Continental shelves are predominately (70%) covered with permeable, sandy sediments.While identiﬁed as critical sites for intense oxygen, carbon, and nutrient turnover, constituent exchangeacross permeable sediments remains poorly quantiﬁed. The central North Sea largely consists of permeablesediments and has been identiﬁed as increasingly at risk for developing hypoxia. Therefore, we investigatethe benthic O2exchange across the permeable North Sea sediments using a combination of in situ micro-proﬁles, a benthic chamber, and aquatic eddy correlation. Tidal bottom currents drive the variable sedimentO2penetration depth (from 3 to 8 mm) and the concurrent turbulence-driven 25-fold variation in thebenthic sediment O2uptake. The O2ﬂux and variability were reproduced using a simple 1-D model linkingthe benthic turbulence to the sediment pore water exchange. The high O2ﬂux variability results fromdeeper sediment O2penetration depths and increased O2storage during high velocities, which is then uti-lized during low-ﬂow periods. The study reveals that the benthic hydrodynamics, sediment permeability,and pore water redox oscillations are all intimately linked and crucial parameters determining the oxygenavailability. These parameters must all be considered when evaluating mineralization pathways of organicmatter and nutrients in permeable sediments.
- eddy correlation
- permeable sediments
- benthic oxygen exchange
- North Sea
McGinnis, D. F., Sommer, S., Lorke, A., Glud, R. N., & Linke, P. (2014). Quantifying tidally driven benthic oxygen exchange across permeable sediments: An aquatic eddy correlation study. Journal of Geophysical Research, 119(10), 6918-6932. https://doi.org/10.1002/2014JC010303