ABOUT

I am a postdoctoral researcher at the Center for Coastal Studies in Provincetown, MA. I am researching the sediment dynamics of the Herring River and Wellfleet Harbor on outer Cape Cod, MA, to document pre-restoration baseline conditions and support meaningful projections of future conditions with the Herring River Restoration Project, the largest tidal restoration project in New England.

Previously, I was a postdoctoral fellow appointed jointly with Northeastern University's Marine Science Center and The Nature Conservancy, studying nature-based shoreline stabilization techniques and marsh resilience to storms. I received my PhD from the MIT-WHOI Joint Program, where I studied how major storms impacted coastal New England over the last 2,000 years. I also received a master's in marine affairs from the University of Rhode Island, where I studied the relationships between salt marsh restoration and the shellfishing industry on the outer Cape.

As coastal populations continue to grow in both size and wealth, hurricanes and other major storms pose a growing threat to infrastructure, life, and environment. Sea-level rise has continued to threaten coastal communities at alarming rates, and evidence suggests that sea-level rise will exacerbate the effects of storm surge, increasing the potential for land loss. In New England, where both population and economic resources are concentrated largely along the coast, research into the impacts of increased storm intensity and sea-level rise, as well as research into shoreline stablization and restoration techniques, is imperative to resilience of these coastal communities.

RESEARCH

Enhancing coastal protection through nature-based solutions

In the face of rapidly accelerating climate change, natural infrastructure will be essential to preserving the resilience of vulnerable coastal communities, especially when retreat is not possible. Nature-based solutions, including living shorelines, marsh restoration, and hybrid green/grey infrastructure, provide unique opportunities build coastal resilience from physical, biological, and social perspectives. Understanding the physical limitations of natural systems to extreme events in a changing climate is imperative for their utilization. Through understanding the social drivers of coastal restoration and the barriers to the implementation of nature-based solutions, we can work toward developing effective, sustainable systems.
Influence of storms on the resilience of coastal bays and marshes

Coastal bay systems play an integral role in protecting coastal communities from flooding and other destruction associated with hurricanes and nor'easters. As sea level continues to rise and tropical cyclones and other storms increase in intensity, these coastal bays and marsh systems are increasingly at risk for destruction. Salt marshes in particular have long been lauded as buffers to storm surges, wind-generated waves, and elevated water levels.

Following Redfield's bi-directional model of salt marsh evolution, salt marshes along the eastern coast of the United States keep pace with moderate sea-level rise. Recent geological evidence, however, suggests that some extreme storm events may cause significant marsh erosion. Other studies suggest that extreme storm events cause net influx of sediment to the system, improving the resilience of marshes to extreme weather. This spectrum of impacts has major implications for coastal inundation risk to lives and property, as well as the resilience of these coastal wetlands to a changing climate.

OUTREACH

As an environmental educator, I love opportunities to share science in fun and accessible ways. I am always happy to share demonstrations or lead field trips on various topics including climate, hurricanes, salt marshes, storm surge, coastal protection, sediment coring, and Cape Cod natural history. For more information about my outreach activities, please see my outreach resources webpage.

Woods Hole Science and Technology Education Partnership (WHSTEP) Family Science Night, Woods Hole, MA. Photo credit: WHSTEP.

Panelist for Wild Weather Weekend at the Boston Museum of Science, Boston, MA. Photo credit: E. Wallace.

Demonstrating storm surge for a third grade unit on extreme weather, East Falmouth, MA. Photo credit: EFES.

Leading a field lesson on overwash for Mashpee Wompanoag summer camp students, Falmouth, MA. Photo credit: S. Madsen.

