A Surface Elevation Table (SET) is used to measure changes in the elevation of the marsh surface at three long term marsh fertilization experimental research sites. The sites include one Typha-dominated brackish marsh, one Spartina alterniflora-dominated salt marsh, and one S. patens-dominated salt marsh. Sites are located on the Rowley and upper Parker Rivers in the Plum Island Ecosystem (PIE) LTER site.
This data set is part of a study including three on-going plot-level fertilization sites. The first (LTE-MP-LPA) is in the S. alterniflora-dominated low marsh at Law's Point between the Rowley River and West Creek. The second (LTE-MP-LPP) is in the S. patens-dominated high marsh at Law's Point between the Rowley River and West Creek. The third (LTE-MP-ORT) is in a Typha-dominated brackish water marsh on an upstream tributary of the Parker River. SET sampling at the LTE-MP-ORT)was discontinued after May 2008.
At each site a system of boardwalks was built to incorporate 12 experimental plots (1m2 each). There are 4 treatments (three repslicates each) within the boardwalk structure. The 4 treatments are Control, N-fertilized, P-fertilized, N+P fertilized. Additionally, at each site there are 3 control plots and 3 N+P fertilization plots external to the boardwalk structure. These external plots contain porewater samplers, and, in some cases, biomass census plots. In May 2006 the control porewater plots and control census plots at all three sites were moved because of potential contamination from fertilized plots.
Fertilizer is buried at several locations within each plot, approximately monthly, from May-Sept. From 1999-2001 the annual fertilization rate was 30 molN/m2/y and /or 15 mol P/m2/y. From 2002 to present the fertilization rate is 7.5 mol N/m2/y and/or 3.75 mol P/m2/y. N fertilizer was NH4NO3 through 2008, and currently is nitrate/urea/sulfate (34-0-0). P fertilizer is P2O5 (0-44-0).
Triplicate original-style SET benchmark posts were installed between fertilized and control plots in 1999 at LTE-MP-LPA and 2000 at LTE-MP-LPP and LTE-MP-ORT. Each SET consists of a permanently-installed post and a removable arm. The arm has a vertical and a horizontal component. The vertical component fits into the SET benchmark post; the horizontal component reaches out over an experimental subplot and has a square plate at the end , with 9 collars through which fiberglass pins are lowered. Each SET benchmark post is positioned such that 27 elevation readings can be taken in a fertilized plot (9 readings in each of 3 subplots) and 27 elevation readings can be taken in a control plot (9 readings in each of 3 subplots). Plots are numbered; subplots are identified as L, C, or R for left, center and right, when facing the plot (back to the SET post). To measure pin heights, the SET arm is locked in place over each subplot and the plate at the end of the arm is leveled. The 9 brass pins are then lowered to touch the sediment surface and held in place with a clip. Pin heights are measured from the top of the nut that fastens the collar to the plate, to the top of the pin, and read into a digital recorder. The recordings are transcribed into one master SET pin height data set. SET readings occur approximately monthly, from May-October at LTE-MP-LPA and LTE-MP-LPP, and in May and October only at LTE-MP-ORT. Sampling at the ORT SET was discontinued in 2008.
The horizontal portion of the removable part of the PIE LTER SET can be correctly installed and leveled in several positions: i.e. the arm can be extended all the way forward, all the way back, and anywhere in between. All SET measurements are made with the arm all the way back, i.e. with the plate being as close to the SET post as possible and the SET arm being as short as possible.
In 2014 the original pins were replaced with longer fiberglass pins. The pin heights included in this data set have been standardized to the original pin heights.
The SET was manufactured by Nolan’s Machine Shop in Lafayette LA; 337-235-5261. Replacement pins or collars can be purchased from Nolan’s. Stainless steel parts (roll pins etc) come from McMaster-Carr. Measuring pins are held in place with badge clips, available at office supply stores.
