| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4396055 | Journal of Experimental Marine Biology and Ecology | 2012 | 6 Pages |
Bioturbation plays a crucial role in benthic nutrient cycling in many sedimentary environments. Burrowing animals affect benthic–pelagic coupling by mixing sediment and porewater and increasing the effective area of diffusive exchange between oxidizing and reducing environments. Here, we report on a coupled laboratory-modeling experiment that explores organism distribution patchiness and its implications on sedimentary oxygen fluxes. Microcosms were established with three different arrangements of artificial burrows. Data from the laboratory were used to parameterize a three-dimensional diffusion–reaction model, and the impact of burrow distribution on benthic O2 fluxes at the plot (decimeter) scale was assessed for a range of sediment reactivities representing a variety of benthic habitats. At high O2 consumption rates, as seen in the microcosms, burrow spacing had little to no effect on sedimentary O2 uptake; at intermediate rates, the overlap of oxic halos surrounding burrows and benthic O2 uptake depended significantly on the burrow distribution pattern. Using observed relationships between benthic O2 flux and oxygen penetration depth in marine sediments, we predict that burrow patchiness has its greatest impact in settings with benthic oxygen fluxes on the order of 1–10 mmol m− 2 d− 1, typical for the continental shelf and slope. The biogeochemical heterogeneity caused by burrows also affects the interpretation of concentration measurements, and we present an estimate of the number of measurements needed to reliably estimate bulk O2 concentrations in cohesive sediments as a function of organism density, measurement scale and sediment reactivity.
► Microcosm experiments and modeling quantify the impact of infaunal arrangement. ► Burrow distribution affects sediment O2 demand and biogeochemical heterogeneity. ► The impact of infaunal patchiness is highest at intermediate sediment reactivities. ► The number of measurements needed to reliably estimate bulk O2 levels is estimated.
