In northern peatlands, near‐saturated surface conditions promote valuable ecosystem services such as carbon storage and drinking water provision. Peat saturated hydraulic conductivity ( K sat ) plays an important role in maintaining wet surface conditions by moderating drainage and evapotranspiration. Peat K sat can exhibit intense spatial variability in three dimensions and can change rapidly in response to disturbance. The development of skillful predictive equations for peat K sat and other hydraulic properties, akin to mineral soil pedotransfer functions, remains a subject of ongoing research. We report a meta‐analysis of 2,507 northern peat samples, from which we developed linear models that predict peat K sat from other variables, including depth, dry bulk density, von Post score (degree of humification), and categorical information such as surface microform type and peatland trophic type (e.g., bog and fen). Peat K sat decreases strongly with increasing depth, dry bulk density, and humification; and increases along the trophic gradient from bog to fen peat. Dry bulk density and humification are particularly important predictors and increase model skill greatly; our best model, which includes these variables, has a cross‐validated r 2 of 0.75 and little bias. A second model that includes humification but omits dry bulk density, intended for rapid field estimations of K sat , also performs well (cross‐validated r 2 = 0.64). Two additional models that omit several predictors perform less well (cross‐validated r 2 ∼ 0.5), and exhibit greater bias, but allow K sat to be estimated from less comprehensive data. Our models allow improved estimation of peat K sat from simpler, cheaper measurements.

Most bioscientists need to report mean values, yet many have little idea of how many digits are significant, and at what point further digits are mere random junk. Thus a recent report that the mean of 17 values was 3.863 with a standard error of the mean (SEM) of 2.162 revealed only that none of the seven authors understood the limitations of their work. The simple rule derived here by experiment for restricting a mean value to its significant digits (sig-digs) is this: the last sig‑dig in the mean value is at the same decimal decade as the first sig-dig (the first non-zero) in the SEM. An extended rule for the mean, and a different rule for the SEM itself are also derived. For the example above the reported values should be a mean of 4 with SEM 2.2. Routine application of these simple rules will often show that a result is not as compelling as one had hoped.

Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ecologically relevant questions and hypotheses.

The first International Peat Congress (IPC) held in the tropics - in Kuching (Malaysia) - brought together over 1000 international peatland scientists and industrial partners from across the world (“International Peat Congress with over 1000 participants!,” 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat.

The late Hugh Ingram (HAPI) contributed many things to our knowledge of peatlands. The two best known are probably the acrotelm/catotelm terminology (Ingram 1978), and the application of Childs & Youngs (1961) hemi-elliptical groundwater mound to the cross-section of raised bogs (Ingram 1982). As a tribute to HAPI, I combine these concepts with three others to create a video showing the development of a notional raised bog during 10,000 years. After that, I consider some of the limitations of this simplistic model and why, nevertheless, it is still useful.

