Research Seminar: Anna Atencio

A research seminar presented by UNC-CH Department of Marine Sciences graduate student, Anna Atencio.

Seminar Title: Working better together or apart? Variations in sediment accumulation rates among salt-marsh and intertidal oyster-reef landscapes

Abstract: In the estuarine system, salt marshes and intertidal oyster reefs protect the coast from the erosive energy of waves and storms and provide many other ecosystem services including fish habitat, carbon burial, and improvement of water quality.  Both of these habitats have lost greater than 50% area globally, which has driven an increase in conservation and restoration.  Intertidal habitats must accrete vertically at the rate of sea-level rise to persist, which should be a primary metric for labeling a restoration or conservation project as being successful.  On annual to centennial timescales it is well known that salt marshes can keep pace with increases in relative sea level. Similarly, oyster-reef growth measured over annual timescales has been shown to match short-term increases in relative sea-level rise (sea-level anomalies).  It is unknown, however, how oyster reefs interact with a rising sea-level on decadal timescales or longer and how landscape setting impacts sediment accumulation of oyster reefs and salt marshes. Here, we study natural salt marshes and their adjacent oyster reefs in Back Sound and the North River Estuary, North Carolina to determine the vertical accretion rates on decadal timescales via ²¹⁰Pb geochronology. We compare 3 oyster reefs morphologies, fringing, spit, and detached, to give insight to how various reef morphologies accrete, and how the marshes adjacent to them are affected. Our goal is to determine which oyster reef morphologies are viable for keeping up with sea-level rise on decadal timescales. These findings, based on natural reefs and marshes, could give feedback for ecological engineering of restored areas.