Defense Coastal/Estuarine Research Program 2 (DCERP2)

Transcription

1 Defense Coastal/Estuarine Research Program 2 (DCERP2) ANNUAL REPORT III (FOR THE PERIOD 2015) September 2016 Prepared for: Strategic Environmental Research and Development Program (SERDP) Prepared by: RTI International * 3040 Cornwallis Road P.O. Box Research Triangle Park, NC

2 Defense Coastal/Estuarine Research Program (DCERP2) Annual Report Views, opinions, and/or findings contained in the report are those of the authors and should not be construed as an official U.S. Department of Defense position or decision unless so designated by other official documentation. Funding for this research was provided by the Strategic Environmental Research and Developmental Program Defense Coastal/Estuarine Research Program Project RC DCERP2 Annual Report III ii September 2016

3 DCERP2 Annual Report III Abstract The potential impacts of climate change on military training landscapes and associated infrastructure are a growing challenge to our nation s military readiness. U.S. Department of Defense (DoD) installations in estuarine/coastal areas are at particular risk from climate change associated with extreme weather (i.e., severe droughts, heavy rainfall events, and warming temperatures) and rising sea level compounded by storm surge. In addition, DoD installations will be challenged with managing the trade-offs between sustaining military training, ecosystem health, carbon storage, and other ecosystem services to achieve installation management goals under future climate conditions. To balance military training and testing needs and sustainable natural resources management, installation managers need easy-to-use decision-support tools, models, and other products to assist them with making often complex, ecosystem-based management decisions. The Defense Coastal Estuarine Research Program 2 (DCERP2) Team conducts integrated research and monitoring to understand how climate change and local installation and regional activities affect critical ecosystem processes at the primary study site, Marine Corps Base Camp Lejeune (MCBCL), and at secondary installation study sites at Fort Bragg and Marine Corps Air Station (MCAS) Cherry Point (both in North Carolina) and at Eglin Air Force Base (in Florida). DCERP2 seeks to understand the ecosystem processes associated with the carbon cycle, nutrient utilization, and sediment transport within the context of climate change impacts. Scientific understanding of ecological processes and the models, tools, and other products being developed at MCBCL are transferrable to other DoD installations in similar ecological settings. DCERP2 is also providing its scientific findings through peer-reviewed publications and presentations to DoD installation managers, regional stakeholders, and the general public. DCERP1 was conducted from July 2006 through January 2013 and focused on understanding coastal and estuarine ecosystem composition, structure, and function within the context of a military training environment. DCERP2 is being conducted from February 2013 through November The following outcomes, findings, and accomplishments not only represent progress made in 2015, but also represent cumulative progress made since DCERP s inception in During 2015, monitoring and research efforts continued to focus on the major objective of defining an estuarine/coastal carbon budget. In 2015, the following three research projects were initiated: the development of climate histories and future climate projections for eastern North Carolina that were needed by many of the DCERP2 ecosystem models, the development of a morphology model to predict the future sustainability of Onslow Beach, and quantification of the carbon exchanges in marshes to define boundary conditions of the carbon budget. The Interactive Mapping Application (imap) was further refined based on input from the MCBCL staff to enhance the transferability of DCERP data and products for management decisions. By the end of 2016, the team will finish the final year of field sampling activities and focus efforts on synthesizing and integrating findings, finalizing model development, and using these models to forecast impacts of various management practices and climate change. DCERP2 Annual Report III A-1 September 2016

