Pot experiment on fresh and brackish marsh plants responses to salinity pulses in summer 2013

We collected 35 individuals of three freshwater species (Zizaniopsis miliacea, Pontederia cordata, Polygonum hydropiperoides) and brackish species (Juncus roemerianus, Schoenoplectus americanus, and Spartina cynosuroides) from the tidal marshes of the Altamaha River estuary, Georgia, USA (31.4° N, 81.4° W). Plants were collected on March 9 - March 11, 2013, and were potted individually in 12 L pots in sediments collected from the same location as plants. Individual potted plants were placed inside dish pans with drain holes at mid-pot height. For salinity treatments, plants were watered once a day with saline water (5 psu: practical salinity units, created using Instant Ocean Sea Salt, Aquarium System Inc., Mentor, OH, USA) for 1, 2, 4, 8, 16, or 31 days per month, and then returned to freshwater. For the control treatment, plants were watered with freshwater daily. Treatments were ran from May 26 to August 28, 2013, and stem height of each plant was measured once a month. The experiment was harvested on August 28, 2013. Individual plants were separated into aboveground and belowground biomass, washed to remove soil, and dried at 60 °C to constant mass.