Further considerations regarding the antiquity of the abyssal fauna with evidence for a changing abyssal environment

Further considerations regarding the antiquity of the abyssal fauna suggest continued confusion regarding the terms ‘Ancient’ and ‘Deep’ with reference to the marine fauna.

Two hypotheses concerned with ecological conditions in the abyss of the oceans prevail. Zenkevitch and Birstein (1960) adhere to a belief in constancy of abyssal conditions with the passage of time. Assembled here are data suggesting changing abyssal conditions with time. These opposing views lead to quite different concepts of the antiquity of the abyssal fauna.

The available data suggest that abyssal depths are populated with recent as well as ancient types of organisms and also that the abyssal fauna is far more diverse than has been previously recognized. Arguments are presented in support of the validity of oxygen isotope measurements on benthic Foraminifera from abyssal sediments.

A plea is made for careful, critical studies on the zoology, paleontology, and geochemistry of long cores of submarine sediment as a means of obtaining additional evidence for the understanding of the present composition of the abyssal fauna.