4 Defense Coastal/Estuarine Research Program (DCERP2) Abstract Major Highlights and Accomplishments from DCERP in 2015 Key outcomes with implications for management: The Estuarine Simulation Model (ESM) results for MCAS Cherry Point revealed the potential impacts of increased water temperatures on the number of days with hypoxic conditions (low dissolved oxygen concentrations) in the Neuse River Estuary. Far greater reductions in nutrient loads will be needed to counter the effects of higher temperatures, and the ESM showed that the upper estuary responded strongly to watershed load reductions whereas the lower estuary primarily responded to reductions in nutrient loads from the Pamlico Sound. The management implication is that to reduce hypoxic conditions, which can result in fish kills, decreases in nutrient inputs to improve water quality must be from both the watershed and the Pamlico Sound. Loadings from the Pamlico Sound are conveyed into the estuary by tidal action and may be a more difficult source of nutrient input to control. Fertilization of marsh plots at MCBCL increased stem growth and sediment accretion in Spartinadominated marshes, but not in Juncus-dominated marshes. This finding suggests that fertilization can be an adaptive management tool for marsh restoration efforts to enhance surface elevation only for Spartina marshes. Key scientific findings: The preliminary New River Estuary (NRE) carbon budget challenges the conventional view that all estuaries are large, persistent atmospheric carbon dioxide (CO2) sources. Instead, the NRE yields only a small net release of atmospheric CO2 and efficiently buries particulate carbon delivered from the surrounding watersheds in sediments. However, our data also suggest that the NRE may be prone to large episodic CO2 releases driven by major storms, particularly hurricanes and nor easters. In eastern North Carolina, field measurements collected in tidal creeks with wide, bay-like mouths were found to have only half the suspended sediment concentration (SSC) compared to narrow, winding tidal creeks. This correlation of SSC to creek structure is useful because it allows scientists to predict SSC from aerial imagery of creeks instead of having to collect water samples. This finding will help increase the accuracy of broad-scale, high-resolution marsh modeling efforts to forecast marsh growth and response to sea level rise throughout the Southeastern United States. The prevailing theory for coastal barrier evolution is that overwash and deposition of a washover fan result from a single storm event, and the dune line recovers rapidly (typically within one year). However, between 2012 and 2015, we documented 81 separate overwash events at one location on Onslow Beach. The initial washover fan was associated with a storm, but the data showed that more sand was transported across the island by overwash after the initial storm. This finding alters the current understanding of barrier overwash processes and will improve predictions of shoreline position, dune elevation, and resistance to flooding. DCERP programmatic accomplishments: Several data gaps were identified in our understanding of the NRE carbon budget, specifically in processes related to boundary conditions such as the air water, air marsh, and marsh water interfaces. Additional research and monitoring efforts are underway to fill these data gaps and further constrain uncertainty in the estuarine/coastal carbon budget. imap was integrated into the DCERP Data and Information Management System (DIMS), which enables users to explore all archived monitoring and research data, as well as model outputs. This integration allows managers to use various data sets to inform their ecosystem-based management decisions. Seven peer-reviewed journal articles were published, and 34 presentations were given at various scientific meetings by DCERP researchers. These efforts exemplify the importance of the methods and scientific discoveries resulting from DCERP in advancing the understanding of coastal ecosystems. DCERP2 Annual Report III A-2 September 2016

5 DCERP2 Annual Report III SERDP Project Number: RC-2245 Chapter 1 Programmatic Overview Principal Investigator: Dr. Patricia Cunningham, RTI International patc@rti.org September 2016

6 Defense Coastal/Estuarine Research Program (DCERP2) Chapter 1 Acronyms and Abbreviations AE CB CC CDOM CH4 CO2 CW DCERP DCERP1 DCERP2 DIMS DoD EC imap MARDIS MCBCL MEM NRE PI RC RCC SAB SDSS SERDP T TAC TSP Aquatic/Estuarine (Module) Coastal Barrier (Module) Climate Change (Module) chromophoric dissolved organic matter methane carbon dioxide Coastal Wetlands (Module) Defense Coastal/Estuarine Research Program first cycle of DCERP second cycle of DCERP Data and Information Management System U.S. Department of Defense Executive Committee Interactive Mapping Application Monitoring and Research Data and Information System Marine Corps Base Camp Lejeune Marsh Equilibrium Model New River Estuary Principal Investigator Resource Conservation and Climate Change (a SERDP program area) Regional Coordinating Committee Scientific Advisory Board Spatial Decision Support System Strategic Environmental Research and Development Program Terrestrial (Module) Technical Advisory Committee Translating Science into Practice (Module) DCERP2 Annual Report III 1-2 September 2016

7 Defense Coastal/Estuarine Research Program (DCERP2) Chapter Overview of the Program Chapter 1 Programmatic Overview Critical military training and testing on lands along the nation s coastal and estuarine shorelines are increasingly placed at risk because of development pressures in surrounding areas, impairments due to other anthropogenic disturbances, and increasing requirements for compliance with environmental regulations. To expand its commitment to improving military readiness, the Strategic Environmental Research and Development Program (SERDP) funds research and monitoring projects that support the science-based ecosystem management needed to ensure the continued sustainability of military training and testing in ecologically and economically important coastal areas. To accomplish this goal, SERDP launched the Defense Coastal/Estuarine Research Program (DCERP) at Marine Corps Base Camp Lejeune (MCBCL) in North Carolina (Figure 1-1). The first cycle of DCERP (DCERP1) was conducted from July 2006 January DCERP1 focused on understanding coastal and estuarine ecosystem composition, structure, and function within the context of a military training environment. The second cycle of DCERP (DCERP2) is being conducted from February 2013 through November DCERP2 focuses on understanding how coastal and estuarine ecosystems respond to climate change and the processes associated with the carbon cycle in these ecosystems. DCERP2 also focuses on the development of decision-support tools and models that can translate complex scientific findings to the scientific community and into information that managers can use to make decisions on U.S. Department of Defense (DoD) installations and provide guidance to other local, state, and regional stakeholders, including coastal managers and the general public. Figure 1-1. Site map of MCBCL. DCERP2 Annual Report III 1-3 September 2016

