WHAT SIZE OF THE BENTHIC FORAMINIFERAL TEST WAS STUDIED IN THE DEEP SEA SEDIMENTS OF THE OCEAN DURING THE 20TH CENTURY?

Reviewing research on the deep sea benthic foraminifera, the size fractions of the specimens examined have varied, e.g., greater than 300µm, >250µm, >149 or 150µm, >125µm, and >63µm. In order to know which size fractions of specimens were most studied, we investigated articles in the Initial Report of the Deep Sea Drilling Project and the Proceeding of the Ocean Drilling Project (1868–1999). Among the 130 articles, 53 studied benthic foraminifera larger than 63µm, 24 papers studied benthic foraminifera larger than 125µm, and 23 papers studied specimens larger than 149µm. The first group studied benthic foraminifera in the sand of washed material of the deep sea sediments (>63µm) while the latter two groups did not study benthic foraminifera contained in very fine sand (63–125µm).

In 1953, Parker et al. studied benthic foraminifera larger than 149µm with a note that finer fraction of sediments (63–149µm) contain an abundance of small specimens, a large proportion of which is probably juvenile and cannot be identified with certainty. However, these small specimens were mostly identified in the studies that followed. Kurihara and Kennett (1985) examined samples from the three deep sea drilling sites of the South West Pacific, and pointed out that specimens between 63–149µm consist 78% to 89% of the benthic foraminiferal assemblages larger than 63µm.

We suggest that research that study benthic foraminiferal tests larger than 125µm or 149µm should have more scientific reasons to why smaller specimens are omitted.