Carbon Storage in Peat - Planet Earth Online

The flat farmland area in the east of England, known as the fens, isn't everyone's cup of tea, but the rich peaty soil is of particular interest to climate scientists.

Now a team from the University of Leicester have developed an experiment in the centre of a field to measure how much carbon is absorbed and released by this peaty soil.

Planet Earth's Richard Hollingham, went to see the experiment...where he spoke to Ross Morrison and, first, the head of the project, Heiko Balzter...

Heiko - We are trying to get to the bottom of the carbon emissions that are coming off these soils and the different conditions, both different land use conditions and extreme weather as well.  We've had very extreme dry conditions last year lasting until about Easter and this year, of course, it has been one of the wettest summers in the last 100 years in Britain, so we are trying to find out what that does to the carbon exchange between the land surface and the atmosphere.  The carbon emissions coming off the peatlands here, of course, contribute to the global warming problem, so there is the feedback between the land and climate system and we are trying to get numbers of emissions that are coming off the ground.

Richard - Now, Ross, you're responsible for the experiment here which is cordoned off behind a barbed wire fence.  It's a series of solar panels, I'm guessing for electricity.  There is a substantial, almost like a fridge-sized green box and then a very peculiar - I don't know how best to describe this!  It's obviously some sort of weather instrument but it looks like a weather instrument crossed with a whisk, what is it?

Ross - This is a weather station but quite an advanced weather station.  It's got all the elements you would expect from a normal weather station, for example, we're measuring temperature, relative humidity and radiation and that sort of thing, but then the bit that looks a bit like a whisk is the more advanced part of this.  What we have here is a device, an anemometer that basically measures atmospheric turbulence and then we have the other device which basically measures the concentration of CO₂ and water vapour in the atmosphere.

Richard - And you're measuring the carbon dioxide, what, coming off the peat and going into the peat? The exchange of gases?

Ross - At certain times of year plants take up carbon dioxide from the atmosphere and throughout the year soils basically lose carbon dioxide to the atmosphere and so essentially using this instrument we can basically calculate how much is moving over quite a high frequency and every half an hour we get a measurement from this.  Then, obviously, over longer periods of time we can build that up to get an idea of how much carbon and we're gaining at certain times of the year and then losing at other times of the year and then the balance over time between that.

Richard - So when there's a crop in the field - so spring/summer then you'd expect the carbon dioxide to be coming into the peats and this time of year you would expect the carbon dioxide to be leaving?

Ross - Yes, at the moment there's a vegetation cover but this is just coming back naturally-

Richard - Nettles and weeds and bits and pieces?

Ross - Yes. When the crop is actually growing it does accumulate quite a lot of carbon, at least the crop we measured this year which was iceberg lettuce.  This did, on some part of the growing season, actually result in a net removal of carbon dioxide from the atmosphere as the crop was maturing.  Then at other times of the year following ploughing and this sort of stuff, at this time of year when essentially most of the soil is bare we would be expecting to see a net loss of carbon to the atmosphere.

Richard - Heiko, this isn't the only set up you've got, you're looking at other sites as well?

Heiko - Yes that's right. We have three towers in total in the fens now.  One is operated by the Centre of Ecology and Hydrology and two are operated by the University of Leicester.  They are covering a land use gradient with three different types of land use.  One is in the semi-natural fen in Wicken fen which is one of the few remaining areas of pristine peatland in the fens.  The second one is in a restored area that is Baker's fen near Wicken that is now managed by the National Trust for nature conservation purposes and is trying to re-wet the soil that was previously used to agriculture and this third one that was set up this year is the first one that is on agricultural soil on farmland.

Richard - And how will the information from this be used? What do you want to do with it?

Heiko - Well it has huge implications for knowing exactly the amount of greenhouse gasses that are omitted from the land surface areas.  First of all because we need to understand the earth system fully and we need to know how important the greenhouse gas emissions are from this area and to assess how important it is to protect the carbon that is locked in the soils here.  Secondly there is of course an implication for the farm managers in the sense that we are trying to identify the best way of actually helping them to reduce and control their carbon emissions which is in their own interest and it is one of the motivations why this farm manager here has made the land for us available to install the instrumentation.