In the dark: A review of ecosystem processes during the Arctic polar night

Berge, Jørgen; Renaud, Paul E.; Darnis, Gérald; Cottier, Finlo; Last, Kim S.; Gabrielsen, Tove M.; Johnsen, Geir; Seuthe, Lena; Węsławski, Jan Marcin; Leu, Eva; Moline, Mark A.; Nahrgang, Jasmine; Søreide, Janne E.; Varpe, Øystein; Lønne, Ole Jørgen; Daase, Malin; Falk‐Petersen, Stig

doi:10.1016/j.pocean.2015.08.005

Cited by 163 publications

(138 citation statements)

References 166 publications

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“…references 13, 15, and 40). Diatom cells present in Kongsfjorden during the polar night period showed a rapid response to light levels as low as 0.1 to 1 mol photons s Ϫ1 m 2 (12). Thus, phototrophs seem to exist in the water column as active cells to a larger degree than previously recognized.…”

Section: Discussionmentioning

confidence: 79%

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Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

Marquardt

Vader²,

Stübner

et al. 2016

Appl Environ Microbiol

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101

107

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bThe Adventfjorden time series station (IsA) in Isfjorden, West Spitsbergen, Norway, was sampled frequently from December 2011 to December 2012. The community composition of microbial eukaryotes (size, 0.45 to 10 m) from a depth of 25 m was determined using 454 sequencing of the 18S V4 region amplified from both DNA and RNA. The compositional changes throughout the year were assessed in relation to in situ fjord environmental conditions. Size fractionation analyses of chlorophyll a showed that the photosynthetic biomass was dominated by small cells (<10 m) most of the year but that larger cells dominated during the spring and summer. The winter and early-spring communities were more diverse than the spring and summer/autumn communities. Dinophyceae were predominant throughout the year. The Arctic Micromonas ecotype was abundant mostly in the early-bloom and fall periods, whereas heterotrophs, such as marine stramenopiles (MASTs), Picozoa, and the parasitoid marine alveolates (MALVs), displayed higher relative abundance in the winter than in other seasons. Our results emphasize the extreme seasonality of Arctic microbial eukaryotic communities driven by the light regime and nutrient availability but point to the necessity of a thorough knowledge of hydrography for full understanding of their succession and variability. Microbial eukaryotes are critically important for the functioning of marine ecosystems as primary producers (1, 2) and consumers (3, 4) of carbon, as well as maintainers of biogeochemical cycles (5-7). In Arctic waters, where marine planktonic cyanobacteria are infrequent, marine microbial eukaryotes are the predominant primary producers (8-10). In spite of their importance, our knowledge of the diversity and role of picosized (0.2 to 2 m) and nanosized (2 to 20 m) (11) eukaryotic plankton is still limited in extreme areas.High-Arctic regions are characterized by extreme seasonality in light conditions, with 24 h of sunlight in summer giving way to several months of complete darkness in winter. The cold, dark polar night period at high latitudes strongly limits the activity of autotrophic organisms, and Arctic species in general have to adjust to the timing of seasonal events (12). The few studies performed during the Arctic winter-spring transition suggest a strong seasonal response by the microbial community to irradiance (13)(14)(15). Most studies of Arctic microbial eukaryotes have so far utilized traditional identification techniques, such as microscopy, and focused on bloom-forming pelagic protists (4, 16-18). The development of molecular techniques, especially high-throughput sequencing (HTS), has made it possible to study the diversity and assemblages of pico-and nanosized eukaryotic plankton as well (19)(20)(21)(22). This has resulted in several diversity surveys of microbial eukaryotes from the Arctic Ocean and the shelf seas (23-27). Pico-and nanosized planktons are now known to govern major processes in the oceans to a larger degree than previously assumed (6,7,28,29). Furthermore, 18S ...

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Section: Discussionmentioning

confidence: 79%

“…The cold, dark polar night period at high latitudes strongly limits the activity of autotrophic organisms, and Arctic species in general have to adjust to the timing of seasonal events (12). The few studies performed during the Arctic winter-spring transition suggest a strong seasonal response by the microbial community to irradiance (13)(14)(15).…”

mentioning

confidence: 99%

Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

Marquardt

Vader²,

Stübner

et al. 2016

Appl Environ Microbiol

Self Cite

101

107

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“…The sea ice pack, drifting with the Sørkapp Current from Storfjorden and the Barents Sea, occasionally enters Hornsund and may remain until July (Styszyńska and Kowalczyk 2007;Styszyńska and Rozwadowska 2008;Styszyńska 2009). The formation of fast ice was also a regular phenomenon in Kongsfjorden in the past, but in recent years, the fast ice has been forming only in the inner, most sheltered bay (Nicolaus et al 2003;Hop et al 2006;Gerland et al 2008;Dieckmann et al 2010;Berge et al 2015), and compared to Hornsund, it covers a much smaller part of the fjord surface (Table 2).…”

