X-ray micro-CT scanning of tests of three planktic foraminiferal species to clarify dissolution process and progress

Here we observed test dissolution processes of the planktic foraminifera Trilobatus sacculifer, Globigerinoides ruber, and Neogloboquadrina dutertrei from mid-latitudes of the western North Pacific; in these three species, we tested the ability of a new dissolution index using data from X-ray micro-computed tomography scanning (XMCT).

Although the dissolution process of foraminiferal tests differed slightly among species, dissolution of all species was equally assessed by the calcite density distribution (%Low-CT-number calcite volume) calculated from the CT number histogram. As for T. sacculifer and G. ruber, the test area density, a conventional proxy for assessing test condition based on weight measurement, is affected by variance in the thickness of the outermost chamber wall; thus, this conventional proxy can be affected by sea surface conditions during test calcification.