temporal and spatial patterns of internal phosphorus
TRANSCRIPT
Supplemental Material
Temporal and Spatial Patterns of Internal Phosphorus Recycling in a South Florida (USA) Stormwater Treatment Area Forrest E. Dierberg,* Thomas A. DeBusk, Jaimee L. Henry, Scott D. Jackson, Stacey Galloway, and Mark C. Gabriel
F.E. Dierberg, T.A. DeBusk, J.L. Henry, S.D. Jackson, and S. Galloway, DB Environmental, Inc., 365 Gus Hipp Blvd., Rockledge, FL 32955-4816; and M.C. Gabriel, Florida Water Management District, 3301 Gun Club Rd., West Palm Beach, FL 33406-3007, Currently at USEPA/ORD/NERL Ecosystems Research Division, Athens, GA, 30605.
* Corresponding author ([email protected]).
# of Pages: 7
# of Figures: 2
# of Tables: 3
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Supplemental Fig. S1. Regional map of south Florida depicting Stormwater Treatment Areas (STAs), Water Conservation Areas (WCAs), and the Everglades Agricultural Area (EAA). Also shown are the field monitoring and sample collection locations along transects within Cell 1 of STA-2.
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Supplemental Fig. S2. Vertical profiles of dissolved calcium (Ca), pH, alkalinity and dissolved iron (Fe) concentrations from the bottom waters and pore waters at three transects in STA-2 Cell 1 on three occasions. Error bars represent ±1 standard error of the mean of three stations along each transect. The thick horizontal line signifies the soil-water interface. See Supplemental Fig. S1 for station locations.
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11/19/2008-12/3/2008 6/2/2009-6/19/2009 2/17/2010-3/3/2010
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Field Quality Assurance Program
Field Blanks
Concentrations for the field blanks collected at time of sampling the equilibrators for porewaters were less
than the method detection limits (MDLs) for all the measured analytes except for TDP and total alkalinity
on the last (March 3, 2010) deployment when each was only slightly higher than their MDLs. Field
blanks for surface water TP and TDP ranged from <3 to 17 μg L-1.
Field Duplicates
The percent relative standard deviation (% rsd) for each analyte measured was calculated for
corresponding 2-cm depth intervals in each duplicate equilibrator (n=7-8). Results of duplicate porewater
equilibrators placed within 2-3 meters of each other at station A2.5 in STA-2 Cell 1 (Supplemental Fig.
S1) on each occasion indicated fine-scale spatial heterogeneity exists within the cell. The best precision
(i.e., < 29% rsd) for the measured analytes occurred with the first deployment on November 19 to
December 3, 2008. The lower precisions (50-100% rsd) were associated with the more limiting and
biogeochemically active ions such as SRP, DOP, TAN, TS, and Fe during the last two deployments.
Duplicate surface water samples collected at station A2.5 were usually within 30% rsd for each analyte
over all three sampling events. An exception was diss Fe on March 3, 2010, when the rsd was 92%.
Extractable (1M HCl) SRP for the soil from station A2.5, as well as TP concentrations, were duplicated
within 35% rsd.
Laboratory Quality Assurance Program
Laboratory analyses underwent rigorous quality assurance. The lab quality assurance program is under the
guidelines administered by the National Environmental Laboratory Accreditation Program (NELAP). The
acceptance criteria for method blanks, spike recoveries, internal check standards, high and low secondary
standards, and lab duplicates are shown in Table S2, whereas the detection limit of each analysis method
is found in Table S3. In nearly all cases, the water and soil parameters analyzed in this study met these
criteria.
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Supplemental Table S1. List of quality assurance objectives performed in the lab and their acceptance criteria.
Lab Quality Assurance Objective Analysis Frequency Range Acceptance
Criterion (%)
Method Blank Initially and every 20 samples BDL*
Spike Recovery Every 10-20 samples Low 65-135 High 75-125 Internal Check Standard Every 10-20 samples 80-120 Secondary Standard Initially Low 75-125 High 80-120 Lab Duplicate Every 10-20 samples Low 0-50 High 0-40 Coefficient of Determination r2≥0.99 *below method detection limit
Supplemental Table S2. Method detection limits for analytes measured.
