186 American Fisheries Society 



9.6 and 72.3 milligrams per 10 liters of sea water. No 

 relation could be shown to exist between the weather 

 conditions and amount of detritus in the water. 



The conclusion to be drawn from these results is that 

 sea water is rich in the quantity of detritus it contains. 



The next question which arises is, what value does 

 this organic matter of the sea bottom possess as a source 

 of nourishment for the benthos or bottom fauna? 



Assuming that the organic matter of the sea bottom 

 forms a source of nourishment for the majority of the 

 fauna living in and near the bottom Jensen considered 

 it advisable to investigate the question as to how far 

 suitable nourishment for such fauna can be shown to 

 exist among the substances of which the sea floor is 

 composed. 



Since eel grass contributes most of the organic matter 

 of the bottom it was natural to examine quite closely 

 the chemical composition of this weed. It was found to 

 compare favorably with the composition of the common 

 fodder grasses. Protein was found present to the amount 

 of 7.5% and pentosan 8-9%. No fat determination was 

 made. 



When eel grass is treated with pancreatin from 23 to 

 26% of the nitrogen is digested. Since the eel grass con- 

 tains 7.5% proteins, of which about y± is digestible by 

 pancreatin the amount of digestible proteins contained 

 may be put at 1.08%. Decomposed eel grass contains 

 less nitrogen and is less digestible. For example black 

 eel grass (dead) was found to contain 1.39% nitrogen 

 of which but 6.6% was digestible. These figures should, 

 however, in all probability mainly be taken as minimal. 



Experiments on the digestible nitrogenous com- 

 pounds in the sea bottom brought out the fact that there 

 is only a very small amount of proteins in the bottom 

 which are digestible with pancreatin. In fact the 

 amount is so small as to be very nearly within the limits 

 of possible error. The analyses for the top layer, how- 

 ever, give such positive results that it is justifiable to 

 conclude that the upper-most layer of the bottom really 



