Georgia Coastal Ecosystems LTER Data Set Details

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GCE-LTER Data Set Summary

Accession:

MSH-GCEM-2508

Research Theme:

Marsh Ecology (Monitoring)

Contributors:

Peter Hawman, Deepak Mishra, Wade Sheldon

Title:

Eddy covariance (EC) vertical carbon fluxes from a Georgia tidal salt marsh from 2014 to 2024

Abstract:

We present our methodology and data for science ready vertical carbon fluxes from a Spartina alterniflora tidal salt marsh as part of the Georgia Coastal Ecosystems Long Term Ecological Research (GCE-LTER) site on Sapelo Island, Georgia, USA. Vertical carbon fluxes were measured through the eddy covariance (EC) method from 2014 to 2024. The EC flux tower was located on the western side of Sapelo Island bounded by the Duplin River and Barn Creek. The proportional influence of marsh habitats on the flux measurements were 4% tall, 38% short, and 58% medium height form Spartina alterniflora. We present the net ecosystem exchange (NEE), ecosystem respiration (ER), and gross primary production (GPP) at 30-minute fluxes (μmol CO2 m-2 s-1), daily averages (μmol CO2 m-2 s-1) and totals (g C m-2 day-1), and annual (g C m-2 year-1) quantities. We provide estimated uncertainty for each flux at each integrated timescale as 95% confidence intervals. Providing open access to 10-year carbon flux datasets can facilitate collaboration for advancing regional and global blue carbon synthesis and scale-up studies.

DOI:

10.6073/pasta/e9371ead3fbe0cdf67083fe7c97c2893

Key Words:

carbon assimilation, carbon cycling, carbon dioxide, carbon fluxes, Duplin River, ecology, ecosystems, GCE, Georgia, LTER, marshes, photosynthesis, Plant Monitoring, Sapelo Island, vegetation

LTER Core Area:

Primary Production

Research Themes:

Marsh Ecology, Plant Ecology

Study Period:

01-Jan-2014 to 31-Dec-2024

Study Sites:

GCE_Flux -- GCE Flux Tower Marsh, Sapelo Island, Georgia

» Download Geographic Coverage: Google Earth

Research Protocols:

Protocol for calculating sampling error in CO2 flux measurements (Journal of Geophysical Research)

Impact of post-field data processing on eddy covariance flux estimates and energy balance closure (Meteorologische Zeitschrift)

Averaging Detrending and Filtering of Eddy Covariance Time Series (Handbook of Micrometeorology)

A system to measure surface fluxes of momentum, sensible heat, water vapour and carbon dioxide (Journal of Hydrology)

Quality Control and Flux Sampling Problems for Tower and Aircraft Data (Journal of Atmospheric and Oceanic Technology)

Correction of flux measurements for density effects due to heat and water vapour transfer (Quarterly Journal of the Royal Meteorological Society)

Sonic Anemometer Tilt Correction Algorithms (Boundary-Layer Meteorology)

Downloads:

Data Table: MSH-GCEM-2508_30min (30-minute NEE, ER, and GPP data, 192864 records)

Access: Public (released 15-Aug-2025)

Metadata: Text (ESA FLED), XML (Ecological Metadata Language)

Data Formats: Spreadsheet (CSV) [39918.68kb], Text File [41330.51kb], MATLAB (GCE Toolbox) [21974.14kb], MATLAB (Variables) [21975.72kb], Text Report [42572.19kb]

Column List:(display)

