Abstract:

Live and dead above-ground biomass, stem density, median stem height, and litter biomass, as well as below-ground biomass of Spartina alterniflora, were determined from 1-3 plots at three Louisiana salt marshes in 2016-2018. The sites were sampled monthly. Additional ancillary data on soil and water parameters such as soil and water temperature, redox potential, pH, organic matter content, dissolved concentrations of nitrate &nitrite, phosphate, and ammonium are included when available.

Suggested Citation:

Roberts, Brian. 2019. Plot level plant data and ancillary parameters in Louisiana Universities Marine Consortium (LUMCON) area salt marshes from January 2016 to December 2018. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-pcwv-td49

Purpose:

This dataset was developed as part of a research project investigating the effects of the Deepwater Horizon oil spill on salt marsh biogeochemistry. This component of the Coastal Waters Consortium (CWC) research effort originated in 2013 during CWC-I and the data presented here was collected as part of CWC-II. It focused on determining temporal and spatial patterns in Spartina alterniflora biomass and productivity.

Data Parameters and Units:

Year: Year of sampling; Month-name: month of sampling; Month-number: month of sampling (1= Jan, 2 = Feb, etc.); Region: Region of collection (e.g. LUMCON); Site: Site identifier; Latitude (decimal degrees): Latitude of the sampling site; Longitude (decimal degrees): Longitude of the sampling site; Plot: plot sampled (A=clip plot where stem heights and weights measured and ancillary soil characteristics measured when available; B and C=non-destructively sampled plots with only stem heights measured); Live stem density (stems/m2): density of live stems in plot; Live median stem height (cm): median height of live stems in plot; Live aboveground biomass (g/m2): mass of live biomass in plot (A was measured from sum of individual stem masses; B and C determined from heights and allometric relationships); Dead stem density (stems/m2): density of dead stems in plot; Dead median stem height (cm): median height of dead stems in plot; Dead aboveground biomass (g/m2): mass of dead biomass in plot (A was measured from sum of individual stem masses; B and C determined from heights and allometric relationships); Litter biomass (g/m2): mass of litter in plot; Live belowground biomass (0-30 cm; g/m2): live belowground biomass in top 30cm in each plot; Dead belowground biomass (0-30 cm; g/m2): dead belowground biomass in top 30cm in each plot; Total belowground biomass (0-30 cm; g/m2): total belowground biomass in top 30cm in each plot; Soil T (°C): soil temperature in plot; pH: pH of soil in plot; Bulk density (g/cm3): bulk density of top 5cm of soil in plot; Gravimetric water content (%): percent gravimetric water content of top 5cm of soil in plot; Organic matter (%): percent organic matter content of top 5cm of soil in plot; Organic carbon (%): percent organic carbon content of top 5cm of soil in plot; Total nitrogen (%): percent total nitrogen content of top 5cm of soil in plot; Total phosphorus (micrograms per gram dry weight of soil): total phosphorus content of top 5cm of soil in plot; Porewater salinity (psu): salinity of surface (0-5cm) soil porewater in plot; Water T (°C): water temperature of baywater adjacent to site; Salinity (psu): salinity of baywater adjacent to site; Specific conductance (mS): specific conductance of baywater adjacent to site; Dissolved NO3 + NO2 (micromoles per liter): concentration of dissolved nitrate (NO3-) + nitrite (NO2-) in baywater adjacent to site; Dissolved NH4 (micromoles per liter): concentration of dissolved ammonium (NH4+) in baywater adjacent to site; Dissolved PO4 (micromoles per liter): concentration of dissolved orthophosphate (PO4) in baywater adjacent to site.

Methods:

Soil properties were obtained following the procedures detailed in Marton and Roberts (2014) and Marton et al. (2015). Soil temperature and redox potential (Eh) were measured using a handheld thermometer and probe (Orion Star A221 pH meter with Orion Sure-Flow Combination Redox/ORP electrode, Thermo Fisher Scientific), respectively, that were inserted directly into the soil. The salinity and temperature of the adjacent bay water were measured using a handheld meter (YSI 30). 250 mL bay water samples were collected, stored in the dark on ice, and filtered through acid-washed (10% v/v HCl) 0.2 μm filters (Pall Life Sciences Supor®-200) within two hours of collection. The filtrate was stored frozen until nutrient analysis. Filtered bay water was analyzed for dissolved inorganic nutrients (NO3-N+ + NO2-N, PO4-N, and NH4-N) using a Lachat Instruments QuickChem® FIA+ 8000 Series Automated Ion Analyzer with an ASX‌-400 Series XYZ Autosampler. Samples were analyzed simultaneously for dissolved NO3-N + NO2-N (by Cu-Cd reduction followed by azo colorimetry) and PO4-P (by the automated ascorbic acid reduction method), but were analyzed separately for dissolved NH4-N (by phenate colorimetry) to prevent contamination of the samples by fumes from the NH4Cl buffer used in the analysis for NO3-N + NO2-N.

Provenance and Historical References:

Marton, J. M., & Roberts, B. J. (2014). Spatial variability of phosphorus sorption dynamics in Louisiana salt marshes. Journal of Geophysical Research: Biogeosciences 119(3), 451–465. doi:10.1002/2013jg002486 Marton, J. M., Roberts, B. J., Bernhard, A. E., & Giblin, A. E. (2015). Spatial and Temporal Variability of Nitrification Potential and Ammonia-Oxidizer Abundances in Louisiana Salt Marshes. Estuaries and Coasts 38: 1824-1837. doi:10.1007/s12237-015-9943-5

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