Overriding water table control on managed peatland greenhouse gas emissions.

Global peatlands store more carbon than is naturally present in the atmosphere1,2. However, many peatlands are under pressure from drainage-based agriculture, plantation development and fire, with the equivalent of around 3 per cent of all anthropogenic greenhouse gases emitted from drained peatland3-5. Efforts to curb such emissions are intensifying through the conservation of undrained peatlands and re-wetting of drained systems6. Here we report eddy covariance data for carbon dioxide from 16 locations and static chamber measurements for methane from 41 locations in the UK and Ireland. We combine these with published data from sites across all major peatland biomes. We find that the mean annual effective water table depth (WTDe; that is, the average depth of the aerated peat layer) overrides all other ecosystem- and management-related controls on greenhouse gas fluxes. We estimate that every 10 centimetres of reduction in WTDe could reduce the net warming impact of CO2 and CH4 emissions (100-year global warming potentials) by the equivalent of at least 3 tonnes of CO2 per hectare per year, until WTDe is less than 30 centimetres. Raising water levels further would continue to have a net cooling effect until WTDe is within 10 centimetres of the surface. Our results suggest that greenhouse gas emissions from peatlands drained for agriculture could be greatly reduced without necessarily halting their productive use. Halving WTDe in all drained agricultural peatlands, for example, could reduce emissions by the equivalent of over 1 per cent of global anthropogenic emissions.

The impacts of prescribed moorland burning on water colour and dissolved organic carbon: a critical synthesis.

Discolouration of natural surface waters due to the humic component of dissolved organic carbon (DOC) is a costly problem for water supply companies. This paper reviews what is known about the impacts of prescribed moorland vegetation burning on water colour. Relevant research has taken place at three scales: laboratory experiments on peat cores, plot scale sampling of soil waters and catchment scale sampling of stream waters. While laboratory studies suggest burning increases colour production, the evidence from catchment and plot studies is contradictory. Plot studies suggest colour production may decrease or remain unchanged following burning although there is evidence for some transient changes. Catchment studies suggest prescribed moorland burning causes stream water colour to increase, although in most cases the evidence is not clear cut since most studies could not clearly disentangle the effects of burning from those of vegetation cover. The differences in findings between plot and catchment studies may be explained by: i) the short-term nature of some studies which do not measure long-term response and recovery times to burning; ii) the lack of colour measurements from shallow soil depths which contribute more to streamflow than soil water from deeper in the peat; and iii) the possibility of hydrological interactions occurring between different experimental plots at some sites. Additionally, the increase in recent patch burning in some catchments that has been statistically attributed by some authors to increases in stream water colour cannot be reconciled with theoretical calculations. When dilution with waters derived from other parts of the catchment are taken into account, large values of colour have to be theoretically derived from those recently burnt areas that occupy a small proportion of the catchment area in order to balance the change in stream water colour observed in recent years. Therefore, much further process-based work is required to properly investigate whether prescribed vegetation burning is a direct driver of enhanced colour and DOC in upland streams, rivers and lakes.

A comparison of porewater chemistry between intact, afforested and restored raised and blanket bogs.

Afforestation is a significant cause of global peatland degradation. In some regions, afforested bogs are now undergoing clear-felling and restoration, often known as forest-to-bog restoration. We studied differences in water-table depth (WTD) and porewater chemistry between intact, afforested, and restored bogs at a raised bog and blanket bog location. Solute concentrations and principal component analysis suggested that water-table drawdown and higher electrical conductivity (EC) and ammonium (NH4-N) concentrations were associated with afforestation. In contrast, higher dissolved organic carbon (DOC) and phosphate (PO4-P) concentrations were associated with deforestation. Drying-rewetting cycles influenced seasonal variability in solute concentrations, particularly in shallower porewater at the raised bog location. WTD was significantly deeper in the oldest raised bog restoration site (~9 years post-restoration) than the intact bog (mean difference = 6.2 cm). However, WTD in the oldest blanket bog restoration site (~17 years post-restoration), where furrows had been blocked, was comparable to the intact bog (mean difference = 1.2 cm). When averaged for all porewater depths, NH4-N concentrations were significantly higher in the afforested than the intact sites (mean difference = 0.77 mg L-1) whereas significant differences between the oldest restoration sites and the intact sites included higher PO4-P (mean difference = 70 µg L-1) in the raised bog and higher DOC (mean difference = 5.6 mg L-1), EC (mean difference = 19 µS cm-1) and lower SUVA254 (mean difference = 0.13 L mg-1 m-1) in the blanket bog. Results indicate felled waste (brash) may be a significant source of soluble C and PO4-P. Mean porewater PO4-P concentrations were between two and five times higher in furrows and drains in which brash had accumulated compared to other locations in the same sites where brash had not accumulated. Creating and maintaining brash-free buffer zones may therefore minimise freshwater impacts.

