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Stream.CO2.CH4.concentrations.Sweden
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
2017 (English)Data set, Primary data
Physical description [en]

Title of dataset

Stream.CO2.CH4.concentrations.Sweden

URL of dataset

http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-332472

Abstract

The study includes a compilation of published and unpublished data on low-order stream CO2 and CH4 concentrations. Based on these data together with modelling of gas transfer velocities

Keywords

CO2 and CH4 concentrations of Swedish streams

Dataset lead author

Marcus Wallin

Position of data author

Researcher

Address of data author

Uppsala University, Department of Earth Sciences, 75236 Uppsala, Sweden

Email address of data author

marcus.wallin@geo.uu.se

Primary contact person for dataset

Same as above

Position of primary contact person

Same as above

Address of primary contact person

Same as above

Email address of primary contact person

Same as above

Organization associated with the data

As the study is partly built on existing published data, several of the universities in Sweden are involved including Uppsala University, SLU, Umeå University and Linköpings University.

Usage Rights

The stream CO2 and CH4 concentration data set is a compilation of mostly already published data, the original studies are responsible for the data.

Geographic region

Entire Sweden

Geographic coverage

Entire Swden

Temporal coverage - Begin date

2005

Temporal coverage - End date

2016

General study design

The study is a scaling exercise to estimate stream CO2 and CH4 emissions of the entire network of low-order streams of Sweden. CO2 and CH4 concentration data is combined with an empirically derived gas transfer model and the characteristics of a virtual stream network of Sweden in order estimate stream CO2 and CH4 emissions of all Swedish low-order streams.

Methods description

The stream CO2 and CH4 concentration data set is based on a compilation of published and unpublished data collected during 2005-2016. There were two criteria for data inclusion, 1) the data must be based on direct concentration measurements of CO2 and CH4, and 2) included streams must be of low order, ranging from 1st to 4th Strahler stream order (SO). The first criterion excludes data where CO2 has been indirectly determined by calculation from alkalinity, pH, and temperature. The data set represents a mixture of sampling methods including different headspace (CO2 and CH4) and sensor (CO2) techniques. For sampling and analysis details concerning included data, see the specific data sources (Table 1). All unpublished data is based on sampling and analytical methods described in (Wallin et al., 2010; 2014) and (Åberg and Wallin, 2014). Concentrations of CO2 and CH4 are reported in mg C L-1 and µg C L-1 respectively and with associated standard deviation (SD). The included concentration data represents a combination of regional and catchment surveys within Sweden (see Figure.1), with regional studies characterized by many stream sites (typically ca 100 per region) sampled at one or a few occasions (DAL, LAVI, SES, KRY), and catchment studies including fewer sampled streams (typically <20) but with more observations over time (ABI, KRY, GADD, UPP, SKOG). As the dataset of CO2 and CH4 concentrations was very heterogeneous in terms of spatiotemporal coverage and number of observations, with different sampling designs and purposes of the original studies, it was hard to fully evaluate concentration differences among the different catchments/regions. The catchments/regions spanned a large geographical and hydro-meteorological range covering a large part of Sweden including subarctic (ABI), boreal (KRY, DAL, GADD) and hemiboreal (UPP, SKOG, LAVI, SES) regions (Figure 1, Table 1). The main land use in each stream specific catchment were dominated by mires and shrubs in ABI, by forest and mires in KRY, DAL, GADD, SKOG, LAVI and SES, and by agricultural land in UPP. Meteorological data (precipitation and annual mean air temperature) for each catchment/region represents the 30 year mean values (1961-1990) according to the Swedish Meteorological and Hydrological Institute (Raab and Vedin, 1995).

