INTERNAL ECONOMY OF THE SEA _ 83 
Danish naturalists, Petersen and Jensen, show that 
the organic matter of the sea-floor in the sheltered 
waters of fjords and bays is mainly due not to the 
sinking down of the minute Plankton organisms, 
but to the detritus of the sea-grass (Zostera) and 
its associates in shallow water. This is of enormous 
practical importance, since it is in man’s hands to 
cultivate, if need be, the littoral vegetation, and 
thus cast bread upon the waters, to be gathered 
again after many days. But aquiculture is not yet 
a pressing need. 
As to a heresy started some years ago by Profes- 
sor Putter, that sea-water contains large quantities 
of dissolved organic matter—a sort of fundamental 
“stock” of the sea-soup—and that this accounts 
for the sustenance of many marine animals whose 
food supply has been confessedly difficult to dis- 
cover, it cannot be said to have been confirmed 
by further investigation. In fact, recent work by 
Professor Benjamin Moore and others at Port Erin 
Biological Station is quite against it. The prob- 
ability is that sufficient importance has not been 
attached to the nutritive rdle played by the organ- 
isms of the Dwarf Plankton (Nanno-plankton), 
which abound beyond telling in the open sea, and are 
so extremely minute that they pass through the 
invisible pores of the finest silk cloth used in tow- 
netting. There is thus no reason to depart from 
the conclusion that the producers in the economy 
of the sea are the chlorophyll-possessing plants, 
both of high and low degree, and such small animal 
