scholarly journals Decoupled trophic responses to long‐term recovery from acidification and associated browning in lakes

2019 ◽  
Vol 25 (5) ◽  
pp. 1779-1792 ◽  
Author(s):  
Taylor H. Leach ◽  
Luke A. Winslow ◽  
Nicole M. Hayes ◽  
Kevin C. Rose
Keyword(s):  
Recovery From Acidification ◽  
Trophic Responses

scholarly journals Land use influences on acidification and recovery of freshwaters in Galloway, south-west Scotland

2001 ◽  
Vol 5 (3) ◽  
pp. 451-458 ◽  
Author(s):  
R. C. Helliwell ◽  
R. C. Ferrier ◽  
L. Johnston ◽  
J. Goodwin ◽  
R. Doughty
Keyword(s):  
Surface Waters ◽  
Chemical Recovery ◽  
Dry Period ◽  
Sulphur Deposition ◽  
South West ◽  
Recovery From Acidification ◽  
Long Term Trends ◽  
Acid Status ◽  
Annual Discharge

Abstract. The long term response of surface waters to changes in sulphur deposition and afforestation is investigated for three upland river systems in the Galloway region of south-west Scotland. From 1984-1999, these rivers exhibited a statistically significant decline in non-marine sulphate concentrations in response to reduced acid deposition. This reduction in non-marine sulphate was, however, insufficient to induce a pH recovery over the period. A statistically significant increase in river pH was observed between 1956-1970 (0.05 yr-1) when subsidised agricultural lime payments were at a maximum. In 1976, this subsidy ceased and surface waters have progressively acidified. In addition, climatic change is found to influence long-term trends in pH. Mean annual pH was greatest during a dry period between 1969-1973 when total annual discharge was low. Thereafter, pH declined gradually in response to higher rainfall and increased total annual discharge. Overall, surface waters draining the afforested catchments of the Rivers Cree and Bladnoch are more acid than those draining the moorland catchment of the Luce. These results indicate that in afforested catchments, current reductions in sulphur emissions have not led to an observed improvement in the acid status of surface waters. Forestry, therefore, represents a confounding factor with regard to chemical recovery from acidification in this region. Keywords: acidification, afforestation, deposition, rivers, lochs, non-marine sulphate, pH

scholarly journals Recovery from acidification of lochs in Galloway, south-west Scotland, UK: 1979-1998

2001 ◽  
Vol 5 (3) ◽  
pp. 421-432 ◽  
Author(s):  
R. C. Ferrier ◽  
R. C. Helliwell ◽  
B. J. Cosby ◽  
A. Jenkins ◽  
R. F. Wright
Keyword(s):  
General Pattern ◽  
Base Cations ◽  
Rapid Decline ◽  
Sea Salts ◽  
South West ◽  
Acid Neutralising Capacity ◽  
Sulphate Deposition ◽  
Recovery From Acidification ◽  
Chloride Concentrations

Abstract. The Galloway region of south-west Scotland has historically been subject to long-term deposition of acidic precipitation which has resulted in acidification of soils and surface waters and subsequent damage to aquatic ecology. Since the end of the 1970s, however, acidic deposition has decreased substantially. The general pattern is for a rapid decline in non-marine sulphate in rainwater over the period 1978-1988 followed by stable concentrations to the mid-1990s. Concentrations of nitrate and ammonium in deposition have remained constant between 1980 and 1998. Seven water quality surveys of 48 lochs in the Galloway region have been conducted between 1979 and 1998. During the first 10 years, from 1979, there was a major decline in regional sulphate concentrations in the lochs, which was expected to have produced a decline in base cations and an increase in the acid neutralising capacity. But sea-salt levels (as indicated by chloride concentrations) were approximately 25% higher in 1988 than in 1979 and thus short-term acidification due to sea-salts offset much of the long-term recovery trend expected in the lochs. During the next 10 years, however, the chloride concentrations returned to 1979 levels and the lochs showed large increases in acid neutralising capacity despite little change in sulphate concentrations. From the observed decline in sulphate deposition and concentrations of sulphate in the lochs, it appears that approximately 75% of the possible improvement in acid neutralising capacity has already occurred over the 20-year period (1979-1998). The role of acid deposition as a driving factor for change in water chemistry in the Galloway lochs is confounded by concurrent changes in other driving variables, most notably, factors related to episodic and year-to-year variations in climate. In addition to inputs of sea-salts, climate probably also influences other chemical signals such as peaks in regional nitrate concentrations and the sharp increase in dissolved organic carbon during the 1990s. Keywords: acidification, recovery, Galloway, sulphur, nitrogen

