2. Instrumentation 
a. Current Situation The measurement of under- 
water physical, chemical, geological, and biological 
parameters is accomplished predominantly with 
devices lowered from surface craft or suspended 
from floating or submerged buoys (Figure 2). 
Such measurements are limited generally to basic 
parameters required to identify water masses and 
determine their movement or to provide gross 
identification of biological activity and nutrients. 
Limited measurements from submersibles have 
included stereophotography for topographic 
studies, temperature, salinity, and on-site sound 
velocity measurements in upper sediment layers. 
Figure 2. Meteorologic (left) and oceano- 
graphic (right) sensor packages of ODESSA 
system, which gathers data from unmanned 
buoys over wide ocean areas. (ESSA photo) 
Measurements by divers in the water mass have 
been limited to a few physical parameters, such as 
distance and temperature, requiring only such 
rudimentary devices as bulb thermometers, mag- 
netic compasses, and measuring sticks or cords. Jn 
situ. measurements have been made of sediment 
shear strength. However, diver monitoring and 
manipulation of instruments lowered from surface 
craft have been an important aid to such measure- 
ments as sound velocity in sediments. 
Only chemical parameters of very general inter- 
est, such as salinity, pH, and dissolved oxygen have 
been measured with other than sophisticated 
laboratory instrumentation or methods of volu- 
metric analysis. Some application has been made 
of fluorescence, spectroscopy, radioactive tracers, 
and neutron activation analysis in tracing sediment 
and water movement. Little has been done to 
adapt instruments for analysis in geochemical 
surveying, pollution monitoring, nutrient assess- 
ment, and other ocean activities of growing inter- 
est and concern. 
Biological measurements are completely infer- 
ential, consisting of chemical and physical meas- 
urements that can be correlated with biological 
concentrations, movement, and activity. Biologi- 
cally important properties such as oxygen, total 
organics, salinity, Eh, and pH? plus the physically 
important parameters can be compared with bio- 
logical observations and bioacoustic measurements 
to predict response to environmental factors, 
productivity, and migration. 
New developments by the Atomic Energy 
Commission and the Navy include a deep water 
isotopic current analyzer, a nuclear sediment 
density probe, and an in situ oxygen analyzer. 
b. Future Needs New instrumentation is needed 
to study biological species, their distribution, 
feeding habits, reproduction, and migration as a 
function of chemical and physical parameters. In 
addition, assistance to the biologist in the acquisi- 
tion of field data can be provided through (1) 
development of automatic discrimination of acous- 
tic signals generated by marine species, (2) obser- 
vation of movement of species by acoustic net- 
works, (3) counting marine species migration 
through fish passes or other constrictions, and (4) 
other survey techniques. 
Submersibles should be particularly well 
adapted to on-site measurements of physical prop- 
erties of sea water and sediment. Sediment meas- 
urements are needed for basic design criteria for 
bottom emplacement, construction, tunneling, and 
laying of pipelines and cables as well as for 
'Eh and pH = are defined in the subsection on 
environmental considerations of this section. 
