Key rules of life and the fading cryosphere: Impacts in alpine lakes and streams

Elser, James J.; Wu, Chenxi; Gonzalez, Andrea F.; Shain, Daniel H.; Smith, Heidi J.; Sommaruga, Rubén; Williamson, Craig E.; Brahney, Janice; Hotaling, Scott; Vanderwall, Joseph; Yu, Jinlei; Aizen, Vladimir; Aizen, Elena M.; Battin, Tom J.; Camassa, Roberto; Feng, Xiu; Jiang, Hongchen; Lu, Lixin; Qu, John J.; Ren, Ze; Wen, Jun; Wen, Li; Woods, H. Arthur; Xiong, Xiong; Xu, Jun; Yu, Ge; Harper, Joel T.; Saros, Jasmine E.

doi:10.1111/gcb.15362

Cited by 57 publications

(51 citation statements)

References 116 publications

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“…Because microorganisms allocate resources to substrate acquisition depending on substrate availability, pairwise comparisons of EEA can indirectly inform us on substrate limitation. Comparing total C (AG + BG) versus N (LAP + NAG) and P (AP) acquiring EEA showed that generally more microbial effort is directed toward the acquisition of N and P as compared to C, indicating that communities were generally nutrient limited, with the majority of the GFSs being N-limited ( Figures 3A-D), which agrees well with past predictions for GFS microbial communities (Ren et al, 2019;Elser et al, 2020). High rates of weathering are hypothesized to take place beneath glaciers, which has the potential to liberate large quantities of P. However, much of this P is sediment-bound (Hawkings et al, 2016), and only a minority is thought to be bioavailable (only ∼1% by one estimate, Hodson et al, 2004).…”

Section: Biomass and Extracellular Enzyme Activity Across The Environsupporting

confidence: 88%

“…In addition to sediments and water, GFSs also deliver DOC (e.g., Hood et al, 2009Hood et al, , 2015Singer et al, 2012), nitrogen (N) (Hodson et al, 2005;Wadham et al, 2016;Colombo et al, 2019), and phosphorus (P) (Hodson et al, 2004;Föllmi et al, 2009;Hawkings et al, 2016) to downstream ecosystems-all of them typically at low concentrations. However, concentrations of P generally increase with greater glacier influence in comparison to N, probably due to elevated rates of rock comminution beneath the glacier and dust deposition on glacier surfaces (Elser et al, 2020). Therefore, N limitation is predicted to be common for microbial life in GFSs (Ren et al, 2019;Elser et al, 2020), yet few studies have directly assessed nutrient limitation on the microbial life of GFSs (e.g., Robinson et al, 2002;Kohler et al, 2016), representing a considerable barrier in our understanding of the ecology of these habitat types.…”

Section: Introductionmentioning

confidence: 99%

“…However, concentrations of P generally increase with greater glacier influence in comparison to N, probably due to elevated rates of rock comminution beneath the glacier and dust deposition on glacier surfaces (Elser et al, 2020). Therefore, N limitation is predicted to be common for microbial life in GFSs (Ren et al, 2019;Elser et al, 2020), yet few studies have directly assessed nutrient limitation on the microbial life of GFSs (e.g., Robinson et al, 2002;Kohler et al, 2016), representing a considerable barrier in our understanding of the ecology of these habitat types.…”

Section: Introductionmentioning

confidence: 99%

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Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams

et al. 2020

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Glacier-fed streams (GFSs) exhibit near-freezing temperatures, variable flows, and often high turbidities. Currently, the rapid shrinkage of mountain glaciers is altering the delivery of meltwater, solutes, and particulate matter to GFSs, with unknown consequences for their ecology. Benthic biofilms dominate microbial life in GFSs, and play a major role in their biogeochemical cycling. Mineralization is likely an important process for microbes to meet elemental budgets in these systems due to commonly oligotrophic conditions, and extracellular enzymes retained within the biofilm enable the degradation of organic matter and acquisition of carbon (C), nitrogen (N), and phosphorus (P). The measurement and comparison of these extracellular enzyme activities (EEA) can in turn provide insight into microbial elemental acquisition effort relative to environmental availability. To better understand how benthic biofilm communities meet resource demands, and how this might shift as glaciers vanish under climate change, we investigated biofilm EEA in 20 GFSs varying in glacier influence from New Zealand’s Southern Alps. Using turbidity and distance to the glacier snout normalized for glacier size as proxies for glacier influence, we found that bacterial abundance (BA), chlorophyll a (Chl a), extracellular polymeric substances (EPS), and total EEA per gram of sediment increased with decreasing glacier influence. Yet, when normalized by BA, EPS decreased with decreasing glacier influence, Chl a still increased, and there was no relationship with total EEA. Based on EEA ratios, we found that the majority of GFS microbial communities were N-limited, with a few streams of different underlying bedrock geology exhibiting P-limitation. Cell-specific C-acquiring EEA was positively related to the ratio of Chl a to BA, presumably reflecting the utilization of algal exudates. Meanwhile, cell-specific N-acquiring EEA were positively correlated with the concentration of dissolved inorganic nitrogen (DIN), and both N- and P-acquiring EEA increased with greater cell-specific EPS. Overall, our results reveal greater glacier influence to be negatively related to GFS biofilm biomass parameters, and generally associated with greater microbial N demand. These results help to illuminate the ecology of GFS biofilms, along with their biogeochemical response to a shifting habitat template with ongoing climate change.

