Estimated impacts from the Deepwater Horizon Oil Release on High Marsh Systems in Mississippi: A systems modeling approach

MARK T. BROWN; LUCÍA ZARBÁ

Gainesville

Congreso; Emergy Synthesis 9: Theory and Applications of the Emergy Methodology; 2016

The emergy value of ecosystem services of the high marsh ecosystem wasevaluated using a combination of systems modeling and emergy evaluation toquantify the impacts of oiling that resulted from the Deepwater Horizonaccident. An energy systems diagram of the high marsh ecosystem, containingeleven compartments (trophic levels) was constructed and flows and storages ofcarbon and driving energy were estimated from the literature. A flow matrix wasconstructed to evaluate the quality of carbon (specific emergy) as it wasconcentrated through the marsh ecosystem food chain. Conversion of ?carbonquality factors? to monetary value was computed for the US economy in 2010-2011 using 2.0E+12 sej $-1.Using the energy systems diagram of the marsh, a simulation model wasconstructed to evaluate temporal impacts of oil release on the high marsh. Themodel was simulated for a period of two years using average climatic conditionstaken from the decade beginning in 2000. First, the coefficients and storageswere adjusted so that the model generated a steady-state solution. Then thesimulation is run and the stochastic impact (moderate oiling) is introduced intothe program 25 days after the simulation starts. The model is allowed to run forthe entire 2 years. Output from the second simulation with the stochastic impactis subtracted from the steady state solution to obtain a net impact to each of thecompartments. We conducted Hundreds of simulations were conducted varyingcoefficients on pathways +/- 25% to develop range of responses. Impacts variedbetween a low of 1% (mammals) to a high of 82% (Juncus).Conversion factors between ?carbon quality factors? and monetary valuewere computed for the US economy in 2010-2011. Finally, the computed?quality factors? were combined with the quantity impacts experienced by eachcompartment derived from the simulation model to quantify the monetary valueof losses associated with the oil release. Estimates of the monetary value ofecosystem services lost per hectare for moderately oiled high marsh ranged fromem$5,836 to em$8,050 for the suite of simulations resulting in an average ofem$6,943 per hectare. Highest losses were to mammals ($1,229 ha-1) and Juncus($1,208 ha-1)