The first International Peat Congress (IPC) held in the tropics – in Kuching (Malaysia) – brought together over 1000 international peatland scientists and industrial partners from across the world (‘International Peat Congress with over 1000 participants!’, 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat. However, recent encouraging developments towards better management of tropical peatlands have been undermined by misleading newspaper headlines and statements first published during the conference. Articles in leading regional newspapers (‘Oil palm planting on peat soil handled well, says Uggah, 2016b; Cheng & Sibon, 2016; Nurbianto, 2016a,b; Wong, 2016) widely read across the region portrayed a general consensus, in summary of the conference, that current agricultural practices in peatland areas, such as oil palm plantations, do not have a negative impact on the environment. This view is not shared by many scientists or supported by the weight of evidence that business-as-usual management is not sustainable for tropical peatland agriculture. Peer-reviewed scientific studies published over the last 19 years, as reflected in the Intergovernmental Panel on Climate Change (IPCC) Wetland Supplement on greenhouse gas inventories, affirm that drained tropical peatlands lose considerable amounts of carbon at high rates (Drösler et al., 2014). Tropical peat swamp forests have sequestered carbon for millennia, storing a globally significant reservoir below ground in the peat (Page et al., 2011; Dommain et al., 2014). However, contemporary agriculture techniques on peatlands heavily impact this system through land clearance, drainage and fertilization, a process that too often involves fire. Along with biodiversity losses driven by deforestation (Koh et al., 2011; Posa et al., 2011; Giam et al., 2012), the carbon stored in drained peatlands is rapidly lost through oxidation, dissolution and fire (Couwenberg et al., 2009; Hirano et al., 2012; Ramdani & Hino, 2013; Schrier-Uijl et al., 2013; Carlson et al., 2015; Warren et al., 2016). Tropical peat fires are a major contributor to global greenhouse gas emissions and produce transboundary haze causing significant impacts on human health, regional economies and ecosystems (Page et al., 2002; Marlier et al., 2012; Jaafar & Loh, 2014; Chisholm et al., 2016; Huijnen et al., 2016; Stockwell et al., 2016). With future El-Niño events predicted to increase in frequency and severity (Cai et al., 2014) and with fire prevalence now decoupled from drought years (Gaveau et al., 2014), future large-scale fire and haze events are imminent given the extensive areas of now-drained fire-prone drained peatlands (Kettridge et al., 2015; Turetsky et al., 2015; Page & Hooijer, 2016). In reality, just how much of the estimated 69 gigatonnes of carbon (Page et al., 2011) stored in South-East Asian tropical peatlands is being lost due to agricultural operations under the current management regime is still uncertain. Of great concern is that none of the agricultural management methods applied to date have been shown to prevent the loss of peat and the associated subsidence of the peatland surface following drainage (Wösten et al., 1997; Melling et al., 2008; Hooijer et al., 2012; Evers et al., 2016). Recent projections suggest that large areas of currently drained coastal peatlands will become undrainable and progressively be subjected to longer periods of inundation by river and ultimately sea water (Hooijer et al., 2015a,b; Sumarga et al., 2016). With growing risk of saltwater intrusion, agriculture in these coastal lands will become increasingly untenable, calling into question the very notion of ‘long-term sustainability of tropical peatland agriculture’. A more accurate view of drained peatland agriculture is that of an extractive industry, in which a finite resource (the peat) is ‘mined’ to produce food, fibre and fuel, driven by global demand. In developing countries with growing populations, there are strong socio-economic arguments for exploiting this resource to support local livelihoods and broader economic development (Mizuno et al., 2016). However, we must accept that ongoing peat loss is inevitable under this scenario. Science-based measures towards improved management, including limitations on the extent of plantation development, can be used to minimize the rate of this peat loss (President of Indonesia, 2011). Such an evidence-based position, supported with data and necessary legal instruments, is needed for sustainable futures. The scientifically unfounded belief that drained peatland agriculture can be made ‘sustainable’, and peat loss can be halted, via unproven methods such as peat compaction debilitates the effort to find sustainable possibilities. To a large extent, the issues surrounding unsustainable peatland management have now been recognized by sections of industry (Wilmar, 2013; APP, 2014; Cargill Inc., 2014; Mondelēz International, 2014; Sime Darby Plantation, 2014; APRIL, 2015; Olam International, 2015), government (President of Indonesia, 2014, 2016, Mongabay, 2015; Mongabay Haze Beat, 2015; Hermansyah, 2016) and consumers (Wijedasa et al., 2015). In recognition of the constraints and risks of peatland development, many large and experienced oil palm and pulpwood companies have halted further development on peat and introduced rigorous management requirements for existing peatland plantations (Lim et al., 2012). However, the denial of the empirical basis calling for improved peatland management remains persistent in influential policy spaces, as illustrated by the articles reporting on the conference (‘Oil palm planting on peat soil handled well, says Uggah, 2016b; Cheng & Sibon, 2016; Nurbianto, 2016a,b). The search for more responsible tropical peatland agriculture techniques includes promising recent initiatives to develop methods to cultivate crops on peat under wet conditions (Giesen, 2015; Dommain et al., 2016; Mizuno et al., 2016). While a truly sustainable peatland agriculture method does not yet exist, the scientific community and industry are collaborating in the search for solutions (International Peat Society, 2016), and for interim measures to mitigate ongoing rates of peat loss under existing plantations. Failing to recognize the devastating consequences of the current land use practices on peat soils and failing to work together to address them could mean that the next generation will have to deal with an irreversibly altered, dysfunctional landscape where neither environment nor society, globally or locally, will be winners. Open access facilitated by Greifswald Mire Centre and Department of Forestry Sciences, University of Helsinki.