Section: Study Ar Eamentioning

confidence: 99%

“…There is also a characteristic summer horizontal gradient in the microplankton distribution within the fjord, with flagellates and mixotrophs dominating the turbid waters of the inner basins, while the open outer fjord part is inhabited by larger-sized diatoms and dinoflagellates (Piwosz et al 2009). The highest reported biomass of microplankton ranged from 2.3 g C m -2 in spring (GAME project data) to 2.1 g C m -2 in summer (Piwosz et al 2009 ; Table 3) and dropped down to single cells observed during the winter dark season (Węsławski et al 1990;Wiktor 1999;Berge et al 2015;Błachowiak-Samołyk et al 2015).…”

Section: Primary Producersmentioning

confidence: 99%

Primary producers and production in Hornsund and Kongsfjorden – comparison of two fjord systems

Smoła¹,

Tatarek²,

Wiktor³

et al. 2017

Polish Polar Research

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Hornsund and Kongsfjorden are two similar-sized Arctic fjords on the West coast of Spitsbergen. They are influenced by cold coastal Arctic water (Hornsund) and warmer Atlantic water (Kongsfjorden). Environmental conditions affect the timing, quantity, spatial distribution (horizontal and vertical) of spring and summer blooms of protists as well as the taxonomic composition of those assemblages. Here, we compile published data and unpublished own measurement from the past two decades to compare the environmental factors and primary production in two fjord systems. Kongsfjorden is characterized by a deeper euphotic zone, higher biomass and greater proportion of autotrophic species. Hornsund seems to obtain more nutrients due to the extensive seabird colonies and exhibits higher turbidity compared to Kongsfjorden. The annual primary production in the analysed fjords ranges from 48 g C m -2 y -1 in Kongsfjorden to 216 g C m -2 y -1 in Hornsund, with a dominant component of microplankton (90%) followed by macrophytes and microphytobenthos.

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“…The Arctic ocean is for phototrophic organisms with respect to light availability an extreme habitat (Hop et al 2002;Berge et al 2015b). In Svalbard, the polar night lasts for about 4 months from the end of October to the mid of February.…”

Section: Introductionmentioning

confidence: 99%

Effects of prolonged darkness and temperature on the lipid metabolism in the benthic diatom Navicula perminuta from the Arctic Adventfjorden, Svalbard

et al. 2017

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which could consequently lead to a depletion of this energy reserves before the end of the polar night. On the other hand, the membrane building phospho-and glycolipids remained unchanged during the 8 weeks darkness, indicating still intact thylakoid membranes. These results explain the shorter survival times of polar diatoms with increasing water temperatures during prolonged dark periods. Abstract The Arctic represents an extreme habitat for phototrophic algae due to long periods of darkness caused by the polar night (~4 months darkness). Benthic diatoms, which dominate microphytobenthic communities in shallow water regions, can survive this dark period, but the underlying physiological and biochemical mechanisms are not well understood. One of the potential mechanisms for long-term dark survival is the utilisation of stored energy products in combination with a reduced basic metabolism. In recent years, water temperatures in the Arctic increased due to an ongoing global warming. Higher temperatures could enhance the cellular energy requirements for the maintenance metabolism during darkness and, therefore, accelerate the consumption of lipid reserves. In this study, we investigated the macromolecular ratios and the lipid content and composition of Navicula cf. perminuta Grunow, an Arctic benthic diatom isolated from the microphytobenthos of Adventfjorden (Svalbard, Norway), over a dark period of 8 weeks at two different temperatures (0 and 7 °C). The results demonstrate that N. perminuta uses the stored lipid compound triacylglycerol (TAG) during prolonged dark periods, but also the pool of free fatty acids (FFA). Under the enhanced temperature of 7 °C, the lipid resources were used significantly faster than at 0 °C, Keywords

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In the dark: A review of ecosystem processes during the Arctic polar night

Cited by 163 publications

References 166 publications

Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

Strong Seasonality of Marine Microbial Eukaryotes in a High-Arctic Fjord (Isfjorden, in West Spitsbergen, Norway)

Primary producers and production in Hornsund and Kongsfjorden – comparison of two fjord systems

Effects of prolonged darkness and temperature on the lipid metabolism in the benthic diatom Navicula perminuta from the Arctic Adventfjorden, Svalbard

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