Dataset title: Flux data from the Peat Collapse-Saltwater Intrusion Field Experiment within Everglades National Park, collected from October 2014 to September 2016 Dataset ID: FCE1224 Research type: Short-term Dataset Creator Name: Dr. Benjamin Wilson Position: Project Collaborator Organization: Southeast Environmental Research Center Address: Florida International University University Park OE 148 Miami, FL 33199 USA Phone: 305-348-1453 Fax: 305-348-4096 Email: bwils034@fiu.edu URL: http://wetland.fiu.edu/ Name: Dr. Tiffany Troxler Position: Project Collaborator Organization: Southeast Environmental Research Center Address: Florida International University University Park OE 148 Miami, FL 33199 USA Phone: 305-348-1453 Fax: 305-348-4096 Email: troxlert@fiu.edu URL: http://wetland.fiu.edu/ Metadata Provider Organization: Florida Coastal Everglades LTER Program Address: Florida International University University Park OE 148 Miami, FL 33199 USA Phone: 305-348-6054 Email: fcelter@fiu.edu URL: http://fcelter.fiu.edu Dataset Abstract With sea level rise increasing, saltwater intrusion into low-lying coastal wetlands is likely to occur.  We simulated saltwater intrusion into an Everglades marsh through monthly additions of elevated salinity water. Monthly ecosystem flux measurements were taken from a brackish water and freshwater marsh. Ecosystem flux was measured 24 hours after dosing. Measurements occurred from Oct 2014 - Sep 2016. Ecosystem flux measured includes gross ecosyetem production, ecosystem respiration of CO2, net ecosystem production, and ecosystem respiration of CH4. These data are published in Wilson, B.J., Servais, S., Mazzei, V., Davis, S.E., Kelly, S., Gaiser, E., Kominoski, J.S., Richards, J., Rudnick, D., Sklar, F., Stachelek, J., and Troxler, T.G. Salinity pulses interact with seasonal dry-down to increase ecosystem carbon loss in marshes of the Florida Everglades. Ecological Applications. Accepted. Geographic Coverage Study Extent Description Bounding Coordinates Geographic description: Coordinates indicate the center of our plots at a brackish water and freshwater marsh within Everglades National Park West bounding coordinate: -80.84 East bounding coordinate: -80.84 North bounding coordinate: 25.22 South bounding coordinate: 25.22 Geographic description: Florida Coastal Everglades LTER Study Area: South Florida, Everglades National Park, and Florida Bay West bounding coordinate: -81.078 East bounding coordinate: -80.490 North bounding coordinate: 25.761 South bounding coordinate: 24.913 Temporal Coverage Start Date: 2014-10-01 End Date: 2016-10-01 Data Table Entity Name: FCE1224_FieldFlux_CO2.txt Entity Description: CO2 measurements from the Peat Collapse Experiment Object Name: FCE1224_FieldFlux_CO2.txt Data Format Number of Header Lines: 1 Attribute Orientation: column Field Delimiter: , Number of Records: Attributes Attribute Name: Site.CO2 Attribute Label: Site.CO2 Attribute Definition: Site name Storage Type: Text Measurement Scale: BW = Brackish water FW = Freshwater Missing Value Code: Attribute Name: Plot.CO2 Attribute Label: Plot.CO2 Attribute Definition: Plot number Storage Type: Text Measurement Scale: Plot number Missing Value Code: Attribute Name: Treatment.CO2 Attribute Label: Treatment.CO2 Attribute Definition: Treatment label Storage Type: Text Measurement Scale: Control = Ambient water added Treatment = saltwater added Missing Value Code: Attribute Name: Date.CO2 Attribute Label: Date.CO2 Attribute Definition: Date Storage Type: datetime Measurement Scale: Missing Value Code: Attribute Name: wet.or.dry.CO2 Attribute Label: wet.or.dry.CO2 Attribute Definition: Wet means water was covering soil surface during measurement, dry means water was below soil surface during measurement Storage Type: Measurement Scale: Wet means water was covering soil surface during measurement, dry means water was below soil surface during measurement Missing Value Code: Attribute Name: GEP.CO2 Attribute Label: GEP.CO2 Attribute Definition: Gross ecosystem Production (grams of Carbon per meters squared per month) Storage Type: data Measurement Scale: Units: gramsPerMeterSquaredPerMonth Number Type: real Missing Value Code: NA (Not available) Attribute Name: ER.CO2 Attribute Label: ER.CO2 Attribute Definition: Ecosystem Respiration (grams of carbon per meter squared per month) Storage Type: data Measurement Scale: Units: gramsPerMeterSquaredPerMonth Number Type: real Missing Value Code: NA (Not available) Attribute Name: NEP.CO2 Attribute Label: NEP.CO2 Attribute Definition: Net ecosystem Production (grams of carbon per meter squared per month) Storage Type: data Measurement Scale: Units: gramsPerMeterSquaredPerMonth Number Type: real Missing Value Code: NA (Not available) Data Table Entity Name: FCE1224_FieldFlux_CH4.txt Entity Description: CH4 measurements from the Peat Collapse Experiment Object Name: FCE1224_FieldFlux_CH4.txt Data Format Number of Header Lines: 1 Attribute Orientation: column Field Delimiter: , Number of Records: Attributes Attribute Name: Site.CH4 Attribute Label: Site.CH4 Attribute Definition: Site name Storage Type: Text Measurement Scale: BW = Brackish water FW = Freshwater Missing Value Code: Attribute Name: Plot.CH4 