In 1966, tritiated water was injected at five sites at depths between 25 and 100 cm into blanket bog at Moor House National Nature Reserve. The distribution of tritium activity on a logarithmically spaced grid around these sites was sampled in 1990, 24 years after placement. The proportions of tritium accounted for ranged from 80 % for the injection at 100 cm deep, to 20 % for the injection at 25 cm deep. Both 80 and 20 should be considered as ± 10 %. Results imply that diffusion close to the injection may have played a part in movement of tritium; evapotranspiration is not inconsistent with the losses inversely proportional to depth of placement; but the main process of movement is probably bulk (mass) flow of water through the peat.

(1) There is evidence of gas-filled voids - ‘bubbles’ - in deep (> 50–100 cm) peat in North America. (2) I used corers, designed to collect samples of accurately known volume, to sample peat profiles down to maximum depth 700 cm at five varied bog sites in northern England and southern Scotland, and measured the proportion of space apparently occupied by bubbles. (3) Of 126 samples in peat below 50 cm depth, three had bubbles occupying 12–15 % of the volume (and one of these was at only 55 cm depth). The other 123 had apparent bubbles distributed in Gaussian fashion, positively and negatively, about zero proportion of total volume and with standard deviation less than 2 %, consistent with these ‘bubbles’ being measurement error. (4) In northern England and southern Scotland, compared with North America, less variable temperature and cooler summers may lead to concentrations of dissolved gas that are generally too low to allow bubbles to form. Even where bubbles do form in summer, they may re-dissolve at winter temperatures.

Diffusion is usually thought to be ineffective at transporting solutes over distances of several metres – the depth of many peat deposits. But this is to neglect the importance of time. We derive equations that show that in peat that has accumulated over millennia then diffusion alone can remove to the air about 95 % of the gases carbon dioxide and methane generated by microbial decay within the main peat mass. Gas concentration profiles in simulations of peat grown slice-by-slice over 10,000 years have a smooth convex profile with concentration increasing downwards, as they do in Nature.

Peatland ecosystems store about 500-600 Pg of organic carbon, largely accumulated since the last glaciation. Whether they continue to sequester carbon or release it as greenhouse gases, perhaps in large amounts, is important in Earth's temperature dynamics. Given both ages and depths of numerous dated sample peatlands, their rate of carbon sequestration can be estimated throughout the Holocene. Here we use average values for carbon content per unit volume, the geographical extent of peatlands, and ecological models of peatland establishment and growth, to reconstruct the time-trajectory of peatland carbon sequestration in North America and project it into the future. Peatlands there contain similar to 163 Pg of carbon. Ignoring effects of climate change and other major anthropogenic disturbances, the rate of carbon accumulation is projected to decline slowly over millennia as reduced net carbon accumulation in existing peatlands is largely balanced by new peatland establishment. Peatland; are one of few long-term terrestrial carbon sinks, probably important for global carbon regulation in future generations. This study contributes to a better understanding of these ecosystems that will assist their inclusion in earth-system models, and therefore their management to maintain carbon storage during climate change. (C) 2012 Elsevier Ltd. All rights reserved.

In 65 samples, we got values (unusually replicable and consistent for this type of work) of concentration, 14C/13C (AMS) age, and δ13C for: peat, dissolved organic carbon (DOC), peat fractions, and dissolved CO2 and CH4 at 50-cm intervals down to 700 cm in Ellergower Moss, a rainwater-dependent raised (domed) bog in southwest Scotland. (1) We attribute the consistency of the results to Ellergower Moss being unusually homogeneous, with unusually low hydraulic conductivity, and containing only a few gas spaces; and to the sampling methods including 18-month equilibration of in situ samplers. (2) The dissolved gas concentration depth profiles are convex and very similar to each other, though CO2 is 5–10 times more concentrated than CH4, while the profile of DOC is concave. (3) The age profile of peat is near linearly proportional to depth; that for DOC is about 500–1000 yr younger than the peat at the same depth; the dissolved gases are 500–4300 years younger than the peat. The age of the operational peat fractions humic acid and humin is similar to that of whole peat. (4) The δ13C profile for deep peat is almost constant; δ13C–CO2 is more enriched than the peat (δ13C–CO2 35‰ more); δ13C–CH4 is the same amount more depleted. Nearer the surface both dissolved gases become steadily more depleted, δ13C is about 20‰ less at the surface. (5) A simulation shows that mass flow can account for the concentration and age profiles of DOC, but for the gases diffusion and an additional source near the surface are needed as well, and diffusion accounts for over 99% of the dissolved gas movements. (6) The same processes must operate in other peatlands but the results for Ellergower should not be extrapolated uncritically to them.

