Laboratory experiment to study the effect of salinity variations on benthic foraminiferal species - Pararotalia nipponica (Asano)

Abstract

Culture experiment has been carried out to observe the response of Pararotalia nipponica (Asano) to different salinities and its salinity tolerance limits. The specimens of P. nipponica kept in 33‰ saline water achieved optimum growth, while rest of the specimens maintained under either higher or lower salinities showed comparatively lower growth. Pararotalia nipponica specimens kept at 10‰ and 15‰ salinity started becoming opaque and later their test dissolved, within a span of 25 days. Towards the end of experiment in order to find the maximum salinity tolerance limit, the salinity was gradually increased to 100‰, in the culture dishes having specimens at 40‰ saline water and it was noted that P. nipponica specimens were alive even at 100‰ salinity. It is concluded that comparatively lower salinities are much more detrimental to the foraminiferal tests than higher salinities. Results are significant as the salinity response of benthic foraminifera is being used for environmental assessment.