A Close Look at Dissolved Silica Dynamics in Disko Bay, West Greenland

Global Biogeochemical Cycles, Journal Year: 2025, Volume and Issue: 39(1)

Published: Jan. 1, 2025

Abstract Discharge of calved ice, runoff and mixing driven by subglacial discharge plumes likely have consequences for marine biogeochemistry in Disko Bay, which hosts the largest glacier northern hemisphere, Sermeq Kujalleq. Glacier retreat increasing may impact silica cycle because glaciers deliver elevated concentrations dissolved (dSi) compared to other macronutrients. However, annual flux dSi delivered ocean from Greenland Ice Sheet is poorly constrained difficulties distinguishing overlapping influence different sources. Here we constrain dynamics around including Ilulissat Icefjord four regions receiving with contrasting levels productivity turbidity. Both Si* ([dSi]‐[NO x − ]) indicated conservative two fjords land‐terminating glaciers, consistent results experiments. In three marine‐terminating macronutrient‐salinity distributions were strongly affected entrainment nutrients plumes. Entrainment saline waters explained 93 ± 51% enrichment outflowing plume Icefjord, whereas direct contribution freshwater was 0%–3%. Whilst not distinguished herein, minor regional sources include icebergs dissolution amorphous (aSi) either pelagic or benthic environments. Our suggest that supplemented as a source fluxes 0.25 0.67 Gmol yr −1 ∼1.9 year aSi dissolution.

Language: Английский

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High‐Resolution Sensors Reveal Nitrate and Dissolved Silica Dynamics in an Arctic Fjord

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(3)

Published: March 1, 2025

Abstract Subglacial weathering releases biologically important nutrients into meltwaters that have the potential to influence downstream ecosystems. There is a need understand how accelerated glacial retreat could impact biogeochemical cycling in coastal regions near future. However, fjords—important gateways connecting Greenland ice sheet and oceans—are highly heterogeneous environments both space time. Here, we investigate temporal variability of nutrient dynamics glacier‐fed fjord (Nuup Kangerlua, Greenland) using high resolution record nitrate + nitrite (∑NO x ) dissolved silica (DSi), coupled with temperature salinity, submersible situ sensors. During 3‐month monitoring period (14th June 13 September 2019), ∑NO varied between 0.05 10.07 μM (±0.2 μM), whereas DSi 0.35 14.98 (±0.5 μM). Both started low (following spring bloom) increased throughout period. Several large peaks were observed, these can largely be associated meltwater runoff upwelling events. Peaks likely direct result pulses, elevated concentrations system meltwater‐induced marine sources. did not observe case simple conservative mixing, suggesting other processes (e.g., differential biological uptake remineralization) may decouple relationship two nutrients. This data set was used changes glacier input melt season.

Language: Английский

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Insights into silicon cycling from ice sheet to coastal ocean from isotope geochemistry

Communications Earth & Environment, Journal Year: 2025, Volume and Issue: 6(1)

Published: April 19, 2025

Language: Английский

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Diatom silicon isotope ratios in Quaternary research: Where do we stand?

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 344, P. 108966 - 108966

Published: Sept. 16, 2024

Language: Английский

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Incubation Experiments Characterize Turbid Glacier Plumes as a Major Source of Mn and Co, and a Minor Source of Fe and Si, to Seawater

Global Biogeochemical Cycles, Journal Year: 2024, Volume and Issue: 38(10)

Published: Oct. 1, 2024

Abstract Glaciers are a source of fine‐ground rock flour to proglacial and coastal marine environments. In these environments, suspended may affect light (micro)nutrient availability primary producers. Due high loads glacier flour, the particulate metal load runoff typically exceeds dissolved load. As is deposited in downstream short‐term exchange between phases have moderating influence on concentrations. Here we compare behavior iron (Fe), manganese (Mn), cobalt (Co) silica (Si) following addition different glacier‐derived sediments into seawater under conditions varying sediment (20–500 mg L −1 ), time (0.5 hr–21 days), temperature (4–11°C) exposure (dark/2,500 Lux). Despite moderately labile Fe content across all particle types (0.28–3.50 g dry sediment), only 0.27–7.13 μg was released seawater, with less efficient release as increased. Conversely, Si, Mn, Co exhibited more constant rate release, which sensitive Dissolved Si equivalent 17% ± 22% amorphous after 1–2 weeks. Mn concentrations most incubations exceeded within 1 hr despite being 12‐fold lower than content. Our results show potential for particles be large waters add growing evidence that bio‐essential affected by glacier‐associated sources.

Language: Английский

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Detrital Input Sustains Diatom Production off a Glaciated Arctic Coast

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(12)

Published: June 12, 2024

Abstract In the Arctic and subarctic oceans, relatively low supply of silicon (compared to other nutrients) can make it limiting for growth diatoms, a fundamental building block oceanic food web. Glaciers release large quantities dissolved dissolvable solid amorphous silica phases into high‐latitude estuaries (fjords), but role these glacially‐derived in sustaining diatom coastal open‐water sectors remains unknown. Here we show how stable radiogenic isotopes be used together address this question, using southwest Greenland as case study. This study finds enhanced levels detrital (i.e., mineral) silica, likely glacially‐sourced, portion observed off coast, revealing phytoplankton community function during high‐meltwater periods.

Language: Английский

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Silicon isotopes reveal the impact of fjordic processes on the transport of reactive silicon from glaciers to coastal regions

Chemical Geology, Journal Year: 2024, Volume and Issue: 670, P. 122403 - 122403

Published: Sept. 11, 2024

Language: Английский

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