Attribute Label: Plot.CH4 Attribute Definition: Plot number Storage Type: Text Measurement Scale: Plot number Missing Value Code: Attribute Name: Treatment.CH4 Attribute Label: Treatment.CH4 Attribute Definition: Treatment label Storage Type: Text Measurement Scale: Control = Ambient water added Treatment = saltwater added Missing Value Code: Attribute Name: Date.CH4 Attribute Label: Date.CH4 Attribute Definition: Date Storage Type: datetime Measurement Scale: Missing Value Code: Attribute Name: wet.or.dry.CH4 Attribute Label: wet.or.dry.CH4 Attribute Definition: Wet means water was covering soil surface during measurement, dry means water was below soil surface during measurement Storage Type: Text Measurement Scale: Wet means water was covering soil surface during measurement, dry means water was below soil surface during measurement Missing Value Code: Attribute Name: CH4 Attribute Label: CH4 Attribute Definition: Ecosystem Respiration of CH4 (milligrams of methane per meter squared per day) Storage Type: data Measurement Scale: Units: milligramsPerMeterSquaredPerDay Number Type: real Missing Value Code: NA (Not available) Methods Sampling Description Method Step Description This study was conducted in Everglades National Park, Florida, USA along the southeastern boundary of Shark River Slough, the largest drainage basin in the southern Everglades. The coastal Everglades range along a gradient from freshwater sawgrass ridges and sloughs to coastal mangrove forests. We chose two sites for our study: a brackish marsh that was already experiencing saltwater intrusion and a freshwater marsh that, to our knowledge, had not experienced elevated salinity. The brackish marsh (25°13’13.17” N, 80°50’36.96” W) was dominated by Cladium jamaicense (sawgrass) sparsely interspersed with Conocarpus erectus (buttonwood). The site was non-tidal and characterized by distinct wet-dry hydrologic regimes in which the site was flooded for ~8 months out of the year (mean since 2000, Everglades Depth Estimation Network (EDEN) at station NMP). The freshwater marsh (25°26’07.77” N, 80°46’51.50” W) was co-dominated by sawgrass and Eleocharis cellulosa (spikerush) but also contained other freshwater marsh plants such as Crinum americanum (swamp lily), Bacopa caroliniana (waterhyssop), and Panicum hemitomon (maidencane). The hydrologic regime at the site was characterized as long-hydroperi od, flooded nearly year-round (~11 months, mean since 2000, EDEN at station NP62) during a typical season. The soil properties of each site are given in Table 1. Instrumentation LI-COR 840 Method Step Description In September 2014, 16 plots were established at each site along an 80-m long constructed boardwalk (Fig. 1). In twelve plots, we installed 1.4-m diameter, 0.4-m tall clear, cylindrical, polycarbonate chambers by inserting them 30-cm into the soil. We designated 4 additional plots as “no-chamber” controls, and these had no chamber installed around them. Each chamber had a movable collar with a series of 10-cm diameter holes that could be closed during application of dosing water but were open to natural flow at all other times. Six ambient-water addition (“+AMB”) plots were established upstream in the natural flow, while 6 treatment (+saltwater, “+SALT”) plots were established downstream to avoid salt contamination into the +AMB and “no-chamber” control plots. The 4 “no-chamber” controls, which were interspersed within the +AMB plots (Fig. 1), did not receive any water additions and were used only for C flux and redox potential measurements (see below). A 3-m “buffer zone” was established to avoid contamination between salt-dosing and control plots. Instrumentation HP 5890 Gas Chromatograph Method Step Description Experimental water additions began in October 2014 and were conducted monthly for 2 years (see Stachelek et al. (2018) for detailed methods). The volume and salinity of brine solution mixed to deliver our dose varied for each dosing month in order to reach porewater concentration targets. The volume and salinity of the brine solution was calculated based on both water height from soil surface and surface water salinity so that we could reach the target of twice ambient porewater salinity, 2-5 ppt at the FW site and 20 ppt at the BW site. Our brine solution during dosing ranged from 30.7-65.0 ppt at the FW site and 26.8-68.0 ppt at the BW site (Stachelek et al. 2018). The dosing solution was prepared using source water obtained at each study site (when the marsh was wet) or from a nearby canal (when the marsh was dry) with similar nutrient concentrations found in freshwater wetlands of the Everglades (C-111; 25°17'31.74" N, 80°27'21.59" W; Wilson et al. in review); source water was combined with a commercially available sea salt mix (Instant Ocean ® (Atkinson and Bingman 1997)). An equal volume of site surface water or canal water was added to the +AMB plots each month to account for the addition of water in the absence of salinity. Method Step Description The movable collar on the chambers was used to close the chambers while dosing to ensure that the dosing water remained within the chamber. Doses were delivered from elevated boardwalks running alongside each chamber