Are methane emissions from mangrove stems a cryptic carbon loss pathway? Insights from a catastrophic forest mortality.
New Phytol
; 224(1): 146-154, 2019 10.
Article
in En
| MEDLINE
| ID: mdl-31211874
ABSTRACT
Growing evidence indicates that tree-stem methane (CH4 ) emissions may be an important and unaccounted-for component of local, regional and global carbon (C) budgets. Studies to date have focused on upland and freshwater swamp-forests; however, no data on tree-stem fluxes from estuarine species currently exist. Here we provide the first-ever mangrove tree-stem CH4 flux measurements from >50 trees (n = 230 measurements), in both standing dead and living forest, from a region suffering a recent large-scale climate-driven dieback event (Gulf of Carpentaria, Australia). Average CH4 emissions from standing dead mangrove tree-stems was 249.2 ± 41.0 µmol m-2 d-1 and was eight-fold higher than from living mangrove tree-stems (37.5 ± 5.8 µmol m-2 d-1 ). The average CH4 flux from tree-stem bases (c. 10 cm aboveground) was 1071.1 ± 210.4 and 96.8 ± 27.7 µmol m-2 d-1 from dead and living stands respectively. Sediment CH4 fluxes and redox potentials did not differ significantly between living and dead stands. Our results suggest both dead and living tree-stems act as CH4 conduits to the atmosphere, bypassing potential sedimentary oxidation processes. Although large uncertainties exist when upscaling data from small-scale temporal measurements, we estimated that dead mangrove tree-stem emissions may account for c. 26% of the net ecosystem CH4 flux.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Carbon
/
Forests
/
Plant Stems
/
Avicennia
/
Methane
Country/Region as subject:
Oceania
Language:
En
Year:
2019
Type:
Article