Shoreline of Barnegat Bay

Shoreline of Barnegat Bay, showing color-coded USGS bathymetric data (deeper toward blue end of spectrum, shallower toward red end) collected in November 2011 and March 2012, and locations of bottom-sediment-sampling stations (black dots) visited in March 2012. Despite a survey-trackline spacing of 50 meters (55 yards), 100-percent bathymetric coverage of the estuary seafloor was impossible because of the estuary's shallow depths. Inset A, Detailed bathymetry of channel leading out to Barnegat Inlet, with numerous bedforms, such as sand waves, lining channel floor. Inset B, Subset of the sidescan-sonar data, which achieved 100-percent coverage of the estuary seafloor. Analysis of sediment samples shows that lower backscatter (darker in this image) represents silt and higher backscatter (lighter) represents silty sand. Yellow dashed lines delineate zone of low backscatter that overlies relict tidal channels mapped beneath the estuary's seafloor, indicating a link between the geologic history of the estuary and modern sediment distribution.