scholarly journals Elevated hydrostatic pressure activates sodium/hydrogen exchanger-1 in rat optic nerve head astrocytes

2009 ◽  
Vol 297 (1) ◽  
pp. C111-C120 ◽  
Author(s):  
Amritlal Mandal ◽  
Mohammad Shahidullah ◽  
Nicholas A. Delamere ◽  
Marcos A. Terán
Keyword(s):  
Optic Nerve ◽  
Hydrostatic Pressure ◽  
Protein Expression ◽  
Optic Nerve Head ◽  
Elevated Hydrostatic Pressure ◽  
Cultured Astrocytes ◽  
Sodium Hydrogen Exchanger ◽  
Recovery From Acidification ◽  
Nhe1 Activity

Optic nerve head astrocytes become abnormal in eyes that have elevated intraocular pressure, and cultured astrocytes display altered protein expression after being subjected for ≥1 days to elevated hydrostatic pressure. Here we show that 2-h elevated hydrostatic pressure (15 or 30 mmHg) causes phosphorylation of ERK1/2, ribosomal S6 protein kinase (p90RSK), and Na/H exchanger (NHE)1 in cultured rat optic nerve head astrocytes as judged by Western blot analysis. The MEK/ERK inhibitor U0126 abolished phosphorylation of NHE1 and p90RSK as well as ERK1/2. To examine NHE1 activity, cytoplasmic pH (pHi) was measured with BCECF and, in some experiments, cells were acidified by 5-min exposure to 20 mM ammonium chloride. Although baseline pHi was unaltered, the rate of pHi recovery from acidification was fourfold higher in pressure-treated astrocytes. In the presence of either U0126 or dimethylamiloride (DMA), an NHE inhibitor, hydrostatic pressure did not change the rate of pHi recovery. The findings are consistent with NHE1 activation due to phosphorylation of ERK1/2, p90RSK, and NHE1 that occurs in response to hydrostatic pressure. These responses may precede long-term changes of protein expression known to occur in pressure-stressed astrocytes.

scholarly journals Interpretation of trends in acidic deposition and surface water chemistry in Scotland during the past three decades

2001 ◽  
Vol 5 (3) ◽  
pp. 407-420 ◽  
Author(s):  
R. Harriman ◽  
A. W. Watt ◽  
A. E. G. Christie ◽  
P. Collen ◽  
D. W. Moore ◽  
...  
Keyword(s):  
Acidic Deposition ◽  
High Elevation ◽  
Ecological Condition ◽  
Sulphur Deposition ◽  
Surface Water Chemistry ◽  
The Past ◽  
Recovery From Acidification ◽  
Ionic Components ◽  
Carbon Concentrations

