Inorganic carbon in a high latitude estuary-fjord system in Canada’s eastern Arctic

Turk, Daniela; Bedard, Jeannette; Burt, William J.; Vagle, Svein; Thomas, Helmuth; Azetsu-Scott, Kumiko; McGillis, Wade R.; Iverson, Sara J.; Wallace, Douglas W.R.

doi:10.1016/j.ecss.2016.06.006

Cited by 11 publications

(14 citation statements)

References 59 publications

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“…For C T and salinity, the relationship yielded C T = 82.9S -696 (r 2 = 0.76; in the aragonite saturation state (∆Ω total ) are determined from monthly changes in ∆C T and ∆A T for each of the key physical and biogeochemical processes, salinity changes (∆Ω sal ), mixing (∆Ω mix ), photosynthesis/respiration (∆Ω bio ), calcium carbonate formation/dissolution (∆Ω CaCO 3 ), air-sea CO 2 exchange (∆Ω flux ) and per sampling month during the 2017-2018 annual cycle at the central hydrographic station of the outer (T1), middle (T2), and inner (T3) transects. DOI: https://doi.org/10.1525/elementa.438.f12 se = 102 µmol kg -1 ; p < 0.0001: n = 235), which indicates a deficit in C T in freshwater, as reported for freshwater A T endmember estimates from salinity relationships by Turk et al (2016). A second approach in estimating the freshwater A T endmember is using the relationship with δ 18 O, as a comparison.…”

Section: Seasonality In Freshwater and Deep-water Effectsmentioning

confidence: 94%

Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

et al. 2020

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Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (CT), alkalinity (AT), major nutrients and calcium carbonate saturation (Ω) were driven by freshwater discharge, biological production and mixing with subsurface carbon-rich coastal water. Stable oxygen isotope ratios indicated that meteoric water (snow melt, river runoff, precipitation) had stratified and freshened surface waters, contributing to 81% of the monthly CT deficit in the surface layer. The timing and magnitude of freshwater inputs played an important role in Ω variability, reducing AT and CT by dilution. This dilution effect was strongly counteracted by the opposing effect of primary production that dominated surface water Ω seasonality. The spring phytoplankton bloom rapidly depleted nitrate and CT to drive highest Ω (~2.3) in surface waters. Calcification reduced AT and CT, which accounted for 21% of the monthly decrease in Ω during a coccolithophore bloom. Freshwater runoff contributed CT, AT and silicates of terrestrial origin to the fjord. Lowest surface water Ω (~1.6) resulted from organic matter remineralisation and mixing into subsurface water during winter and spring. Surface waters were undersaturated with respect to atmospheric CO2, resulting in modest uptake of –0.32 ± 0.03 mol C m–2 yr–1. Net community production estimated from carbon drawdown was 14 ± 2 g C m–2 yr–1 during the productive season. Kaldfjorden currently functions as an atmospheric CO2 sink of 3.9 ± 0.3 g C m–2 yr–1. Time-series data are vital to better understand the processes and natural variability affecting biogeochemical cycling in dynamic coastal regions and thus better predict the impact of future changes on important fjord ecosystems.

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Section: Seasonality In Freshwater and Deep-water Effectsmentioning

confidence: 94%

Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

et al. 2020

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“…Upwelling via the same hypothetical 250 m 3 s −1 discharge as per the Arctic scenario would generate a combined upwelled and discharge flux (after estuarine removal processes) of 0.89-89 kmol Fe with 2 %-52 % of the Fe arising from upwelling and 48 %-98 % from freshwater. Using an intermediate Fe : C value of 5 mmol Fe mol −1 C, which is broadly applicable to the coastal environment (Twining and Baines, 2013), this would correspond to a biological pool of 0.019-1.9 Gmol C. It should be noted that the uncertainty on this calculation is particularly large because, unlike NO 3 upwelling, there is a lack of in situ data to constrain the simultaneous mixing and non-conservative behaviour of Fe.…”

Section: The Subglacial Discharge Pump; From Macronutrients To Ironmentioning

confidence: 99%

“…To date, Fe fluxes from glaciers into the ocean have primarily been constructed from an inor- Table 5. Suppositional effect of different discharge scenarios calculated from the Redfield ratio 106 C : 16 N : 1 P : 0.005 Fe (Redfield, 1934;Twining and Baines, 2013). A steady freshwater discharge of 250 m 3 s −1 is either released from a land-terminating glacier or from a marineterminating glacier at 100-250 m depth, in both cases for two months into Fe-replete, NO 3 -deficient or Fe-deficient, NO 3 -replete marine environments.…”

Section: The Subglacial Discharge Pump; From Macronutrients To Ironmentioning

confidence: 99%

Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

et al. 2020

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Abstract. Freshwater discharge from glaciers is increasing across the Arctic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier–ocean interactions in recent years, especially with respect to fjord/ocean circulation, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing the importance of glaciers for the marine ecosystem, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Kangerluarsuup Sermia/Bowdoin Fjord, Young Sound and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord–shelf exchange, nutrient availability, the carbonate system, the carbon cycle and the microbial food web are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating), fjord–glacier geometry and the limiting resource(s) for phytoplankton growth in a specific spatio-temporal region (light, macronutrients or micronutrients). Arctic glacier fjords therefore often exhibit distinct discharge–productivity relationships, and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems.

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“…Alkalinity measurements of glacial discharge across the Arctic reveal a range from 20-550 µmol kg -1 (Yde et al, 2005;Sejr et al, 2011;Rysgaard et al, 2012;Evans et al, 2014;Fransson et al, 2015Fransson et al, , 2016Meire et al, 2015;Turk et al, 2016). Similar to Si concentrations, the broad range is likely explained by different degrees of interaction between meltwater and bedrock, with higher alkalinity corresponding to greater discharge-bedrock interaction (Wadham et al, 2010;Ryu and Jacobson, 2012).…”

Section: Effects On the Carbonate Systemmentioning

confidence: 99%

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Hopwood¹,

Carroll²,

Dunse³

et al. 2019

Preprint

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Abstract. Freshwater discharge from glaciers is increasing across the Artic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier-ocean interactions in recent years, especially with respect to fjord/ocean circulation in the marine environment, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing ‘The importance of glaciers for the marine ecosystem’, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Bowdoin Fjord, Young Sound, and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord-shelf exchange, nutrient availability, the carbonate system, and the microbial foodweb are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive, or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating) and the limiting resource for phytoplankton growth in a specific spatiotemporal region (light, macronutrients or micronutrients). Glacier fjords therefore often exhibit distinct discharge-productivity relationships and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems.

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Inorganic carbon in a high latitude estuary-fjord system in Canada’s eastern Arctic

Cited by 11 publications

References 59 publications

Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

Review Article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic?

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