Coastal scientists at the BGS, in collaboration with the universities of Bangor and Aberystwyth, are examining how the flux of material in estuaries responds to short-term events such as river floods.
We aim to study the Dyfi Estuary in Wales, UK, to understand how the terrestrial (from the land) biogeochemical components change in response to different physical forcings such as tides, storms, transport distance and salinity using the molecular tracer lignin. What is lignin?
The Dyfi estuary is in west Wales, north of Aberystwyth. This estuary has been selected as it is a pristine catchment with no industrial centres to contaminate the sediment and affect the results.
Estuaries are key environments linking the land to the sea. Since estuaries have a high biological productivity they not only generate their own organic matter, but also receive terrestrial organic matter inputs from the surrounding catchment, as well as from the sea.
Consequently, the accumulation, preservation, as well as chemical degradation processes that occur in the coastal-river transition zone, are an important part of the global organic carbon cycle.
At present, scientists have a rather poor understanding of how terrestrial inputs of organic matter are transported through the river-estuarine and coastal system.
Lignin is a highly cross-linked aromatic structural polymer, virtually unique to terrestrial vascular plant tissues. It is used by plants as natural scaffolding and is fairly resistant to degradation by microbes in the environment (see references below).
These characteristics make lignin an ideal terrestrial carbon tracer, providing information on plant source origin, amount of terrestrial material and also residence time in soils and flood plain deposits.
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Vane, C H, Drage, T C, Snape, C E, Stephenson, M H, and Foster, C B. 2005. Decay of cultivated apricot wood (Prunus armeniaca) by the ascomycete Hypocrea sulphurea using solid state 13C NMR and Off-line TMAH thermochemolysis with GC-MS. International Biodeterioration and Biodegradation, 55, 175-185.
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Vane, C H. 2003. The molecular composition of lignin in spruce decayed by white-rot fungi (Phanerochaete chrysosporium and Trametes versicolor) using Pyrolysis–GC-MS and Thermochemolysis with Tetramethylammonium Hydroxide. International Biodeterioration and Biodegradation: 51, 1, 67–75.
Vane, C H, Martin, S C, Snape, C E, and Abbott, G D. 2001. Degradation of lignin in wheat straw during growth of the Oyster mushroom (Pleurotus ostreatus) using off-line thermochemolysis with tetramethylammonium hydroxide and solid state 13C NMR. Journal of Agriculture and Food Chemistry: 49, 2709–2716.
Vane, C H, Abbott, G D, and Head, I M. 2001. The effect of fungal decay (Agaricus bisporus) on wheat straw lignin using pyrolysis-GC-MS in the presence of tetramethylammonium hydroxide (TMAH). Journal of Analytical and Applied Pyrolysis, 60, 1, 69–78.