8 Defense Coastal/Estuarine Research Program (DCERP2) Chapter Program Organization RTI International is leading the DCERP2 research and monitoring effort and has assembled a diverse team of experts, henceforth referred to as the DCERP2 Team, to conduct program activities. DCERP is a collaborative effort between SERDP, the Naval Facilities Engineering and Expeditionary Warfare Center, MCBCL, and the DCERP2 Team. To facilitate a better understanding of the ecological systems, processes, and the dynamics of the MCBCL coastal region, DCERP2 was divided into the following four ecosystem modules: the Aquatic/Estuarine (AE), Coastal Wetlands (CW), Coastal Barrier (CB), and the Terrestrial (T) Modules. Two additional cross-cutting modules coordinate with the four ecosystem modules to provide integrated climate change information (Climate Change [CC] Module) and decision-support tools that inform science-based adaptive management at MCBCL and that can be easily transferred to other DoD installations (Translating Science into Practice [TSP] Module). As the DCERP Principal Investigator (PI), Dr. Patricia Cunningham of RTI manages DCERP2 with support from an Executive Committee (EC). The EC consists of three team members who provide their specific professional expertise and represent the different ecosystem modules. The EC meets regularly with the DCERP PI to discuss ongoing activities and ensure that DCERP2 is meeting the goal of providing ecosystem-based management recommendations to DoD. Two additional committees provide guidance and input to DCERP: the Technical Advisory Committee (TAC) and the Regional Coordinating Committee (RCC). The TAC is a group of discipline experts from academia, industry, government, and the military that provides scientific and technical reviews and guidance to ensure the quality and relevance of DCERP. The RCC is a group of local and regional stakeholders that serves as one of the recipients of outreach activities. During annual meetings, the DCERP2 Team provides a summary of research findings to both the TAC and RCC. In addition, DCERP2 s progress is reviewed annually by SERDP s In-Progress Review Committee, which consists of representatives from the various military service branches, the U.S. Environmental Protection Agency, and the U.S. Department of Energy. The SERDP Scientific Advisory Board (SAB), consisting of various discipline experts, also assesses progress and recommends program improvements annually throughout the implementation period Overarching Strategy DCERP2 is built on the previous 6 years of research at MCBCL (i.e., DCERP1) and the DCERP2 Team adapted the program to focus on the new priorities of climate change, carbon cycling, and translating science into practice. The program is structured to use measurements and develop conceptual and mechanistic models and tools that inform science-based adaptive management at MCBCL and that can be easily transferred to other DoD installations. The monitoring program is designed to document trends through a number of environmental, as well as ecological measurements, and to be sufficiently adaptive to capture extremes and ecosystem threshold events and to support the research program by satisfying fundamental data needs. Together, these research and monitoring activities represent an integrated continuum of ecosystem response to changing climate, with respect to carbon cycling, nutrient utilization, sediment loading, and ecosystem services and sustainability. The 13 research projects described DCERP2 Annual Report III 1-4 September 2016