Spatial variation in concentrations of dissolved nitrogen species in an upland blanket peat catchment.

The concentration of nitrogen (N), particularly as nitrate (NO3-N), in upland streams, lakes and rivers is frequently used as a diagnostic of the vulnerability of upland ecosystems to increased atmospheric nitrogen deposition and N saturation. The N content of running waters, however, is generally assessed on the basis of sampling at a limited number of points in space and time within the catchment under investigation. The current study was conducted at Trout Beck, an 11.5 km2 blanket peat-dominated catchment in the North Pennine uplands of the UK. Results from sampling at 33 sites within this catchment demonstrated that the concentrations of all dissolved N species were highly variable, even over short distances. Statistical relationships between the concentrations of NO3-N and dissolved organic nitrogen (DON) and percentage catchment cover of Calluna/Eriophorum and Eriophorum vegetation were found. However, it was also noted that in catchments containing limestone outcrops, NO3-N concentration was much higher than in catchments where runoff was sourced directly from the blanket peat surface. It is possible that NH4-N and DON leached from the blanket peat are mineralised and nitrified, providing a source for the NO3-N found in the river channels. Overall, the current study suggests that interpretations of N-saturation based on river water chemistry measurements at a single point must be treated cautiously, and that the influence of catchment-scale physical factors, such as vegetation and geology cover on the concentration of dissolved N species in upland river waters should not be ignored.

A randomized comparison of single-agent doxorubicin and epirubicin as first-line cytotoxic therapy in advanced breast cancer.

One hundred forty-one patients with advanced breast cancer who had not received prior chemotherapy were randomly assigned to receive doxorubicin 60 mg/m2 or epirubicin 90 mg/m2 every 3 weeks. These doses were selected to produce equivalent toxicities. All patients were assessed for toxicity, and 138 patients were assessable for response. After a median of five treatment cycles, 47% (32 of 68) of doxorubicin-treated patients achieved a partial or complete response. Response duration and survival were 10 and 12 months for doxorubicin and 8 and 10 months for epirubicin, respectively. Noncardiac toxicities were similar for both drugs. Of 41 patients receiving doxorubicin who had serial left ventricular ejection fraction assessments, seven sustained a fall of 10% or more, and one patient developed congestive cardiac failure at a cumulative doxorubicin dose of 489 mg/m2. Of 39 patients receiving epirubicin who had serial cardiac assessments, five sustained left ventricular ejection fraction falls of 10% or more and two patients developed congestive cardiac failure at cumulative doses of 178 mg/m2 and 833 mg/m2. These data indicate that an epirubicin dose of 90 mg/m2 produces toxicity equivalent to doxorubicin 60 mg/m2 but does not improve response rates, response duration, or survival in advanced breast cancer.

The influence of slope and peatland vegetation type on riverine dissolved organic carbon and water colour at different scales.

Peatlands are important sources of fluvial carbon. Previous research has shown that riverine dissolved organic carbon (DOC) concentrations are largely controlled by soil type. However, there has been little work to establish the controls of riverine DOC within blanket peatlands that have not undergone major disturbance from drainage or burning. A total of 119 peatland catchments were sampled for riverine DOC and water colour across three drainage basins during six repeated sampling campaigns. The topographic characteristics of each catchment were determined from digital elevation models. The dominant vegetation cover was mapped using 0.5m resolution colour infrared aerial images, with ground-truthed validation revealing 82% accuracy. Forward and backward stepwise regression modelling showed that mean slope was a strong (and negative) determinant of DOC and water colour in blanket peatland river waters. There was a weak role for plant functional type in determining DOC and water colour. At the basin scale, there were major differences between the models depending on the basin. The dominance of topographic predictors of DOC found in our study, combined with a weaker role of vegetation type, paves the way for developing improved planning tools for water companies operating in peatland catchments. Using topographic data and aerial imagery it will be possible to predict which tributaries will typically yield lower DOC concentrations and which are therefore more suitable and cost-effective as raw water intakes.

