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Award Detail

Doing Business As Name:University of North Carolina at Chapel Hill
  • Fredrick J Fodrie
  • (919) 966-3411
  • Richard A Luettich Jr
Award Date:02/17/2012
Estimated Total Award Amount: $ 510,000
Funds Obligated to Date: $ 510,000
  • FY 2012=$510,000
Start Date:03/15/2012
End Date:02/28/2017
Transaction Type:Grant
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Collaborative Research: Interacting Effects of Local Demography and Larval Connectivity on Estuarine Metapopulation Dynamics
Federal Award ID Number:1155628
DUNS ID:608195277
Parent DUNS ID:142363428

Awardee Location

Street:104 AIRPORT DR STE 2200
County:Chapel Hill
Awardee Cong. District:04

Primary Place of Performance

Organization Name:Institute of Marine Sciences
Street:3431 Arendell Street
City:Morehead City
County:Morehead City
Cong. District:03

Abstract at Time of Award

Intellectual Merit: The PIs will use the eastern oyster (Crassostrea virginica) in Pamlico Sound, North Carolina, as a model system and will attempt to optimize the design of networks of no-take reserves as a strategy for maintaining metapopulations of this commercially harvested species. The project specifically recognizes that network persistence depends on (1) the potential for growth, survival, and reproduction within reserves, and (2) the potential to distribute offspring among reserves. Thus, demographic processes within reserves and settling areas play important roles, along with variability of physical transport. The PIs plan to: (1) test and refine 3D bio-physical models of connectivity due to oyster larval transport in a shallow, wind-dominated system; (2) test, refine, and apply technology to detect natal origins of larvae using geochemical tags in larval shell; and (3) integrate regional connectivity and demographic rates to model metapopulation dynamics. Broader Impacts: This study will produce new tools and test and refine others used for studying larval connectivity, a fundamentally important process in the maintenance of natural populations, and thus in biological conservation and resource management. The tools include a hydrodynamic modeling tool coupled with an open-source particle tracking model that will be available on-line with computer code and user guide. The project will use integrated modeling approaches to evaluate the design of reserve networks: results will be directly useful to improving oyster and ecosystem-based management in Pamlico Sound, and the methods will inform approaches to network design in other locations. There is extensive education and outreach in the form of training undergraduate and graduate students, mentoring post-docs, and providing hands-on research opportunities for high school students and their teachers.

Publications Produced as a Result of this Research

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Gittman, RK, and DA Keller "Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat." Ecology, v.94, 2013, p.2709.

Puckett, B.J., Eggleston, D.B., Kerr, P.C. and Luettich, R.A., "Larval dispersal and population connectivity among a network of marine reserves" Fisheries Oceanography, v., 2014, p..

Gittman, RK, and DA Keller "Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat" Ecology, v., 2013, p..

Walles, B, FJ Fodrie, S Nieuwhof, PMJ Herman, and T Ysebaert "Guidelines for evaluating performance of oyster habitat restoration should include tidal emersion: reply to Baggett et al." Restoration Ecology, v., 2016, p..

Ridge, JT, AB Rodriguez, FJ Fodrie, NL Lindquist, JH Grabowski, MC Brodeur, SE Coleman, EJ Theuerkauf "Maximizing oyster-reef growth supports green infrastructure with accelerating sea-level rise." Nature Scientific Reports,, 2015, doi:na 

Rodriguez, AB, FJ Fodrie, JT Ridge, EJ Theuerkauf, SE Coleman, JH Grabowski, MC Brodeur, RK Gittman, DA Keller, MD Kenworthy, and NL Lindquist "Will oyster reefs keep their heads above water?" Nature Climate Change, v.4, 2014, p.493. doi:na 

Gittman, RK, FJ Fodrie, AM Popowich, DA Keller, JF Bruno, CA Currin, CH Peterson, and MF Piehler "Engineering away our natural defenses: an analysis of shoreline hardening in the United States." Frontiers in Ecology and the Environment, v., 2015, p..

Rodriguez, AB, FJ Fodrie, JT Ridge, NL Lindquist, EJ Theuerkauf, SE Coleman, JH Grabowski, MC Brodeur, RK Gittman, DA Keller, and MD Kenworthy "Oyster reefs can outpace sea-level rise." Nature Climate Change, v., 2014, p..

Gittman, RK, CH Peterson, CA Currin, FJ Fodrie, MF Piehler, and JF Bruno "Living shorelines can enhance the nursery role of threatened coastal habitats over time." Ecological Applications, v., 2016, p..

Fodrie, FJ, AB Rodriguez, CJ Baillie, MC Brodeur, SE Coleman, RK Gittman, DA Keller, MD Kenworthy, AK Poray, JT Ridge, EJ Theuerkauf, and NL Lindquist "Classic paradigms in a novel environment: inserting food-web and productivity lessons from rocky shores and saltmarshes in to biogenic reef restoration." Journal of Applied Ecology, v., 2014, p..

Puckett, BJ, DB Eggleston, PC Kerr, and RA Luettich "Larval dispersal and population connectivity among a network of marine reserves." Fisheries Oceanography, v.23, 2014, p.342. doi:na 

Gittman, RK, and DA Keller "Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat." Ecology, v.94, 2013, p.2709.

Kroll, IR, AK Poray, BJ Puckett, DB Eggleston, and FJ Fodrie "Environmental effects on elemental uptake in the shells of the Eastern oyster, Crassostrea virginica: implications for the use of geochemical tagging to assess connectivity." Marine Ecology Progress Series, v., 2016, p..