9 Defense Coastal/Estuarine Research Program (DCERP2) Chapter 1 in the DCERP2 Research Plan (RTI, 2013a) and associated monitoring activities described in the DCERP2 Monitoring Plan (RTI, 2013b) are presented in Tables 1-1 and 1-2 of this chapter. Conceptual models are used to illustrate the key biological processes (e.g., primary production), chemical processes (e.g., nutrient cycling), and physical processes (e.g., hydrodynamics, sedimentation) of the ecosystem, as well as the key anthropogenic and natural stressors that alter those processes. DCERP2 s overarching conceptual model highlights the interconnections among the various ecosystems in examining the estuarine and coastal processes that are affected by climate change and that drive carbon cycling (Figure 1-2). Module Aquatic/ Estuarine Coastal Wetlands Figure 1-2. The overarching conceptual model for DCERP2. Table 1-1. Summary of DCERP2 module-specific monitoring activities Activities Physical/hydrodynamics: Temperature, light, and stream flow and discharge Chemistry: Carbon, chromophoric dissolved organic matter (CDOM), nutrients, salinity, ph, and oxygen Sedimentology: Suspended sediment concentration (New River), total suspended solids (New River Estuary [NRE]), and turbidity (NRE) Biology: Primary productivity, phytoplankton biomass and community composition, and benthic microalgal biomass Shoreline delineation: Surface elevation change, topography, morphology, and marsh edge erosion Hydrodynamics: Tide gauges (water level, temperature, and salinity) Marsh vegetation: Distribution, composition, stem height, and grazer density (snails) Sedimentology: Sedimentation rates, organic content, and particle size DCERP2 Annual Report III 1-5 September 2016

10 Defense Coastal/Estuarine Research Program (DCERP2) Chapter 1 Table 1-2. Research projects to be conducted during DCERP2 ( ) Research Project Title AE-4: Nutrient Driven Eutrophication and Carbon Flux Modulated by Climate Change in the NRE AE-5: Climate and Land Use Impacts on Exports of Carbon, Sediments, and Nutrients from Coastal Subwatersheds AE-6: Climatic Drivers Regulating Benthic Pelagic Carbon and Associated Nutrient Exchanges in the NRE CW-4: Improving Model Predictions for Marsh Response to Sea Level Rise and Implications for Natural Resource Management Senior Researchers/Duration Hans Paerl; 3/ /2017 Michael Piehler; 3/ /2017 Iris Anderson; 3/ /2017 Carolyn Currin; 3/ /2017 CW-5: Marsh Atmosphere and Marsh Creek Exchanges of Carbon Iris Anderson; 2/ /2016 CB-4: Predicting Sustainability of Coastal Military Training Environments: Developing and Evaluating a Simplified, Numerical Morphology Model CB-5: Linking Barrier Island Transgression Induced by Storms and Sea Level Rise to the Carbon Cycle T-1: Effects of Different Understory/Midstory Restoration Management Options on Terrestrial Ecosystem Plant and Arthropod Communities T-3: Forest Management, Species Habitat, and Implications for Carbon Flux and Storage T-4: Impacts of Climate Change on Management of Red-Cockaded Woodpeckers at MCBCL CC-1: Development of Uniform Historical and Projected Climate to Support Integrated Coastal Ecosystem Research TSP-1: Development of a Common Spatial Decision-Support System (SDSS) Framework TSP-2: Coupled Ecosystem Modeling of the NRE for Research, Synthesis, and Management Jesse McNinch; 5/ /2017 Antonio Rodriguez; 3/2013 3/2017 Norman Christensen; 5/2015 6/2017 Norman Christensen and Steve Mitchell; 3/2013 6/2017 Jeffrey Walters; 3/2013 6/2016 Ryan Boyles; 3/ /2017 Patrick Halpin; 3/ /2017 Mark Brush; 3/ /2017 During DCERP1, the DCERP Team developed the Data and Information Management System (DIMS). The DIMS includes a public Web site that allows general access to information about DCERP and restricted Web-based access that allow the DCERP researchers, MCBCL staff, and registered users to access DCERP data. During DCERP2, DIMS was expanded to incorporate the Spatial Decision-Support System (SDSS), which includes the Interactive Mapping Application (imap) and visualization of model and tool outputs, representing a variety of management and climate scenarios. The DIMS consists of several distinct component systems as shown in Figure 1-3. DCERP2 Annual Report III 1-6 September 2016

