100 



WORK OF THE CARNEGIE AND SUGGESTIONS FOR FUTURE SCIENTIFIC CRUISES 



the collection and study of living forms as they exist in 

 shallow waters and near reefs below the surface, a 

 diving hood was used which enabled an observer to walk 

 about freely and comfortably. 



When there was an opportunity, while in ports, land 

 collections were made of the plants, insects, and birds, 

 with a view to enriching already existing collections and 

 to further our knowledge of the geographical distribution 

 of plants and animals over the world. 



The chemical program was designed to olrtain data 

 concerning the factors governing the distribution of-ma- 

 rine organisms. No attempt was made to determine 

 more fully the exact composition of sea water. An anal- 

 ysis was made of some constituents dissolved in the 

 oceanic waters which are known vitally to affect the life 

 in the water. Inorganic phosphate determinations were 

 made as possible indications of the fertility of the water, 

 a factor which is known to have a direct bearing on the 

 phytoplankton. Silicate determinations were made to 

 study the dependence of diatoms on this constituent in 

 sea water. Of the gases dissolved in oceanic waters, 

 oxygen and carbon dioxide are the most closely inter- 

 related with the occurrent organisms. It was not possi- 

 ble to include determinations of the carbon dioxide ten- 

 sion in the Carnegie program but analyses for dissolved 

 oxygen were made regularly during the last part of the 

 cruise. The hydrogen-ion concentration which is such 

 an important ecological factor in any environment, was 

 determined regularly for all samples collected. Salini- 

 ties, which have a more hydrographic significance, were 

 determined regularly for all depths by electrometric 

 means with a Wenner salinity bridge, the results occa- 

 sionally being checked by titrations. Following the poli- 

 cy set at the beginning of the cruise, all the determina- 

 tions were made on board at sea. 



An oceanographic station was occupied regularly 

 every second day, making the stations about two to three 

 hundred mUes apart. The vessel was hove to and a 

 series of observations and specimens were taken which 

 included the collection of sea-water samples from the 

 surface down to great depths. These samples were col- 

 lected in Nansen deep-sea, reversing water bottles to 

 which were attached thermometers for recording the 

 temperatures at which the samples were taken. Bottles 

 were lowered in two series. The first, the shallow 

 series, collected samples at the surface, 5, 25, 50, 75, 

 100, 150, 200, 300, 400, and 500 meters. The second, 

 the deep series, collected samples at 500, 700, 1000, 

 1500, 2000, 2500, 3000, 3500, and 4000 meters. Condi- 

 tions of current and sea sometimes prevented the ob- 

 taining of the samples at the greater depths in the deep 

 series. 



As the series was hauled in, the bottles were de- 

 tached and placed in a rack on the gear box and samples 

 were immediately drawn from these into glass bottles to 

 be taken to the laboratory. Three samples were drawn 

 from the Nansen bottles which were of a capacity of 1.25 

 liters. First, the sample for oxygen determination, 

 which was immediately fixed to prevent any gas exchange 

 with the atmosphere, was drawn into a 100-cc pressure- 

 stoppered bottle. Then a sample was run into a citrate- 

 of-magnesia bottle for other chemical determinations. 

 Lastly a magnesia bottle was filled for salinity deter- 

 minations. 



Glass- stoppered bottles were used for storing the 

 samplesduring part of the cruise but pressure-stoppered 

 bottles were found to be more convenient, as with the 



latter there was less danger of the samples coming in 

 contact with the atmosphere owing to the displacement 

 of the stoppers. The bottles used for the oxygen sam- 

 ples were of 100-cc capacity with rubber-washered, 

 enameled, pressure stoppers as furnished by Richter 

 and Wiese. Four-ounce "juice bottles," procurable 

 from any large bottle maker, fitted with magnesia-bottle 

 stoppers will do as well and are obtainable in this coun- 

 try. If larger samples had been available, larger bottles 

 would have been used, as a larger sample reduces the 

 experimental error of the determination. The samples 

 were drawn from the Nansen bottles through a straight 

 piece of glass tubing long enough to reach to the bottom 

 of the collecting bottles and attached to the valve of the 

 Nansen bottle by a short piece of rubber tubing. The 

 oxygen and magnesia bottles were carried about in com- 

 partment trays. These and the rack for the Nansen bot- 

 tles were covered with a temporary canvas shelter on 

 rainy or bright sunny days to prevent dilution of the 

 samples with rain water during the filling of the bottles 

 or to prevent undue decomposition or photo synthetic ac- 

 tivity on the part of entrapped organisms. As soon as 

 the samples were drawn from the Nansen bottles they 

 were removed to the oceanographic laboratory and kept 

 in a dark place. The determinations were begun immed- 

 iately. 



Four chemical determinations were run on the 

 samples regularly for each station, namely, of hydrogen- 

 ion concentration, of phosphates, of silicates, and of dis- 

 solved oxygen. The hydrogen-ion concentration was de- 

 termined first so that there would be no change in the 

 pH value of the samples due to interchange of atmospheric 

 carbon dioxide when the bottles were opened for the run- 

 ning of other determinations. For determining the hydro- 

 gen-ion concentration, a double-wedge comparator was 

 used as designed by Seiwell (4), constructed according 

 to the principle used in the apparatus designed by Bar- 

 nett and Barnett (5) and modified by Moberg (6), using 

 cresol red as indicator. With this apparatus, readings 

 were made accurately within 0.02 pH. Determinations 

 of phosphates were made following the method of Denig^s 

 (7) and of the dissolved silicates after Dienert (8). For 

 these two determinations a colorimeter was designed 

 which permitted a comparison of color intensities of the 

 samples against a standard in long, graduated tubes in 

 which the columns of liquids could he varied until a 

 match in intensity was obtained. Determinations of the 

 dissolved oxygen were made according to the method of 

 Winkler (9). Although salinities were determined regular- 

 ly with the Wenner salinity bridge, the bridge frequently 

 was checked by chemical determinations. The latter 

 chemical determinations were done by titrating the chlo- 

 rides in the water with silver nitrate, using a Knudsen 

 burette and computing the total salinity with the use of 

 Knudsen' s hydrographical tables. 



A great deal of trouble was encountered in the sili- 

 cate determinations owing to the leaching of silicates 

 from the glass of the magnesia bottles. Some bottles 

 showed very evident leaching in less than one day's 

 storage. The experience on the Carnegie indicated the 

 great desirability of having some hard glass or other 

 type of container for storing the silicate samples. 



Distilled water for the chemical laboratory was car- 

 ried in five-gallon carboys which were filled at each 

 port. There always was difficulty in getting water suf- 

 ficiently pure to be used for making the phosphate stand- 

 ards for the delicate Denig^s test. Sufficient quantities 



