Award: OCE-1057707

Our research focused on how the invasion of the red seaweed Gracilaria vermiculophylla affects the ecology of SC and GA estuaries. We found that Gracilaria provisions food and structure important to benthic species, and fuels microbial production by leeching sugars while alive and producing detritus after death. Gracilaria is successful in these estuaries because of a novel mutualism with a non-native decorator worm called Diopatra cuprea. Our results add to a growing recognition in the literature that non-native species can increase local ecosystem functioning (e.g., productivity) in some habitats. Gracilaria seems to have a lot of positive interactions with the other species in the estuaries by boosting primary and secondary productivity, increasing detrital inputs, and removing excess nitrogen from the water. Funds from this grant allowed us to genotype 2500+ individuals at multiple microsatellite loci, which revealed substantial genetic variation within invasive populations previously thought to be genetically depauperate based on a single mitochondrial locus (cytochrome oxidase I). We also found that this genetic diversity within populations of Gracilaria may potentially facilitate the invasion, by increasing primary productivity at a small scale. Our work supported one PhD dissertation and 3 undergraduates in REU research. We initiated a citizen science project in collaboration with graphic designers, UGA Marine Extension, and staff at the Skidaway Institute of Oceanography (SKIO). We developed educational signs on Gracilaira that are placed at strategic positions of heavy foot traffic in the Savannah-Charleston region. The signs encourage people to submit a picture of the mudflat from a fixed vantage point to document the presence and extent of Gracilaria coverage. The submitted pictures are time and date stamped and compiled into a time-lapse data base of Gracilaria on the mudflat. We worked with the development office at Odum School of Ecology to help crowdfund this project aspect. This project is designed to raise awareness of invasive species, but specifically Gracilaria, on the Georgia coast. Other outreach included an article for Savannah Now by Mary Landers, an article for the Oconee Rivers Audubon Society monthly newsletter, a public presentation to hundreds at the Skidaway Institute of Oceanography Marine Science Day, and a scientific presentation at the Southeastern Ecology and Evolution Conference. Graduate student Linsey Haram also has disseminated much information about our project through a research blog (https://snailsnotwhales.wordpress.com/ ) that was created as a way to continue to engage the general public. Other outreach includes guest lectures for the National Estuarine Research Reserve at North Inlet, the Charleston Audubon Society, and the Georgia Dept. of Natural Resources. Ms. Haram also serves as a volunteer and interpreter for the Savannah National Wildlife Refuge which allows her to interact with mixed audiences - general public, educators, master naturalists, scientists, and managers. We have registered our project with BCO-DMO at: http://www.bco-dmo.org/project/564687. We have posted data there related to the ecological interactions of Gracilaria with the native tube worm Diopatra cuprea (from Kollars et al. 2016, MEPS). We also have several files on the genetics of invasive Gracilaria vermiculophylla including raw genotype scores. This dataset contains the genotypes from 9 microsatellites generated on individuals of the red invasive seaweed Gracilaria vermiculophylla. The same data were also used in the Kollars et al. 2015 PeerJ and were submitted to that journal as Supplemental Files. These files also include our GenBank accession numbers associated with this work. Last Modified: 08/22/2016 Submitted by: James Byers