Farms, factories and fertiliser: the effects of air pollution on peatlands

Blog originally written for

When I was a teenager I spent a lot of time walking the moors of the Peak District National Park in northern England. I guess we all tend to think that the landscapes we grow up with are ‘normal’ and it didn’t occur to me then that there was anything unusual about a landscape of bare black peat, deep erosion gullies and heather. I accepted the chance of sinking to my armpits in sludgy foul-smelling black peat as part of the ‘fun’! However if you head up to the moors with a shovel you can quickly tell that the landscape wasn’t always like this. Dig down a bit and you can find peat full of the remains of Sphagnum mosses, species that you will struggle to find at all in the area today.

The Peak District lies between the great industrial cities of Sheffield and Manchester; the wealth of Victorian Britain was built on Manchester cotton and Sheffield steel and both of these industries were powered by coal. The fumes from burning vast quantities of coal, rich in sulphur and heavy metals, ended up on the Peak District, acidifying the peat and killing the crucial carpet of plants which held the moors together. As the plants were lost erosion started and huge quantities of peat have been washed and blown away over the last 150 years. Ironically, as the peat eroded it began to cause problems for us as the eroding peat released accumulated heavy metals back into our water supplies and turned drinking water an unpleasant dark brown. Air pollution hasn’t been the only cause of peatland damage in the Peak District; over-grazing, fire and walkers like me have paid a role too, but the intense pollution on top of these other factors has tipped the balance towards total destruction. Today the great Victorian industries are largely gone but the power stations and vehicle emissions of modern Britain continue to exact their toll on the moors.

Air pollution comes in many forms. Sulphur, and heavy metals were major causes of damage to bogs in the past and ozone may be damaging bogs in ways we don’t fully understand today. However, the pollutant which causes the most conservation concern is nitrogen. Nitrogen is in the air all around us as stable di-nitrogen (N2). This form of nitrogen is inert and doesn’t cause pollution problems. It takes a large amount of energy to break the bond holding the two nitrogen atoms together but when broken nitrogen becomes highly reactive. It is this ‘reactive nitrogen’, which cause pollution problems.

There are two main types of nitrogen pollution; oxides of nitrogen (NOy) are primarily a by-product of fossil fuel consumption and reduced nitrogen (NHx) which is derived primarily from agricultural fertilisers. This is an environmental issue which doesn’t excite the public imagination but the problem is vast. Human production of reactive nitrogen is now more than double natural nitrogen fixation; there is nowhere on the surface of the planet which doesn’t show the signature of human meddling in the global nitrogen cycle. The huge changes we have wrought have been called the first ‘planetary-scale experiment with geoengineering’. The negative impacts of nitrogen cost the countries of the European Union alone up to €320 billion a year.

Reactive nitrogen is essential to all life on earth but most species have developed in conditions where it is rare. We know from decades of experimental studies that excess nitrogen deposition leads to a reduction in biodiversity and dominance by ‘weedy’ species which can exploit these extra resources. In bogs this often means a loss of the crucial Sphagnum mosses and dominance by vascular plants such as Purple Moor Grass (Molinia caerulea). A particularly extreme example is carnivorous plants like Sundew (Drosera spp.) which have evolved to cope with a limited supply of nitrogen by capturing and consuming insect prey. However, in a world where large quantities of nitrogen are (literally) falling from the sky the plants have no need to capture insects; they switch to using nitrogen from the soil and prosper in the short-term but are ultimately out-competed by other plants which can better exploit the new regime (see paper here).

While most peatlands are quite remote from pollution sources the long distances which nitrogen pollution can travel and high rainfall in peatland areas mean that they can be heavily affected. Most bogs are poor in nutrients and weakly-buffered so even small amounts of nutrients and acids can produce big impacts. In the UK the average nitrogen pollution exposure of peatlands is almost three times greater than the recognised ‘safe’ level. The impacts of nitrogen pollution we see in experiments can be drastic; you can even see the trail of damage from ammonia released in the Whim Moss experiment from a satellite! Similar impacts are starting to be detected in real peatland landscapes. A recent study showed that areas of UK bog with more nitrogen pollution had consistently fewer plant species while cleaner areas had more.

In Europe we have been quite successful at tackling oxidised nitrogen emissions with a 60% reduction over the last 40 years in the UK. However, reduced nitrogen emissions remain stubbornly high. Since the invention of the Haber-Bosch process we have become reliant on cheap, readily available nitrogen fertilisers to increase and maintain agricultural productivity. It is estimated that half of the global population would not be alive without industrially-produced fertilisers so reducing this reliance is not easy.

In the Peak District the good news is that thanks to restoration work by fantastic organisations like Moors for the Future the moors are now in a much better state than when I was a teenager; there is less bare peat, less erosion and you will even find Sphagnum in a few spots. However getting the moors to this state hasn’t been easy or cheap. Gully sides have been stabilised with geotextiles, lime and grass seed have been dropped from helicopters to neutralise and re-vegetate the bare peat and new flagstone paths have been constructed to minimise the impact of walkers. It is simply impossible to do this sort of intensive restoration for all the world’s peatland which is currently damaged by air pollution or may be in the future. Our only alternative is to stop peatlands deteriorating to this point. It is possible to change the trajectory; the Netherlands used to have perhaps the highest levels of nitrogen pollution in the world but has succeeded in making big reductions by mandating the use of better agricultural technologies. We can all make a difference by reducing our use of fossil fuels and cutting down on the meat in our diets. Start by using the excellent nitrogen footprint calculator to calculate how much you contribute to the problem.