Fodrie, FJ, AB Rodriguez, CJ Baillie, MC Brodeur, SE Coleman, RK Gittman, DA Keller, MD Kenworthy, AK Poray, JT Ridge, EJ Theuerkauf, and NL Lindquist "Classic paradigms in a novel environment: inserting food-web and productivity lessons from rocky shores and saltmarshes in to biogenic reef restoration." Journal of Applied Ecology, v.51, 2014, p.1314. doi:na 

Project Outcomes Report


This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Larval connectivity of fishes and invertebrates has broad implications for population dynamics (e.g., recruitment pulses to fisheries), stock delineation, and mechanisms of evolution. Therefore, a major challenge in marine ecology and marine resource management is describing patterns of larval dispersal and population connectivity in the sea. The goal of this study was to gain insight into the larval connectivity and dispersal of a commercially and ecologically important invertebrate, the Eastern oyster (Crassostrea virginica), within a large estuarine system along the eastern US (Pamlico Sound, NC). To accomplish this, we applied two approaches: geochemical tags stored in the shell of oysters formed during the larval stage, and computer model simulations that accounted for physical transport processes and larval swimming behaviors.


Studies utilizing natural or artificial tagging methods have greatly enhanced our quantitative understanding of larval connectivity in the ocean. Geochemical markers (e.g., Strontium, Barium, Manganese) stored within growing calcified structures, such as fish “ear stones” and bivalve shells, are useful for examining marine larval connectivity as many marine organisms begin recording environmental signatures with these “hard parts” soon after egg fertilization. Thus, provided that there are spatial gradients in environmental conditions, these hard parts can carry a permanent record/tag that allows researchers to retroactively track individuals through time and space (i.e., a flight data recorder). Estuarine systems provide an ideal setting in which to apply geochemical tagging methods and explore larval connectivity as they are characterized by high environmental variation, encompass complex and patchy habitat landscapes, and function as important nursery, juvenile, and adult habitats for many marine organisms of ecological and economic value.


We began by evaluating the utility of geochemical tagging methods to discern oyster larval connectivity among reefs across Pamlico Sound. We used both laboratory incubations and field surveys to assess how gradients in temperature, salinity, and trace metal concentrations affect the incorporation of geochemical signals in larval oyster shells. Our studies demonstrated that across regional (35 km) scales within Pamlico Sound, spanning salinity and temperature gradients, there were distinct multi-elemental signatures between potential natal sites for oysters. For instance, we observed higher Sr concentrations within larval shells in cooler and fresher water, such as occurs in the northwestern portion of the Sound.


Following these ground-truthing efforts, we used geochemical tagging to assess estuarine-scale larval connectivity among subpopulations of oysters. To generate ‘atlases’ of geochemical signatures associated with potential spawning sites, we outplanted/incubated recently spawned oyster larvae at multiple stations across Pamlico Sound. Using these atlases, we predicted the natal origin (i.e., connectivity) for newly settled oysters (spat) during three field trials conducted over two summers (2013- 2014). Patterns of larval connectivity varied both seasonally and annually, but were predominately directed south to north following wind patterns. Predicted self-recruitment was variable, as 0-100% of spat in a given region displayed signatures consistent with natal origin within that same region.


We also used a biophysical model to simulate dispersal of eastern oyster larvae and connectivity among an existing network of 10 oyster reserves in Pamlico Sound. Modeling parameters were varied to assess the relative importance of spawning location, spawning date, larval behavior, larval mortality, and adult reproductive output to predicted dispersal and connectivity patterns. Spawning location and date of spawning relative to physical processes, particularly frequency of wind reversals, were the dominant drivers of dispersal and connectivity patterns. To a lesser extent, larval behavior (i.e., vertical depth regulation) and mortality modified dispersal and connectivity, whereas spatiotemporal variability in adult reproductive output was of minimal importance. Over a 21-day larval duration, mean dispersal distance of passive surface particles ranged from 5-40 km. Reserves were too small (<1 km2) relative to mean dispersal distances to promote extensive local retention or promote extensive inter-reserve connectivity. Reserves did, however, serve as notable “sources” for larval oysters that dispersed to non-reserve sites throughout Pamlico Sound.


Collectively, these results highlight that oyster sub-populations (reefs) in Pamlico Sound are well connected and demographically “open” over annual (or longer) timescales. Thus, fewer large or several small reserves could both perform well in this system. Broadly speaking, natal sources in the southern half of Pamlico Sound were more typically larval source areas, and therefore could be targeted for the siting of future oyster reserve sites.


To date, the project has supported 10 publications appearing in Ecology, Frontiers in Ecology and the Environment, Ecological Applications, Fisheries Oceanography, Journal of Applied Ecology, Marine Ecology Progress Series, Nature Climate Change, Restoration Ecology, Scientific Reports, and Proceedings of the Royal Society B, as well as 2 additional submitted manuscripts (Limnology and Oceanography, and Marine Ecology Progress Series). Two Ph.D. students worked on this study, with both students having published first-authored papers that acknowledge NSF support. One student has accepted a tenure-track position at East Carolina University, while the other currently works as a Knauss Fellow for the US Fish and Wildlife Service.



Last Modified: 06/23/2017
Modified by: Fredrick J Fodrie

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