University of Nottingham
In the Laboratory
The lab work is nearly complete.
I have been extremely busy over the last few months. I am not a chemist, but this PhD required a good chunk of chemistry. It has been a huge learning curve for me.
All my experiments so far have told me how well the heather is growing in the soils that I collected from around the country, all with different nitrogen deposition values. These new experiments will tell me WHY the plants grew the way that they did by telling me how much nitrogen and phosphorus they took in during growth. Both these elements are essential in plant growth.
During December, I was in the lab virtually every day trying to learn the tecniques involved. Things didn't always go to plan. I would fill fifty tubes with all the chemicals, only to find out that the reactions didn't take place. I remade all the reagents, but it still didn't work. It took over a week, and a great deal of research, to find out that one of the dry chemicals isn't stable in solution. It could work for three weeks, and then suddenly stop working.
During January and February I have been putting my techniques into practice. Data collection begun on January 11th. All has gone to well so far, and I hope to be finished by next week. After these experiments are complete I will hopefully start writing my first paper, and start to write my final thesis.
In the meantime, these two videos explain what I have been doing for the last few months.
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Harvesting Complete
All 514 seedlings have been harvested.
It took a good week or so to separate all the seedlings from the soil, dry them in an oven to remove the water, and then to weigh them.
It looks like the initial results are OK; there is some relationship between plant size and nitrogen deposition. However, there are still a great many factors that need to be included in the analysis which could explain the differences in plant size.
These include the vegetation survey data, plant chemistry, the size of heathlands, management strategies, and many others.
Currently I am analysing the plants for nitrogen and phosphorus content, both of which indicate soil fertility.
A new video coming soon....
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In the lab and field
My seedlings in the lab have been growing for nearly four months.
Still the tallest plant is only a few centimeters tall.
This video shows the seedlings in June, just after they had germinated.
Four months on the video below shows the seedlings in all their glory. It's nearly time to begin harvesting them for analysis, but before that I need to spend a few days finishing up some work that took an entire summer to do.
I revisited all my sites again to collect vegetation data. This involved allocating a 50x50m area of heathland, dropping twenty 50x50cm squares (quadrats) within that area, and then recording all the plants, lichens and mosses within each quadrat.
Not only was this great fun, mainly because I got to fly in a helicopter to Lundy Island, and drive all the way up to Scotland, but it also provided me with a great deal of information about my sites.
Next comes the harvesting phase...
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Soil sample month
Two hundred and fifty-seven samples collected!
It took four weeks, and a good few thousand miles, but finally all the soil samples have been collected. These have now been placed in pots, and two heather seedlings are growing in each sample.
Currently the seedlings are less than 3mm high, but within the next six months they will grow slowly, to around 5cm!
The next step is to collect some other data from the soil. I dry a sample in an oven at 85°C, and then combust it in a furnace for eight hours at 550°C. This will provide loss on combustion data, which essentially tells me how much organic matter is in the soil, as opposed to mineral matter, such as sand. This might affect how the heather grows, but I will have to wait another six months to find that out!
Now I am preparing for a summer of vegetation surveys around my heathland sites. If you want to see me in action collecting soils, check out this video:
There is also more fun science-related stuff on TestTube...
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Soil Collection Begins
To start my nitrogen pollution experiments, I have to collect soil samples from every site.
I only need a small amount, so it won’t be damaging to the habitats. Each site has different levels of nitrogen pollution, so I am hoping that each soil sample with be different. Once I have collected the soil I will bring it back to my laboratory and grow heather in it for a number of months.
If all goes well, analysis of the heather plants will tell me if the soil fertility is different, depending on the nitrogen deposition from the atmosphere. Does the fertility of the soil affect the disappearance of heathland? That's what I hope to find out!
Currently I am germinating 1,050 heather seeds in the lab. I only need 250, but it is always best to overestimate the number of seeds that you think will germinate. I expect around 60-70%... we will see.
I will next update the blog after I have collected all my soil samples from across the country.
From Inverness to Lundy Island
The last few months has been spent travelling from one end of the UK to the other in order to find heathland sites.
I can't use just any sites. I want to study whether soil fertility is affected by nitrogen pollution. This pollution can come from factories, cities or farming, and too much of it can cause heathlands to disappear. My heathland sites must have a certain nitrogen deposition (fertility), they can't have too much rainfall, they can't be too high up, they can't contain plants which affect nitrogen concentration in the soil...the list goes on.
But I have found 26 great sites so far, from near Inverness in Scotland, to The Lizard in Cornwall, to Lundy Island! The next step is to start collecting soils.
Here I am surveying one site in the East Midlands! In the background you can see one plant which affects nitrogen concentration in the soil: Ulex europaeus, more commonly known as gorse.
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