— Scavenging and dissolution processes (require paral- 

 lel measurements in the water column and accounting 

 for lateral motions that may amount to thousands of 

 miles). 



These studies would give source functions for the in situ production 

 and consumption of dissolved materials. They are particularly important 

 for the radioactive constituents, especially the plutonium isotopes dis- 

 cussed in Session C. They would also indicate to what extent the various 

 species dissolve on the bottom or during sinking. 



Analyses of particulate matter collected from the water column should 

 include 



1 . Physical composition and morphology by x-ray diffraction, scanning 

 electron microscopy, electron probe, and biological species identifica- 

 tion (size, frequency, and distribution) 



2. Chemical: Elemental composition of the organic fraction; C:N:P 

 ratios; characterization of protein, lipid, and carbohydrate components; 

 composition of inorganic fraction by neutron activation, x-ray fluores- 

 cence, atomic absorption, mass spectrometry, and leaching experiments 



3. Radiochemical analyses: Silicon-32, carbon- 14, and radium-226 

 to be determined on all samples, Lead-210 and thorium isotopes on 

 the upper portion of bottom samples and iron-55 and other artificially 

 produced isotopes on shallow samples 



4. Stable isotope measurements. 



ROLE OF BOTTOM DEPOSITS 



IN MODIFYING SEA WATER COMPOSITION 



In addition to the controls of clay and calcium carbonate on the overall 

 chemical state of seawater, there are specific modifications in the con- 

 centration of trace and minor components in the water column resulting 

 from processes occurring at the ocean bottom. None of these processes 

 is as yet sufficiently understood, especially with regard to their relative 

 importance in modifying the composition of seawater. The specific 

 areas needing more research include 



1. The flux of elements in and out of the water by reactions with 

 igneous rocks on the ocean floor 



2. Transport to the deep ocean of elements brought in by hot fluid 

 transport from depth 



3. The eff"ect of minerals in sediments which sequester elements 

 from seawater and interstitial waters. In particular, the flux of radium-226 

 and radon-220 to the deep ocean from bottom sediment will be controlled 

 by the presence or absence of radium traps such as barite and phillipsite 

 in the sediment. These two nuclides are of interest in ocean circulation 



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