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Abstract Detail



Ecological Section

Flowers, Knox [1], Boyette, Jerrid [1], Kuehn, Kevin [1], Davis, Micheal [1].

Oiling Increases Marsh Sediment CO2 Effluxes.

There are justifiable concerns over the effects of the Deepwater Horizon incident on marsh ecosystem processes. In late 2011, we conducted intensive field studies to assess the effects of the oil spill on marsh sediment respiration rates (CO2 efflux rates: μmol m¯²s¯¹) in nine different marsh sites along the Mississippi coast (6 oiled and 3 unoiled). At each site, we measured diurnal sediment CO2 effluxes during three separate sampling periods (September, October, and December; n=3310). Data were collected using a LICOR LI-8100 automated CO2 soil efflux system with four long term chambers positioned within a fifteen meter radius in stands of Spartina alterniflora and Juncus roemerianus. Using a mixed model ANOVA for statistical analyses (α=0.05), a nearly significant effect of oil exposure was observed, with higher overall sediment CO2 efflux in oiled (o) marsh sites compared to unoiled (uo) sites [F(1,3291)= 5.07, p=0.06; mean efflux: 1.44 (o) vs. 0.91 (uo) μmol m¯²s¯¹]. A highly significant difference in overall mean efflux was higher in Spartina in relation to Juncus (F(1,3291)= 97.03, p<0.0001*; mean efflux: 1.54 vs. 1.0 μmol m¯²s¯¹ ). After analyzing the interaction with a Tukey’s HSD to determine the effects of oiling and species treatments, there was a higher overall mean flux observed in oiled Spartina stands when compared to unoiled Spartina or oiled/unoiled Juncus stands, which had no significant differences (F(1,3291)= 145.36, p<0.0001*). A Tukey’s HSD was also used to determine the effects of month and species treatments, there was a discernible trend of higher mean flux exhibited in Spartina in relation to Juncus across the months of this study (F(2,3291)= 4.16, p=0.02*). Current data are unable to discern the biological driver behind the observed CO2 flux rates. The phenomenon is likely of microbial origin, however it is unclear whether the response is caused by saprophytic microbes growing on decomposing/damaged plant roots or by hydrocarbon-degrading microbes utilizing oil/dispersant residues.

Broader Impacts:


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1 - University of Southern Mississippi , Biological Sciences, 118 College Drive, Box #5018, Hattiesburg, MS , 39406, USA

Keywords:
Deepwater Horizon Oil Spill
Marsh
CO2 Efflux.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:45 PM
Number: PEC019
Abstract ID:548
Candidate for Awards:Ecological Section Best Graduate Student Poster


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