uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Groundwater carbon within a boreal catchment - spatiotemporal variability of a hidden aquatic carbon pool
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.ORCID iD: 0000-0002-0078-2810
2019 (English)Data set, Primary data
Physical description [en]

Data set for a study we quantified dissolved and gaseous carbon species in the groundwater across a mesoscale boreal catchment at depths between 3 and 20 m.

The study was carried out within the 68 km2 large Krycklan Catchment area (64°14′N, 19°46′E) located in the boreal region of northern Sweden. Sampling was performed in the main Krycklan catchment (C16) and five sub-catchments (C2, C7, C8, C9 and C13). Groundwater was collected from 16 wells, at depths ranging from 3.4 to 19.5 m. The diameter of each groundwater well is 8.7 cm. Sampling was performed at three different occasions (summer, autumn and spring). Summer sampling took place on the 12th to 16th of June 2017, autumn sampling on the 11th to 15th of September 2017 and spring sampling on the 7th to 11th of May 2018. The water level in each well was measured before sampling to allow calculation of the total volume of water in the well. Prior to sampling at least three times the volume of the well of water was removed using a submersible centrifugal pump such that only the new infiltrating water was used for analysis. Groundwater was collected from approximately 10 cm above the bottom of the well.

For the partial pressure of CO2 (pCO2), triplicate samples of 30 mL were taken with a 60 mL syringe. For dissolved inorganic carbon (DIC) and methane (CH4) determination, a 5 ml sample of bubble-free water was taken directly from the pump-connected tube using a sterile syringe, which was flushed with groundwater before sampling. For δ13C-DIC determination, a 2 ml water sample was injected into a helium flushed 12 ml bromobutyl septa capped Exetainer glass vial. Samples for dissolved organic carbon (DOC) were collected without headspace in 250 ml acid washed high-density polyethylene bottles.

Analysis of pCO2 was conducted in the field using the headspace equilibrium method. Equilibrated gas samples were analyzed on a portable infrared gas analyzer . Headspace CO2 and CH4 concentrations were analyzed by a GC‐FID. Concentrations of DIC and CH4 were then calculated from the GC determined headspace of pCO2 and partial pressure of CH4 (pCH4).  For δ13C-DIC, samples of 100 µL headspace gas were analyzed using an isotope ratio mass spectrometer. The DOC was measured as total organic C (TOC) on a Shimadzu TOC-VCPH.  The pH was analyzed using a closed pH cell to avoid any outgassing of CO2 and measured with a Mettler Toledo Digi117-water combined pH meter

Abstract [en]

Groundwater is an essential resource providing water for societies and sustaining surface waters. Although groundwater at intermediate depth could be highly influential at regulating lake and river surface water chemistry, studies quantifying organic and inorganic carbon (C) species in intermediate depth groundwater are still rare. Here, we quantified dissolved and gaseous C species in the groundwater of a boreal catchment at 3 to 20 m depth. We found that the partial pressure of carbon dioxide (pCO2), the stable carbon isotopic composition of dissolved inorganic carbon (δ13C-DIC) and pH showed a dependency with depth. δ13C-DIC, and between pCO2 and pH. We attribute the negative pCO2-pH relationship along the depth gradient to increased silicate weathering and decreased soil respiration. Silicate weathering consumes carbon dioxide (CO2) and release base cations, leading to increased pH and decreased pCO2. We observed a positive relationship between δ13C-DIC and depth, potentially due to diffusion-related fractionation in addition to isotopic discrimination during soil respiration. Soil CO2 may diffuse downward, resulting in a fractionation of the δ13C-DIC. Additionally, the dissolved organic carbon (DOC) at greater depth may be recalcitrant consisting of old degraded material with a greater fraction of the heavier C isotope. Our study provides increased knowledge about the C biogeochemistry of groundwater at intermediate depth, which is important since these waters likely contribute to the widespread CO2 oversaturation in boreal surface waters.

Place, publisher, year
2019.
Keywords [en]
carbon dioxide, dissolved inorganic carbon, stable carbon isotopic composition of dissolved inorganic carbon, carbonate system, dissolved organic carbon
National Category
Biological Sciences
Research subject
Biology with specialization in Limnology
Identifiers
URN: urn:nbn:se:uu:diva-396272OAI: oai:DiVA.org:uu-396272DiVA, id: diva2:1367162
Funder
EU, Horizon 2020, 643052
Note

Version 2. 2019-11-28

Available from: 2019-11-01 Created: 2019-11-01 Last updated: 2019-11-28Bibliographically approved

Open Access in DiVA

Metadata(21 kB)7 downloads
File information
File name DATASET03.xlsxFile size 21 kBChecksum SHA-512
0055e6035c2bd3463bb6f861f14e8d94d418f1835daad4415ac475558096bab2daf16dbfdb24fc212b81748930dc800f9fd770a2d6074c3ee1042a539bdff77a
Type datasetMimetype application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Dataset(3 kB)8 downloads
File information
File name DATASET04.csvFile size 3 kBChecksum SHA-512
942f8135223d9a14128ecbe3e81c0a4b4f5cf11d3a132068771410121454bb39422042d9c62f5b1f633b2be27b47fcb6089972adf776356560eecf4374881ac5
Type datasetMimetype text/csv

Authority records BETA

Nydahl, Anna

Search in DiVA

By author/editor
Nydahl, Anna
By organisation
Limnology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 0 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 140 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf