Carbon Capture & Pigment Workshop
Emily Terry reports on the Carbon Capture and Pigment Workshop held on Saturday 23rd April at Long Mead Barn, Eynsham:
The fourth of Nature Recovery Network’s Art and Science Workshops was titled, Carbon Capture and Pigment and was hosted by Long Mead. The twenty or so C-minded individuals , ranging from professional artists to budding young scientists, first enjoyed homemade biscuits with a cup of coffee/tea whilst bonding over… yes, you guessed it… carbon!
Carbon (C; atomic number 6; atomic weight 12) is the foundation of all life on Earth. Actually, there's not a lot of it around - it makes up only about 0.025 percent of the Earth's crust, but its atomic stucture gives it properties that allows it to make more compounds than all other elements put together. Our problem is that carbon-based gases are 'greenhouse gases', that result in the Earth warming when they accumulate too much in the atmosphere.
Dr. Clare Lawson from the Floodplain Meadows Partnership at The Open University began the Workshop by explaining how the species-rich floodplain wildflower meadows are first and foremost a part of modern agriculture, providing healthy grazing and hay crops to sustain livestock throughout the winter, and producing a crop without inputs like artificial fertilisers, herbicides or pesticides.
Animals like cows and sheep digest, by fermentation, plant cellulose - a long chain of glucose molecules called a 'polysaccaride' that has the chemical formula (C6H10O5)n. The animals generate the greenhouse gases of carbon dioxide (CO2) and biogenic methane (CH4), which is a more potent greenhouse gas than CO2, but CH4 is a 'flow gas' which has a much shorter lifespan in the atmosphere than CO2, which is a 'stock' gas that stockpiles in the atmosphere. Theoretically, animals who feed exclusively on grass - pasture and/or hay - are 'carbon neutral' in the sense that their metabolic processes simply release carbon that was originally captured through photosynthesis by their plant food. This is known as the 'biogenic carbon cycle'. Only a tiny percentage of farm animals are exclusively grass-fed, however.
Along with many other socio-economic and environmental benefits, floodplain meadows are a particularly effective, reliable, and a long-term 'nature-based' solution for sequestering atmospheric carbon dioxide and in this respect should be recognised as equal in 'eco-system services' to forests, peat bogs and sea grass.
Clare took soil cores down to a depth of 800mm from Long Mead meadow itself (see figure above). We could see the differences in colour between the dark carbon organic matter closest to the surface, compared to the deeper sections of soil, containing less carbon, which were more clayey and lighter in colour.
We learnt that the greatest fraction of carbon in soil is stored in the top layers, where carbon organic matter is found. But when conventional agricultural fields are ploughed, all this carbon is oxidised and released into the atmosphere as carbon dioxide. Clare explained there are alternative methods to ploughing, like seed drilling, which are becoming more popular and do not lose excessive carbon dioxide by soil disturbance. By contrast, floodplain wildflower meadows are never ploughed and they are by definition wetter and so the carbon in the top-most layers is less prone to oxidation. Therefore a large fraction of the carbon sequestered by the plants and excreted through the roots into the soil remains as part of the soil organic carbon. In floodplain meadows virtually all the plants are perennial, so the critical mycorrrhizal fungi are not disturbed.
Ancient species-rich floodplain meadows include species of plants with roots reaching almost to three metres, allowing carbon storage to occur at greater depths. In all, soil carbon (organic and inorganic) represents fully 80% of all the carbon found in terrestrial ecosystems.
During the second ‘Pigment’ half of the workshop, Eric White gave a talk on the use of charcoal as a medium for creating artworks. He gave us each two small sticks of charcoal, one of which he had made himself from a willow tree, heating the sticks at a high temperature until all that was left was charcoal. We experimented with numerous techniques, from faintly brushing the charcoal against the paper, to applying greater pressure creating thick dark lines, to smudging the drawings with our fingers and rubbing out with white bread. Yum!
We took inspiration from Eric’s own artwork, as well David Hockney’s charcoal drawings, which Eric showed us, before heading out into Long Mead to put our teachings into practice, using charcoal to depict the meadow - the same meadow that has all that carbon stored under its surface...
The NRN is grateful to Natural England for supporting the four Wild Arts, Art and Science, Workshops.