The length and number of creek fractures in the high marsh turf near the low marsh/high marsh border were measured in Rowley River tidal creeks associated with long term fertilization experiments, Rowley and Ipswich, MA. The TIDE project aims to simulate eutrophication on a large scale by the addition of NO3- aiming to reach 70μM concentrations from May to September every year during the growing season. This fertilization of the marsh has been going on at Sweeney Creek since the 2004 growing season through 2012 and at Clubhead Creek in 2005 and from 2009 till 2012
Creek geomorphology was measured during the growing season. Fractures, defined as a visible break in the high marsh (S. patens-dominated) turf that paralleled the creek channel (Fig. S1) within 3 m of the S. alterniflora/S. patens border were measured early in the growing season before the grass obscured fractures. Both sides of each creek were sampled for fractures in contiguous 50m reaches from the 0-m mark to 250-300-m landward. The number of fractures and their characteristics (length, width and depth of fracture) was recorded within each reach. Percent mud was determined by point-intercept transects in the mid growing season, when the grass canopy was fully developed, at 1-m increments for both sides of each creek channel starting at the 0-m mark and extending landward 250-300 m in contiguous 50-m reaches. Observations were made 1-m perpendicular and creekward of the S. alterniflora/S. patens border. Each meter was scored as “vegetated” – with S. alterniflora culms within a 30 cm diameter circle of the point, or “bare mud” – without S. alterniflora. The fraction of points within each 50 m reach was considered a single observation. Year - The calender year the data was collected Years enriched- The number of years creeks have experienced artificial nutrient enrichment Creeks- Reference creeks are West and Nelson Nutrient Enriched creeks are Sweeney and Clubhead. Sweeney has been fertilized every summer from 2004-2012 Clubhead had been fertilized in 2005 and then from 2009-2012. Section - Four reaches within each tidal creek were sampled. One = 0-50 m, two =50-100m, three=100=150m, four=150-200m All creeks have 2 branches (left and right) determined by remaining at confluence of branches and facing upland areas.
On going collections Version 01: September 24, 2012, updated data and metadata. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 3/23/12 12:08 PM for QA/QC to EML 2.1.0 Version 02: June 20, 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.xlsm 3/14/13 12:02 PM for QA/QC to EML 2.1.0