using a submersible bilge-style pump (Xylem Inc, USA). The outlet hose was fitted with a spreader device that split the large output stream into six smaller streams. This design was intended to maximize mixing with ambient site water while minimizing disturbance to sensitive benthic periphyton. Emergent plants were briefly sprayed with freshwater following dosing to avoid potential damage from direct salt application. Chambers remained closed for 24 hours to allow the elevated-salinity water to penetrate into the porewater, then chambers were opened to prevent closure artifacts. Method Step Description Within each plot, one 0.5 x 0.5 m polycarbonate collar was permanently installed 10-cm into the soil and extended 5-cm above the soil surface for ecosystem C flux measurements. Each collar had eight 2.5-cm diameter holes at the soil surface level to allow for natural flow of water when measurements were not occurring. Plot-scale CO2 exchange was measured monthly using a transparent static chamber (0.25 m2 x 1.5 m; after Neubauer et al. 2000, Wilson et al. 2015). Prior to measurements being taken, each hole in the collar was plugged with a rubber stopper, the chamber was placed into a lip in the collar and sealed, and the system was allowed to equilibrate for 2 minutes. Measurements were then made for 3 minutes each in full light and in the dark, with the chamber lid removed in between each measurement to allow the chamber to return to atmospheric conditions (LI-COR 840, Lincoln, NE; Wilson et al. in press). All measurements made at each site were taken within ± 3 hours of solar noon and on the same day. Missing measurements occurred when there was either equipment failure (BW site, Jul – Aug 2016) or when water levels were higher than the boardwalk (FW site, Dec 2015 – Apr 2016), limiting access to the plots. Method Step Description Methane exchange measurements were conducted monthly from October 2014 – February 2016. After the dark CO2 exchange measurement was conducted, the chamber was kept in the dark and resealed for 20 minutes. Air from the chamber was continually pumped through a closed loop with a sampling port attached. Gas samples were taken at 0, 10, and 20 minutes using a 60-mL syringe to withdraw 25-mL of air from the sampling port placed in line with the chamber. The sample was then injected into a 20-mL evacuated vial. Methane concentrations were determined using a gas chromatograph (Hewlett-Packard 5890, Palo Alto, CA, USA), and the change in concentration over time was used to calculate the flux. Quality Control Data are QA/QC'ed by visually plotting and inspecting data and removing any data points that are plus or minus two standard deviations away from the average Distribution Online distribution: http://fcelter.fiu.edu/perl/public_data_download.pl?datasetid=FCE1224_FieldFlux_CO2.txt Intellectual Rights This information is released under the Creative Commons license - Attribution - CC BY (https://creativecommons.org/licenses/by/4.0/). The consumer of these data ("Data User" herein) is required to cite it appropriately in any publication that results from its use. The Data User should realize that these data may be actively used by others for ongoing research and that coordination may be necessary to prevent duplicate publication. The Data User is urged to contact the authors of these data if any questions about methodology or results occur. Where appropriate, the Data User is encouraged to consider collaboration or co-authorship with the authors. The Data User should realize that misinterpretation of data may occur if used out of context of the original study. While substantial efforts are made to ensure the accuracy of data and associated documentation, complete accuracy of data sets cannot be guaranteed. All data are made available "as is." The Data User should be aware, however, that data are updated periodically and it is the responsibility of the Data User to check for new versions of the data. The data authors and the repository where these data were obtained shall not be liable for damages resulting from any use or misinterpretation of the data. Thank you. Publications citing this dataset Wilson, Benjamin J., Shelby Servais, Viviana Mazzei, John S. Kominoski, Minjie Hu, Stephen E. Davis, Evelyn Gaiser, Fred Sklar, Laura Bauman, Stephen Kelly, Christopher Madden, Jennifer Richards, David Rudnick, Jemma Stachelek, and Tiffany G. Troxler. 2018. Salinity pulses interact with seasonal dry-down to increase ecosystem carbon loss in marshes of the Florida Everglades. Ecological Applications 28: 2092-2108. DOI: 10.1002/eap.1798 Dataset Keywords sea level carbon flux salinity ecosystem respiration carbon dioxide methane FCE Florida Coastal Everglades LTER ecological research long-term monitoring flux Sea level rise Saltwater intrusion Peat collapse net ecosystem production gross ecosystem production Data Submission Date: 2018-08-17 Dataset Contact Position: Information Manager Organization: Florida Coastal Everglades LTER Program Address: Florida International University University Park OE 148 Miami, FL 33199 USA Phone: 305-348-6054 Fax: 305-348-4096 Email: fcelter@fiu.edu URL: http://fcelter.fiu.edu Dataset Submission Date 2018-08-17