6. Under-water photography as developed in the U.S.A. during the war. If 

 the technique could be applied to greater depths, that would be of outstanding 

 importance. 



7. Current and silt measurements close to the bottom under varying circum- 

 stances, especially during rough weather and along breaks in slope. This would 

 teach us more of the transport of sediment and the existence of new-depositional 

 environments. 



8. Chemistry of sea-water, especially the problem of solution and precipitation 

 of lime (bottom water, surface layer). 



9. Chemical analyses of sediments, both of bulk samples and individual samples, 

 for geochemical investigations. 



10. Radioactive age determination of log samples. 



11. The influence of organisms on the deposition of fine particles. 



12. The compilation of a new world chart. 



Addenda 



(') Sounding of the European continental slope will require the co-operation 

 of hydrographic surveys. An outstanding problem is to carry the investigation of 

 a few submarine canyons right out to the deep-sea floor to ascertain whether they 

 end in a " delta " or otherwise. Position flnding by radar might solve the problem 

 of locating the position of soundings. 



(2) Many thousands of samples will have to be taken from the cores and 

 examined regarding mineralogical, radio-active, chemical and physical properties. 



Professor Hans Pettersson urged the very great importance of inter- 

 national co-operation, especially in deep oceanic work ; he emphasized 

 that the determination of the age of cores by means of radio-active 

 measurement can only be done in deep-sea sediments. 



Professor Proudman called the attention of the Committee to the 

 oceanographic investigations that could be undertaken by the meteoro- 

 logical observation vessels and the necessity for the co-operation of the 

 International Association (of Physical Oceanographers) and their 

 collaboration with the International Committee on Oceanography. 

 Such vessels would provide opportunities for continuous observations 

 in more or less fixed positions. The British vessels would probably be 

 able to carry out observations on the surface water, and possibly each 

 country concerned in the scheme would organize certain researches for 

 its own vessels. 



The Committee discussed the possibility of the re-establishment of 

 the Oceanographic Institute at Monaco as an operating Oceanographical 

 Laboratory. 



Dr. Boschma submitted to the Committee a report b}^ Dr. Margaretha 

 Brongersma-Sanders, of Leiden, Holland, on the occurrence and causation 

 of mortality in fish on the coast of South-west Africa (particularly Walvis 

 Bay) associated with the presence of " red water," and urging the 

 desirability of carrying out research into certain phenomena in this region. 

 A precis of the report follows : — 



In some of the bays on the coast of South-west Africa (especially Walvis Bay) 

 and sometimes in the neighbouring open sea there is a periodic mass-mortality of 

 fish, which always occurs in the southern summer (December). In the same area 

 there is a peculiar bottom sediment, characterized by a high organic content, great 

 quantities of HgS. gas and a nearly complete absence of living organisms, other 

 than anaerobic bacteria ; in this deposit are numerous fish remains and a verj^ 

 high percentage of the skeletons of diatoms. This azoic area extends from Cape 

 Cross to south of Conception Bay (lat. 21° 20'-24° 30' S.) and from near the coast- 

 line out to about the 77 fathom line, a width of about 25-30 miles. , The azoic area 

 is separated from the shore by a coastal belt in which the bottom is fine grey sand 

 and there is an absence of H2S. 



The active cause of the mortality is by many attributed to the H jS gas, but; the 

 origin of this gas is in dispute. It may be either (1.) carried down as sulphur com- 

 pounds from the land by rivers, or (2) due to the reduction of sulphates in the 

 sediment by anaerobic bacteria. 



150 



