REMOTS® Sediment-Profile Imaging 



REMOTS® sediment profile imaging is a benthic sampling technique in which a 

 specialized camera is used to obtain undisturbed, vertical cross-section photographs {in situ 

 profiles) of the upper 15 to 20 cm of the seafloor. This is a reconnaissance survey technique 

 used for rapid collection, interpretation and mapping of data on physical and biological 

 seafloor characteristics; measurements obtained from sediment-profile images can be used to 

 characterize sediment types, evaluate benthic habitat quality, map disturbance gradients and 

 follow ecosystem recovery after disturbance abatement. 



The REMOTS® hardware consists of a wedge-shaped optical prism having a standard 

 35-mm camera mounted horizontally above in a watertight housing. The prism resembles an 

 inverted periscope, with a clear Plexiglas window measuring 15 cm wide and 20 cm high and 

 an internal mirror mounted at a 45° angle to reflect the image in the window up to the camera 

 (Figure 2-2). To equalize pressure, the prism is filled with water, and light is provided by an 

 internal strobe. The prism sits inside a stainless steel external frame, and the entire assembly 

 is lowered to the seafloor using a standard winch mounted aboard the survey vessel. Upon 

 contact with the bottom, the prism descends slowly into the seafloor, cutting a vertical cross- 

 section profile of the upper 15 to 20 cm of sediment, and a photograph is taken of the 

 sediment in contact with the window. The resulting 35-mm slides (images) showing 

 relatively undisturbed sediment profiles are then analyzed for a standard suite of measured 

 parameters (Rhoads and German© 1982; 1986). 



Computer-aided analysis of each REMOTS® sediment profile image yielded a suite of 

 measurements. The standard measured parameters are sediment grain size major mode 

 (expressed in phi units), benthic habitat classification, camera prism penetration depth (an 

 indirect measure of sediment bearing capacity/density), depth of the apparent redox potential 

 discontinuity (RPD), infaunal successional stage, and Organism-Sediment Index (a summary 

 parameter reflecting the overall benthic habitat quality). 



A total of 22 REMOTS® sediment profile photography stations were established over 

 the Morris Cove borrow pit to evaluate the distribution and thickness of dredged material 

 layers and to assess benthic recolonization. The stations were arranged in a radial pattern 

 centered at the MCDA disposal buoy position and spaced at 25, 50, 100 and 150 meter 

 intervals from the buoy (Figure 2-3; Table 2-1). In addition, a five-station REMOTS® grid 

 was established over the nearby reference area located in New Haven Harbor approximately 

 800 m to the west of the borrow pit (MC REF; 41° 15.615' N, 72° 54.553' W; see Figure 1- 

 1). One station was established over the center reference point, while four additional 

 stations were randomly distributed within a 75 -meter radius. At both the borrow pit and 

 reference area REMOTS® stations, the sediment profile camera was lowered at least three 

 times in an attempt to obtain three replicate images suitable for subsequent analysis. 



Monitoring Cruise at the Morris Cove Borrow Pit 



