Abstract
Shallow coastal sediments and their burrowing invertebrate (infauna) communities are important for nutrient cycling and carbon storage. In the northern Gulf of Mexico, frequent storms disturb infauna and resuspend sediments. Re-consolidation of sediments following a storm impacts infaunal habitat suitability and community recovery, but this has been poorly studied. In this study, we compared how different geological and geotechnical properties of recently disturbed mud changed over time. We expected that post-disturbance changes to properties relating to mud cohesion would continue to occur after compaction stabilized. Cohesion is likely important in mud habitat suitability, thus may be a more relevant parameter in considering infaunal community recovery. We collected mud from 10m depth offshore of Dauphin Island, AL, and resuspended the top 5cm, simulating storm disturbance. At several timepoints following resuspension (1-30 days), we measured sediment properties providing metrics of compaction (sediment-water interface height, water content, acoustic sound speed and attenuation) and metrics of surface and subsurface cohesion (erodibility, fracture behavior, organic content, and exopolymeric substances (EPS)). Preliminary data suggest that sediment compaction occurred rapidly over the first 3 days after resuspension and stabilized within 7 days. Erodibility rapidly decreased over the first 3 days but began to increase from 14 to 30 days after disturbance, likely due to infaunal activity. This suggests mud compaction alone does not indicate overall restabilization, which is likely important to post-disturbance recovery of infauna communities.