Tillage-induced erosion of herbicides bound to airborne soil particles has not been quantified as a mechanism for offsite herbicide transport. This study quantifies the release of two preemergent herbicides, metolachlor and pendimethalin, to the atmosphere as gas- and particle-phase species during soil incorporation operations. Fine particulate matter (PM2.5) and gas-phase samples were collected at three sampling heights during herbicide disking into the soil in Davis, CA, in May 2000 and May 2001 using filter/PUF sampling. Quartz fiber filters (QFFs) were used in May 2000, and Teflon membrane filters (TMFs) were used in May 2001. The field data were combined with laboratory filter/PUF partitioning experiments to account for adsorption to the filter surfaces and quantify the mass of PM2.5-bound herbicides in the field samples. Laboratory results indicate a significant adsorption of metolachlor, but not pendimethalin, to the quartz filter surfaces. Metolachlor partitioning to PM2.5 collected on TMF filters resulted in corrected PM2.5 field partition coefficient values, Kp,corr = Cp/Cg, of approximately 10(-3.5) m3/microg, indicating its preference for the gas phase. Pendimethalin exhibited more semivolatile behavior,with Kp,corr values that ranged from 10(-3) to 10(-1) m3/ microg and increased with sampling height and distance downwind of the operation. An increase in pendimethalin enrichment at a height of 5 m suggests winnowing of finer, more sorptive soil components with corresponding higher transport potential. Pendimethalin was enriched in the PM2.5 samples by up to a factor of 250 compared to the field soil, indicating thatfurther research on the processes controlling the generation of PM-bound herbicides during agricultural operations is warranted to enable prediction of off-site mass fluxes by this mechanism.

Failing head (and a few rising head) measurements were made of hydraulic conductivity k in a profile of a 7 m deep, small raised bog in southwest Scotland. The seven piezometer pipes were 39 mm diameter, and most of the measurements were made with attached tubes of 2.5 mm diameter, so that only 2-3 mm of water crossed the peat inter-face during a run. There were no consistent effects of pre-flushing, direction of flow (failing, rising), or measuring-tube size. Variability of 10-20% in k did not obscure an exponential decrease with depth from 5 x 10(-6) cm s(-1) at 100 cm to 0.7 x 10(-6) cm s(-1) at 500 cm. This decrease was uncorrelated with dry bulk density or peat stiffness, and only loosely so with a measure of humification. Calculated mean bulk velocity of pore water may be as low as 1 mm year(-1). Pressure in the silty sand below the peat was 180 mbar less than expected, suggesting a thin highly impermeable layer ('pan'?) at the peat base. The substratum may have hydrological connection with an adjacent lake. The hydraulic properties of this raised bog contrast strongly with those of a raised bog in Minnesota, and do not fit the assumptions made for Ingram's simple groundwater mound model of raised bog shape. Copyright (C) 2004 John Wiley Sons, Ltd.

The editors of Journal of Ecology would like to thank the following colleagues for their assistance in evaluating manuscripts during 2003. Their opinions have been greatly appreciated. We hope that the already high percentage of referees willing to work within our new web-based system will continue to increase, but are happy to make alternative arrangements for those who find it difficult to review in this way. All we ask is that you should, if at all possible, upload your report via the system or, failing that, e-mail a copy of your report to the Managing Editor, in addition to any hard copy you return by post. We do try to spread the workload but we are particularly grateful to colleagues who have been willing to help on several occasions throughout the year (see p. 3).