Cloning, physical mapping and expression of chromosomal genes specifying degradation of the herbicide 2,4,5-T by Pseudomonas cepacia AC1100.

A genomic library of total DNA of Pseudomonas cepacia AC1100 was constructed on a broad-host-range cosmid vector pCP13 in Escherichia coli AC80. A 25-kb segment was isolated from the library which complemented a Tn5-generated, 2,4,5-trichlorophenoxyacetic acid-negative (2,4,5-T-) mutant, P. cepacia PT88. This mutation was partially characterized and appeared to be lacking functional enzyme required for metabolism of an intermediate of the 2,4,5-T pathway, recently identified as 5-chloro-1,2,4-trihydroxybenzene [Chapman et al., Abstr. Soc. Environ. Toxicol. Chem. USA 8 (1987) 127]. A simple colorimetric assay was developed to detect the presence of this active enzyme in intact cells and was used to determine the expression of complementing genes. Subcloning experiments showed that a 4-kb BamHI-PstI fragment and a 290-bp PstI-EcoRI fragment, separated by 1.3-kb, were required for complementation. Both fragments are identified to be chromosomal in origin. Hybridization studies using the subcloned fragments revealed that in addition to a Tn5 insertion, mutant PT88 contained an extensive chromosomal deletion accounting for its 2,4,5-T- phenotype. The cloned fragments did not show homology to plasmid DNAs carrying degradative genes for toluene, naphthalene and 3-chlorobenzoate.

Purification and properties of a plasmid-encoded 2,4-dichlorophenol hydroxylase.

2,4-Dichlorophenol hydroxylase, an enzyme involved in the bacterial degradation of the herbicide 2,4-dichlorophenoxyacetate (2,4-D) was purified from two bacterial strains that harbored the same 2,4-D plasmid, pJP4. The purified enzymes (Mr 224 000) from the two transconjugants were indistinguishable; they contained FAD and were composed of non-identical subunits, Mr 67 000 and 45 000, respectively. Various substituted phenols were hydroxylated, using either NADH or NADPH. The amino acid composition of the native enzyme was determined.

Fossil fuel biodegradation: laboratory studies.

Biodegradation of the polycyclic aromatic hydrocarbons of creosote by undefined bacterial cultures was shown to be accompanied by the accumulation of neutral and acidic oxidation products. Formation of a number of identified neutral products is accounted for by demonstration of anomalous actions of an arene dioxygenase on the benzylic methylene and methylene carbons of napthenoaromatic hydrocarbons. Both neutral and acidic water-soluble fractions are also formed when various mixed bacterial cultures degrade weathered crude oil. While constituents of these fractions are not yet identified, the neutral materials have been shown to be toxic to developing embryos of invertebrates. These observations are discussed in relation to chemical and toxicological assessments of biodegradation of the complex chemical mixtures of fossil fuels.

para-hydroxybenzoate as an intermediate in the anaerobic transformation of phenol to benzoate.

Anaerobic phenol transformation was studied using a consortium which transformed phenol to benzoate without complete mineralization of benzoate. Products of monofluorophenol transformation indicated para-carboxylation. Phenol and benzoate were detected during para-hydroxybenzoate (p-OHB) degradation. p-OHB was detected in phenol-transforming cultures containing 6-hydroxynicotinic acid (6-OHNA), a structural analogue of p-OHB, or at elevated initial concentrations of phenol (greater than or equal to 5 mM), or benzoate (greater than or equal to 10 mM).

Prognostic and therapeutic considerations in clinical primary pulmonary hypertension.

Twenty-two patients with primary pulmonary hypertension were reviewed to assess the correlation of clinical and haemodynamic features with prognosis. A relationship between resting haemodynamic measurements and survival was sought in all 22 patients, and the effect of vasodilator therapy in 13 was reviewed. Those who survived 12 months or less (seven patients) or 40 months or more (seven patients) from catheterization were classified into short or long survival groups respectively. Clinical, haemodynamic and pulmonary angiographic features of patients in these groups were compared. In the whole group, mean pulmonary artery pressure and pulmonary vascular resistance were inversely related to survival. Multivariate analysis of mean pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), mean right atrial pressure (RAP), systemic vascular resistance (SVR) and cardiac index (CI) in the whole group identified RAP and PVR as the model which best predicted survival time. The short survival group had a higher prevalence of electrocardiographic evidence of right ventricular hypertrophy, higher mean pulmonary artery pressure and pulmonary vascular resistance than the long survival group. Our experience with vasodilator therapy was less encouraging than that described by other workers. Two of six patients on long-term treatment appeared to stabilize. Two other untreated patients showed spontaneous improvement. Prediction of prognosis in the individual patient is difficult.

