Spring-time dynamics of diatom communities in landfast and underlying platelet ice in Terra Nova Bay, Ross Sea, Antarctica

• Published in: Journal of marine systems Vol. 166; pp. 26 - 36
• Main Authors: Saggiomo, Maria, Poulin, Michel, Mangoni, Olga, Lazzara, Luigi, De Stefano, Mario, Sarno, Diana, Zingone, Adriana
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2017
• Subjects: Antarctica; Bacillariophyceae; Communities; Diatoms; Dynamical systems; Fragilariopsis; Marine; Nova; Plankton; Platelets; Ross Sea; Sampling; Sea ice; Water circulation; PS, Antarctica, Ross Dependency, Terra Nova Bay; PS, Ross Sea; Ross Sea; Antarctica; Diatoms; Sea ice
• ISSN: 0924-7963; 1879-1573
• DOI: 10.1016/j.jmarsys.2016.06.007

We investigated the composition of diatom communities in annual fast ice and their variations over time during the 1999 austral spring in Terra Nova Bay (Ross Sea, Antarctica). Diatoms varied along the ice core in both cell abundance and species composition, with a minimum in the lower layer and a peak in the platelet ice. Planktonic species constituted in total about 98% of the diatom assemblage in the surface layers of the ice core down to the thickness of 220cm. In the bottom ice and the underlying platelet-ice layer, the contribution of planktonic diatoms was lower (60% and 65%, respectively) at the beginning of the sampling period, and then decreased further to reach 30% in the bottom ice, where a remarkable biomass increase over time was caused by in situ growth and accumulation of benthic species.
By contrast in the platelet-ice layer only small changes were recorded in the composition of the diatom assemblage, which was mainly constituted by the bloom of Fragilariopsis nana. The benthic species are generally not found in the water column, while species in the platelet-ice layer presumably constitute the seed for the initial plankton bloom during the ice-free periods in Terra Nova Bay.
•Spring evolution of diatom species in landfast ice of Terra Nova Bay (Antarctica)•Change in abundance and species composition along the ice core and over time•Conspicuous biomass increase in the bottom and the platelet-ice layer•Dominance of planktonic species in the platelet-ice layer•Shift from planktonic to benthic species dominance in the bottom ice over time