Salt Marsh Restoration: Changes in Plant Biomass and Gas Flux
Abstract
Temperate salt marshes are among the most important and productive coastal wetland ecosystems globally. Their value is determined by the high primary productivity in salinized environments combined with the excessive sequestration rate of carbon into sediment and biomass. One of the most significant anthropogenic threats to coastal wetlands is the construction of dikes, bridges, and dams. Organic material that was once reduced in decay due to being under anaerobic conditions is now converted to aerobic respiration, releasing carbon dioxide and methane gas. On Cape Cod, salt marsh restoration has been conducted within the last decade. We measure the CO2 and CH4 fluxes in restored, degraded, and natural salt marshes and assessed the above-ground, below-ground biomass. We hypothesize that plant biomass yield in restored sites is greater than biomass in the corresponding natural sites; higher methane flux is present in restored sites compared to natural sites. To measure the GHG emissions, a Picarro C02 - CH4 analyzer connected gas chamber recorded salt marsh gas flux. Biomass was measured with the exact same processes as stated above; following gas measurements, the biomass above-ground was collected in marked containers. After harvest of biomass, additional measurements of below-ground respiration was assessed by the same static chamber method. Calculations were made using MATLAB software. Results supported the hypotheses; of the five sites we examined, three displayed higher biomass in restored sites. Additionally, methane gas flux in restored sites is indeed significantly greater significantly greater than the natural sites but lower than the degraded marsh. In conclusion, Restored sites have higher plant biomass, which coincide with higher Net Ecosystem Production. Excess CH4 emissions in restored sites are due to a reduction in soil salinity compared to natural sites. The fact of how valuable C sequestration capacity of vegetated coastal wetlands are, it is important that we improve our understandings of how these systems function as carbon sinks and how they are likely to be affected.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.B13A0562F
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 0490 Trace gases;
- BIOGEOSCIENCESDE: 0497 Wetlands;
- BIOGEOSCIENCES