SELECTED PUBLICATIONS

Castagno, K. A., Ganju, N.K., Beck, M.W., Bowden, A., Scyphers, S. (2022). How Much Marsh Restoration Is Enough to Deliver Wave Attenuation Coastal Protection Benefits? Frontiers in Marine Science. https://doi.org/10.3389/fmars.2021.756670
Many restoration projects seek to maximize the ecosystem service of wave attenuation, but how much marsh restoration is enough to deliver measurable coastal protection benefits is still unknown. This question is critical to guiding assessments of cost effectiveness and for funding, implementation, and optimizing of marsh restoration for risk reduction projects. This study uses SWAN model simulations to determine empirical relationships between wave attenuation and marsh vegetation, finding that up to a 95% reduction in wave energy is seen at as low as 50% vegetation cover.
Castagno, K. A., Tomiczek, T., Shepard, C., Beck, M.W., Bowden, A., O’Donnell, K., Scyphers, S. (2021). Resistance, resilience, and recovery of salt marshes in the Florida Panhandle following Hurricane Michael. Scientific Reports. (20381). https://doi.org/10.1038/s41598-021-99779-8
This study uses high-resolution aerial imagery to quantify the impacts of Hurricane Michael, a category 5 hurricane, on coastal salt marshes in the Florida Panhandle, USA. Marshes were highly resistant to storm damages even under extreme conditions. Marsh management mattered for resistance and resilience; marshes on publicly-managed lands were less likely to be damaged and more likely to recover quickly from storm impacts than marshes on private land, emphasizing the need to incentivize marsh management on private lands.
Castagno, K. A., Bowden, A., Roberts, E., Burns, S., Harlan, S. L., Senier, L., Scyphers, S. (2021). Conservation practice insights from a comparative case study of two shoreline stabilization projects in Boston Harbor, MA. Conservation Science and Practice. 3 (8). https://doi.org/10.1111/csp2.465
This case study contrasts two shoreline stabilization projects directly across from each other on the banks of the Mystic River, Boston Harbor, MA. This study documents the evolution of both projects, highlighting common challenges in permitting and vegetation maintenance, as well as critical differences in project goals, funding sources, and biodiversity impacts, to advance the practice of nature-based solutions to shoreline stabilization.
Castagno, K. A., Donnelly, J. P., and Woodruff, J. D. (2021). Grain-size analysis of hurricane-induced event beds in a New England salt marsh. Journal of Coastal Research. 37 (2), 326-336. https://doi.org/10.2112/JCOASTRES-D-19-00159.1
This study determines grain-size trends in storm-induced overwash deposits along a transect of sediment cores from a salt marsh in Mattapoisett, MA, in order to characterize sorting trends and compare deposits associated with individual storms. This new in-depth, transect-based approach has utility for improving the accuracy of future storm reconstructions, particularly for events for which we have no historic record.
Castagno, K. A., Donnelly, J. P., and Woodruff, J. D. (2021). Storm processes and salt marsh dynamics, in Marshes: Function, Dynamics and Stresses, Eds. Fitzgerald, D. and Hughes, Z., Cambridge Univ. Press. IBSN: 9781316888933
This book chapter chronicles the various impacts that storms have on salt marshes globally. The chapter discusses both stratigraphic evidence of storms and modern storm impacts, as well as implications for the utility of marshes to attenuate storm waves and build coastal resilience.
Castagno, K. A.(2018). Salt Marsh Restoration and the Shellfishing Industry: Co-evaluation of Success Components. Coastal Management, 46 (4), 297-315. https://doi.org/10.1080/08920753.2018.1474069
A product of my master's thesis, where I researched the ecologic and social linkages between salt marsh restoration and the shellfishing industry on outer Cape Cod, MA. Restoration projects are valued for far more than their direct provisioning ecosystem services, with many shellfishermen emphasizing the cultural value of the salt marsh above all else.
Castagno, K. A., Jiménez‐Robles, A. M., Donnelly, J. P., Wiberg, P. L., Fenster, M. S., & Fagherazzi, S. (2018). Intense Storms Increase the Stability of Tidal Bays. Geophysical Research Letters, 45, 5491-5500. https://doi.org/10.1029/2018GL078208
In order to counteract rising sea levels, a coastal bay needs to increase its bottom elevation by trapping enough sediment in salt marshes and tidal flats. Here, we show that intense storms provide sediments to the bay and marsh systems of the Virginia Coast Reserve, thereby increasing their long‐term stability.