diver safety, breathing gas technology, body heat 
retention, diver speech, diver nutrition, and de- 
compression technology. 
Experiments should be conducted exposing 
lower animals to inert gases and mixtures up to 
one month at various pressures, temperatures, 
humidities, and activity levels to determine guide- 
lines and limitation of diver exposure. 
A national program to train medical personnel 
and expand facilities for diver medical treatment 
and research should be established. 
|. Environmental Considerations 
The major features of the geophysical environ- 
ment—air, sea, and the land beneath the sea—must 
be understood to further ocean technology. The 
systems and techniques to study these features 
encompass ships, aircraft, satellites, buoy systems, 
undersea fixed platforms, and maneuverable sub- 
mersibles. Much basic technology of marine 
science is at hand to make great progress, but 
efforts are fragmented and information is scat- 
tered. 
A thorough understanding of the following 
factors is necessary for operations in and under the 
sea. 
—Submarine topography, stability of slopes, 
microbathymetry, bottom composition, engineer- 
ing and chemical properties, and bottom currents 
(including turbidity flow). 
—Temperature, salinity, density, dissolved gases, 
pH, Eh, and nutrients. 
—Fouling, bioluminescence, dangerous animals, 
and false-target and sound-scattering organisms. 
—Currents, waves, breakers, surf, internal waves, 
sea level, and tides. 
—Distribution, concentration, and thickness of sea 
ice. 
—Spatial and temporal variation, deflection of 
vertical anomalies of gravity and magnetism. 
It should not be inferred that knowledge is 
completely lacking in the above factors, but 
improvements in environmental measurement and 
prediction are essential for success in increasing 
national capabilities in the ocean. 
VI-62 
The near-surface environment of the oceans 
varies greatly from place to place and time to time. 
However, near-surface current velocity, sea state, 
visibility, background noise, and sound propaga- 
tion are probably less variable and influential on 
undersea systems than ocean floor and sub-bottom 
environmental differences like bathymetry, sedi- 
ment distribution, and acoustic characteristics. 
The sea floor is much less well known than the 
nearsurface environment. 
Improved techniques for undersea surveys are 
needed for economical and timely completion of 
such needed ocean information as the following: 
—Gross bathymetry, slope, and roughness. 
—Small scale bottom roughness. 
—Sediment shear strength. 
—Liquid-solid interaction and bearing strength. 
—Geological patterns, salt domes, and examination 
of outcrops. 
—Gravity and magnetic readings and false magnetic 
targets. 
—Small scale reflection profiles and seismic charac- 
teristics. 
—Temperature and heat conductance. 
—Circulation and tidal currents, including turbidity 
currents. 
—Internal waves. 
—Behavior of visible light and water clarity. 
—Sound propagation, background noise, and false 
acoustic targets. 
Data collection techniques now utilized (mainly 
analog) require lengthy processing and analysis 
procedures. Use of digital techniques, including 
realtime data collection and processing at sea, is 
increasing, but much still must be done to meet 
basic needs (Figure 22). 
1. Sea Floor and Bottom Strata 
a. Current Situation Submarine topography and 
microbathymetry operations include (1) prepara- 
tion of bathymetric (bottom topographic) charts 