The role of peatlands in the global carbon cycle is confounded by two inconsistencies. First, peatlands have been a large reservoir for carbon sequestered in the past, but may be either net sources or net sinks at present. Second, long-term rates of peat accumulation (and hence carbon sequestration) are surprisingly steady, despite great variability in the short-term rates of peat formation. Here, we present a feedback mechanism that can explain how fine-scale and short-term variability in peat-forming processes is constrained to give steady rates of peat accumulation over longer time-scales. The feedback mechanism depends on a humpbacked relationship between the rate of peat formation and the thickness of the aerobic surface layer (the acrotelm), such that individual microforms (hummocks, lawns, hollows and pools) expand or contract vertically in response to fluctuations in the position of the water table. Hummocks (but not hollows) 'evolve' to a steady state where changes in acrotelm thickness compensate for climate-mediated variations in surface wetness. With long-term growth of a topographically confined peat deposit, the steady state gradually shifts to a thicker acrotelm (i.e. taller hummocks) and lower rates of peat formation and carbon sequestration.

We made an experiment on a 30 cm diameter core of Sphagnum‐dominated vegetation and peat to estimate the parameters controlling methane oxidation during movement to the ambient air: 13CH4 was added at the water table, and excess 13CO2 appeared in the gas space above the core. At 20°C in otherwise undisturbed conditions, ∼22% of CH4 was oxidized to CO2 during passage up through the overlying 10‐cm thick unsaturated peat and plants. We simulated the experiment, with seven parameters: transfer coefficients in water, in the gas phase, and through the container wall; the rate of CH4 and of CO2 generation; and the two parameters of a hyperbolic relation between CH4 concentration and the rate of CH4 oxidation. We optimized these parameters to fit the experimental results, and then were able to generalize to any temperature (0°−25°C) and any depth (0‐55 cm) of water table. Changing temperature has important effects on the proportion of CH4 oxidized.

