Thin-layer sediment placement: evaluating an adaptation strategy to enhance coastal marsh resilience across the NERRS
Lead Investigator: Dr. Kenny Raposa, Research Coordinator, Narragansett Bay National Estuarine Reserve
WBNERR Project Contact: Dr. Megan Tyrrell
8 Reserves Included in Project: Great Bay NH, Waquoit Bay MA, Narragansett Bay RI, Chesapeake Bay MD, Chesapeake Bay VA, North Carolina, Grand Bay MS, Elkhorn Slough CA
Tidal marshes provide key ecosystem services, but are threatened by sea level rise. Narragansett Bay and Elkhorn Slough NERRs recently led a project to assess marsh resilience to sea level rise across 16 NERR sites, resulting in a scientific publication, user-friendly summary, and DIY tool. Currently, eight NERR sites across the East, Gulf and West coasts are actively testing strategies to examine the effectiveness of thin-layer sediment placement as a climate adaptation strategy.
Novel aspects of our project include the broad geographic scale, the examination of effectiveness at different marsh elevations, standardized monitoring, and the incorporation of biochar as a soil amendment to enhance carbon sequestration. Beneficial use of dredged sediment to enhance coastal resilience is a concept that resonates in many coastal states, and we have interviewed end-users from eight states interested in funding, permitting, implementation or monitoring of thin-layer sediment projects.
Lead Investigator: Robinson W. “Wally” Fulweiler, Sarah Foster, PhD student, Mollie Yacano, undergraduate researcher
Affiliation: Boston University, Earth and Environment Department
Funding Source(s): Undergraduate Research Opportunities Program (UROP), Boston University
Jarret Byrnes, Farah Ahmad
Tanya Rogers, David Kimbro (Northeastern University Marine Science Center)
Funding Source(s): Northeastern University; National Science Foundation
Kevin Kroeger, Meagan Gonneea (U.S. Geological Survey: Woods Hole Coastal and Marine Science Center)
Aleck Wang (WHOI)
Funding Source(s): USGS, NSF
Funding Source(s): WHOI
Harriet Booth, Patrick Barrett, Meredith Burke, Dr. David Kimbro
Funding Source(s): Northeastern University
Principal Investigators: Dr. Faming Wang, Dr. Jianwu (Jim) Tang, Marine Biological Laboratory
We use commercially available tea bags as standardized test kits to gather data on salt marsh decomposition rates. This is a cost-effective, well-standardised method. By using two tea types with contrasting decomposability, we can construct a decomposition curve using a single measurement in time. We will compare the decomposition rate within the high marsh and low marsh, and also in the warmed chamber versus ambient reference. Our data was also included in a worldwide cooperation network to investigate the decomposition rate in different ecosystems using the tea bag method.
To read more about the tea bag experiment and its relationship to blue carbon research, please visit:
PI: Hanu Singh, WHOI
David Fisichella, WHOI
Jim Rassman, WBNERR
WHOI scientists are working with Reserve staff, using a small hobby-plane equipped with GPS and camera to take high-resolution photos of the salt marsh and shore at South Cape Beach. These photos are useful for public presentations, but more importantly can map change over time, damage from storms, results of controlled burns, animal populations (such as seals), etc.
PI: Anna Michel, Princeton University (WHOI in Fall 2012)
Funding: WHOI and submitted grants (NSF, MIT Seagrant)
PIs: Gina Wimp, Georgetown University
Dan Lewis, Georgetown University
Shannon Murphy, Denver University
PI: Camille David, UMASS-Dartmouth, PhD Candidate
Advisor: Brian Howes, UMASS-Dartmouth
Funding: UMASS-Dartmouth, WBNERR collaborative in-kind
Comparing Methods and the Stability of Deep-Driven Rod Elevation Benchmarks and SETs in a Salt Marsh Environment
PIs: Philippe Hensel, National Geodetic Survey
Galen Scott, National Geodetic Survey, University of RI
Jim Lynch, US Geological Survey
WBNERR Staff: Jim Rassman, Jordan Mora, Chris Weidman
Description: Sediment Elevation Tables (SETs) and benchmarks are used to measure change in marsh elevation with millimeter scale accuracy to determine sedimentation rates. This information, combined with accurate water level measures, can assess whether salt marshes are keeping up with sea level rise or risk being “drowned.” Traditionally SETs and benchmarks are installed by driving metal rods deep into the earth until they hit resistance. This can be difficult and costly as each 4’ length of rod is expensive. This project is investigating whether it is necessary to drive the rods that deep, or whether they are just as stable at, say, 20’ depth. Rods have been driven to different depths in the South Cape Beach salt marsh and are being “leveled” regularly – measured against a known point – to see if they have shifted. If not, this research could result in new standards for installation of this infrastructure which would save significant time and money. This is one of a growing number of projects in the new “Climate Change Observatory” in this marsh.
PI: Chris Maio, UMASS-Boston, PhD Candidate.
Advisor: Allan Gontz, UMASS-Boston
Funding: UMASS-Boston, Geological Society of America Research Award, collaborative in-kind-WBNERR
My research looks at coastal changes that have occurred in response to sea-level rise and storminess during the past 4000 years. I use a variety of methods including sediment core analysis, ground penetrating radar, GIS, and radiocarbon dating. Learning about how the Waquoit estuarine system responded to past sea level-rise and storminess will provide needed context for understanding and anticipating future changes.
