Increased organic carbon concentrations in Estonian rivers in the period 1992–2007 as affected by deepening droughts

Pärn, Jaan; Mander, Ülo

doi:10.1007/s10533-011-9604-0

Cited by 24 publications

(21 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…During the 1900 s, drought frequency in Europe generally appears to have increased (Worrall et al , ; Pärn and Mander, ), although the temporal scale of this dynamic remains unclear. For example, an earlier onset of spring warming has already been noted during the 19th century in the southern part of the Baltic sea (Tarand and Nordli, 2001), implying better conditions for the development of water deficit in forest fuels during the fire season.…”

Section: Discussionmentioning

confidence: 99%

A 700-year record of large fire years in northern Scandinavia shows large variability and increased frequency during the 1800 s

et al. 2015

View full text Add to dashboard Cite

Years with climatically mediated increases in boreal forest fire activity, referred to as large fire years (LFYs), contribute to a disproportionally large portion of the burned area over centuries, and are important drivers of ecosystem processes by affecting forest structure, biodiversity, and carbon balance at regional and continental scales. We analysed changes in LFY return intervals in northern Sweden (the area above 60 °N) over 1273–1960 using a network of 29 sites with dendrochronologically reconstructed fires, complemented by documentary records of fires available from forestry statistics. We observed large variability in return intervals of LFYs, an increase in LFY frequency during the 1800 s, and consistent associations between LFY occurrence and 500‐hPa pressure anomalies over the European sub‐continent over 1800xps2#1960. An increase in LFY frequency during the 1800 s might be climatically driven, and would thus long precede the period of likely human‐induced climatic changes of the 1900 s. Long‐term variability in climatically driven LFYs may present a challenge in partitioning the effects of human‐related and human‐independent components of climatic forcing upon forest fire activity.

show abstract

Section: Discussionmentioning

confidence: 99%

A 700-year record of large fire years in northern Scandinavia shows large variability and increased frequency during the 1800 s

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Concerning methodological issues, some studies follow tendencies directly in the surrogate parameter as such [26,60,61,65,72,77] but a common practice is to establish an empirical correlation between the parameter values and OC concentrations using data simultaneously measured over a short period of time [29,38,48,50,53,61] and discuss tendencies, causes, etc. in terms of OC concentrations.…”

Section: Organic Carbon Concentration Measurementsmentioning

confidence: 99%

“…Even extrapolating synchronous data between close systems seems questionable. For instance, Pärn and Mander showed that TOC and COD for rivers in Estonia, a small country, showed different Spearman's correlation coefficients depending on the area considered (much higher in the North than in the South) [26].…”

Section: Organic Carbon Concentration Measurementsmentioning

confidence: 99%

Long-term Trends of Organic Carbon Concentrations in Freshwaters: Strengths and Weaknesses of Existing Evidence

Filella

Rodríguez-Murillo

2014

Water

View full text Add to dashboard Cite

Many articles published in the last few years start with the assumption that the past decades have seen an increase in dissolved organic carbon (DOC) concentrations in the rivers and lakes of the Northern Hemisphere. This study analyses whether the existing evidence supports this claim. With this aim, we have collected published studies where long series of organic carbon concentrations (i.e., longer than 10 years) were analyzed for existing trends and have carefully evaluated the 63 articles found. Information has been collated in a comprehensive and comparable way, allowing readers to easily access it. The two main aspects considered in our analysis have been the analytical methods used and the data treatment methods applied. Both are sensitive issues because, on the one hand, the difficulties associated with correctly determining organic carbon concentrations in surface waters are well known, while, on the other, dealing with real environmental data (i.e., lack of normality, censoring, missing values, etc.) is an extremely intricate matter. Other issues such as data reporting and the geographical location of the systems studied are also discussed. In conclusion, it is clear that organic carbon concentrations have increased in some surface waters in the Northern Hemisphere since the 1990s. However, due to a lack of data in many parts of the world, it is not known whether this phenomenon is general and, more importantly, in the areas for which such data do exist, the reporting and methodological problems in the published studies prevent any conclusion on the existence of a general temporal behavior of organic carbon from being drawn.

show abstract

“…It has been hypothesized that this “browning” trend may be associated with drivers of global change, including altered land-use [12], precipitation patterns [13], temperatures [14], and atmospheric deposition [15]. Regardless of the controlling factors, there is considerable uncertainty about how aquatic ecosystems will respond to increasing inputs of terrestrial DOC [16].…”

Section: Introductionmentioning

confidence: 99%

A Source of Terrestrial Organic Carbon to Investigate the Browning of Aquatic Ecosystems

et al. 2013

View full text Add to dashboard Cite

There is growing evidence that terrestrial ecosystems are exporting more dissolved organic carbon (DOC) to aquatic ecosystems than they did just a few decades ago. This “browning” phenomenon will alter the chemistry, physics, and biology of inland water bodies in complex and difficult-to-predict ways. Experiments provide an opportunity to elucidate how browning will affect the stability and functioning of aquatic ecosystems. However, it is challenging to obtain sources of DOC that can be used for manipulations at ecologically relevant scales. In this study, we evaluated a commercially available source of humic substances (“Super Hume”) as an analog for natural sources of terrestrial DOC. Based on chemical characterizations, comparative surveys, and whole-ecosystem manipulations, we found that the physical and chemical properties of Super Hume are similar to those of natural DOC in aquatic and terrestrial ecosystems. For example, Super Hume attenuated solar radiation in ways that will not only influence the physiology of aquatic taxa but also the metabolism of entire ecosystems. Based on its chemical properties (high lignin content, high quinone content, and low C:N and C:P ratios), Super Hume is a fairly recalcitrant, low-quality resource for aquatic consumers. Nevertheless, we demonstrate that Super Hume can subsidize aquatic food webs through 1) the uptake of dissolved organic constituents by microorganisms, and 2) the consumption of particulate fractions by larger organisms (i.e., Daphnia). After discussing some of the caveats of Super Hume, we conclude that commercial sources of humic substances can be used to help address pressing ecological questions concerning the increased export of terrestrial DOC to aquatic ecosystems.

show abstract

Increased organic carbon concentrations in Estonian rivers in the period 1992–2007 as affected by deepening droughts

Cited by 24 publications

References 33 publications

A 700-year record of large fire years in northern Scandinavia shows large variability and increased frequency during the 1800 s

A 700-year record of large fire years in northern Scandinavia shows large variability and increased frequency during the 1800 s

Long-term Trends of Organic Carbon Concentrations in Freshwaters: Strengths and Weaknesses of Existing Evidence

A Source of Terrestrial Organic Carbon to Investigate the Browning of Aquatic Ecosystems

Contact Info

Product

Resources

About