1. Salt marsh nitrogen cycling: where land meets sea.
- Author
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Bowen, Jennifer L., Spivak, Amanda C., Bernhard, Anne E., Fulweiler, Robinson W., and Giblin, Anne E.
- Subjects
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NITROGEN cycle , *SALT marshes , *SOIL salinity , *ELECTRON donors , *DENITRIFICATION , *WATERLOGGING (Soils) , *ELECTROPHILES - Abstract
Salt marshes are hot spots for nitrogen (N) cycling due to complex and dynamic redox gradients. Soils of salt marshes contain a wide diversity of microbes capable of carrying out steps in the N cycle. Recent discoveries demonstrate that chemolithotrophic (e.g., sulfide oxidation coupled with N 2 fixation), as well as heterotrophic metabolisms, are important for N cycling in salt marshes. N removal via denitrification is an important ecosystem service provided by salt marshes. N fixation and N retention due to dissimilatory nitrate reduction to ammonium (DNRA) are more important than previously thought and may contribute to salt marsh productivity. Salt marshes sit at the terrestrial–aquatic interface of oceans around the world. Unique features of salt marshes that differentiate them from their upland or offshore counterparts include high rates of primary production from vascular plants and saturated saline soils that lead to sharp redox gradients and a diversity of electron acceptors and donors. Moreover, the dynamic nature of root oxygen loss and tidal forcing leads to unique biogeochemical conditions that promote nitrogen cycling. Here, we highlight recent advances in our understanding of key nitrogen cycling processes in salt marshes and discuss areas where additional research is needed to better predict how salt marsh N cycling will respond to future environmental change. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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