Abstract. Trends in major ionic components of bulk precipitation were analysed for two sites, Faskally and Loch Ard forest in Scotland, for the period 1972-2000. The pattern of change was not linear. Large reductions in sulphur deposition occurred in the early 1980s and, to a lesser extent, during 1995-2000, with a period of relative stability between 1988-95. pH increased significantly at both sites but nitrate and ammonia only increased significantly at Loch Ard forest. Long-term chemical data from a total of 37 streams and lochs in four selected regions of Scotland were analysed over three time periods (all available data (mostly 1978-2000), 1988-98 and 1995-2000) to match the deposition patterns. For the whole study period a significant decline in non-marine sulphate was found at all sites while the most consistent increases in pH and alkalinity were recorded at all the high elevation loch sites in the Galloway area. Significant reductions in toxic forms of aluminium were also recorded, mostly at sites where pH had increased. Nitrate trends were equivocal except for catchments with clear-felling operations. For these sites, negative trends were found where felling occurred in the 1980s, while positive trends were found at sites with felling in the 1990s. With the exception of one site, dissolved organic carbon concentrations increased significantly with moorland sites showing smaller increases than forested sites. Associated with this change was a significant increase in complexed forms of aluminium. Trends for the 1988-98 period were much smaller than those for the whole study period and in many cases were insignificant. This contrasts with the 1995-2000 period when large and significant reductions in sulphate and nitrate were recorded along with increases in marine salts, probably as a result of climatically related events. Qualitative, experimental and monitoring data from lochs in the Galloway area revealed evidence of recovery of fish populations. Interpretation of chemical and biological trends was clearly influenced by the choice of the time series, especially in relation to deposition and climatic changes. Nevertheless, all the fresh waters included in this study are currently in the best ecological condition since the 1970s in the context of recovery from acidification. Keywords: deposition, trends, acidification, forestry, recovery, fish, climate

Long-Term Trends in Stream Nitrate Concentrations and Losses Across Watersheds Undergoing Recovery from Acidification in the Czech Republic

Ecosystems ◽  
2008 ◽  
Vol 11 (3) ◽  
pp. 410-425 ◽  
Author(s):  
Filip Oulehle ◽  
William H. McDowell ◽  
Jacqueline A. Aitkenhead-Peterson ◽  
Pavel Krám ◽  
Jakub Hruška ◽  
...  
Keyword(s):  
Czech Republic ◽  
The Czech Republic ◽  
Nitrate Concentrations ◽  
Recovery From Acidification ◽  
Long Term Trends ◽  
Stream Nitrate

Role of T3 in thermogenic and trophic responses of brown adipose tissue to cold

1989 ◽  
Vol 257 (1) ◽  
pp. E81-E87 ◽  
Author(s):  
I. R. Park ◽  
D. B. Mount ◽  
J. Himms-Hagen
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Uncoupling Protein ◽  
Optimal Growth ◽  
Endogenous Production ◽  
Brown Adipose ◽  
Trophic Responses ◽  
Optimal Growth Rate

Cold-induced growth of brown adipose tissue (BAT) was studied in thyroidectomized rats that received low doses of either thyroxine (T4) or 3,5,3'-triidothyronine (T3). The objective was to find out whether the cold-induced increase in activity of T4 5'-deiodinase, and thus increased endogenous T3 generation in BAT itself, was necessary for growth of BAT or whether T3 from the blood could serve as effectively as T3 produced endogenously. The acute thermogenic response of BAT to cold (15 h at 4 degrees C), as measured by the increase in mitochondrial GDP binding, was abolished by thyroidectomy, as seen previously, and restored by T3 as well as by T4 treatment. The long-term trophic response to cold (20–25 days at 4 degrees C), as indicated by increases in protein and DNA and in mitochondrial concentrations of GDP-binding sites and uncoupling protein, occurred whether T3 or T4 was administered to these thyroidectomized rats. We conclude that endogenous T3 production in BAT does not direct and is not essential for the long-term trophic response of this tissue to cold. We are not able to exclude, on the basis of the present results, that an optimal growth rate during the initial phase of the trophic response may require enhanced endogenous production of T3 in BAT. The cold-induced increase in T4 5'-deiodinase activity, presumably mediated by an action of norepinephrine, does not require the presence of either T3 or T4, as seen previously by others.

scholarly journals Long-term patterns in dissolved organic carbon, major elements and trace metals in boreal headwater catchments: trends, mechanisms and heterogeneity

2013 ◽  
Vol 10 (4) ◽  
pp. 2315-2330 ◽  
Author(s):  
S. K. Oni ◽  
M. N. Futter ◽  
K. Bishop ◽  
S. J. Köhler ◽  
M. Ottosson-Löfvenius ◽  
...  
Keyword(s):  
Water Quality ◽  
Trace Metals ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Temporal Trends ◽  
Monotonic Increase ◽  
Surface Water Hydrology ◽  
Organic Carbon Concentration ◽  
Recovery From Acidification