An ancient red cedar forest was first revealed after a series of storms in 2010 resulted in significant erosion along South Cape Beach revealing 111 subfossil stumps along the beach and into the water. Thirteen stumps were radiocarbon dated and ranged in age from ~413-1200 years old. We assume this age represents the time at which the ancient trees were drowned by marine waters. Shoreline change analysis showed that between 1846 and 2008, the shoreline fronting the paleoforest retreated landward by 70 m at a long-term rate of 0.43 m/yr.
Sediment cores were analyzed to determine storm and sea level history. Radiocarbon dates of bivalve microfossils indicate that Waquoit Bay was first inundated by marine waters approximately 3600 years ago. The ongoing research will help decipher the relationship between sea-level rise, storminess, and the inundation of terrestrial ecosystems and will help to illuminate what caused the drowning of the South Cape Beach paleoforest.
PI: Sarah Corman, Brown University, PhD Candidate.
Funding: NERRS Graduate Research Fellowship at WBNERR (current)
“The goal of my research at WBNERR is to investigate how Spartina alterniflora, the foundation species of salt marshes, will respond to rising temperatures, and to what extent salt marshes can resist drowning under predicted rates of sea level rise. Aboveground growth, in stems and leaves, and belowground growth, in roots and rhizomes, work in concert to maintain elevation and resist marsh drowning, and yet we don’t understand the patterns and processes driving the relationship of above to belowground growth. I am also exploring how the timing of flowering in Spartina influences elevation change and seed production. Understanding these mechanisms in salt marshes is critical to predicting potential loss of these ecosystems in the future.” http://sarahcorman.wordpress.com/
PIs: Serena Moseman-Valtierra, University of Rhode Island, Jianwu Tang, MBL Ecosystems Center, Kevin Kroeger, USGS-Woods Hole Science Center,
Funding: MIT Seagrant
The general goal for the project is to measure potential greenhouse gas (GHG) emissions and net CO2 uptake in coastal wetlands under a range of realistic nitrogen (N) loads and inundation (sea) levels. By meeting this goal, we aim to improve the information with which managers and policy makers can maintain and maximize ecosystem productivity, reduce harmful feedbacks of climate, and assess the potential for these ecosystems to enter C markets.
We will examine how GHG emissions from salt marshes vary along an existing gradient of anthropogenic N loading in Waquoit Bay, MA (WB-NERR). Further, we will test for relationships between N loads to the marshes and plant productivity. To investigate the influence of anticipated future increases in sea level, we will use existing gradients in marsh soil elevation (and therefore a gradient in soil water saturation and in frequency and duration of soil inundation) as a space-for-time substitution simulating future inundation of soils.
Carbon Management in Coastal Wetlands: Quantifying Carbon Storage and Greenhouse Gas Emissions by Tidal Wetlands to Support Development of a Greenhouse Gas Protocol and Economic Assessment
Project Lead: Alison Leschen, Waquoit Bay Reserve Manager
Collaborative Lead: Tonna-Marie Rogers, Waquoit Bay Coastal Training Program Coordinator
PIs: Jianwu Tang, MBL Ecosystems Center, Kevin Kroeger, USGS-Woods Hole Science Center, Neil K. Ganju, USGS-Woods Hole Science Center, Serena Moseman-Valtierra, University of RI, Omar Abdul-Aziz, Florida International Univ., Stephen Emmett-Mattox, Restore America’s Estuaries, Igino Emmer, Silvestrum, Stephen Crooks, Consultant to RAE, Pat Megonigal, Smithsonian ERC, Thomas Walker, Manomet CCS, Chris Weidman, Waquoit Bay Reserve Research Coordinator,
Funding: NERRS Science Collaborative
Increasing atmospheric concentrations of three major greenhouse gases (GHG) are the main drivers of climate change. Efforts to ameliorate rising levels of GHG include the protection and restoration of ecosystems that constitute major carbon (C) sinks and minor sources of CH4 and N2O emissions. Tidal marshes are prime candidates for such efforts as their sediments display high C sequestration. Loss of wetlands through human impacts such as land conversion, sediment supply disruption, nutrient loading, and with sea level rise, reduces future sequestration capacity and places at risk stores of C that built up over past centuries. Improved management of coastal C and nitrogen (N), based upon sound science, is a critical first step towards mitigation of climate change and management of coastal ecosystems. Management must address N loading that has the dual impact of 1) contributing to climate change through production of N2O, and 2) reducing production of root and soil matter by plants which can decrease the C sequestration capacity and resilience of marshes to sea level rise. Recognition of the importance of coastal marine systems in terms of C storage has led to national and international efforts to place monetary value on preserving or restoring the “blue carbon” in those systems, analogous to the value placed on forests. The barrier to incorporation of tidal wetlands into C markets is the absence of agreed upon GHG offset protocols that set guidelines for monitoring and verification requirements for wetlands projects, and a lack of data and knowledge regarding C and GHG fluxes in wetlands to support model development.
The project goals are to provide scientific information that can inform both C and N management as well as wetlands protection and restoration strategies for supporting development of policy frameworks and market-based mechanisms to reduce GHG.