During my studies of biology, I focused on the marine biodiversity of the Wadden Sea and became interested in biogeochemical cycles in the sediment, and how they are impacted by the flora and fauna, as well as by abiotic conditions. Consequently I started a PhD on the effects of global warming on greenhouse gas cycles in freshwater lakes, at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries. My interest in methane emission pathways ultimately led me to my current PostDoc at the University College Dublin, where I'm studying the impact of coastal wetland vegetation on greenhouse gas emissions and carbon sequestration.
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Invasive Spartina alterniflora increase greenhouse gas fluxes from coastal vegetated wetlands
A. FUCHS, I. DAVIDSON, C. SIMANKIN, J. DEVANEY, J. P. MEGONIGAL, G. NOYCE, M. LU, G. COTT
University College Dublin, School of Biology and Environmental Sciences, Belfield, Dublin 4, Ireland
Coastal wetlands are among the most carbon-rich ecosystems on Earth, providing shelter to a multitude of birds, fish, and invertebrates, stabilising the shoreline against erosion and storm surges, and sequestering atmospheric carbon dioxide. Spartina alterniflora is a fast-growing C4 grass species, that was introduced intentionally to China in the 1980s to protect the coast, and has invaded many native saltmarsh and mangrove habitats in Asia since then, transforming them into S. alterniflora monocultures. S. alterniflora has an extensive network of roots an rhizomes and a high abundance of aerenchyma, which facilitate the uptake and plant-mediated emission of methane to the atmosphere. We conducted a meta-analysis to evaluate the net effect of invasive S. alterniflora on greenhouse gas emissions, and correlated it to effects on plant biomass and soil carbon content. We found consistent and long-lasting increases of methane emissions in all types of invaded wetlands, which correlated to soil organic carbon and are likely driven by methylated compounds from root exudates as well. The effects of invasive S. alterniflora on nitrous oxide and carbon dioxide varied among native species. Most notable, mangrove habitats were the only system where invasive S. alterniflora increased nitrous oxide emissions in addition to methane.