Oxygen modulates bacterial community composition in the coastal upwelling waters off central Chile

Aldunate, Montserrat; Iglesia, Rodrigo De la; Bertagnolli, Anthony D.; Ulloa, Osvaldo

doi:10.1016/j.dsr2.2018.02.001

Cited by 76 publications

(45 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…Calculating the bacterial uptake of DOC from production rates and a more conservative BGE between 10 % and 30 % as previously suggested (Rivkin and Legendre, 2001) for the in situ temperature of 14 to 19 • C, 3 %-209 % of the DOC loss and 1 %-62 % of oxygen loss could be attributed to bacterial degradation of DOM. The first approach reveals an average BGE (6.5 % and 5.0 %) that is still within the range of previous reports for upwelling systems of the Atlantic (< 1 %-58 %) and northeastern Pacific (< 10 %) (Alonso-Sáez et al, 2007;Del Giorgio et al, 2011). The high variability in BGE is a topic of ongoing research.…”

Section: Discussionsupporting

confidence: 81%

“…In general, bacterial community composition in OMZs has been shown to be strongly impacted by oxygen. In the OMZ near the shelf off Chile, Arctic96BD-19 and SUP05 dominate heterotrophic and autotrophic groups in hypoxic waters (Aldunate et al, 2018). Next to the appearance of autotrophic bacteria that are related to sulfur (e.g., SUP05) or nitrogen cycling (e.g., Planctomycetes), bacteria related to cycling of complex carbohydrates have also been discovered in OMZs (Callbeck et al, 2018;Galán et al, 2009;Thrash et al, 2017) and may explain the unaltered high potential (V max ) of the extracellular enzymes GLUCase and heterotrophic bacterial production in suboxic waters in our study (Figs.…”

Section: Discussionmentioning

confidence: 99%

Bacterial degradation activity in the eastern tropical South Pacific oxygen minimum zone

Maßmig¹,

Lüdke²,

Krahmann³

et al. 2020

Biogeosciences

View full text Add to dashboard Cite

Abstract. Oxygen minimum zones (OMZs) show distinct biogeochemical processes that relate to microorganisms being able to thrive under low or even absent oxygen. Microbial degradation of organic matter is expected to be reduced in OMZs, although quantitative evidence is low. Here, we present heterotrophic bacterial production (3H leucine incorporation), extracellular enzyme rates (leucine aminopeptidase/β-glucosidase) and bacterial cell abundance for various in situ oxygen concentrations in the water column, including the upper and lower oxycline, of the eastern tropical South Pacific off Peru. Bacterial heterotrophic activity in the suboxic core of the OMZ (at in situ ≤ 5 µmol O2 kg−1) ranged from 0.3 to 281 µmol C m−3 d−1 and was not significantly lower than in waters of 5–60 µmol O2 kg−1. Moreover, bacterial abundance in the OMZ and leucine aminopeptidase activity were significantly higher in suboxic waters compared to waters of 5–60 µmol O2 kg−1, suggesting no impairment of bacterial organic-matter degradation in the core of the OMZ. Nevertheless, high cell-specific bacterial production was observed in samples from oxyclines, and cell-specific extracellular enzyme rates were especially high at the lower oxycline, corroborating earlier findings of highly active and distinct micro-aerobic bacterial communities. To assess the impact of bacterial degradation of dissolved organic matter (DOM) for oxygen loss in the Peruvian OMZ, we compared diapycnal fluxes of oxygen and dissolved organic carbon (DOC) and their microbial uptake within the upper 60 m of the water column. Our data indicate low bacterial growth efficiencies of 1 %–21 % at the upper oxycline, resulting in a high bacterial oxygen demand that can explain up to 33 % of the observed average oxygen loss over depth. Our study therewith shows that microbial degradation of DOM has a considerable share in sustaining the OMZ off Peru.

show abstract

“…In general, bacterial community composition in OMZs has been shown to be strongly impacted by oxygen. In the OMZ near the shelf off Chile Arctic96BD-19 and SUP05 dominate heterotrophic and autotrophic groups in hypoxic waters (Aldunate et al, 2018). Next to the appearance of autotrophic bacteria that are related to sulphur (e.g.…”

Section: Discussionmentioning

confidence: 99%

High bacterial organic carbon uptake in the Eastern Tropical South Pacific oxygen minimum zone

Maßmig¹,

Lüdke²,

Krahmann³

et al. 2019

Preprint

View full text Add to dashboard Cite

Abstract. Oxygen minimum zones (OMZs) show distinct biogeochemical processes that relate to microorganisms being able to thrive under low or even absent oxygen. Microbial degradation of organic matter is expected to be reduced in OMZs, although quantitative evidence is low. Here, we present heterotrophic bacterial production (3H leucine-incorporation), extracellular enzyme rates (leucine aminopeptidase/&#223;-glucosidase) and bacterial cell abundance for various in situ oxygen concentrations in the water column of the Eastern Tropical South Pacific off Peru. Bacterial heterotrophic activity in the suboxic core of the OMZ (at in situ &#8804;&#8201;5&#8201;&#181;mol O2&#8201;kg&#8722;1) ranged from 0.6 to 160&#8201;&#181;mol&#8201;C&#8201;m&#8722;3&#8201;d&#8722;1 and was not significantly lower than in waters of 5&#8211;60&#8201;&#181;mol&#8201;O2&#8201;kg&#8722;1. Moreover, bacterial abundance in the OMZ was slightly and leucine aminopeptidase activity even significantly higher in suboxic waters compared to the upper oxycline suggesting no impairment of bacterial organic matter degradation in the core of the OMZ. Nevertheless, high cell-specific bacterial production and extracellular enzyme rates were observed in samples from the upper or lower oxyclines corroborating earlier findings of highly active and distinct micro-aerobic bacterial communities. To assess the impact of bacterial degradation of dissolved organic matter for oxygen loss in the Peruvian OMZ, we compared diapycnal fluxes of oxygen and dissolved organic carbon (DOC) and their microbial uptake within the upper 60&#8201;m of the water column. Our data indicate bacterial growth efficiencies of 0.5&#8211;8.6&#8201;% at the upper oxycline, resulting in a high bacterial oxygen demand that can explain up to 33&#8201;% of the observed average oxygen loss over depth. Our study therewith shows that microbial degradation of DOM has a considerable share in sustaining the OMZ off Peru.

show abstract

Oxygen modulates bacterial community composition in the coastal upwelling waters off central Chile

Cited by 76 publications

References 62 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

Bacterial degradation activity in the eastern tropical South Pacific oxygen minimum zone

High bacterial organic carbon uptake in the Eastern Tropical South Pacific oxygen minimum zone

Contact Info

Product

Resources

About