Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord

Sinha, Rupesh Kumar; Krishnan, K. P.; Kerkar, Savita; David, T. Divya

doi:10.1007/s12088-016-0621-5

Cited by 10 publications

(10 citation statements)

References 35 publications

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“…To date, very few studies have focused on diversity patterns in fjordic environments, particularly those of the eukaryotic community, often excluding large taxa and targeting specific groups such as protists (Orsi et al, 2012; Piquet et al, 2010). The results obtained on dominantly identified phyla in the present study are consistent with previous reports on marine and fjord systems, which were dominated by Proteobacteria (Aldunate et al, 2018; Sinha et al, 2017; Spietz et al, 2015; Vander Roost et al, 2018; Zaikova et al, 2010), Bacteroidetes (Aldunate et al, 2018; Fernández-Gómez et al, 2013; Sinha et al, 2017; Spietz et al, 2015), Opisthokonta (Del Campo et al, 2015), and SAR (Guillou et al, 2008).…”

Section: Discussionsupporting

confidence: 92%

Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords

Tobias-Hünefeldt

Wing

Espinel-Velasco

et al. 2019

Preprint

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SummarySystems with strong horizontal and vertical gradients, such as fjords, are useful models for studying environmental forcing. Here we examine microbial (prokaryotic and eukaryotic) community changes associated with the surface low salinity layer (LSL) and underlying seawater in multiple fjords in Fiordland National Park (New Zealand). High rainfall (1200-8000 mm annually) and linked runoff from native forested catchments results in surface LSLs with high tannin concentrations within each fjord. These gradients are expected to drive changes in microbial communities. We used amplicon sequencing (16S and 18S) to assess the impact of these gradients on microbial communities and identified depth linked changes in diversity and community structure. With increasing depth we observed significant increases in Proteobacteria (15%) and SAR (37%), decreases in Opisthokonta (35%), and transiently increased Bacteroidetes (3% increase from 0 to 40 m, decreasing by 8% at 200 m). Community structure differences were observed along a transect from inner to outer regions, specifically 25% mean relative abundance decreases in Opisthokonta and Bacteroidetes, and increases in SAR (25%) and Proteobacteria (>5%) at the surface, indicating changes based on distance from the ocean. This provides the first in-depth view into the ecological drivers of microbial communities within New Zealand fjords.

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Section: Discussionsupporting

confidence: 92%

Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords

Tobias-Hünefeldt

Wing

Espinel-Velasco

et al. 2019

Preprint

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“…The ratios of bacterial production (BP) to primary production (PP) vary from 0.03 to 0.32 (Sturluson et al, 2008;Uchimiya et al, 2016;Piontek et al, 2021); in several sites of the Arctic Ocean, these ratios were higher than 0.11, a common value in other oceans (Kirchman et al, 1993;Ducklow et al, 1995), which indicates that the fraction of PP that passes through DOM-bacteria coupling is not low under cold conditions, signifying an important role of bacteria in the carbon dynamics within the Arctic Ocean. Bacterial assemblages in marine oligotrophic settings, such as the Arctic Ocean, exhibit a high degree of metabolic adaptability to be able End of July 1995 11 (0.97-28.0)5.9 (2.8-11.0)3.6 (2.4-4.7)1.9 (1.0-3.5) (Børsheim, 2000) Greenland Sea and Norwegian Sea 0-1 Sept 2000 0.22-6.0 (Naganuma et al, 2006) Chukchi Sea Shelf <20 10-26 Sept 2013 4.2-6.0 (Uchimiya et al, 2016) Coastal Beaufort Sea ≤32 26 July-2 Aug 2004 6.7 (Vallières et al, 2008) East Siberian Sea Shelf ≤47 5-7 Sept 2017 5.9-20.9 (Kopylov et al, 2021) Laptev (Müller et al, 2018) 5-80 June-Oct 2012 0.14-5.0 (Sinha et al, 2017) to access scarce carbon sources for growth (Sala et al, 2008). In addition, bacterial communities in the Arctic can adjust their metabolism to the high-latitude cycles of PP (Hop and Wiencke, 2019).…”

Section: Bacterial Cell Size and Activitymentioning

confidence: 99%

Climate warming-driven changes in the flux of dissolved organic matter and its effects on bacterial communities in the Arctic Ocean: A review