Leave a comment

Filed under Uncategorized

Research Opportunities in Scotland

We have three potential research opportunities available at Stirling, or in collaboration with other institutions:

1. We have a fully-funded MSc by research studentship available jointly between Stirling and ERI-Thurso. The student will work on a Carnegie Trust-funded project looking at peatland C accumulation in peatlands in northern Scotland using tephra layers. We are looking for a talented final-year undergrad or taught MSc student, with previous experience in peatlands or geochronology a plus. Further details here:

2. Also starting this autumn we have an opening for a soil ecology apprentice to work on testate amoebae as restoration indicators in Scottish peatlands. The apprenticeship is funded by TCV Scotland and is open to people of all ages, including those with non-traditional backgrounds. Further details here:

3. Finally, myself and Lucy Sheppard at CEH Edinburgh are looking for somebody to work on testate amoebae and nitrogen deposition at the Whim Moss experiment. For people from outside the UK funding may be available through the expeer project and we have a proposal written for this purpose- we are hoping that somebody may be interested in coming to work on this project for a short research stay of maybe six weeks. The scheme is open to people at all career stages but might particularly suit a recent PhD graduate.

If you are interested please get in touch.

PS it’s nothing to do with me but since I’m writing this, I know that Dundee are also advertising for a PhD position in peatland science here: which may also be of interest.



Leave a comment

Filed under Uncategorized

Borth in the sunshine (for a change!)


For once it’s been really nice weather in west Wales.Image

A good day for fieldwork. Image

This is our climate change experiment at Cors Fochno.

Leave a comment

Filed under Uncategorized

Impressions of the European Parliament

I spent last week at the European Parliament in Brussels. The British Ecological Society run a scheme where early career ecologists spend two days shadowing somebody involved in environmental policy making. I spent a very informative couple of days with an MEP. Some -entirely informal- impressions:

  1. These people work hard, really hard. They make most academics look like slackers!
  2. To get science results to politicians seems to really requires intermediaries like NGOs, thinktanks, and the media. Probably making sure these organisations aware of scientific results should be the top priority if we want to communicate policy-relevant results.
  3. The simultaneous translation is hugely impressive. I amused myself by listening to some of the more boring bits in Maltese and Lithuanian!
  4. Most of the politicians I met seemed to be in it with a genuine aim to make things better. Probably they also quite like the power and prestige.
  5. I was surprised how separately MEPs seem to operate from Westminster and how little party politics is involved in the process.
  6. I can kindof see why so many politicians seem to have affairs with their secretaries!- it’s a pretty intense and personal relationship.
  7. I was surprised how informal the place feels.
  8. Policy-makers knowledge of environmental issues seems quite shallow, but quite broad.
  9. I’d forgotten how much I like Brussels as a city, it’s a really nice relaxed and liveable sort of city.
  10. I’m now really curious how Westminster compares to Brussels, I suspect quite drastically different (at least if The Thick of It and Yes Minister are anything to go by!).

Leave a comment

Filed under Uncategorized

I am a peatnik!

For those of you wondering about the name of this blog; a peatnik is an informal term for a peatland scientist- like a beatnik or peacenik but with more mud! The word is used fairly often but I gather it was originally coined by Lisa Belyea at QMUL. I have made it ‘peatniks’ plural in the blog title as I hope some of my students and colleagues will also contribute in due course.

Leave a comment

Filed under Uncategorized

Back to Cors Fochno

ImageOne of the major projects I have been working on over the last four years is a climate change impacts study. The impacts of climate change on peatlands is a key uncertainty in our understanding of possible future carbon cycles. We have been simulating climate change on two bogs: Whixall Moss on the English-Welsh border and Cors Fochno (Borth Bog) on the Welsh coast not far from Aberystwyth. The original aim of having two sites was to consider the possible role of pollution in sensitising peatlands to climate change: Whixall Moss has high levels of nitrogen pollution while Cors Fochno is quite clean (in hindsight it seems likely that other factors are more important in the differences between the two sites). Our experiments have two treatments: warming and drought. The plots are 2x2m and surrounded by plastic piling, the warmed plots have transparent plastic open top chambers to passively warm the surface while the drought plots have a (globally-unique!) system where water is actively pumped out of the plots. The experiments were originally part of the PEATBOG project which finished last year: you can find out more about that on the website and our former blog. Since the formal end of the project we have been keeping the Cors Fochno experiment on tick-over while we removed the Whixall experiment earlier in the year as we don’t have the resources to keep both running. I will write more about the results of the study some other time. On Wednesday we are interviewing for a new PhD student who will work on the experiment as part of a NERC algorithm studentship. When the student starts we hope to resume more intensive sampling. I am writing this from our usual B&B in Borth having just spent the day in the field. In this tick-over phase we are just downloading data-loggers, measuring CO2 fluxes and collecting litterbags. Today’s fieldwork has been delightfully warm and sunny, something of a rarity in west Wales! Fingers-crossed it continues for tomorrow.

Leave a comment

Filed under Uncategorized

Why this blog?

The aim of this new blog is to communicate the research that I, and we at the University of Stirling, do on peatlands and environmental change. Peatlands are fascinating and really important ecosystems, but they’ve had a bad press over the years. Often viewed as wastelands, peatlands around the world have been drained and damaged. We are only now realising quite what a bad thing this has been. Peatlands are receiving increasing attention by scientists and policy makers due to the ammount of carbon they contain- equivalent to somewhere between half and all the CO2 in the atmosphere (depending on which estimate you use). Making sure all this carbon stays safely locked away in the peat in the future is a serious concern. We study the impacts on bogs of direct disturbances like drainage and afforestation and indirect impacts through climate change and pollution. I think peatlands are beautiful, fascinating ecosystems but the scale of that beauty is just different to other ecosystems- you have to look closely to appreciate the intricate beauty of Sphagnum moss or the wealth of weird and wonderful small creatures. I hope this bog will, in some small way, help more people to appreciate and value peatlands.

1 Comment

Filed under Uncategorized