Analyte Matrix Detection Limit Total Phosphorus/Total Dissolved Phosphorus Surface Water 3µg L-1 Soluble Reactive Phosphorus Surface Water 2µg L-1 Total Ammoniacal Nitrogen Surface Water 20µg L-1 Sulfide Surface Water 3µg L-1 Sulfate Surface Water 0.5mg L-1 Dissolved Calcium Surface Water 0.5mg L-1 Dissolved Iron Surface Water 25µg L-1 Alkalinity Surface Water 3mg CaCO3 L-1 Specific Conductivity Surface Water 6µS cm-1 Bulk Density Sediment 0.100g cm-3 Dry Weight Sediment 0.01% Total Phosphorus Sediment 10mg kg-1 Phosphorus extractions Sediment * * Detection limits for P-extractions depend on sample wet weight, extraction volume, dilution, and the lowest standard, all of which varied.
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Correlations between Chemical Parameters Measured at Each of the Three Transects within STA-2 Cell 1 Supplemental Table S3. Pearson product-moment correlation coefficients for porewater constituents measured within the 0-10 cm soil layers for three stations along each of three transect locations within STA-2 Cell 1 during three porewater equilibrator deployments from November 19 to December 3, 2008, June 2 to 19, 2009, and February 17 to March 3, 2010. The porewater concentrations of each analyte within the 0-2, 2-4, 4-6, 6-8, and 8-10 cm soil depth intervals were averaged at each station prior to performing the correlation analysis for each transect (N = 9; three stations per transect per deployment x three deployments). See Supplemental Fig. S1 for station locations. SRP = soluble reactive phosphorus; TS = total sulfide; DOP = dissolved organic phosphorus; Fe = iron; Ca2+ = calcium; TAN = total ammoniacal nitrogen. Inflow Transect (A)
SRP TS Sulfate Diss Fe TAN DOP Ca2+ Alk. pH SRP 1.000 TS -0.572 1.000 Sulfate -0.542 0.200 1.000 Diss Fe 0.374 -0.266 -0.517 1.000 TAN 0.610* -0.137 -0.833† 0.834† 1.000 DOP 0.590* -0.424 -0.663* 0.902† 0.898† 1.000 Ca2+ 0.396 -0.153 -0.689* 0.765† 0.880† 0.834† 1.000 Alkalinity 0.444 -0.245 -0.714* 0.921† 0.930† 0.939† 0.941† 1.000 pH -0.531 -0.169 0.649* -0.515 -0.771† -0.533 -0.597* -0.629* 1.000
Mid Transect (E)
SRP TS Sulfate Diss Fe TAN DOP Ca2+ Alk. pH SRP 1.000 TS -0.780† 1.000 Sulfate -0.108 -0.201 1.000 Diss Fe 0.537 -0.355 0.213 1.000 TAN 0.960† -0.625* -0.208 0.420 1.000 DOP 0.967† -0.688* -0.175 0.531 0.944† 1.000 Ca2+ 0.815† -0.615* 0.331 0.541 0.832† 0.770† 1.000 Alkalinity 0.927† -0.567 -0.338 0.483 0.959† 0.886† 0.740* 1.000 pH -0.691* 0.596* -0.473 -0.568 -0.684* -0.635* -0.958† -0.613* 1.000
Outflow Transect (J)
SRP TS Sulfate Diss Fe TAN DOP Ca2+ Alk. pH SRP 1.000 TS -0.031 1.000 Sulfate -0.307 -0.673* 1.000 Diss Fe 0.560 -0.032 -0.055 1.000 TAN 0.184 0.244 -0.695* 0.096 1.000 DOP 0.879† -0.118 -0.440 0.329 0.442 1.000 Ca2+ 0.416 0.081 -0.641* 0.244 0.898† 0.634* 1.000 Alkalinity -0.021 0.389 -0.473 0.457 0.306 -0.141 0.338 1.000 pH -0.450 -0.508 0.733* -0.570 -0.611* -0.433 -0.732* -0.718* 1.000 † significant at p ≤ 0.01; * significant at p ≤ 0.05.
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High Porewater Concentrations and Variability along the Mid-Transect in March 2009
The mid transect, during the second deployment following the prolonged drought, exhibited the highest
porewater SRP, DOP, and TAN concentrations of any transect or deployment period (Figs. 4-5 in the
manuscript). The lowest pH values were also found at this transect during the second deployment.
Repeated surface water depth measurements along this transect consistently showed the middle station
(E2.5) was shallower than either of the other two stations. This suggests that higher soil elevation at E2.5
could have resulted in more time to aerobically oxidize the organic matter during the drawdown, and
explains why the porewater concentrations of most of the dissolved analytes at this station were the
highest found over the entire study. This also contributed to the wide variability in the analyte
concentrations among the three stations along this transect in June 2009 (Figs. 4-5 in the manuscript).