et al. 2022

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The warming of the Arctic Ocean impacts the dissolved organic matter (DOM) imports into the Arctic region, which affects the local bacterial communities. This review addressed the current status of DOM inputs and their potential influences on bacteria data (e.g., population, production, and metabolic activity of bacteria), as well as the projected changes of DOM inputs and bacterial communities as a result of climate warming. Microbial communities are likely affected by the warming climate and the transport of DOM to the Arctic Ocean. Imported DOM can alter Arctic bacterial abundance, cell size, metabolism, and composition. DOM fluxes from Arctic River runoff and adjacent oceans have been enhanced, with warming increasing the contribution of many emerging DOM sources, such as phytoplankton production, melted sea ice, thawed permafrost soil, thawed subsea permafrost, melted glaciers/ice sheets, atmospheric deposition, groundwater discharge, and sediment efflux. Imported DOM contains both allochthonous and autochthonous components; a large quantity of labile DOM comes from emerging sources. As a result, the Arctic sea water DOM composition is transformed to include a wider range of various organic constituents such as carbohydrates (i.e., glucose), proteinaceous compounds (i.e., amino acid and protein-like components) and those with terrigenous origins (i.e., humic-like components). Changes to DOM imports can alter Arctic bacterial abundance, cell size, metabolism, and composition. Under current global warming projections, increased inflow of DOM and more diverse DOM composition would eventually lead to enhanced CO2 emissions and frequent emergence of replacement bacterial communities in the Arctic Ocean. Understanding the changes in DOM fluxes and responses of bacteria in the Arctic broadens our current knowledge of the Arctic Ocean’s responses to global warming.

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“…Studying the spatial and temporal (on seasonal/interannual timescales) variations of the basal properties of this glacier, Vallot et al [66] pointed out its sliding behavior over an annual scale, primarily driven by changes in the amount of meltwater reaching the bottom. From a 376-day time series of water temperature measurements performed by a LoTUS buoy moored at a depth of 67 m and about 1 km from the calving front of Kronebreen, Holmes et al [67] assessed the dynamics of frontal ablation from August 2016 to September 2017, recording an increasing trend in glacial retreat, an average of 1.03 m/day (396.8 m in the whole study period); these values were comparable to annual retreat values previously reported [66]. Indeed, Kronebreen is considered a fast-moving tidewater glacier with surface speeds of 2-3 m/day; its surface melting results in freshwater runoff that not only freshens fjord waters but also plays a key role in glaciomarine sedimentary processes, transporting sediment material into the fjord [68].…”

Section: Environmental Characterizationmentioning

confidence: 99%

Microbial Abundance and Enzyme Activity Patterns: Response to Changing Environmental Characteristics along a Transect in Kongsfjorden (Svalbard Islands)

Caruso

Madonia

Bonamano

et al. 2020

JMSE

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Svalbard archipelago is experiencing the effects of climate changes (i.e., glaciers' thickness reduction and glacier front retreat), but how ice melting affects water biogeochemistry is still unknown. Microbial communities often act as environmental sentinels, modulating their distribution and activity in response to environmental variability. To assess microbial response to climate warming, within the ARctic: present Climatic change and pAst extreme events (ARCA) project, a survey was carried out along a transect in Konsfjorden from off-shore stations towards the Kronebreen glacier. Total bacterial abundance and the fraction of actively respiring cells (labelled by cyanotetrazolium chloride, CTC), cultivable heterotrophic bacterial abundance, and extracellular enzymatic activities (leucine aminopeptidase (LAP), beta-glucosidase (GLU), and alkaline phosphatase (AP)) were measured. In addition, water temperature, salinity, dissolved oxygen, turbidity, total suspended matter (TSM), particulate and chromophoric dissolved organic matter (CDOM), chlorophyll-a (Chl-a), and inorganic compounds were determined, in order to evaluate whether variations in microbial abundance and metabolism were related with changes in environmental variables. Colder waters at surface (3.5–5 m) depths and increased turbidity, TSM, and inorganic compounds found at some hydrological stations close to the glacier were signals of ice melting. CDOM absorption slope values (275–295 nm) varied from 0.0077 to 0.0109 nm−1, and total bacterial cell count and cultivable heterotrophic bacterial abundance were in the order of 106 cells/mL and 103 colony forming units/mL, respectively. Enzymatic rates <1.78, 1.25, and 0.25 nmol/l/h were recorded for AP, LAP, and GLU, respectively. Inorganic compounds, TSM, and turbidity correlated inversely with temperature; AP was significantly related with CDOM absorption spectra and heterotrophic bacteria (r = 0.59, 0.71, P < 0.05); and LAP with Chl-a, Particulate Organic Carbon (POC) and Particulate Organic Nitrogen (PON) (0.97, 0.780, 0.734, P < 0.01), suggesting that fresh material from ice melting stimulated the metabolism of the cultivable fraction.

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Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord

Abstract: Kongsfjorden is a glacial fjord in the Arctic that is influenced by both Atlantic and Arctic water masses. In the present report retrievable heterotrophic bacteria isolated from two distinct zones (outer and inner fjord) of Kongsfjorden was studied during summer to fall of 2012.

Cited by 10 publications

References 35 publications

Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords

Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords

Climate warming-driven changes in the flux of dissolved organic matter and its effects on bacterial communities in the Arctic Ocean: A review

Microbial Abundance and Enzyme Activity Patterns: Response to Changing Environmental Characteristics along a Transect in Kongsfjorden (Svalbard Islands)

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