Wave‐driven porewater and solute circulation through rippled elastic sediment under highly transient forcing

Abstract

Lay AbstractWaves over permeable and porous sediment induce movement of water through the pores of the sediment. This leads to circulation of seawater infiltrating into the sediment and then eventually exfiltrated back into the sea. This porewater circulation is caused by pressure variations along the surface of the seabed due to the passing of waves. However, previous studies have considered pressure along the seabed as steadily varying. This is not the case when flow associated with waves is turbulent, which is practically all the time. Using advanced computational modeling tools that more explicitly represent pressure variations occurring at short time intervals and the physical response of sediment to these pressure fluctuations, this study shows that pressure variations occurring at short timescales not considered before enhances the circulation and exchange of water between the seabed and the ocean. This also leads to larger exchange fluxes of dissolved material in the water circulating through the sediment. Since the seabed host many chemical and ecological processes that depend on the delivery of fluids and their dissolved content, accurate estimation of the importance and the rate at which these chemical and ecological processes occur would require a closer inspection of the effects of short time pressure fluctuations induced by turbulence and waves.