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Section: Biomass and Extracellular Enzyme Activity Across The Environsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams

et al. 2020

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“…The surfaces of CRLs are typically boulder‐strewn and heterogeneous, and include dry, rocky ridges, sediment‐filled depressions and unstable, shifting margins (Figure 2). Paired with the environmental challenges that already stem from high‐elevation habitat in mountain ecosystems (e.g., extreme cold, intense solar radiation, reduced oxygen availability; Birrell et al, 2020; Elser et al, 2020), instability of CRL mantles, routine avalanches, and rockfall make their surfaces particularly harsh environments. For temperature, cold is not the only risk.…”

Section: Cold Habitats For Biodiversitymentioning

confidence: 99%

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity

Brighenti

Hotaling

Finn

et al. 2021

Global Change Biology

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Mountains are global biodiversity hotspots where cold environments and their associated ecological communities are threatened by climate warming. Considerable research attention has been devoted to understanding the ecological effects of alpine glacier and snowfield recession. However, much less attention has been given to identifying climate refugia in mountain ecosystems where present‐day environmental conditions will be maintained, at least in the near‐term, as other habitats change. Around the world, montane communities of microbes, animals, and plants live on, adjacent to, and downstream of rock glaciers and related cold rocky landforms (CRL). These geomorphological features have been overlooked in the ecological literature despite being extremely common in mountain ranges worldwide with a propensity to support cold and stable habitats for aquatic and terrestrial biodiversity. CRLs are less responsive to atmospheric warming than alpine glaciers and snowfields due to the insulating nature and thermal inertia of their debris cover paired with their internal ventilation patterns. Thus, CRLs are likely to remain on the landscape after adjacent glaciers and snowfields have melted, thereby providing longer‐term cold habitat for biodiversity living on and downstream of them. Here, we show that CRLs will likely act as key climate refugia for terrestrial and aquatic biodiversity in mountain ecosystems, offer guidelines for incorporating CRLs into conservation practices, and identify areas for future research.

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“…We build on related reviews (e.g., Elser et al, in press; Hotaling et al., 2017; Jacobsen & Dangles, 2017; McGregor et al., 1995; Milner & Petts, 1994; Ward, 1994) by synthesizing the physiological challenges beyond temperature extremes that insects face in high elevation streams, from both singular and interactive perspectives. We explore the knowledge gaps identified above by first describing the physical and physiological challenges of life in high‐elevation streams and how they are being altered by climate change.…”

Section: Introductionmentioning

confidence: 99%

Insects in high‐elevation streams: Life in extreme environments imperiled by climate change

Birrell

Shah

Hotaling

et al. 2020

Global Change Biology

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High-elevation streams are some of the most extreme ecosystems on Earth, yet they harbor extensive aquatic insect biodiversity and support a high degree of endemism (Hotaling et al., 2017). Highelevation streams occur from >2,000 m (at higher latitudes) to >4,000 m (lower latitudes) and represent nearly 5% of the world's waterways (Figure 1). They are typically fed by multiple meltwater sources, can be covered by snow and ice for most of the year, and are often fragmented and isolated, with cold, turbulent, fast-flowing water, low ionic strength, low oxygen availability, and high levels of UV radiation (when not covered by snow; Jacobsen & Dangles, 2017). High-elevation stream conditions are also highly variable in space and time, depending on source, drainage geology, elevation, aspect, latitude, and time of year. Collectively, however, high-elevation streams are experiencing some of the most rapid climate-driven

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Key rules of life and the fading cryosphere: Impacts in alpine lakes and streams

Cited by 57 publications

References 116 publications

Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams

Patterns and Drivers of Extracellular Enzyme Activity in New Zealand Glacier-Fed Streams

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity

Insects in high‐elevation streams: Life in extreme environments imperiled by climate change

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