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Figure 3. Port-side view of the National Oceanic and Atmospheric Administration Ship Thomas Jefferson at sea.

Figure 4. The National Oceanic and Atmospheric Administration (NOAA) Launch 3102 being deployed from the NOAA Ship Thomas Jefferson.

Figure 5. Starboard-side view of the National Oceanic and Atmospheric Administration Launch 3102 at sea.

Figure 6. A Klein 5000 sidescan-sonar system hull-mounted to a National Oceanic and Atmospheric Administration launch.

Figure 7. The RESON SeaBat 8101 hull-mounted to the National Oceanic and Atmospheric Administration Launch 3102.

Figure 8. The RESON SeaBat 8125 hull-mounted to the National Oceanic and Atmospheric Administration Launch 3101.

Figure 9. SBE SEACAT conductivity-temperature-depth (CTD) profiler.

Figure 10. A port-side view of the U.S. Geological Survey research vessel Rafael, which was used to collect bottom photography and sediment samples in the vicinity of Rocky Point, New York.

Figure 11. The small Seabed Observation and Sampling System (SEABOSS), a modified Van Veen grab sampler equipped with still and video photographic systems, mounted on the aft starboard side of the research vessel Rafael.

Figure 12. Locations of stations at which bottom samples and photographs were taken during cruise 09059 of research vessel Rafael to verify bathymetric and backscatter data.

Figure 13. Correlation chart showing the relationships among phi sizes, millimeter diameters, size classifications (Wentworth, 1922), and American Society for Testing and Materials and Tyler sieve sizes.

Figure 14. Sediment-classification scheme from Shepard (1954), as modified by Schlee (1973).

Sidescan Sonar and Bathymetry

The NOAA Ship Thomas Jefferson and two 8.5–m aluminum Jensen launches (3101 and 3102) deployed from the ship acquired sidescan-sonar and multibeam-bathymetric data from the study area over an approximately 21.6–km² area during 2008 (figs. 3, 4, 5). The sidescan-sonar data, which cover approximately 13.4 km² along the shoreward part of the study area, were acquired with a Klein 5000 sidescan-sonar system hull mounted to launch 3102 (fig. 6). The system was set to sweep 100 m to either side of the launch tracks. The system transmits at 455 kilohertzs (kHz). Daily confidence checks were made of the sidescan-sonar system by observing the outer ranges of the sonar images. The data were acquired in XTF (extended Triton data format), recorded digitally through an ISIS data acquisition system, and processed using CARIS SIPS (Sidescan Image Processing) software for quality control, and to produce a composite sidescan-sonar image at 1–m horizontal resolution. As part of this process, the sidescan-sonar data were demultiplexed and filtered to remove speckle noise and to correct for slant-range distortions. Image 'shine through,' to account for areas of overlap, and auto-contrast adjustment were applied. Contrast enhancement based on the dynamic range of the data was applied to the mosaic, and it was then projected into UTM Zone 18 to produce the GeoTIFF image.  Adobe Photoshop CS2 and ArcGIS 9.2 were used to refine the grayscale stretch and enhance the imagery.

The multibeam echosounder (MBES) data were collected with hull-mounted RESON SeaBat 240–kHz 8101 and 455–kHz 8125 shallow-water systems aboard the launches (figs. 7, 8) and a RESON dual frequency (200–kHz/400–kHz) 7125 system aboard the NOAA Ship Thomas Jefferson. Original horizontal resolution of the multibeam bathymetric data was 0.5 m for water depths less than 20 m and 2 m for the deeper parts of the survey area. The bathymetric datasets were acquired in XTF, recorded digitally through an ISIS data acquisition system, and processed by NOAA using CARIS HIPS (Hydrographic Image Processing System) software for quality control, to incorporate sound velocity and tidal corrections, and combined into a 2–m grid to produce the final digital terrain model. A more detailed description of the acquisition parameters and processing steps performed by NOAA and the USGS to create the datasets presented in this report is included in the metadata files. These files can be accessed through the Data Catalog section of this report. Vertically exaggerated (5x), hill-shaded (illuminated from 0° north at an angle of 45°) imagery was created using CARIS HIPS software.

Horizontal positioning was by differential global positioning systems (D GPS); Hypack MAX was used for acquisition-line navigation. Sound-velocity corrections were derived with frequent conductivity-temperature-depth profiles using a Sea-Bird Electronics, Inc. SEACAT CTD (fig. 9). Tidal zone corrections were calculated from data acquired by the National Water Level Observation Network stations at New London and New Haven, Connecticut. The vertical datum is mean lower low water. Detailed descriptions of the MBES and sidescan-sonar acquisition and processing can be found in the descriptive report (National Oceanic and Atmospheric Administration, 2008).

Sampling and Photography

The sediment sampling and bottom photography were conducted during November 2009 aboard the research vessel (RV) Rafael during cruise 09059 (fig. 10). Bottom photography was collected at 19 stations with a modified Van Veen grab sampler equipped with still- and video-camera systems; surficial sediment samples (0-2 cm below the sediment-water interface) were collected at 12 of the stations (figs. 11, 12). The photographic data were used to appraise intra-station bottom variability, faunal communities, and sedimentary structures (indicative of geological and biological processes) and to observe boulder fields, where samples could not be collected. A gallery of images collected as part of this project is provided in the Bottom Photography section; locations of the bottom photographs can be accessed through the Data Catalog section.

In the laboratory, the sediment samples were disaggregated and wet sieved to separate the coarse and fine fractions. The fine fraction (less than 62 microns) was analyzed by Coulter counter; the coarse fraction was analyzed by sieving; and the data were corrected for salt content. Sediment descriptions are based on the nomenclature proposed by Wentworth (1922; fig. 13) and the size classifications proposed by Shepard (1954; fig. 14). A detailed discussion of the laboratory methods employed is given in Poppe and others (2005). Because biogenic carbonate shells commonly form in situ, they usually are not considered to be sedimentologically representative of the depositional environment. Therefore, gravel-sized bivalve shells and other biogenic carbonate debris were ignored. The grain-size analysis data can be accessed through the Data Catalog section of this report and in the Sediment Distribution section.

To facilitate interpretations of the distributions of surficial sediment and sedimentary environments, these data were supplemented by sediment data from compilations of earlier studies (Poppe and others, 1998a; Poppe and others, 2000) and unpublished datasets from the National Geophysical Data Center. The interpretations of sea-floor features, surficial-sediment distributions, and sedimentary environments presented herein are based on data from the sediment-sampling and bottom-photography stations, on tonal changes in backscatter on the imagery, and on the bathymetry. For the purposes of this paper, bedforms are defined by morphology and amplitude. Sand waves are higher than 1 m; megaripples are 0.2 to 1 m high; ripples are less than 0.2 m high. The bathymetric grids and imagery released in this report should not be used for navigation.

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