Primary pulmonary hypertension and thromboembolic pulmonary hypertension--similarities and differences.

In a retrospective study of 36 patients with primary pulmonary hypertension (PPH) and 16 patients with chronic large vessel thromboembolic pulmonary hypertension (TPH) the diagnostic value of clinical features, chest radiographs, electrocardiographs, radionuclide lung scanning and cardiac catheterization was assessed. PPH patients were younger, had higher prevalence of Raynaud's phenomenon, right axis deviation, right ventricular hypertrophy on electrocardiograph and higher pulmonary artery pressures than TPH patients, but these features were not diagnostic. Although pulmonary angiography is considered by some to be necessary in distinguishing these two conditions, radionuclide lung scanning proved a safe and effective noninvasive method for this purpose.

Successful use of captopril in the treatment of "scleroderma renal crisis".

A 53-year-old man with scleroderma and severe renal failure was treated with the angiotensin converting enzyme inhibitor captopril. Adequate control of blood pressure was achieved with this single agent and an impressive improvement of renal function followed. This case illustrates many features of the syndrome of "scleroderma renal crisis" and supports the use of captopril for its treatment.

Players' attitudes to mouthguards and prevalence of orofacial injuries in the 1987 U.S. Rugby Football Team.

This report shows that although 95.4% of players in the U.S. Rugby Team believed mouthguards provided local protection, only half wore a mouthguard. However, 90.9% of mouthguard wearers would not play without their mouthguard and 54.5% believed wearing mouthguards should be made compulsory in rugby football. Approximately one-third of the team had sustained an orofacial injury that required treatment and none were wearing a mouthguard at the time of injury. These and other results are compared to an identical study of the 1984 Australian Rugby Team, the only previous such study reported.

The nitrogen composition of streams in upland Scotland: some regional and seasonal differences.

The nitrogen (N) composition of streams draining four upland regions of Scotland was compared in samples collected monthly between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), dissolved organic N (DON) and dissolved organic carbon (DOC). Concentrations of TN were small, generally less than 1 mg l(-1) , dominated by dissolved forms of N, and varied significantly between upland regions. Nitrate accounted for most of the variability in TN; largest concentrations were observed in the Southern Uplands and smallest concentrations were observed in the Highlands. Nitrate concentrations were positively correlated with the percentage cover of improved grasslands and brown forest soils and negatively correlated with the percentage cover of peat. Concentrations of DON also varied between regions, but to a lesser extent than those of NO3. Largest concentrations occurred in SW Scotland and smallest concentrations in the Cairngorms. Although a significant positive correlation between DON and DOC was observed, stream water DON content was not related to the percentage cover of peat in the catchment, as was the case for DOC. The average DOC:DON ratio was narrower for streams in the Southern Uplands than for those in the Cairngorms and Highlands. Nitrate and DON displayed contrasting seasonal trends; NO3 concentrations were larger in the winter while DON concentrations were larger in the summer. Only a small proportion, < 8% and < 7%, of TN was PN and NH4, respectively, the majority of N was present as either NO3 or DON. Nitrate was the dominant fraction (58-65%) in all regions except the Highlands where DON accounted for 57% of TN. However, the relative importance of the DON component increased in the summer in all regions. This study has demonstrated that the DON fraction is an important component of the total N transported by streams from upland catchments in Scotland. Thus, assessments of anthropogenic impacts on N losses from upland ecosystems need to consider not only the dissolved inorganic species but also DON.

Dental status of pregnant women attending a Brisbane maternity hospital.

A sample of 314 consecutive women attending for their first antenatal visit at a public hospital were examined according to the WHO survey procedure. The women's age ranged from 16 to 42 yr with a mean of 23.5 yr. Only 3% were edentulous in both jaws, but 13% had some form of denture. A quarter had pocketing in at least one sextant and only 16% were free of gingivitis. The average number of DMF teeth was 15.8, comprising 2.7 decayed, 4.5 missing and 8.6 filled teeth; 70% had teeth needing restoration and 10% had at least one tooth needing extraction. There were significant relationships between DMF score and age (positive) and between number of teeth needing restoration and age, educational level, and the woman's own perception of her dental health (all inverse). Some form of dental attention was needed by 86% of the women; 12% had conditions needing immediate attention. By comparison with a 1971 study of pregnant women in Brisbane, there has been a marked decline in DMFT score (from 19.1 to 15.8).

