ON THE SALINITY TOLERANCE OF THE PLANKTONIC FORAMINIFER NEOGLOBOQUADRINA PACHYDERMA FROM ANTARCTIC SEA ICE (17th Symposium on Polar Biology)

• Main Author: Michael SPINDLER
• Format: Report
• Language: English
• Published: Proceeding 1996
• Subjects: Antarctic; Antarc*; Neogloboquadrina pachyderma; Polar Biology; Proceedings of the NIPR Symposium on Polar Biology; Sea ice
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5306; http://id.nii.ac.jp/1291/00005306/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5306&item_no=1&attribute_id=18&file_no=1

The sea ice of both of the Earth's polar regions contains an internal system of delicate brine channels and pockets which serve as a habitat for a variety of organisms including plants and animals. The large standing stock of algae in the ice provides an ample food source for heterotrophic consumers. The sea ice habitat is characterised by low temperatures and correspondingly high salinities. During winter, temperatures as low as-15℃ and salinities as high as 177 psu were recorded in the brine channel system of the upper part of Antarctic sea ice. The tolerance of sympagic organisms to increased salinities is remarkable. Algae grow in salinities of up to 95 psu and also sea ice animals can survive, grow and partly reproduce under high salinities. The foraminifer Neogloboquadrina pachyderma was subjected to a variety of different salinities. Formation of new chambers occurs in salinities of up to 58 psu, specimens survive 82 psu for at least a week, and drastic changes in salinity are tolerated, e.g. direct transfer from 30 to 60 psu or from 60 to 40 psu. Chamber formation rates are slightly slower at higher salinities and the final size of specimens decreases with increasing salinity. Reproduction was never observed in salinities above 50 psu, which corroborates earlier results that N. pachyderma does not reproduce within the sea ice.