determination of currents and provide clues to 

 biological conditions. 



1-6 Chemical Oceanography. — The field of 

 chemical oceanography is concerned with the 

 determination of the various constituents of sea 

 water and their distribution. The salinity of 

 sea water is of major importance in computing 

 densities and dynamic currents as well as sound 

 velocities. Analyses to determine nutrient con- 

 centration (phosphate, nitrate, silicate, etc.), 

 the pH (acidity), and the content of dissolved 

 gases (oxygen and carbon dioxide) provide in- 

 formation which aid in determining age, origin, 

 and movement of water masses and their influ- 

 ences upon marine life. Some of these analyses 

 must be made immediately after sampling. 

 Other samples may be stored and analyzed 

 ashore at a later date if the facilities of the ship 

 are not adequate. In others, such as carbon-14, 

 part of the analyses are run aboard ship and 

 final determinations made ashore from the 

 reduced samples. 



1-7 Meteorological Oceanography. — The in- 

 teraction of sea and air and the influence of one 

 medium upon the other is a very important part 

 of oceanographic studies. Prevailing winds in 

 certain areas affect ocean currents while in 

 others the air temperatures are tempered by 

 the sea surface. Solar radiation affects the heat 

 budget and influences biological conditions. 

 Thus, the types of meteorological information 

 which must accompany all oceanographic ob- 

 servations must include: air temperatures, 

 humidity, wind direction and speed, atmos- 

 pheric pressure, cloud types, and amount, and 

 visibility; along with the oceanographic vari- 

 ables of sea surface temperature, wind waves, 

 and swell. 



1-8 Biological Oceanography. — Biological 

 oceanography is concerned with both plant and 

 animal life in the sea. Animal life is divided 

 into three general groups — the benthos (bottom 

 living) , the nekton (swimming) , and the plankton 

 (wanderers — the floating and drifting life). 

 The plankton are further divided into phyto- 

 plankton (plant forms) and zooplankton (ani- 

 mal forms). Little is known of the life cycles 

 of marine life, and we are only now beginning 

 to realize how little is known of the pelagic 

 populations of the sea. We are interested in 

 the distribution of plankton populations, from 

 both quantitative and qualitative points of 

 view, as well as the distribution and habits of 

 the benthos and nekton. Different types of 

 nets are towed in the efforts to sample the 

 marine life. It is considered that studies in 

 this field may solve problems which are be- 

 lieved to be of biological origin. Among these 



H. O. 607 



are the influence that marine life may have on 

 the transmission of underwater sound. 



1-9 Geological Oceanography. — A most im- 

 portant aspect of oceanography is submarine 

 geology. Although considerable strides have 

 been made in the past few years with the ad- 

 vancement of instrumentation, less is known 

 about it than any other field of geology. The 

 techniques of echo sounding, seismic explora- 

 tion, underwater photography, and various 

 types of sampling and coring are gradually 

 providing a better idea of the shape, character, 

 and history of the ocean bottom. 



1-10 SHIPBOARD EQUIPMENT AND 

 FACILITIES. — The most basic requirement for 

 an oceanographic vessel is to provide as stable 

 a platform as possible from which observations 

 at sea can be made. The more stable the plat- 

 form, the greater the number of working days 

 possible under adverse weather and sea condi- 

 tions, with the resulting greater return of more 

 accurate data. Coupled with stability is the 

 ability to remain on station with a minimum 

 amount of drift. Thus a deep draft vessel with 

 a minimum amount of freeboard to give windage 

 is desirable. Other basic requirements for an 

 oceanographic ship include adequate deck 

 working space and machinery, laboratory facil- 

 ities, cruising range, and living accommodations 

 for the scientists and crew. Other desirable 

 features include control of the ship's heading 

 at very slow speeds and while lying to on 

 station, ability to maintain silent ship (battery) 

 conditions for periods up to at least 12 hours, 

 and adequate weight-handling equipment such 

 as booms or cranes. 



1-11 Deck Space and Machinery. — Open 

 and uncluttered deck space is very important 

 in order to handle the numerous pieces of large 

 oceanographic equipment. Often these pieces 

 are very heavy while others are long and awk- 

 ward to handle. Deck machinery essential to 

 the oceanographer are winches, booms, and 

 cranes usually of special design. The largest 

 type of winch used by oceanographic research 

 ships is the deep-sea anchoring winch. This 

 winch uses steel wire rope in lengths of 20,000 

 to 35,000 feet. Some winches use specially 

 tapered wire, while others use wire of about 

 }^-inch diameter. The tapered wire can be used 

 to greater depths than the untapered wire 

 because it has been calculated that a vertical 

 steel wire of any diameter will not support its 

 own weight with a safety factor of two if it is 

 more than 30,000 feet long (Von Arx, 1954, 

 after Stommel) . Such a winch is used for deep- 

 sea anchoring at great depths for periods rang- 

 ing from a few hours to a month. Other uses 



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