to early cultivation and grazing over centuries to millennia.lake-water quality | carbon cycling | land use | Holocene | paleoecology O ver the past three decades, monitoring programs have recorded a widespread increase of organic carbon (OC) concentrations in surface waters in parts of Europe and North America (1-4). OC in lakes and rivers plays a major role in the global carbon cycle by transporting carbon from terrestrial to freshwater and marine environments (5), determining drinking water quality and associated treatment costs (6), and affecting aquatic ecosystem functioning. In aquatic ecosystems, OC influences energy mobilization, light conditions (7), water acidity (8), as well as the transport of metals and pollutants (9). The widespread occurrence of this increase in surface water OC, also referred to as browning or brownification due to an associated increase in color, suggests that regional rather than local factors are the drivers behind this phenomenon, but at present the underlying mechanisms are still controversial.Several hypotheses have been proposed to explain this recent OC increase, from climate change to changes in anthropogenic forcing such as declining atmospheric acid deposition or alterations in landscape utilization. A number of climate-sensitive mechanisms have been suggested to cause an increase in OC export from the terrestrial to the aquatic environment; for example, increased temperatures enhance decomposition rates in organic-rich soils (10) and promote vegetation cover (11). Changes in the amount and timing of precipitation potentially lead to alteration...

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“…Lake Neden was heavily contaminated by acid rain during the 1980s and 1990s, and was subsequently treated with lime, as were most of the lakes in that area of southwestern Sweden. As a result, the organic matter concentration was suppressed temporarily but is currently recovering to its natural values, similar to many other lakes in the area [22]. In this area, it was observed that the water colour more than doubled during 2007-2012 [23].…”

Section: Raw Water Source Qualitymentioning

confidence: 56%

“…In this projection, it is assumed that the current character of DOC in the raw water sources from Lake Neden and the current groundwater well (i.e., SUVA) would not change over time, while a steady increase for DOC is defined with 0.05 mg L −1 per year in the surface water from Lake Neden. This low annual increase, in comparison with the other sites in the area [22], was chosen to account for the potential breakdown of terrestrial TOC during the five-year turnover time. In addition to this change in DOC, the effect of increasing the fraction of groundwater to raw water (i.e., 20% and 25%, instead of the current 15% contribution) was studied.…”

Section: Scenario Analysis and Evaluation Of Uf Performance During Comentioning

confidence: 99%

Combined Coagulation and Ultrafiltration Process to Counteract Increasing NOM in Brown Surface Water

Keucken

Heinicke

Persson

et al. 2017

Water

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Membrane hybrid processes-coagulation coupled with ultrafiltration (UF)-have become a common method to comply with the legal, chemical, and microbiological requirements for drinking water. The main advantages of integrating coagulation with membrane filtration are the enhanced removal of natural organic matter (NOM) and reduced membrane fouling. With in-line coagulation, coagulants are patched into the feed stream directly prior to the membrane process, without removing the coagulated solids. Compared with conventional coagulation/sedimentation, in-line coagulation/membrane reduces the treatment time and footprint. Coagulant dosing could be challenging in raw water of varying quality; however, with relatively stable specific ultraviolet absorbance (SUVA), dosing can be controlled. Recent studies indicate that UV absorbance correlates well with humic substances (HS), the major fraction to be removed during coagulation. This paper describes and evaluates a 30-month UF pilot trial on the surface water of Lake Neden (Sweden), providing drinking water to 60,000 residents. In this study, automatic coagulant dosing based on online measurement was successfully applied. Online sensor data were used to identify the current optimal aluminium coagulation conditions (0.5-0.7 mg L −1 ) and the potential boundaries (0.9-1.2 mg L −1 ) for efficient future (2040) NOM removal. The potential increase in NOM could affect the Al dose and drinking water quality significantly within 20 years, should the current trends in dissolved organic carbon (DOC) prevail. UV absorbance, the freshness index, and liquid chromatography-organic carbon detection (LC-OCD) measurements were used to optimise the process. Careful cross-calibration of raw and filtered samples is recommended when using online sensor data for process optimisation, even in low-turbidity water (formazin nephelometric unit (FNU) < 5).

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Simple Models to Estimate Historical and Recent Changes of Total Organic Carbon Concentrations in Lakes

Cited by 19 publications

References 57 publications

Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions

Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions

Early land use and centennial scale changes in lake-water organic carbon prior to contemporary monitoring

Combined Coagulation and Ultrafiltration Process to Counteract Increasing NOM in Brown Surface Water

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