Impact of Hurricane Sandy on CH₄ Released from Vegetated and Unvegetated Wetland Microsites

Abstract

Hurricane Sandy was one of the largest tropical storms to pass over the Atlantic basin, causing destruction along its path as it made landfall in Jamaica, Cuba, the Bahamas, and the United States [Tropical Cyclone Report: Hurricane Sandy; National Weather Service, National Oceanic and Atmospheric Administration, 2012 ()]. Hurricane Sandy passed over the Meadowlands in the midst of our multiyear study on marsh CH4 dynamics, providing a unique opportunity to evaluate the effects of hurricanes on CH4 cycling within an estuarine marsh. We modeled dissolved CH4 distributions in wetland sediments from 2011 (Reid, M. C.; Tripathee, R.; Shäfer, K. V. R.; Jaffé, P. R. Tidal Marsh Methane dynamics: Difference in seasonal lags in emissions driven by storage in vegetated versus unvegetated sediments. J. Geophys. Res.: Biogeosci. 2013, 118, 1802–1813) to 2013 and estimated that Hurricane Sandy did not degas vegetated soils but degassed between 45 and 75% of the dissolved CH4 in unvegetated sediments. Hurricanes may regularly affect coastal wetland CH4 emissions globally, but because these wetland sediments do not store substantial dissolved CH4 late in the year, the degassing of these sediments by Hurricane Sandy did not play an important role in the annual carbon emissions from this marsh.

Methanogenesis in oxygenated soils is a substantial fraction of wetland methane emissions

“…Porewater dialysis samplers (peepers) were used to sample for dissolved CH 4 , CO 2 , and N 2 O below ground monthly, with a vertical resolution of 2.8 cm, throughout the upper 56 cm of soils with minimal disturbance to the soil 29 – 31 . Hydrogen was not measured in porewater from the dialysis peepers.…”

Combining eddy-covariance and chamber measurements to determine the methane budget from a small, heterogeneous urban floodplain wetland park

“…It may be impossible to obtain a 100% footprint contribution from any particular patch type, as was the case in this study and may be the case in most wetlands that are intrinsically heterogeneous. To compensate for this limitation, the incorporation of chamber measurements and other point measurements of fluxes, such as porewater dialysis samplers (Pal et al, 2014;Reid et al, 2013), can allow for correction of flux tower observations with a variable footprint to an equivalent fixed-frame CH 4 flux.…”