Productivity of Spitsbergen fjords ecosystems in summer—Spatial changes of in situ primary production in Kongsfjorden and Hornsund in the period 1994–2019

• Published in: Ecology and evolution 2024-06, Vol.14 (6), p.e11607-n/a
• Main Authors: Dragańska‐Deja, Katarzyna, Stoń‐Egiert, Joanna, Wiktor, Józef, Ostrowska, Mirosława
• Format: Article
• Language: English
• Subjects: 14C isotope method; Biogeochemistry; Biomass; Carbon; Chlorophyll; chlorophyll a; Coasts; Ecosystems; Fjords; Functional Ecology; Glaciers; Hornsund; Kongsfiord; Measurement techniques; Meltwater; Nutrients; Particulate emissions; Particulate matter; Plankton; Primary production; Productivity; Salinity; Spatial distribution; Spitsbergen fjords; Summer; Surface water; Trends; Water; Water circulation; Water column; Water depth; Winter
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.11607

This comprehensive study examines primary production (PP) within the Spitsbergen fjords, Hornsund, and Kongsfjord, over a 25‐year period (1994–2019), across 45 stations and 348 incubation levels at various depths. PP and hydrological parameters were measured at 28 sampling stations in Kongsfjorden and 17 in Hornsund, with the locations of “Glacier,” “Inner,” and “Outer” zones defined to reflect the varying influence of glacial meltwater. Our study revealed spatial and temporal variability in PP, both at the surface and within the water column with very high depth resolution. The highest PP values were observed in the Glacier and Inner zones of Hornsund, particularly in the water layer up to 3 m depth, exceeding 20 mgC m−3 h−1. A notable decline in PP with increasing depth was observed in both fjords, with the Glacier zones displaying the highest productivity at the surface. The study also highlights the influence of glacial meltwater on surface water conditions, affecting the PP in the upper layers of both fjords. The observed gradient in the depth of maximum PP toward the mouth of the fjord varied between the two fjords, with Kongsjord displaying more dynamic variations. The spatial distribution of integrated primary production (Pi) suggested lower productivity in the glacial regions, likely due to light limitation caused by high concentrations of mineral particulate matter. The values of Pi were considerably higher in Hornsund, approximately twice as high overall, with specific emphasis on the Glacier and Inner zones where Pi values were about 6.5 and 2.5 times higher, respectively, when compared to those observed in Kongsfjord. This comprehensive study examines primary production (PP) within the Spitsbergen fjords, in “Glacier,” “Inner,” and “Outer” zones of Hornsund and Kongsfjord, over a 25‐year period (1994–2019), involving 45 experiments and 348 incubations levels at various depths. Our study revealed significant spatial and temporal variability in PP, both at the surface and within the water column and also highlighted the influence of glacial meltwater affecting the PP in the upper layers of both fjords.