NOTE about calculating marsh elevation:
SET sites at LTE-MP-LPA and LTE-MP-LPP were surveyed in 2009 by MBL staff using FastStatic measurements with a Trimble 4800 receiver and TSC-1 controller (from UNAVCO www.unavco.org). At each SET post (3 per site) the elevation of the SET plate was determined when the arm is in the center subplot, pointing north (towards West Creek), and levelled. SET sites were also surveyed in 2011, 2018 and 2019. There was movement (sinking) of the LTE_MP_LPA plots 10&12 SET post during winter 2017/2018. The 2018 and 2019 RTK surveys indicated that the post had sunk 63mm. The elevations of the SET plate in m NAVD88 are listed below:
LTE-MP-LPA plots 2&4: 1.826m
LTE-MP-LPA plots 9&7: 1.799m
LTE-MP-LPA plots 12&10 (2009): 1.832m
LTE-MP-LPA plots 12&10 (2018): 1.774m
LTE-MP-LPP plots 7&5: 2.148m
LTE-MP-LPP plots 10&8: 2.146m
LTE-MP-LPP plots 11&9: 2.200m
The elevation of the SET plate can be used directly with the SET geometry and the pin height measurements found in the dataset to calculate the elevation of the marsh as follows. Total pin length for the original SETs is 91.44cm and the height of the nut on the plate is 1.0 cm. Therefore the marsh surface is at: (plate elevation (in m) - (0.9144 - (pin height (in m) + 0.01)). For example for LPA plot 2 subplot C in June 1999 pin 1 the pin ht is 15.3cm and the plate elevation is 1.826m. The marsh elevation is (1.826-(0.9144-(0.153+0.01))) or 1.0746m above NAVD88.
Collections occur every month from May through October.
Database is updated once annually, usually in the winter.
Study and data collection are ongoing as of Dec 2017.
Version 01: July 11, 2006 Level 3+ EML using Jim Laundre's Excel program
Version 02: January 10, 2007 data and metadata update
Version 03: March 12, 2008 Data and metadata update
Version 04: February 20, 2009 Data and metadata update, Elevation change variable removed from data set
Version 05: January 13, 2010 Data and metadata update
Version 06: October 25, 2011 Data and metadata update
Version 07: January 12, 2012, 2011 data and metadata update, using MarcrosExportEML_HTML (working)pie_excel2007.xlsm 1/12/12 11:51AM for QA/QC to EML 2.1.0
Version 08: March 15, 2013, 2012 data and metadata updated to comply with importation to Drupal and LTER PASTA. Research location name and description updated.Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 3/14/13 12:02 PM for QA/QC to EML 2.1.0
Version 09: January 10, 2014, 2013 data and metadata updated to comply with importation to Drupal and LTER PASTA. Research location name and description updated.Used MarcrosExportEML_HTML (working)pie_excel2007_Sep2013.xlsm 9/30/13 02:57 PM for QA/QC to EML 2.1.0
Version 10: April 17, 2014, 2013 update, data and metadata comply with importation to Drupal and LTER PASTA. Research location name and description updated.Used MarcrosExportEML_HTML (working)pie_excel2007_Sep2013.xlsm 9/30/13 02:57 PM for QA/QC to EML 2.1.0
Version 11: February 11, 2015, data and metadata updates to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2015.xlsm 1/15/15 4:26 PM for QA/QC to EML 2.1.0
Version 12: February 24, 2016, data and metadata updates to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2015.xlsm 1/15/15 4:26 PM for QA/QC to EML 2.1.0
Version 13: September 20, 2017, data and metadata updates to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jun2017.xlsm 6/15/17 10:23 AM for QA/QC to EML 2.1.0
Version 14: June 22, 2018, data and metadata updated to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007_Jan2018.xlsm 6/21/2018 3:53 PM for QA/QC to EML 2.1.0
Version 15: September 17, 2020, data and metadata updates to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007_Sep2020.xlsm 9/17/20 1:11 PM for QA/QC to EML 2.1.0.