Polycystine radiolarians in surface sediments from the Bering Sea Green Belt area and their ecological implication for paleoenvironmental reconstructions

Radiolarians in surface sediments along transects from the shelf edge, along the slope into the deep basin of the northern Bering Sea are dominated by Stylochlamydium venustum, Antarctissa? sp. 1, the Spongodiscidae (juvenile), Pseudodictyophimus gracilipes, Ceratospyris borealis, the Plagoniidae (Phormacantha group and Plectacantha group), Siphocampe arachnea, Cycladophora davisiana and Spongotrochus glacialis. This dominance is most extreme on the shelf edge and slope, where S. venustum, Antarctissa? sp. 1, the Spongodiscidae (juvenile), the Plagoniidae and S. glacialis have their highest relative abundance. There is thus a close relation between radiolarian distribution and the high productivity of the “Bering Sea Green Belt” (BSGB) due to periodic sea ice melt. The radiolarian depth distribution patterns indicate that some radiolarian species have specific ecological preferences. S. venustum, the Spongodiscidae (juvenile), and S. glacialis live close to the surface water under relatively low-temperature and low-salinity conditions due to sea ice melting or melt water influx. Antarctissa? sp. 1 appears to dwell mainly in surface to subsurface waters, but has not been recorded in trap samples of the Bering Sea. The Plagoniidae probably live in subsurface and intermediate waters. S. arachnea and C. davisiana are intermediate to deep dwellers. The close association of these radiolarians with the BSGB and specific water depths provides a valuable reference for paleoenvironmental reconstruction in the region.