The biology and chemistry of land fast ice in the White Sea, Russia: A comparison of winter and spring conditions

• Published in: Polar biology 2003-11, Vol.26 (11), p.707-719
• Main Authors: KRELL, Andreas, UMMENHOFER, Caroline, KATTNER, Gerhard, NAUMOV, Andrei, EVANS, Dylan, DIECKMANN, Gerhard S, THOMAS, David N
• Format: Article
• Language: English
• Subjects: Algae; Ammonium; Bacillariophyceae; Brackish; Dissolved organic carbon; Fast ice; Freshwater; Ice; Ice cover; Marine; Nitrogen; Nitzschia; Nutrients; Phytoplankton; Plankton; Sea ice; Spring; Winter
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-003-0543-7

Various abiotic and biotic parameters, including phytoplankton distribution, were studied to investigate seasonal changes within the fast-ice cover in Chupa Inlet, a freshwater-influenced Arctic-like fjord in Kandalaksha Bay (White Sea). Sea ice and under-ice water were collected along transects in the inlet in February and April 2002. Ice-texture analysis, salinity and delta super(18)O values indicated that the complete ice sheet had transformed within 2 months. This resulted from an upward growth of snow ice and subsequent melting at the underside of the ice, which makes a comparison between the two sampling periods difficult in terms of defining temporal developments within the ice. Nutrients, DOC and DON concentrations in the under-ice water were typical for Russian Arctic rivers. Concentrations of nitrate, silicate and DOC in the ice were lower, which is attributed to a loss as the ice forms. The concentrations were also modified by biological activity. In February, there was a strong correspondence between the distribution of biological parameters, including particulate and dissolved organic carbon and nitrogen (POC and PON, DOC and DON) and inorganic nutrients (nitrate, nitrite, phosphate and silicate), which was not the case in April. The correlation between both DOC and DON with ammonium indicates heterotrophic activity within the winter ice collected in February. Sea-ice organisms were distributed throughout the ice, and several assemblages were found in surface layers of the ice. In April, a more "typical' distribution of biomass in the ice was measured, with low values in the upper part and high algal concentrations in the lower sections of the ice, characteristic of a spring ice-algal bloom. In contrast to the February sampling, there was evidence that the ice-algal assemblage in April was nitrogen-limited, with total inorganic nitrogen concentrations being 98% of all organisms counted.