Sapelo Research Application Form
Research Application ID: GCE-42-2013 (submitted: 03/13/2013, status: approved)
Provide a brief title for web display
Short-term responses of tidal low-salinity marsh vegetation to saltwater intrusion
Investigator Information
On Island Sponsor: GCE SINERR UGAMI GADNR
| Principal Investigator: | Steven C. Pennings | ||
| Home Institution: | University of Houston | ||
| Award Information: | GCE-LTER graduate student support for project related to SALTEX, about $25k for one year. | ||
| Mailing Address: | Department of Biology and Biochemistry | Phone Number: | (713) 743-2989 |
| University of Houston | E-mail Address: | scpennin@central.uh.edu | |
| Houston, Texas 77204-5513 | |||
| Co-investigators: | Fan Li (University of Houston) | ||
Briefly describe the project goals and methodology
In 2013, the Georgia Coastal Ecosystems Long Term Ecological Research program will initiate a long-term experiment of saltwater intrusion, using constant and episodic saltwater addition to mimic effects of sea level rise and drought. To help explain the results of this field manipulation, I (Fan Li, PhD student with Steven Pennings) will conduct a lab experiment to compare the detailed, short-term responses of freshwater and brackish plants to multiple saltwater intrusion scenarios.
The goals of this experiment will be 1) to test the hypothesis that brief saline pulses will increase plant biomass by releasing nutrients from soils [9], and 2) to rank the six common species with respect to tolerance to saline pulses. This information will allow me to predict how saltwater intrusion in nature, and in the GCE experiment, is likely to change plant community structure.
Methods: I will grow six common tidal marsh plants in the experiment: Zizaniopsis miliacea, Pontederia cordata, and Sagittaria lancifolia from fresh marshes; and Juncus roemerianus, Spartina cynosuroides and Schoenoplectus tabernaemontani from brackish marshes. Healthy plants with soil blocks (~20 cm × 20 cm × 20 cm) will be collected in March 2013 near the Altamaha River estuary, GA, and acclimated in fresh water before treatments start.
In the greenhouse, plants will receive different schedules of saline (0, 1, 2, 4, 8, 16, 31 days per month, n=5 replicates per species per treatment) versus fresh water. Porewater salinity will be raised from zero to 5 psu for the saline treatment. Water will be added on a semi-diurnal tide cycle to 5 cm above the soil surface, and then allowed to drain. Treatments will run from May to September, and I will measure plant growth rate by taking periodic measurements of photosynthesis, height, and leaf number. In the end, I will harvest above- and below-ground biomass, and collect leaf samples for organic carbon, nitrogen and phosphate analysis. Data will be analyzed with ANCOVA among treatments and species.
Where will the project be located?
In the greenhouse at UGAMI. No field component other than collecting the plants, which will be done near to GCE 8 (brackish plants) and near to the SALTEX site (freshwater plants).
How will you provide GPS coordinates for study sites?
Research locations are not applicable to my project
What are the expected start and end dates of the project?
Start Date: 03/10/2013 End Date: 12/01/2013
How many people will access the site and at what frequency?
We will only go into the field to collect plants (we are covered by the UGAMI collection permit). All other work will be in the laboratory.
Keywords that describe your project
What equipment will be deployed in the field?
None.
Will plants or animals be collected as part of this study?
Yes, 40 individuals each of 6 species, we are covered by the UGAMI collection permit.
What are the likely impacts of the project on the site?
Temporary disturbance at collection sites. One of the two collection sites is heavily disturbed by pigs (near site 8), and our impact will be minimal against this background. At the other site, we expect that disturbance will be invisible within 3 months.
Will the project design include boardwalks? If not, explain why not.
Not relevant to one-time visit.
How long will impacts persist after the research is concluded?
Less than 3 months.
