Effects of In-Situ Burning on Coastal Wetlands: Soil Temperatures and Regrowth of Marsh Plant Species.
Effects of In-Situ Burning on Coastal Wetlands: Soil
Temperatures and Regrowth of Marsh Plant Species.
(470 K)
Bryner, N. P.; Walton, W. D.; Mendelssohn, I. A.; Lin,
Q.; Mullin, J. V.
Prevention, Preparedness, Response and Restoration:
Perspectives for a Cleaner Environment. International
Oil Spill Conference. IOSC 2003. Proceedings. April
6-11, 2003, Vancouver, British Columbia, Canada, 115-121
pp, 2003.
Keywords:
oil spills; in situ burning; soil temperatures; plants
(botany); experiments; uncertainty; thermal energy;
thermal stresses
Abstract:
Twenty-one full-scale in-situ burn experiments examined
soil temperatures which marsh plants experience during
in-situ burning. Two hundred sixty four plant sods,
including Spartina alteniflora, Spartina patens,
Distichlis spicata, and Sagittaria lancfolia plants,
were exposed in a 6 m diameter tank to burning diesel
fuel or crude oil for intervals ranging from 400 s to
1400 s. Individual sods were instrumented with
thermocouples to track soil temperatures throughout each
burn. After the burns, the sods were returned to the
greenhouse where plant recovery was monitored for up to
a year. The water depth over the soil surface during
in-situ burning was a key factor controlling plant
recovery. For either 400 s or 1400 s burn exposures,
soil temperatures did not exceed 50 deg C and 70 deg C
for 10 cm and 2 centimeters of water overlying the soil
surface, respectively. Ten and 2 centimeters of water
overlying the soil surface were sufficient to protect
all 3 types of marsh plants from burning impacts. In
contrast, 2 cm of soil exposure to the fire during the
burn resulted in high soil temperatures, with 80 deg C
to 100 deg C at 0 cm to 0.5 cm below the soil surface.
The effect of thermal stress on plant survival differed
with species as 2 cm of soil exposure during burning
impeded the post-burn recovery of the salt marsh grass,
S. altemiflora, and fresh marsh species, S. lancuolia.
However, 2 cm of soil exposure during in-situ burning
did not detrimentally affect the post-burn recovery of
the brackish marsh grasses, S. patens and D. spicata.
For plants positioned 10 cm above the water level, peak
surface soil temperatures ranged from 350 deg C to 800
deg C for 400 s and 1400 s burns, respectively. Thermal
stress almost completely inhibited the post-burn
recovery of S. altemiflora in this water level
treatment.