Stream network determination

The stream and river network with associated catchment boundaries were collected from a virtual stream network of Sweden (VIVAN), being based on a digital elevation model (50 × 50 m resolution) (Nisell et al., 2007). From this network, a total of ca 425,000 km of stream and river length (excluding lakes and reservoirs) were identified (Table S1). The total network was further divided into ca 472,000 individual stream segments without any stream junctions. This resulted in an average stream segment length of ca 900 m. Stream characteristics (catchment area, main land-use, stream channel slope) were derived for each individual stream segment. Land use distribution within each catchment was based on the digital versions of the topographic map (1:50000) and the road map (1:100000) (Swedish Land Survey) and separated into three land use classes, Agricultural (including agricultural land, other open and populated areas), Forest and Mire (including clear cut areas) and Alpine. Out of the total stream and river network, stream segments of 1st to 4th order streams (n = 443,763) were used in this study. The stream surface area for each stream segment of 1st to 4th order streams was assumed to be constant over the year and was calculated by multiplying stream section length with stream order specific width estimates derived from data published by Downing et al. (2012) (Table S2).

Modelling of C emission and statistical analysis

Stream CO2 and CH4 emission was calculated for each of the 443,763 individual stream segments by using the diffusive flux equation (Liss and Slater, 1974):                                                      

Where Eg is the emission of the specific gas (CO2 or CH4) for the individual stream segment (mg m-2 d-1); Δ[g] (mg C L-1) is the difference between the in-stream CO2 or CH4 concentration and the concentration that would exist if the stream was in equilibrium with the atmosphere (assuming an atmospheric pCO2 and pCH4 of 400 and 1.9 µatm respectively); kg is the gas transfer velocity (m d-1) and A is the stream surface area of the specific stream segment. Mean stream C emission was calculated using stream order specific median concentrations of ΔCO2 based on all concentration observations. For ΔCH4, the median concentration for all observations included in the study was used for each of the stream segments (see result section for motivation). Mean k was modelled for each individual stream segment based on data presented by Natchimuthu et al. (2017) (see more details in Supplementary Information). Total annual median CO2 and CH4 emission rates with associated 95% confidence interval (CI) were determined using a Monte Carlo experiment. For more detailed description of the emission calculations and uncertainty estimation see the Supplementary Information. Differences in gas concentrations and gas transfer velocities between the different catchments/regions, stream orders and land-use categories were tested on each pair using the non-parametric Wilcoxon´s test (for gas concentrations) and Tukey-Kramer´s test (for gas transfer velocities). Spatial Differences between catchments/regions, stream order or land-use classes were considered significant if p <0.05. The data were logarithmically transformed to achieve normally distribution when needed. JMP 12.0.1 (SAS Institute Inc., Cary, NC, USA) was used for all statistical calculations except for the Monte-Carlo experiment which was run in MatLab.

Laboratory, field, or other analytical methods

As this is a modelling study it is built on mostly published studies, no laboratory of field analysis were conducted.

Quality control

For the stream CO2 and CH4 concentration data, see the original studies cited in the manuscript

Additional information

This is a data compilation and modelling study that has not produced any new data it self.

Description of the variables (i.e., columns) in the dataset in sufficient detail for another user to understand and use the data. If there are 10 variables (i.e., columns) in the dataset, then there should be 10 rows in this column that describe each column.

Column name

CO2

Dissolved concentration of carbon dioxide (mg C/L)

CH4

Dissolved concentration of methane (µg C/L)

Place, publisher, year
Uppsala, 2017.
Version
1.0
National Category
Environmental Sciences
Identifiers
URN: urn:nbn:se:uu:diva-332472OAI: oai:DiVA.org:uu-332472DiVA, id: diva2:1153181
Available from: 2017-10-27 Created: 2017-10-27 Last updated: 2018-01-08Bibliographically approved

Open Access in DiVA

dataset(146 kB)45 downloads
File information
File name DATASET01.xlsxFile size 146 kBChecksum SHA-512
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Type datasetMimetype application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Metadata(20 kB)25 downloadsDescription of content
File information
File name COVER01.xlsxFile size 20 kBChecksum SHA-512Description Metadata describing concentration dataset Stream.CO2.CH4.concentrations.Sweden
d579ab5a0154f9039cb88e36b4df3ff0db75e50897aafe869744dd360dc474700d81df17c8213dcf453cac97a689ce87ce5955cb596986da9a6c679bfd79a4ed
Type coverMimetype application/vnd.openxmlformats-officedocument.spreadsheetml.sheet

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Wallin, Marcus

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Citation style
  • apa
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Language
  • de-DE
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  • nn-NO
  • nn-NB
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More languages
Output format
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  • asciidoc
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