Recent trends in chemical composition of bulk precipitation at Estonian monitoring stations 1994–2001

Treier, K.; Pajuste, K.; Frey, Jane

doi:10.1016/j.atmosenv.2004.05.061

Cited by 14 publications

(17 citation statements)

References 6 publications

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“…However, the rising trend of TOC is in accordance with the suggested dependence on the amount of precipitation, discharge [6,7] and the observed and modelled increase in the number of drought days [8][9][10][11][12]. The trend may also be caused by changes in atmospheric deposition chemistry [15,18], and probably demonstrates a complex positive feedback in the global carbon cycle [2,3,17].…”

Section: Discussionsupporting

confidence: 54%

“…The monitoring programme was divided geographically between four projects: northern, northeastern, southern and southwestern Estonia (Figure 1). Studied catchments in northern (1-9), northeastern (10-15), southern (16)(17)(18)(19)(20) and southwestern Estonia (21). Grey line indicates the border between northern catchments and the rest of studied area.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, Roulet and Moore argue that the export of DOC is probably determined by multiple related geochemical factors [17]. In Estonia, the post-Soviet re-organisation of industry lead to a great decrease in the atmospheric deposition of SO 4 2-and nitrogen compounds in the 1990s [18].…”

Section: Dependence Of Doc On Geochemistrymentioning

confidence: 99%

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Dynamics of concentrations of total organic carbon in Estonian streams, 1992–2007

Pärn

Randmaa

Mander

2009

WIT Transactions on Ecology and the Environment

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Human activities have begun to transform northern peatlands into global sources of dissolved organic carbon (DOC). In Estonia, there are 10,091 km 2 of peatlands, constituting 22.3% of the country's total area. The increasing number of drought days during the last 50 years, which constitutes a threat of an increased flux of dissolved carbon, has also been observed in Estonia. The aim of the current study was to explain organic carbon trends in Estonian streams during the period 1992-2007. The national environmental monitoring programme initiated the measurement of total organic carbon (TOC) in Estonian streams in 1998. We reconstructed the earlier concentrations of TOC through the link with permanganate oxygen consumed (POC). The TOC and POC data of 64 weirs was studied. The determination coefficients between TOC and POC were over 0.75 for the nine North Estonian streams (Kasari, Vihterpalu, Vääna, Keila, Pirita, Jägala, Pudisoo Valgejõgi and Loobu). The R 2 values in the rest of the sampled weirs were below 0.7. Likewise, the temporal trend of both TOC and POC data was insignificant. In northern Estonia, a weak but significant (R 2 =0.09, p<0.05) rising trend in TOC concentrations was observed. This may have resulted from the high percentage of peatlands and more calcareous soils in northern Estonian catchments. The trend corresponds with earlier data from northern catchments, being influenced by the effects of global warming and/or changes in the chemistry of atmospheric deposition, and demonstrating a complex positive feedback in the global C cycle.

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Section: Discussionsupporting

confidence: 54%

Section: Methodsmentioning

confidence: 99%

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Dynamics of concentrations of total organic carbon in Estonian streams, 1992–2007

Pärn

Randmaa

Mander

2009

WIT Transactions on Ecology and the Environment

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“…As there has also been a dramatic decrease in the deposition and agricultural input of nitrogen compounds in Estonia (Mander et al 1998;Treier et al 2004), further investigation is needed to clarify the impact of the soil chemistry on the increase in organic carbon exports (Findlay 2005;Evans et al 2006;Monteith et al 2007). One possible explanation could be the great sulphur supplies accumulated in the soil during the decades of air pollution.…”

Section: Discussionmentioning

confidence: 99%

“…The reduction in the atmospheric deposition of nitrogen compounds can affect soil chemistry in a similar manner (Findlay 2005). In Estonia, the post-Soviet re-organisation of industry that took place in the 1990s led to a great decrease in the atmospheric deposition of SO 4 2-and nitrogen compounds (Treier et al 2004), while nitrate fluxes from agriculture dramatically decreased as well (Mander et al 1998;Iital et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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

Pärn

Mander

2011

Biogeochemistry

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There are 10,091 km 2 of peatlands in Estonia and human activities may have changed the role of northern peatlands from global sinks to global sources of carbon. The aim of this work was to explain the changes in organic carbon exports from eleven Estonian rivers in the period 1992-2007 in terms of land use change, climate change quantified by trends in stream-water discharge and hydrological droughts and reductions in atmospheric sulfate quantified by change in water chemistry. Direct TOC (total organic carbon) measurements had been initiated in 1998. We used CODKMnO 4 (permanganate oxygen consumed) as its surrogate for the whole time span (Spearman's determination coefficient in six small northern Estonian rivers 0.95 [ q 2 [ 0.72; p \ 0.01). The Mann-Kendall test revealed significant trends in the TOC proxy in five small rivers in northern Estonia (M-K stat [ 2.35; p \ 0.05). The trends in the eleven investigated streams correlated closely with the increased 28 ratios of drought days (Spearman's q 2 = 0.68; p \ 0.01). The correlations with land use compositions, decreases in water discharges and SO 4 2-concentrations were insignificant (p [ 0.05). We conclude that the main factor in the increase of organic carbon export is the deepening of droughts driven by climate change, magnified by man-made drainage.

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Interactions of Atmospheric Deposition with Coniferous Canopies in Estonia

Pajuste

Frey

Asi³

2006

Environ Monit Assess

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Throughfall and open field bulk precipitation were measured at three coniferous sites during 1995-2002 in the framework of ICP Integrated Monitoring and at five coniferous sites during 1996-2002 in the framework of ICP Forests (Level II). The coniferous canopies acted as a sink for nitrate and ammonium and as a source for base cations: Ca(2+), Mg(2+) and K(+). The estimated share of SO(4)-S dry deposition from total deposition was 1.5-4 times higher for dormant period compared to growing period. During the study period average annual throughfall and bulk deposition of SO(4)-S decreased significantly, 2.8 and 2.3 times, respectively. Throughfall enrichment with base cations increased in the order Mg < Na < Ca < K. Using Na as a tracer ion, average dry deposition and canopy leaching were calculated. Leaching was the dominant process for TF enrichment by potassium. Leaching of base cations occurred during growing as well as dormant period. The calculated internal flux of Ca(2+) and Mg(2+) varied in the range of 0.6-2.0 and 0.6-1.2 kg ha(-1) per year in spruce and pine stands, respectively. The internal circulation of K(+) was significantly higher (8.9-10.9 kg ha(-1) per year) in spruce stands than in pine stands (2.7-4.4 kg ha(-1) per year).

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Recent trends in chemical composition of bulk precipitation at Estonian monitoring stations 1994–2001

Cited by 14 publications

References 6 publications

Dynamics of concentrations of total organic carbon in Estonian streams, 1992–2007

Dynamics of concentrations of total organic carbon in Estonian streams, 1992–2007

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

Interactions of Atmospheric Deposition with Coniferous Canopies in Estonia

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