Climate change/Sea level rise

Climate change/Sea level rise2019-09-16T12:35:30-04:00

Thin-layer sediment placement: evaluating an adaptation strategy to enhance coastal marsh resilience across the NERRS

Boardwalk_Research Staff 2018
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.

Quantifying the Impact of Low Oxygen Conditions on Sediment Methane Fluxes in Waquoit Bay

Lead Investigator: Wally Fulweiler, Boston University Marine Program
Funding Source: MIT-Seagrant

WallyThe negative consequences of excess nutrient loading alter estuarine sediment nutrient cycling in general and the production of methane in particular.  On a per molecule basis, the impact of methane on climate is over 20 times greater than carbon dioxide (over a 100 year period).  And even though estuaries make up a small portion of the total global ocean area they contribute about 10% of the total ocean methane emissions. Thus, quantifying how the production of methane in estuaries changes seasonally and spatially is an important step in our understanding of coastal systems and future climate. The purpose of this ongoing research is to quantify sediment methane production in Waquoit Bay, MA and to determine how low oxygen conditions alter these rates.  To do this we collect sediment cores at four sites exposed to varying oxygen conditions in the Waquoit Bay system and measure methane fluxes across the sediment-water interface. Additionally, we will conduct experimental manipulations where we alter the oxygen conditions in the overlying water to see how this impacts methane fluxes. For more information please go to: www.fulweilerlab.com and follow us @Fulweilerlab.

Comparing Methods and the Stability of Deep-Driven Rod Elevation Benchmarks and SETs in a Salt Marsh Environment

IMG_2761PIs: 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.

 

The Impact of Nitrogen-loading on Salt Marsh Greenhouse Gas Fluxes

DSC_0125PIs:  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

wetlandsProject 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.

Project website: http://waquoitbayreserve.org/research-monitoring/salt-marsh-carbon-project/

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