Challenger expedition

The major constituents in seawater are conventionally taken to be those elements present in typical oceanic water of salinity 35 that have a concentration greater than 1 mg kg excluding Si, which is an important nutrient in the marine environment. The concentrations and main species of these elements are presented in Table 1. One of the most significant observations from the Challenger expedition of 1872-1876 was that these major components existed in constant relative amounts. As already explained, this feature was exploited for salinity determinations. Inter-element ratios are generally constant, and often expressed as a ratio to Cl%o as shown in Table 1. This implies conservative behaviour, with concentrations depending solely upon mixing processes, and indeed, salinity itself is a conservative index. 

Murray J. and Renard A. F. (1891) Deep-sea Deposits. Report Challenger Expedition (1873-1876), London. 

S04 see Conservative Elements). The analytical results reported by W. Dittmar in 1884 for waters collected during the British RMS Challenger Expedition (1872-1876) from the world s oceans were almost the same as today s values. The constancy of major chemical composition has led oceanographers to define salinity as a fundamental property together with temperature to calculate the density of sea water. It was routine for classic physical oceanographers to titrate sea water for chloride (plus bromide) ion with silver nitrate standard solution, until the mid 1960s when salinity could be determined more practically by measurement of conductivity. 

Both deep sea deposits and sea water were sampled first by the Challenger expedition (1872-1876). William Dittmar analyzed sea water from around the oceans collected by the Challenger expedition and showed the composition was fairly constant so far as the major components of the dissolved salts were concerned. 

J. Y. Buchanan, the chemist in residence on the Challenger expedition. As late as the mid-1960s, it was a common dictum that the optimal number of electronic components for a sea-going instrument was less than one. It is now common practice to carry both electronic and computer technicians on cruises, to tend the rooms full of specialized equipment. We are more and more aware that the act of taking the sample can change some of the very properties in which we are interested. The chapters in this volume point to some of the directions we are now taking, and perhaps hint at several more we should be taking. 

HMS Challenger expedition collects rock and sediments from the ocean floor... 

When the organism dies the skeleton falls to the bottom of the ocean. Many of these skeletons have shapes similar to bubbles trapped in frameworks. Some of the Radiolarian skeletons are shown in Fig. 4.24. These skeletons were obtained by the biologist Ernst Haeckel on the Challenger Expedition of 1873-76. He found the skeletons in samples of mud taken from the ocean bed. Many of the samples are to be found in the Natural History Museum, London, England. Some superb glass models of these skeletons are to be seen at The Natural History Museum in New York City. 

---