This experiment took place in St Joseph Bay, Florida (29° 41'13.87''N, 85° 19'43.67''W) on private land (permission granted by L. Hughes). The experiment did not involve endangered or protected species. At this site, we observed salt marsh disturbance and habitat loss due to wrack accumulation, which had caused patches of bare sediment in otherwise continuous salt marsh meadows (Figure 1) that had persisted for 3-12 months prior to our sampling. Within our study site (total area 7,275 m2) we counted and measured the area of each patch using aerial images. This was achieved using Google, Earth’s polygon function to mark out the perimeter of each halo (imagery date 1/3/2012), followed by Earth Point (www.earthpoint.us) to measure the area of each halo polygon. We haphazardly selected 10 patches, and measured the amount of organic carbon in these bare areas, which we called ‘disturbed’, and compared this to adjacent ‘undisturbed’ salt marsh plots at an equivalent tidal height. Each bare, disturbed area typically represents a separate wrack mat, and we therefore treated each disturbed-undisturbed plot pair (n = 10) as independent.