L.W. Aarssen R. Abbott A. Agrawal R.T. Alisaukas J. Anderson R. Anderson W. Armstrong H. Auge C. Augspurger M. Austin J.P. Bakker K. Barber J.A. Barone S. Bartha C.C. Baskin J.M. Baskin J. Bates A.J. Beattie R. Bekker P. Bellingham R. Bello K.D. Bennett F. Berendse B. Berg E.A. Bernays M. Bertiller M.D. Bertness A. Biere P. Bierzychudek C. Birch H.J.B. Birks R. Bobbink O. Bragg T. Bragg D.D. Briske H. Brix M. Brock N. Brokaw R.W. Brooker N.A.C. Brown N.D. Brown J. Brunet J.M. Bullock M. Burd I.C. Burke D.F.R.P. Burslem R.T. Busing D. Byers M. Cain B.D. Campbell D. Campbell C. Canham S.J.M. Caporn P.D. Carey B.A. Carlsson H. Carrick B.B. Casper F. Chambers J.C. Chambers P.A. Chambers R.L. Chazdon G.P. Cheplick P. Chesson D.A. Clark D.B. Clark P.J. Clarke K. Clay R.S. Clymo M.L. Cody P.D. Coley S. Collins R. Condit J.H. Connell J. Connolly E. Cooch R. Corlett R. Cousens R.M.M. Crawford M. Crawley J. Cresswell T. Croat T. Czaran M.R.T. Dale R.E. Daniels C. d'Antonio M.B. Davis T. Dawson T. de Jong H. de Kroon M.B. de Matos D. de Steven D. Deangelis R. del Moral H. Delcourt J. Denslow J.D. Derner N. Dickinson U. Dieckmann M. Diemer R. Dirzo A.G.F. Dixon R.W. Dolan A. Dyer V.M. Eckhart G. Edwards J.G. Ehrenfeld J. Ehrlen A. Ellison R. Ennos N.J. Enright H.E. Epstein O. Eriksson S. Erland M. Ernebeg A. Escudero J.M. Facelli T. Fahey C. Fastie C. Ferris A. Fielding L. Firbank A.H. Fitter G.N. Flerchinger D. Ford M.J. Fortin B.L. Foster N. Fowler M. Franco D.A. Frank S. Franklin J. Frantzen R.P. Freckleton L. Frelich M.J. Gaillard L. Galloway A. Gange S. Gardner E. Garnier N.C. Garwood K.G. Gaston M. Geber A.E. Giblin C.W.D. Gibson J. Gignoux F. Gilbert F.S. Gilliam H. Gitay T. Givnish P.H. Glaser S. Glenn J.S. Glitzenstein D. Goldberg D. Gordon E. Gorham N. Gotelli L. Gough J. Grace J.B. Grace A. Granstrom A. Gray D. Grigal J.P. Grime E. Grimm P. Groom W. Grosse P.J. Grubb M.E. Hanley I.A. Hanski L.D. Harder K. Harms A. Headley J. Healey A.J. Hector G.W. Heil T. Herben S. Hicks M.O. Hill A. Hladik R. Hobbs C. Holzapfel G. Houle S.P. Hubbell E. Huber-Sannwald R. Hufbauer M.K. Hughes P.E. Hulme L.D. Humphrey C. Humphries R. Hunt B. Huntley M. Huston H.A.P. Ingram D.H. Janzen A.M. Jarosz F. Jeltsch A. Jensen E. John E.A. Johnson P.A. Joli€e S. Jonasson M. Jones R.H. Jones I.S. Jonsdottir B. Jonsson W. Junk V. Kapos P.S. Karlsson K. Karoly P. Keddy J.E. Keeley J.T. Kerr D.A. King K. Kitajima F. Kjellberg J. Klironomos R. Kobe J. Koricheva C. Korner P. Kotanen W.E. Kunin M.M. Kwak H. Lamb R. Law J. Leake M. Lechowicz M.A. Leck D.W. Lee J. Leps P. Lesica D. Lieberman M. Lieberman M. Lonsdale J. Lord C.G. Lorimer C.H. Lusk J. Lussenhop A. Mackenzie J.A. MacMahon M. Macnair M. Manseau T. Maranon J. Maron F. Martin G.R. Matlack D. Matthies M.A. Maun B. Maurer S. Mazer K. McConnaughay R. McCulley K. McKee J.S. McLachlan S. McNaughton G. McPherson R. Meade T. Meagher R. Michalet P. Milberg P. Mitchell R. Mitchell J. Mitchley D. Moe M. Mogie U. Molau M. Molles K.A. Moloney M.D. Morecroft C. Morris D. Morse A.M. Mortimer B. Moss O. Mountford H. Muller R. Myster R. Nathan E.I. Newman K.K. Newsham P. Niklaus C. Nilsson D.A. Norton B. Oborny J. Oksanen L. Oksanen J.G.B. Oostermeijer D.R. Orr N.J. Ouborg M.W. Palmer J. Pannell I. Parker M. Partel R.W. Pearcy B. Peco S. Pennings A. Pentecost J. Perry G. Peterken M. Philipp R. Plotnick A.J. Pollard C. Potvin K. Preston R.B. Primack A. Prins M.C.F. Proctor F.I. Pugnaire F.E. Putz D.A. Pyke S.R. Radosevich B. Rathcke R. Reader E.G. Reekie M. Rees M. Rejmanek J.F. Reynolds M. Riba K. Rice T. Rich A.J. Richards G.P. Robertson J. Roelofs W.R. Rouse S.H. Roxburgh R.W. Ruess C.M. Ru€ner P.W. Rundel J. Runkle G. Rusch D. Ryder N. Saintilan R. Santos F. Scatena M. Sche€er W. Schlesinger P. Schmalzer S.A. Schnitzer T.W. Schoener F.H. Schweingruber R. Scott W.E. Seel K. Seiwa D.M. Seliskar G.R. Shaver K. Shea B. Shipley J. Silvertown Journal of Ecology 2000, 88, 183±184

Efflux of CH4 from natural wetlands commonly occurs through vascular plants. These plants also conduct oxygen from the surface to the rhizosphere, permitting CH4 oxidation to occur at depth. It is therefore important to be able to quantify the extent of plant-mediated gas transport. We treated roots as ubiquitous impermeable hollow tubes open at each end, then incorporated an effective root-ending area density function εr(z) into a standard transient diffusion equation. We were able to simulate (r2=0.98) measured transport of the biologically inert gas Ar into an intact peat core dominated by bogbean (Menyanthes trifoliata). The best-fit function εr(z), itself correlated well (r2=0.85) with the measured root mass density distribution μM(z), suggesting a means to generate εr(z) from root mass data obtained elsewhere. Were such a strategy to have been applied to the core we examined, the simulated data would have correlated reasonably well (r2=0.70) with reality. The generality of the proportionality constant relating root transmissivity [εr(z)] and mass [μM(z)] remains to be established. Where vascular plants are not present (e.g. in a core dominated by the bog mosses Sphagnum cuspidatum and S. papillosum), diffusion occurs in the liquid phase of the peat only.