Award: OCE-1057713

Award Title: Collaborative Research: Cascading effects of an invasive seaweed on estuarine food webs of the southeastern US
Funding Source: NSF Division of Ocean Sciences (NSF OCE)
Program Manager: David L. Garrison

Outcomes Report

Our research focuses 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 (eg., productivity) in some habitats. 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. We initiated a citizen science project in collaboration with Patriots Point Naval and Maritime Museum in Charleston SC. This unique project generates curricular opportunities for students in South Carolina elementary schools. The "Sotka lab" is a Science Spotlight laboratory that will allow students to follow our research throughout the academic school year. We developed lessons about statistics, DNA, and marine ecology using "Case Studies" that are based on real data, some of which the students will be collecting. An intern at Patriots Point has already visited the poorest elementary school in every county in South Carolina, and introduced quadrat methods, ecology and invasive species to 5thgrade children at 21 schools in the 2014-15 academic year. The curriculum was also adapted for sophomore-level students in Ecology at the College of Charleston. For details see "The Sotka Lab" at http://patriotspointsciencespotlight.com and LAMPS ("Lowcountry Algal Monitoring Program for Students":http://www.patriotspointsciencespotlight.com/lamps-introduction.html) Last Modified: 11/09/2015 Submitted by: Erik E Sotka
DatasetLatest Version DateCurrent State
The genotypes from 9 microsatellites generated on individuals of the red invasive seaweed Gracilaria vermiculophylla2015-12-18Final no updates expected
Accession numbers and characteristics of 33 microsatellite loci developed for Gracilaria vermiculophylla2015-12-22Final no updates expected
Abundance of Gracilaria and Diopatra along a tidal mudflat in Charleston Harbor, South Carolina in 2013 (Gracilaria effects project)2016-04-07Final no updates expected
Relative growth rate of Gracilaria in Charleston Harbor, South Carolina in 2013 (Gracilaria effects project)2016-04-07Final no updates expected
Relative growth rate of Gracilaria with depth below the water surface in Charleston Harbor, South Carolina in 2013 (Gracilaria effects project)2016-04-07Final no updates expected
Experimental results on the response of Diopatra size to Gracilaria-mediated resource items in 2013 (Gracilaria effects project)2016-04-07Final no updates expected
Results of stable isotope analysis (C, N) of the posteriorly regenerated muscle tissue of Diopatra from the Georgia and South Carolina coasts in 2013 (Gracilaria effects project)2016-04-07Final no updates expected
Response of Diopatra final size to Gracilaria abundance and the predator-exclusion cages in Fort Johnson, Charleston South Carolina from 2012 (Gracilaria effects project)2016-04-07Final no updates expected
Experimental results on the response of Diopatra final size to Gracilaria abundance after four weeks in 2013 (Gracilaria effects project)2016-04-07Final no updates expected

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Principal Investigator: Erik E. Sotka (College of Charleston)