A personal perspective on four decades of paleolimnology and environmental change research

A personal summary of paleolimnological research activities in the UK and elswehere since the mid 1970s

Endogenous annexin A1 counter-regulates bleomycin-induced lung fibrosis

PMCID: PMC3212807This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Benzolamide improves oxygenation and reduces acute mountain sickness during a high-altitude trek and has fewer side effects than acetazolamide at sea level.

Acetazolamide is the standard carbonic anhydrase (CA) inhibitor used for acute mountain sickness (AMS), however some of its undesirable effects are related to intracellular penetrance into many tissues, including across the blood-brain barrier. Benzolamide is a much more hydrophilic inhibitor, which nonetheless retains a strong renal action to engender a metabolic acidosis and ventilatory stimulus that improves oxygenation at high altitude and reduces AMS. We tested the effectiveness of benzolamide versus placebo in a first field study of the drug as prophylaxis for AMS during an ascent to the Everest Base Camp (5340 m). In two other studies performed at sea level to test side effect differences between acetazolamide and benzolamide, we assessed physiological actions and psychomotor side effects of two doses of acetazolamide (250 and 1000 mg) in one group of healthy subjects and in another group compared acetazolamide (500 mg), benzolamide (200 mg) and lorazepam (2 mg) as an active comparator for central nervous system (CNS) effects. At high altitude, benzolamide-treated subjects maintained better arterial oxygenation at all altitudes (3-6% higher at all altitudes above 4200 m) than placebo-treated subjects and reduced AMS severity by roughly 50%. We found benzolamide had fewer side effects, some of which are symptoms of AMS, than any of the acetazolamide doses in Studies 1 and 2, but equal physiological effects on renal function. The psychomotor side effects of acetazolamide were dose dependent. We conclude that benzolamide is very effective for AMS prophylaxis. With its lesser CNS effects, benzolamide may be superior to acetazolamide, in part, because some of the side effects of acetazolamide may contribute to and be mistaken for AMS

A Bayesian palaeoenvironmental transfer function model for acidified lakes

A Bayesian approach to palaeoecological environmental reconstruction deriving from the unimodal responses generally exhibited by organisms to an environmental gradient is described. The approach uses Bayesian model selection to calculate a collection of probability-weighted, species-specific response curves (SRCs) for each taxon within a training set, with an explicit treatment for zero abundances. These SRCs are used to reconstruct the environmental variable from sub-fossilised assemblages. The approach enables a substantial increase in computational efficiency (several orders of magnitude) over existing Bayesian methodologies. The model is developed from the Surface Water Acidification Programme (SWAP) training set and is demonstrated to exhibit comparable predictive power to existing Weighted Averaging and Maximum Likelihood methodologies, though with improvements in bias; the additional explanatory power of the Bayesian approach lies in an explicit calculation of uncertainty for each individual reconstruction. The model is applied to reconstruct the Holocene acidification history of the Round Loch of Glenhead, including a reconstruction of recent recovery derived from sediment trap data.The Bayesian reconstructions display similar trends to conventional (Weighted Averaging Partial Least Squares) reconstructions but provide a better reconstruction of extreme pH and are more sensitive to small changes in diatom assemblages. The validity of the posteriors as an apparently meaningful representation of assemblage-specific uncertainty and the high computational efficiency of the approach open up the possibility of highly constrained multiproxy reconstructions

Water quality and water availability variations in an upland Galloway loch with special reference to dissolved organic matter and the distribution of benthic diatoms

Upland waters in acid sensitive regions of Scotland are vulnerable to several disturbance processes that most importantly include atmospheric pollution and climate change as well as to local land use. Monitoring in the Round Loch of Glenhead (RLGH) since 1988 has shown that both water acidity and sulphate concentration have declined while the concentration of dissolved organic matter (DOM) has steadily increased. Currently, it is unclear if increasing DOM reflects climate change effects or relief from acid pollution. This report concerns recent research at the RLGH on relating seasonal changes in water supply and coloured dissolved organic matter (cDOM) to the distributions of benthic algae (diatoms). Diatoms are primarily limited by light which in turn varies according to season, water depth and water transparency. cDOM in lake water strongly influences water transparency and our central hypothesis is that benthic diatom distributions are influenced by changes in cDOM concentrations and light availability

Acid Lakes in the Galloway Uplands, South West Scotland: catchments, water quality and sediment characteristics

Reports of diminishing salmonid fisheries and increasing acidity of lakes and streams in S.W. Scotland have attributed the cause to low pH precipitation (Wright &Henriksen 1980) and afforestation effects (Harriman & Morrison 1982). In 1981 we initiated a project with CEGB funding to examine the history of lakewater acidity in both afforested and unafforested catchments in the Galloway uplands (see frontispiece). Analysis of diatom remains in lake sediments is used to reconstruct lake pH change over the past 150 years at each site. Sediment chronology is provided by lead-210 dating (Appleby & Oldfield 1978). Contemporary limnological data on water quality and diatom communities has been collected over an annual cycle (1981-82) to aid evaluation of the sedimentary data

Palaeoecological evidence for the timing and causes of lake acidification in Galloway, South West Scotland

During the contract period sediment cores from six lakes, three with non-afforested and three with partially afforested catchments, were analysed to enable lake water acidity (pH) to be reconstructed over approximately the past 200 years. The sites are all situated on granitic rocks in the Galloway Hills of S.W. Scotland. The results of diatom analysis show that five of the six lakes have become considerably more acid over this time period and that the acidification process is mainly independent of catchment afforestation effects. {210}^Pb dating of the sediment shows that there has been little change in sediment accumulation rates at sites with non-afforested catchments, but there has been significant increases in accumulation rate at afforested sites associated with erosion caused by pre-planting catchment ploughing. Pollen analysis indicates that no major vegetation change has occurred at the non-afforested sites whilst trace metal analysis of L. Enoch (not funded by this contract) shows elevated levels of Pb, Cu, and Zn 1n the upper, post 1800 sediments. It is concluded that acid precipitation is the most likely cause of acidification at these sites