Seasonal microbial processes in a high-latitude fjord (Kongsfjorden, Svalbard): I. Heterotrophic bacteria, picoplankton and nanoflagellates

By Kriss Rokkan Iversen, Lena Seuthe. Polar Biology, 2011

203 citations recorded by the source corpus.

Temporal dynamics of the microbial food web in the Barents Sea and adjacent water masses in the European Arctic are to a large extent unknown. Seasonal variation in stocks and production rates of heterotrophic bacteria and phototrophic and heterotrophic picoplankton and nanoflagellates was investigated in the upper 50 m of the high-latitude Kongsfjorden, Svalbard, during six field campaigns between March and December 2006. Heterotrophic bacteria, picoplankton and nanoflagellates contributed to ecosystem structure and function in all seasons. Activity within the microbial food web peaked during spring bloom in April, parallel to low abundances of mesozooplankton. In the nutrient-limited post-bloom scenario, an efficient microbial loop, fuelled by dissolved organic carbon from abundant mesozooplankton feeding on phytoplankton and protozooplankton, facilitated maximum integrated primary production rates. A tight microbial food web consisting of heterotrophic bacteria and phototrophic and heterotrophic picoplankton and nanoflagellates was found in the stratified water masses encountered in July and September. Microbial stocks and rates were low but persistent under winter conditions. Seasonal comparisons of microbial biomass and production revealed that structure and function of the microbial food web were fundamentally different during the spring bloom when compared with other seasons. While the microbial food web was in a regenerative mode most of the time, during the spring bloom, a microbial transfer mode represented a trophic link for organic carbon in time and space. The microbial food web’s ability to fill different functional roles in periods dominated by new and regenerated production may enhance the ecological flexibility of pelagic ecosystems in the present era of climate change.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/1c63e848d37bf6c9c76fda93fdb151dbe61e2c98

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Citations in the corpus

The importance of tidewater glaciers for marine mammals and seabirds in Svalbard, Norway (2014, background): “Protozoan(ciliates andheterotrophic/mixotrophicdi-no ﬂ agellates) biomass peaks in conjunction with the phytoplankton spring bloom and is controlled by copepod grazing during the summer months, while food availability constrains population size in winter (Seuthe et al., 2011).”
In the dark: A review of ecosystem processes during the Arctic polar night (2015, background): “…(Berge et al., 2009) and nekton (Webster et al., 2013), increased understanding of the microbial community structure and function (Rokkan Iversen and Seuthe, 2011), patterns of bioluminescence by pelagic organisms (Berge et al., 2012a; Johnsen et al., 2014), foraging by predators…”