Abstract. The boreal landscape is a complex, spatio-temporally varying mosaic of forest and mire landscape elements that control surface water hydrology and chemistry. Here, we assess long-term water quality time series from three nested headwater streams draining upland forest (C2), peat/mire (C4) and mixed (C7) (forest and mire) catchments. Acid deposition in this region is low and is further declining. Temporal trends in weather and runoff (1981–2008), dissolved organic carbon concentration [DOC] (1993–2010) and other water quality parameters (1987–2011) were assessed. There was no significant annual trend in precipitation or runoff. However, runoff increased in March and declined in May. This suggested an earlier snowmelt regime in recent years. Significant monotonic increasing trends in air temperature and length of growing season suggested a decrease in snowfall and less spring runoff. Stream [DOC] was positively correlated with some trace metals (copper, iron and zinc) and negatively with several other chemical parameters (e.g. sulfate, conductivity, calcium). Both sulfate and conductivity showed declining trends, while a significant increase was observed in pH during winter and spring. Calcium and magnesium showed monotonic decreasing trends. The declining trajectories of stream base cation and sulfate concentrations during other times of the year were not accompanied by changes in pH and alkalinity. These results indicate subtle effects of recovery from acidification. Water temperature increased significantly both annually and in most months. A simultaneous monotonic increase in iron (Fe) and [DOC] in autumn suggests co-transport of Fe-DOC in the form of organometallic complexes. A monotonic increase in UV absorbance in most months without co-occurring changes in DOC trend suggests a shift in DOC quality to a more humic-rich type. The observed increase in soil solution [DOC] and subtle trends in stream [DOC] suggest that climate rather than recovery from acidification is the dominant driver of DOC trends in the Svartberget catchment.

scholarly journals Recovery from acidification in European surface waters

2001 ◽  
Vol 5 (3) ◽  
pp. 283-298 ◽  
Author(s):  
C. D. Evans ◽  
J. M. Cullen ◽  
C. Alewell ◽  
J. Kopácek ◽  
A. Marchetto ◽  
...  
Keyword(s):  
Surface Waters ◽  
Base Cations ◽  
Quality Data ◽  
Water Quality Data ◽  
Large Spatial Scale ◽  
The United Kingdom ◽  
Acid Neutralising Capacity ◽  
Recovery From Acidification ◽  
The Uk

Abstract. Water quality data for 56 long-term monitoring sites in eight European countries are used to assess freshwater responses to reductions in acid deposition at a large spatial scale. In a consistent analysis of trends from 1980 onwards, the majority of surface waters (38 of 56) showed significant (p ≤0.05) decreasing trends in pollution-derived sulphate. Only two sites showed a significant increase. Nitrate, on the other hand, had a much weaker and more varied pattern, with no significant trend at 35 of 56 sites, decreases at some sites in Scandinavia and Central Europe, and increases at some sites in Italy and the UK. The general reduction in surface water acid anion concentrations has led to increases in acid neutralising capacity (significant at 27 of 56 sites) but has also been offset in part by decreases in base cations, particularly calcium (significant at 26 of 56 sites), indicating that much of the improvement in runoff quality to date has been the result of decreasing ionic strength. Increases in acid neutralising capacity have been accompanied by increases in pH and decreases in aluminium, although fewer trends were significant (pH 19 of 56, aluminium 13 of 53). Increases in pH appear to have been limited in some areas by rising concentrations of organic acids. Within a general trend towards recovery, some inter-regional variation is evident, with recovery strongest in the Czech Republic and Slovakia, moderate in Scandinavia and the United Kingdom, and apparently weakest in Germany. Keywords: acidification, recovery, European trends, sulphate, nitrate, acid neutralising capacity

scholarly journals Long-term dataset on aquatic responses to concurrent climate change and recovery from acidification

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Taylor H. Leach ◽  
Luke A. Winslow ◽  
Frank W. Acker ◽  
Jay A. Bloomfield ◽  
Charles W. Boylen ◽  
...  
Keyword(s):  
Climate Change ◽  
Recovery From Acidification
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