Springtime dynamics, productivity and activity of prokaryotes in two Arctic fjords

Author(s)
A. M. -T. Piquet, D. S. Maat, V. Confurius-Guns, E. Sintes, G. J. Herndl, W. H. van de Poll, C. Wiencke, A. G. J. Buma, H. Bolhuis
Abstract

In the Kongsfjorden-Krossfjorden system (Spitsbergen), increasing temperatures enhance glacier melting and concomitant intrusion of freshwater. These altered conditions affect the timing, intensity, and composition of the phytoplankton spring bloom in Kongsfjorden; yet, the effects on prokaryotes (bacteria and archaea) are not well understood. The aim of this study was to examine springtime prokaryote communities in both fjords as a function of hydrographic and phytoplankton variability. Prokaryote community composition was studied in two consecutive years by molecular fingerprinting of the 16S rRNA gene. In addition, we measured bacterial abundance, productivity (H-3-Leucine uptake), and single-cell activity using catalyzed reporter deposition fluorescence in situ hybridization combined with microautoradiography. Differences in bacterial and archaeal communities were found between Kongsfjorden and Krossfjorden. Furthermore, an increase in productivity, abundance, and proportion of active bacterial cells was observed during the course of spring. Bacteroidetes were the most abundant bacterial group among the assessed taxa in both Kongsfjorden and Krossfjorden. Multivariate analysis of the microbial community fingerprints revealed a strong temporal shaping of both the bacterial and archaeal communities in addition to a spatial separation between the two fjords. A significant part of the observed bacterial variation could be explained by cyanobacterial biomass, as deduced from pigment analysis, and by phosphate concentration. Archaea were mainly controlled by abiotic factors. We speculate that the bacterial response to hydrographic changes and glacier meltwater is mediated through shifts in phytoplankton abundance and composition, whereas archaea are directly influenced by abiotic environmental variables.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
University of Groningen, Royal Netherlands Institute for Sea Research, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Journal
Polar Biology
Volume
39
Pages
1749-1763
No. of pages
15
ISSN
0722-4060
DOI
https://doi.org/10.1007/s00300-015-1866-x
Publication date
10-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
Marine biology
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/springtime-dynamics-productivity-and-activity-of-prokaryotes-in-two-arctic-fjords(79ed1b05-3462-48aa-8ee4-8d056df707f7).html