Sediment Type Determination 
The sediment grain-size major mode and range are visually 
estimated from the photographs by overlaying a grain-size 
comparator composed of seven Udden-Wentworth size classes: >4 phi 
(silt or finer), 4-3 phi (very fine sand), 3-2 phi (fine sand), 2-1 
phi (medium sand), 1-0 phi (coarse sand), O-(-)1 phi (very coarse 
sand), <-1 phi (granules or larger). The accuracy of this method 
has been documented by comparing REMOTS® estimates with grain-size 
statistics determined from laboratory sieve analyses (Table 2-1). 
In most cases where the REMOTS® grain-size estimate is different 
from the granulometric analysis, the major and minor grain-size 
modes have been found in adjacent size classes. The REMOTS® visual 
estimates in some cases can not resolve the major mode when 
adjacent class peaks are comparable. 
Prism Penetration Depth 
The REMOTS® prism penetration depth is determined by 
measuring both the largest and smallest linear distance between 
the sediment-water interface and the bottom of the film frame. 
Prism penetration is potentially a noteworthy parameter; if the 
amount of weight used in the camera is held constant throughout a 
survey, the camera functions as a static-load penetrometer. 
Comparative penetration values from sites of similar grain-size 
can give an indication of the relative sediment water content. 
Surface Boundary Roughness 
Surface boundary roughness is determined by measuring 
the vertical distance (parallel to the film border) between the 
highest and lowest points of the sediment-water interface. In 
addition, the origin of this small-scale topographic relief is 
indicated when it is evident (physical or biogenic). 
Mud Clasts 
When fine-grained, cohesive sediments are disturbed 
either by physical bottom scour or faunal activity (e.g., decapod 
foraging), intact clumps of sediment are often scattered about the 
seafloor and detected in REMOTS® photographs. These mud clasts are 
counted, the diameter of a typical clast measured, and their 
oxidation state assessed. The abundance, distribution, oxidation 
state, and shape of mud clasts are used to make inferences about 
the recent pattern of seafloor disturbance in an area. Mud clasts 
which occur as sampling artifacts (i.e., as a result of physical 
bottom disturbance by the camera prism) usually have an anomolous 
shape or apppearance which allows them to be distinguished from 
those which occur naturally. 
