486 
BULLETIN OF THE BUREAU OF FISHERIES 
a regular seasonal succession there, temperature is undoubtedly an important factor 
in their economy. 
Recent studies 94 have brought out the possibility that flowerings of pelagic 
plants may become self-poisoned under certain circumstances when they are most 
productive by increasing the alkalinity of the water as they draw C0 2 from the 
dissolved bicarbonates through the process of photosynthesis, thus increasing the 
proportionate amount of carbonates and making the solution more alkaline. Moore, 
Whitley, and Webster (1921) have shown that this change probably does exercise 
a profound biologic effect in inclosed pools, first killing off the animals (which are much 
more sensitive to high alkalinity than the plants are) and finally the plants them- 
selves. A slight rise in alkalinity has been found to accompany the vernal multi- 
plication of diatoms, etc., in the Irish Sea (Moore, Prideaux, and Herdman, 1915) 
from Ph 8.1 to 8.16 in December to Ph 8.2 to 8.4 in spring and summer; likewise 
from Ph 8.14 in the English Channel off Plymouth in December to Ph 8.27 in May 
(Atkins, 1923). But none of the determinations of alkalinity that have been made 
anywhere in the open sea have approached the figure fatal to plant cells (Ph about 
9) 95 ; and it seems certain that this never happens in the Gulf of Maine (which is 
one of the less alkaline of seas), a considerable number of tests by Mayer (1922) 
and at our spring, summer, and winter stations for the years 1920 to 1923 giving 
a maximum alkalinity of Ph 8.1. In short, it is hardly conceivable that the life 
or multiplication of diatoms or peridinians is ever hindered in the open gulf by a too 
alkaline state of the water. 
It is also possible that the continued existence of exceptionally rich flowerings 
of diatoms may become self-limited by lack of oxygen, the dissolved supply of this 
element being used up, so to speak, in the oxidation of the dead plants, just as the 
decay of organic matter may reduce the supply of oxygen too low to support animal 
life in water contaminated by sewage. Whether this ever actually takes place in 
the open sea is yet to be learned, but it is not likely to be other than an exceptional 
event and one limited to very special inclosed inlets, probably never occurring in 
waters subject to as free circulation as those of the Gulf of Maine. 
• 4 See especially Moore, Prideaux, and Herdman (1915); Osterhaut and Haas (1918); and Moore, Whitley, and Webster (1921). 
M Atkins (1923) states that he was able to maintain a pure culture of the diatom Nitschia closterium in water as alkaline as Ph 9.4. 
