Dataset title: Leaf nutrient and root biomass data from the Peat Collapse-Saltwater Intrusion Field Experiment within Everglades National Park (FCE), collected from October 2014 to September 2016 Dataset ID: doi:10.6073/pasta/0412d0e992558af65cf22110ef8f0e1b 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. Yearly sawgrass leaf carbon, nitrogen, and phosphorus concentrations and live root biomass measurements were measured from a brackish water and freshwater marsh. All measurements were taken every other month 24 hours after dosing. Measurements occurred from Oct 2014 - Sep 2016. Ecosystem flux measured includes gross ecosystem 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: FCE1221_CNP.txt Entity Description: C,N,P and Biomass data from the Peat Collapse Experiment Object Name: FCE1221_CNP.txt Data Format Number of Header Lines: 1 Attribute Orientation: column Field Delimiter: , Number of Records: Attributes Attribute Name: Site Attribute Label: Site Attribute Definition: Site name Storage Type: Text Measurement Scale: BW = Brackish water FW = Freshwater Missing Value Code: Attribute Name: Plot Attribute Label: Plot Attribute Definition: Plot number Storage Type: Text Measurement Scale: Plot number Missing Value Code: Attribute Name: Treatment Attribute Label: Treatment Attribute Definition: Treatment label Storage Type: Text Measurement Scale: Control = Ambient water added, Treatment Missing Value Code: Attribute Name: Date Attribute Label: Date Attribute Definition: Date Storage Type: datetime Measurement Scale: Missing Value Code: Attribute Name: C Attribute Label: C Attribute Definition: Sawgrass leaf carbon content Storage Type: data Measurement Scale: Units: milligramsPerGram Number Type: real Missing Value Code: NA (Not available) Attribute Name: N Attribute Label: N Attribute Definition: Sawgrass leaf nitrogen content Storage Type: data Measurement Scale: Units: milligramsPerGram Number Type: real Missing Value Code: NA (Not available) Attribute Name: P Attribute Label: P Attribute Definition: Sawgrass leaf phosphorus content Storage Type: data Measurement Scale: Units: microgramsPerGram Number Type: real Missing Value Code: NA (Not available) Attribute Name: Top.Biomass Attribute Label: Top.Biomass Attribute Definition: Live root biomass in the 0-10 cm zone Storage Type: data Measurement Scale: Live root biomass in the 0-10 cm zone Missing Value Code: NA (Not available) Attribute Name: Middle.Biomass Attribute Label: Middle.Biomass Attribute Definition: Live root biomass in the 10-20 cm zone Storage Type: data Measurement Scale: Live root biomass in the 10-20 cm zone Missing Value Code: NA (Not available) Attribute Name: Bottom.Biomass Attribute Label: Bottom.Biomass Attribute Definition: Live root biomass in the 20-30 cm zone Storage Type: data Measurement Scale: Live root biomass in the 20-30 cm zone Missing Value Code: NA (Not available) Attribute Name: Total.Biomass Attribute Label: Total.Biomass Attribute Definition: Live root biomass in the 0-30 cm zone Storage Type: data Measurement Scale: Units: gram 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. 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. 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 Sawgrass leaves were sampled yearly by collecting the youngest mature leaf from 3 randomly selected culms in each plot. These were dried and ground before analysis for C, nitrogen (N; Zimmermann and Keefe 1997), and phosphorus (P; Solorzano and Sharp 1980) content. Macrophyte species richness was estimated by identifying and recording the genus and species of each plant taxon within each plot. Method Step Description Live belowground root biomass was obtained by taking three 2.4-cm diameter soil cores from each plot at the end of year 2 (October 2016). Each core was taken to 30-cm depth, extruded, separated into 10-cm depths, and stored at 4C until analysis (within 1 week). In the lab, the core segment was placed over a 1-mm sieve and washed with a constant stream of water. Live roots, those which floated when submerged in water, were separated from dead roots and peat, dried at 60C, and weighed. 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=FCE1221_CNP.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 biomass roots carbon nitrogen phosphorus FCE Florida Coastal Everglades LTER ecological research long-term monitoring Sea level rise saltwater intrusion sawgrass peat collapse Data Submission Date: 2018-08-14 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 2018-08-14