Attempting to dredge or grab specimens 
from rocky regions is obviously even more un- 
satisfactory. This is compounded by the fact 
that marine environments vary according to 
reef, shoal, or bottom type. It is difficult 
to correlate marine fauna or flora with geolog- 
ical structures when blindly groping the bottom. 
(Fig. 7 Trawls and Grabs) 
Naturally, it is not valid to state that 
scuba is a substitute for plankton nets, under- 
way samplers, or some electronic devices. How- 
ever, a surprising number of conventional 
oceanographic equipments can be used by a scuba 
diver. Among these are small sampling equip- 
ments like slurp guns, water bottles, traps, 
some samplers, some corers, small electronic 
gear, and of course still, movie and TV cameras. 
(Fig. 6 Cameras Used by Scuba Diver) 
Lymnology also contains fertile fields for 
the scuba diver. Most fish are surprisingly 
unafraid of divers. Possibly this is because 
their limited mental capacities have geared 
them to fear only instinctively recognized 
predators. A scuba diver sitting on the bottom 
of a pond becomes the focal point for curious 
fish. It is even possible to catch some species 
in one's bare hands. 
In lake or ocean the relationship of the 
biomass and geology ranging from the hyper- 
benthal down through mesobenthal,hypobenthal 
to the parahypobenthal zones can be convenient- 
ly studied by the scuba diver. He can chip 
materials and organisms from rock or reef. He 
can sit on a reef to make pelagic fish counts. 
He can even spear or catch selected fish. 
The naturalist finds skin and scuba diving 
excellent for observation of shallow water life 
of denizens of the air-water barrier. 
(Fig. 7 Underwater Archeology) 
Other very gratifying pursuits can be 
underwater archeology and underwater 
photography. There is almost no limit of 
uses which an active mind can find for scuba 
diving. 
Let us turn now to the physiological 
aspects of scuba diving. Scuba diving is not 
the peculiar province of the young, healthy 
athlete. This statement needs qualification. 
True, if the diver is participating in a spear- 
fishing contest, is attempting to combat strong 
adverse currents, or is flirting with decom- 
pression sickness, then robust, good health is 
@ great asset. However, we are discussing the 
scientist that drops overside into relatively 
calm waters, swims down to a reef, and stays in 
the immediate vicinity of the boat and another 
qualified diver. 
A major portion of the exertion expended in 
most skin and scuba diving is actually encounter- 
ed above the water. It is no easy chore to lug 
from fifty to over a hundred pounds of cumber- 
some equipment to the diving location.... 
Especially when this may involve unloading a 
vehicle, climbing down slippery cliffs, 
clamboring into a wave-tossed small boat, 
fighting the boat through breakers, struggling 
into the snug fitting suit and equipment straps, 
and finally plunging overside. It is then 
actually a relief to be underwater and neutrally 
buoyant. This feeling of relief may be somewhat 
marred by the thought that after diving he must 
go through the above water ordeal again, in 
reverse order. No wonder physical fitness is 
stressed? 
In most cases the underwater scientist will 
be able to obviate much of the above water 
exertion by diving directly from a larger 
vessel. 
Youth itself is not a criterion of diving. 
There are many divers over 60 years of age, some 
over seventy and even a few diving octogenarians. 
Conversely, there are also a lot of healthy 
younger persons for whom diving is contra- 
indicated. A sound respiratory and circulatory 
system is required. 
The underwater depths which can be tolerated 
vary with the individual. This is not to say 
that the basic laws of underwater physics and 
physiology do not apply to al] of us. Some 
people become distinctly unhappy in the gloom of 
deeper water. Others find themselves quite at 
ease in scuba at greater depths. This is a very 
cogent factor in diving, and because of its 
abstruse nature is seldom mentioned in books on 
diving. Jt is perhaps related to the most common 
sentiment expressed by non-divers: "You wouldn't 
catch me diving around down there!" Many of 
these people discover, to their delight, that 
their fears evaporate as soon as they gain 
confidence in their scuba. These same persons 
may never venture more than thirty feet deep. 
This is perfectly acceptable. A lot of research 
can be done in less than thirty feet of water. 
A good instruction course in skin and scuba 
diving is essential. The neophyte diver can 
then decide whether diving is for him. A 
physical examination is required before taking a 
diving course. Most courses are from 12 to 30 
hours duration. This includes classroom and 
pool work. One of the first, and still one of 
the best, books on scuba diving was written by 
David Owen of Woods Hole Oceanographic Institu- 
tion. There are several other books on diving 
available. None of these books are a substitute 
for a good instruction course. 
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