Ecological Modeling of the Supraglacial Ecosystem: A Process-based Perspective

Stibal, Marek; Bradley, James A.; Box, Jason E.

doi:10.3389/feart.2017.00052

Cited by 9 publications

(7 citation statements)

References 59 publications

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“… 2012 ; Stibal et al . 2017a ; Stibal, Bradley and Box 2017b ), and are manifest through the brownish-greyish colouration they lend to the ice surface, which is often described as dark- or dirty-ice (Yallop et al . 2012 ; Chandler et al .…”

Section: Introductionmentioning

confidence: 99%

Ice algal bloom development on the surface of the Greenland Ice Sheet

Williamson

Anesio

Cook

et al. 2018

FEMS Microbiology Ecology

155

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It is fundamental to understand the development of Zygnematophycean (Streptophyte) micro-algal blooms within Greenland Ice Sheet (GrIS) supraglacial environments, given their potential to significantly impact both physical (melt) and chemical (carbon and nutrient cycling) surface characteristics. Here, we report on a space-for-time assessment of a GrIS ice algal bloom, achieved by sampling an ∼85 km transect spanning the south-western GrIS bare ice zone during the 2016 ablation season. Cell abundances ranged from 0 to 1.6 × 104 cells ml−1, with algal biomass demonstrated to increase in surface ice with time since snow line retreat (R2 = 0.73, P < 0.05). A suite of light harvesting and photo-protective pigments were quantified across transects (chlorophylls, carotenoids and phenols) and shown to increase in concert with algal biomass. Ice algal communities drove net autotrophy of surface ice, with maximal rates of net production averaging 0.52 ± 0.04 mg C l−1 d−1, and a total accumulation of 1.306 Gg C (15.82 ± 8.14 kg C km−2) predicted for the 2016 ablation season across an 8.24 × 104 km2 region of the GrIS. By advancing our understanding of ice algal bloom development, this study marks an important step toward projecting bloom occurrence and impacts into the future.

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Section: Introductionmentioning

confidence: 99%

Ice algal bloom development on the surface of the Greenland Ice Sheet

Williamson

Anesio

Cook

et al. 2018

FEMS Microbiology Ecology

155

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“…Recently, research has focused on blooms of Streptophyte microalgae (hereafter “glacier algae”), which occur in surface ice during summer ablation periods. These highly pigmented cells, often mistaken for dust or impurities, drive reductions in ice surface albedo (reflectance) (Yallop et al, 2012; Lutz et al, 2014; Stibal et al, 2017) with significant implications for accelerating melt (Tedstone et al, 2017; van den Broeke et al, 2017; Ryan et al, 2018). Bacterial abundance in surface ice has been shown to range 1.9–28 × 10 3 cells ml −1 (Stibal et al, 2015); however, only one study has quantified bacterial production within this habitat, indicating rates of BP were 30-times less than net primary production of supraglacial glacier algal communities (Yallop et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Bacterial Dynamics in Supraglacial Habitats of the Greenland Ice Sheet

et al. 2019

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Current research into bacterial dynamics on the Greenland Ice Sheet (GrIS) is biased toward cryoconite holes, despite this habitat covering less than 8% of the ablation (melt) zone surface. In contrast, the expansive surface ice, which supports wide-spread Streptophyte micro-algal blooms thought to enhance surface melt, has been relatively neglected. This study aims to understand variability in bacterial abundance and production across an ablation season on the GrIS, in relation to micro-algal bloom dynamics. Bacterial abundance reached 3.3 ± 0.3 × 10 5 cells ml −1 in surface ice and was significantly linearly related to algal abundances during the middle and late ablation periods ( R 2 = 0.62, p < 0.05; R 2 = 0.78, p < 0.001). Bacterial production (BP) of 0.03–0.6 μg C L −1 h −1 was observed in surface ice and increased in concert with glacier algal abundances, indicating that heterotrophic bacteria consume algal-derived dissolved organic carbon. However, BP remained at least 28 times lower than net primary production, indicating inefficient carbon cycling by heterotrophic bacteria and net accumulation of carbon in surface ice throughout the ablation season. Across the supraglacial environment, cryoconite sediment BP was at least four times greater than surface ice, confirming that cryoconite holes are the true “hot spots” of heterotrophic bacterial activity.

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“…Importantly, data presented here clearly show that, in fact, some microorganisms are much more active than others. It is therefore important to understand and quantify the active and dormant fraction of the microbial community so that the true range of activity (and inactivity) of glacial microorganisms is captured in empirical studies of glacial habitats, and can be accurately incorporated into models (Bradley, Anesio, & Arndt, 2016 ; Stibal et al, 2017 ), including those which explicitly resolve microorganisms and their transitions between active and dormant states (Bär et al, 2002 ; Blagodatsky & Richter, 1998 ; Bradley et al, 2018 , 2019 ; Ingwersen et al, 2008 ; Panikov, 1995 ; Stolpovsky et al, 2011 ).…”

Section: Discussionmentioning

confidence: 99%