Drought impacts on biogeochemistry and microbial processes in salt marsh sediments: a flow-through reactor approach

作者：Palomo Laura; Meile Christof; Joye Samantha B^*

来源：Biogeochemistry, 2013, 112(1-3): 389-407.

DOI：10.1007/s10533-012-9734-z

• Drought
• Salt marsh
• Organic matter mineralization
• Dieback

The effects of drought on salt marsh sediments from Sapelo Island, Georgia, were examined in flow-through reactor experiments. Three hydrological treatments were employed: a continuously flooded anoxic control, a periodic drought treatment that experienced alternate periods of flooding and drying, and a severe drought treatment, where sediment was exposed to drought (drying) for several weeks and then flooded; the effect of both buffered and non-buffered flooding solutions were examined. In permanently anoxic sediments as well as in sediments exposed to drought, organic carbon oxidation was dominated by SO4 (2-) reduction (SR) and SR rates increased over time. The shift from anoxic to oxic conditions in drought treatments significantly altered sediment geochemistry and pathways of microbial metabolism. Drought conditions favored suboxic mineralization processes, such as Fe(III) reduction and denitrification, which was fueled by NH4 (+) oxidation promoted by O-2 delivered during drought conditions. Other major drought-induced changes included pH decrease, and altered concentrations of solid phase adsorbed metals.

• 出版日期2013-3