11 Defense Coastal/Estuarine Research Program (DCERP2) Chapter Introduction to DCERP2 Themes Figure 1-3. Components of the DCERP DIMS. The three major themes of DCERP2 (i.e., climate change, the carbon cycle, and translating science into practice) span the four ecosystem modules and 13 research projects. DoD lands in the United States and abroad include a large number of installations in coastal settings that are vulnerable to climatic drivers (e.g., rising sea level, increased temperatures, extended periods of drought or flood conditions, extreme storm events [i.e., hurricanes, cyclones, nor easters]). To better manage DoD lands and their infrastructure and natural resource assets, it is imperative that installation managers have accurate research findings to inform their management decisions and prepare for future contingencies necessitated by climate change. DCERP2 researchers are developing ecosystem process models that use future climate projections to forecast various management and climate scenarios. The carbon cycle is inextricably linked to climate change and its association with increasing concentrations of greenhouse gases (e.g., carbon dioxide [CO2], methane [CH4]) generated from the use of fossil fuels. A major focus of DCERP2 is to develop a carbon budget for the estuarine/coastal area of MCBCL and an understanding of carbon cycling and exchanges between the estuary, marshes, coastal barrier, coastal ocean, and the atmosphere. DCERP2 builds on information gained from DCERP1 regarding the importance of freshwater discharge, temperature, light availability, and salinity on both metabolic rates and carbon and nitrogencycling rates across the estuary. During DCERP2, team members will determine how episodic events affect metabolic and nutrient cycling rates with a new emphasis on carbon cycling. Team members will also improve and expand several tools and models developed during DCERP1. For example, the Marsh Equilibrium Model (MEM) has been refined to include the use of both Spartina- and Juncus-dominated marshes. The revisions also support the development of a new point-based geospatial model to predict marsh sustainability to sea level rise, as well as carbon sequestration rates, and to determine the efficacy of various adaptive management strategies for sustaining the coastal marshes. In addition, DCERP2 is developing a Forest Carbon Management Tool and a Terrestrial Carbon Accounting Tool for assessing terrestrial carbon storage capacity. The third DCERP2 theme, turning science into practice, requires communicating often complex scientific findings to the three target audiences: the scientific community, DoD managers, and DCERP2 Annual Report III 1-7 September 2016

12 Defense Coastal/Estuarine Research Program (DCERP2) Chapter 1 other stakeholders, including the general public. DCERP researchers excel at communicating their findings through peer-reviewed journal articles and presentations to academic audiences at numerous symposiums and conferences; however, it is a continuing task to make findings easy to understand and actionable for DoD managers, and even more challenging, but of major importance, to explain the science to the general public. With input from MCBCL environmental staff, the researchers are using a variety of methods to showcase the scientific findings in ways that are useful to managers in making management decisions, while promoting understanding the science behind the tools and models. Efforts will continue to bring future findings and recommendations to the three diverse target audiences. 1.3 Integration of Program Elements Integration of the components of the research and monitoring effort is a hallmark of DCERP. Integration is an ongoing process that occurs at the thematic, module, and project levels. From the beginning of the program, the key steps to ensuring integration involved the following: 1. Developing and using conceptual models for each ecosystem module and for the overall program 2. Implementing highly coordinated research and monitoring approaches, including the collection of comparable temporal and spatial information in various ecosystems simultaneously 3. Developing a single source of climate histories and futures data at appropriate temporal and spatial scales to drive ecosystem-based process models; and 4. Integrating results through the use of ecosystem-based process models. The DCERP2 Team is considering climate change as part of its research activities, whether that involves using forecast models or forecast parameters (e.g., elevated temperature and salinity conditions) in experimental studies to simulate future climate conditions. Likewise, the development of a carbon budget is an integrating element that incorporates results from the four ecosystem modules and, through the use of models, can forecast scenarios of changes in the carbon cycle under both current and future management and climate conditions. 1.4 Literature Cited RTI. 2013a. DCERP2 Research Plan. Strategic Environmental Research and Development Program (SERDP) Research Project RC RTI International, Research Triangle Park, NC. RTI. 2013b. DCERP2 Monitoring Plan. Strategic Environmental Research and Development Program (SERDP) Research Project RC RTI International, Research Triangle Park, NC. DCERP2 Annual Report III 1-8 September 2016

13 DCERP2 Annual Technical Report III SERDP Project Number: RC-2245 Chapter 2 Significant Findings and Achievements Principal Investigator: Dr. Patricia Cunningham, RTI International patc@rti.org September 2016

14 Acronyms and Abbreviations C degree Celsius CC Climate Change (Module) CO2 carbon dioxide DCERP Defense Coastal/Estuarine Research Program DCERP1 first cycle of DCERP DCERP2 second cycle of DCERP DoD U.S. Department of Defense ESM Estuarine Simulation Model g C m -2 yr -1 grams of carbon per square meter per year imap Interactive Mapping Application m meter m 2 meter squared m 3 cubic meter MARDIS Monitoring and Research Data and Information System MCBCL Marine Corps Base Camp Lejeune METDATA University of Idaho s Gridded Surface Meteorological Data MFRI mean fire return interval mg L -1 /L milligrams per liter per liter NRE New River Estuary POC particulate organic carbon RC Resource Conservation and Climate Change (a SERDP program area) RCW red-cockaded woodpecker DSS Decision-Support System SERDP Strategic Environmental Research and Development Program SSC suspended sediment concentration TSP Translating Science into Practice (Module) DCERP2 Annual Report III 2-2 September 2016

