Biogeochemical effects of simulated sea level rise on carbon loss in an Everglades mangrove peat soil
Saltwater intrusion and inundation can affect soil microbial activity, which regulates the carbon (C) balance in mangroves and helps to determine if these coastal forests can keep pace with sea level rise (SLR). This study evaluated the effects of increased salinity (+15 ppt), increased inundation (−8 cm), and their combination, on soil organic C loss from a mangrove peat soil (Everglades, Florida, USA) under simulated tides. Soil respiration (CO2 flux), methane (CH4) flux, dissolved organic carbon (DOC) production, and porewater nutrient concentrations were quantified. Soil respiration was the major pathway of soil organic C loss (94–98%) and was approximately 90% higher in the control water level than the inundated treatment under elevated salinity. Respiration rate increased with water temperature, but depended upon salinity and tidal range. CH4 flux was minimal, while porewater DOC increased with a concomitant, significant decline in soil bulk density under increased inundation. Porewater ammonium increased (73%) with inundation and soluble reactive phosphorus increased (32%) with salinity. Overall, the decline in soil organic C mineralization from combined saltwater intrusion and prolonged inundation was not significant, but results suggest SLR could increase this soil’s susceptibility to peat collapse and accelerate nutrient and DOC export to adjacent Florida Bay.
KeywordsSoil carbon Sea level rise Everglades Mangrove Saltwater intrusion Greenhouse gas production
This material was developed in collaboration with the Florida Coastal Everglades Long-Term Ecological Research program under National Science Foundation Grant No. DBI-0620409 and was made possible with support from the South Florida Water Management District and Everglades National Park, who offered site and facility access, equipment, and sampling assistance. This research was also supported through a graduate fellowship from the Everglades Foundation.
- Bouillon, S., J. J. Middelburg, F. Dehairs, A. V. Borges, G. Abril, M. R. Flindt, S. Ulomi & E. Kristensen, 2007. Importance of intertidal sediment processes and porewater exchange on the water column biogeochemistry in a pristine mangrove creek (Ras Dege, Tanzania). Biogeosciences 4: 311–322.CrossRefGoogle Scholar
- Bouillon, S., A. V. Borges, E. Castaneda-Moya, K. Diele, T. Dittmar, N. C. Duke, E. Kristensen, S. Y. Lee, C. Marchand, J. J. Middelburg, V. H. Rivera-Monroy, T. J. Smith & R. R. Twilley, 2008. Mangrove production and carbon sinks: a revision of global budget estimates. Global Biogeochemical Cycles 22: 12.CrossRefGoogle Scholar
- Chambers, L. G., T. Z. Osborne, & K. R. Reddy, 2013. Effect of salinity pulsing events on soil organic carbon loss across an intertidal wetland gradient: a laboratory experiment. Biogeochemistry 115: 363–383.Google Scholar
- IPCC, 2007. Climate Change 2007: A Synthesis Report. In: XXVII IP (ed.). Valencia, Spain: p 22.Google Scholar
- Lugo, A., S. Brown & M. Brinson, 1989. Concepts in wetland ecology. In Lugo, A., S. Brown & M. Brinson (eds), Ecosystems of the World 15. Elsevier, Amsterdam: 53–85.Google Scholar
- Patrick, W. H. & R. D. DeLaune, 1977. Chemical and biological redox systems affecting nutrient availability in the coastal wetlands. Geoscience and Man. 18: 131–137.Google Scholar
- Rivera-Monroy, V. H., K. de Mutsert, R. R. Twilley, E. Castaneda-Moya, M. M. Romigh & S. E. Davis, 2007. Patterns of nutrient exchange in a riverine mangrove forest in the Shark River Estuary, Florida, USA. Hydrobiologia 17: 169–178.Google Scholar
- Sangiorgio, F., A. Basset, M. Pinna, L. Sabetta, M. Abbiati, M. Ponti, M. Minocci, S. Orfanidis, A. Nicolaidouc, S. Moncheva, A. Trayanova, L. Georgescu, S. Dragan, S. Beqiraj, D. Koutsoubas, A. Evagelopoulos & S. Reizopoulou, 2008. Environmental factors affecting Phragmites australis litter decomposition in Mediterranean and Black Sea transitional waters. Aquatic Conservation-Marine and Freshwater Ecosystems 18: S16–S26.CrossRefGoogle Scholar
- Smoak, J. M., J. L. Breithaupt, T. J. I. Smith & C. J. Sanders, 2012. Sediment accretion and organic carbon burial relative to sea-level rise and storm events in two mangrove forests in Everglades National Park. Catena.Google Scholar
- Spalding, M., M. Kainuma & L. Collins, 2010. World Atlas of Mangroves. Earthscan, London.Google Scholar
- Wanless, H., R. Parkinson & L. Tedesco, 1994. Sea level control on stability of Everglades wetlands. In Davis, S. & J. Ogden (eds), Everglades: The Ecosystem and its Restoration. St. Lucie, Boca Raton: 198–224.Google Scholar