Estimating nitrogen removal services of eastern oyster (Crassostrea virginica) in Mobile Bay, Alabama

Eastern oysters have been acknowledged for their important contribution to human well-being by providing goods and services including nitrogen removal from water bodies. In this study, we integrated daily environmental data (2008–2016) and filtration rate model parameter uncertainty to estimate nitrogen removal from denitrification and nitrogen burial services provided by the current extent of oyster (Crassostrea virginica) reefs in Mobile Bay, Alabama. Oyster landing data (2008–2016) in the Bay were also used to estimate nitrogen removal through oyster harvest. A replacement cost method using an engineering solution from wastewater treatment plants was implemented to quantify the economic benefit of the nitrogen removal. The estimated total nitrogen removal services provided by oyster reefs in Mobile Bay was 34,911 ± 5,032 kg N yr⁻¹ (mean ± 1sd), in which 22,095 ± 3,305 kg N yr⁻¹ from denitrification, 11,047 ± 1,652 kg N yr⁻¹ from burial of nitrogen into sediments and 1,769 ± 876 kg N yr⁻¹ by oyster harvest. The mean economic benefit was $76,455 ± 11,020 yr⁻¹ which was estimated as $73.2 ± 11.5 ha⁻¹ yr⁻¹. This method could be used for any time period to estimate the nitrogen removal service in Mobile Bay. With proper modification of model parameters, this method could also be used elsewhere to estimate nitrogen removal services provided by oysters.