Column	Name	Units	Type	Description
1	start_datetime	yyyy-mm-dd HH:MM:SS - GMT	string	Start of 30-min averaging period
2	end_datetime	yyyy-mm-dd HH:MM:SS - GMT	string	End of 30-min averaging period
3	sensor	none	string	Indicator of whether the NEE measurement came from flux1, flux2, and mean of both, or gap-filled
4	NEE	umol/m^2/s	floating-point	net ecosystem exchange (carbon dioxide) averaged over 30 minutes
5	NEE_CI_95	umol/m^2/s	floating-point	95% confidence interval of net ecosystem exchange (carbon)
6	ER	umol/m^2/s	floating-point	ecosystem respiration (carbon dioxide) averaged over 30 minutes
7	ER_CI_95	umol/m^2/s	floating-point	95% confidence interval of ecosystem respiration (carbon)
8	GPP	umol/m^2/s	floating-point	gross primary production (carbon dioxide) averaged over 30 minutes
9	GPP_CI_95	umol/m^2/s	floating-point	95% confidence interval of gross primary production (carbon)
10	wind_speed	m/s	floating-point	Wind speed, 30-minute mean
11	wind_dir	degrees	floating-point	Wind direction, 30-minute mean
12	ustar	m/s	floating-point	Friction velocity (u*)
13	L	meters	floating-point	Monin-Obukhov length
14	Z_L	none	floating-point	Monin-Obukhov stability parameter (z-d)/L
15	v_var	m/s	floating-point	Variance of lateral velocity fluctuations
16	co2_mole_fraction	umol/mol	floating-point	Measured or estimated mole fraction of CO2
17	co2_mixing_ratio	umol/mol	floating-point	Measured or estimated mixing ratio of CO2
18	h2o_mole_fraction	mmol/mol	floating-point	Measured or estimated mole fraction of water vapor
19	h2o_mixing_ratio	mmol/mol	floating-point	Measured or estimated mixing ratio of water vapor
20	co2_flux	umol/m^2/s	floating-point	Corrected carbon dioxide flux
21	qc_co2_flux	none	integer	Quality flag for gas flux
22	co2_strg	umol/m^2/s	floating-point	Estimate of storage carbon dioxide flux

Data Table: MSH-GCEM-2508_daily (daily averages and totals of NEE, ER, and GPP, 4018 records)

Access: Public (released 15-Aug-2025)

Metadata: Text (ESA FLED), XML (Ecological Metadata Language)

Data Formats: Spreadsheet (CSV) [570.86kb], Text File [562.38kb], MATLAB (GCE Toolbox) [405.22kb], MATLAB (Variables) [406.00kb], Text Report [609.88kb]

Column List:(display)

Column	Name	Units	Type	Description
1	Date	yyyy-mm-dd	string	Calendar date of observation
2	proportion_gapfilled	none	floating-point	Proportion of 30-minute flux measurements that were gap-filled
3	NEE_daily_mean	umol/m^2/s	floating-point	Daily mean of 30-minute net ecosystem exchange (carbon dioxide)
4	NEE_daily_std	umol/m^2/s	floating-point	Daily standard deviation of 30-minute net ecosystem exchange (carbon dioxide)
5	NEE_daily_total	g/m^2/day	floating-point	Daily total net ecosystem exchange (carbon)
6	NEE_daily_CI_95	g/m^2/day	floating-point	95% confidence interval of daily total net ecosystem exchange (carbon)
7	ER_daily_mean	umol/m^2/s	floating-point	Daily mean of 30-minute ecosystem respiration (carbon dioxide)
8	ER_daily_std	umol/m^2/s	floating-point	Daily standard deviation of 30-minute ecosystem respiration (carbon dioxide)
9	ER_daily_total	g/m^2/day	floating-point	Daily total ecosystem respiration (carbon)
10	ER_daily_CI_95	g/m^2/day	floating-point	95% confidence interval of daily total ecosystem respiration (carbon)
11	GPP_daily_mean	umol/m^2/s	floating-point	Daily mean of 30-minute gross primary production (carbon dioxide)
12	GPP_daily_std	umol/m^2/s	floating-point	Daily standard deviation of 30-minute gross primary production (carbon dioxide)
13	GPP_daily_total	g/m^2/day	floating-point	Daily total gross primary production (carbon)
14	GPP_daily_CI_95	g/m^2/day	floating-point	95% confidence interval of daily total gross primary production (carbon)

Data Table: MSH-GCEM-2508_yearly (annual quantities or NEE, ER, and GPP, 11 records)

Access: Public (released 15-Aug-2025)

Metadata: Text (ESA FLED), XML (Ecological Metadata Language)

Data Formats: Spreadsheet (CSV) [1.50kb], Text File [1.05kb], MATLAB (GCE Toolbox) [28.99kb], MATLAB (Variables) [30.19kb], Text Report [28.21kb]

Column List:(display)

Statistics:

Generate script code to retrieve data tables for analysis in: MATLAB, R, SAS, SPSS

Citation:

Hawman, Peter. 2025. Eddy covariance (EC) vertical carbon fluxes from a Georgia tidal salt marsh from 2014 to 2024. Georgia Coastal Ecosystems LTER Project, University of Georgia, Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/e9371ead3fbe0cdf67083fe7c97c2893

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