184 American Fisheries Society 



The transformation of nitrogen during the decom- 

 position of eel grass and its relation to the nitrogen 

 content of the organic matter in the sea bottom was also 

 investigated by Jensen. He found that the green eel 

 grass is as rich in nitrogen as peas or beans, which con- 

 tain about 3%. As the eel grass decomposes the per- 

 centage of nitrogen decreases until it is as low as 0.88%, 

 then as decomposition continues it rises again up to 

 1.39%. Analyses of the organic matter in the sea bottom 

 indicate that the average amount of nitrogen present is 

 4%. Thus it is evident that the organic substances of 

 the sea bottom contain a greater proportion of nitrogen 

 than the eel grass. 



Why the organic matter in the sea bottom is so much 

 richer in nitrogen than the eel grass from which it is 

 formed chiefly is readily explained by Jensen. As has 

 been shown the amount of nitrogen in the green eel grass 

 is greater than that in the early stages of decomposition. 

 Later the amount of nitrogen increases becoming much 

 greater than in the green eel grass. The diminution in 

 nitrogen during the first stages may be due to the fact 

 that a portion of the nitrogenous protoplasm is dis- 

 solved in the sea water as the cells die. The increase in 

 proportion of nitrogen in the final stages of decom- 

 position may be due to two causes. (1) Either by the 

 destruction of non-nitrogenous substances in the sea 

 bottom to a greater extent than is the case with the nitro- 

 genous matter, or (2) by the fixation of inorganic or 

 free nitrogen by bacteria. 



It has been established beyond all doubt that non- 

 nitrogenous substances of the sea floor are to a very 

 considerable extent destroyed by bacteria, at least one 

 step in the process being the fermentation of the pen- 

 toses. Another is the formation of methane from the 

 fermentation of cellulose. On the other hand it is prob- 

 able that the nitrogenous substances are acted upon to 

 a lesser degree due to the fact that they are compara- 

 tively easily transformed into humic compounds, which 

 are less easily destroyed. 