Postoperative pain control for outpatient oral surgery.

16 healthy patients requiring removal of bilateral symmetrically-impacted mandibular third molars participated in a double-blind randomised crossover trial to test the effectiveness of postoperative pain control using a long-acting anti-inflammatory agent (diflunisal) in combination with a long-acting local anaesthetic agent (bupivacaine). Results were compared to the more traditional method of using an oral analgesic with shorter duration of action (paracetamol with codeine) with lignocaine as the local anaesthetic. Using a visual analogue pain scale, patients reported that significantly reduced pain was experienced over the first 4 days postoperatively with the diflunisal/bupivacaine treatment and patient preference for this treatment was highly significant. This report represents the first such study of diflunisal used for an extended course in oral surgery with pain assessment over the same period. No significant side-effects or adverse reactions were encountered.

The effects of diflunisal on bleeding time and platelet aggregation in a multidose study.

Diflunisal, a potent nonsteroidal anti-inflammatory agent, has been confirmed as an effective analgesic in oral surgery. It is generally stated that there is only slight impairment of coagulation at the recommended dosage of diflunisal; however, only a few multidose studies have been conducted, most being single dose studies. This report is of a multidose study of the effects of diflunisal on coagulation in 15 oral surgery patients, being the first such study reported. The results showed that the bleeding time was increased in 53% of the group, but in no case did the increase exceed the upper limit of normal. Additionally, platelet aggregation studies were affected in 38% of patients with increased bleeding time. The overall results substantiate the safety of diflunisal in relation to effect on coagulation, and are directly applicable to postoperative use in oral surgery.

Inorganic and organic losses of nitrogen from upland regions of Britain: concentrations and fluxes.

The nitrogen (N) composition of streams draining eight upland regions of Britain was compared using monthly samples collected between April 1997 and April 1998. Stream samples were analysed for total N (TN), particulate N (PN), nitrate (NO3), ammonium (NH4), and dissolved organic nitrogen (DON). Concentrations of TN were small, generally less than 1.5 mg N l(-1), were dominated by dissolved forms of N, and varied significantly between regions. NO3 accounted for the majority of variability. Concentrations of DON also varied between regions but to a smaller extent than those of NO3. There were considerable variations in TN fluxes between upland regions, which ranged between 3.8 and 16.1 kg N ha(-1) year(-1). The majority of the variation was due to NO3 fluxes, which were largest in regions receiving largest inputs of atmospheric N deposition and ranged between 1.4 and 13.5 kg N ha(-1) year(-1). Fluxes of DON ranged between 1 and 3.5 kg N ha(-1) year( -1), while fluxes of PN were generally less than 0.5 kg N ha(-1) year(-1) , and NH4 fluxes ranged between 0.1 and 0.4 kg N ha(-1) year(-1). NO3 was the dominant fraction (47-84%) of N exported from all upland regions except the Highlands, where DON accounted for 52% of the TN flux. This study has shown that the DON fraction is an important component of the total N transported by upland streams in Britain.

Merging nitrogen management and renewable energy needs.

The ARBRE (ARable Biomass Renewable Energy) project, the first large-scale wood-fueled electricity generating plant in the U.K., represents a significant development in realising British and European policy objectives on renewable energy. The plant is fueled by a mix of wood from short rotation coppice (SRC) and forest residues. Where feasible, composted/conditioned sewage sludge is applied to coppice sites to increase yields and improve soil structure. In the Yorkshire Water region, typical total N:P:K composition of composted/conditioned sludge is 2.9:3.8:0.3, respectively. Sludge application is calculated on the basis of total nitrogen (N) content to achieve 750 kg N ha(-1), for 3 years" requirement. Willow coppice forms a dense, widely spaced, root network, which, with its long growing season, makes it an effective user of nutrients. This, in combination with willow"s use as a nonfood, nonfodder crop, makes it an attractive route for the recycling of sewage sludge in the absence of sea disposal, banned under the EC Urban Waste Water Treatment Directive (UWWTD). Further work is required on the nutritional requirements of SRC in order to understand better the quantities of sludge that can be applied to SRC without having a detrimental impact on the environment. This paper suggests the source of N rerouting under the UWWTD and suggests the likely expansion of SRC as an alternative recycling pathway.