15 2.1 Introduction Chapter 2 Significant Findings and Achievements DCERP2 is contributing to the understanding of the factors that regulate the carbon cycle and the current and future responses of the carbon and nutrient cycles, in various coastal ecosystems to climate change. This knowledge has important implications for operations, military training, and ecosystem management at the U.S. Department of Defense s (DoD s) numerous installations across the southeastern region of the United States. Additionally, DCERP2 findings are important to the public and private-sector activities in communities along the southeastern coastline. The significant findings and implications of DCERP2 monitoring and research activities from January through December 2015 are presented in this chapter. The findings are presented at the thematic level (i.e., carbon, climate change, and translating science into practice [TSP]; Figure 2-1) and then at the ecosystem module level (i.e., Aquatic/Estuarine, Coastal Wetlands, Coastal Barrier, and Terrestrial modules). 2.2 Synthesis of DCERP2 Themes Climate Change Figure 2-1. DCERP2 themes. Nearly all DCERP2 research and monitoring activities, including process models, incorporate some components of climate. Our team s comprehensive assessment of the various ecosystems surrounding and including the New River Estuary (NRE) provides cutting-edge science to support decision-making related to future climate change. To exemplify the interdisciplinary nature of the climate change focus of DCERP2, we are highlighting our most recent accomplishments and discoveries related to climate change. In 2015, a critical milestone was achieved with the selection of a common historical climate data product for use across the DCERP2 Team. The Research Project CC-1 Team analyzed three historical climate data products and compared these histories with an independent set of monitoring station data collected across eastern North Carolina. The researchers compared daily temperatures, precipitation, winds, and incoming solar radiation. The analysis showed that the University of Idaho s Gridded Surface Meteorological Data (METDATA) product provides a historical climate at a spatial resolution that can be used to predict future climate conditions for both Marine Corps Base Camp Lejeune (MCBCL) and Fort Bragg (both in North Carolina). METDATA also provides all needed climate variables for DCERP2 process models. Thus, METDATA will be used as the source of historical climate data for forecasting climate futures. The four climate factors on which DCERP2 focuses are increased temperature, changes in frequency and magnitude of rainfall, increased storminess, and sea level rise. Each of these DCERP2 Annual Report III 2-3 September 2016

16 factors affects the ecosystems of MCBCL. For example, the DCERP Team documented the relationship between phytoplankton biomass (chlorophyll a) and flushing time of the estuary and used DCERP1 and DCERP2 data to display this relationship (Figure 2-2). The 2015 data fit the general pattern of low phytoplankton biomass at fast flushing times when the movement of freshwater flow into the estuary dominates and phytoplankton cannot fully use available nutrients. Biomass increases to a maximum when flushing time is approximately 10 days; above this threshold, biomass declines as flushing times increase, which subsequently causes available nutrients to be used up. Grazing and death of phytoplankton cells further reduce biomass. Because the 2015 results were observed under highly variable flow conditions, this strengthens our confidence in the relationship that we observed between flushing time and phytoplankton biomass within the estuary. The 2015 annual mean flow was only the second time during DCERP that the New River annual mean flow exceeded the long-term mean flow. Figure 2-2. Relationship between flushing time and phytoplankton biomass (as chlorophyll a) during DCERP1 and DCERP2. Flushing time is the number of days that it takes water to flow from the head of the estuary at Jacksonville to the New River Inlet. Increased temperature is another factor of future climate conditions. The DCERP2 Estuarine Simulation Model (ESM) developed for Marine Corps Air Station Cherry Point (in Havelock, NC) revealed critical impacts of increased temperatures on the occurrence of spring algal blooms and management of hypoxia (low dissolved oxygen concentrations) in the Neuse River Estuary. Using the ESM, we simulated increasingly warmer temperatures in the Neuse River Estuary in increments of +1 C from the current condition to 5 C above the current conditions. The modeled temperature scenarios resulted in predictions of earlier spring phytoplankton blooms and an increase in phytoplankton net primary productivity compared to current conditions. The frequency of simulated hypoxia in the Neuse River Estuary also responded strongly to external DCERP2 Annual Report III 2-4 September 2016

17 inputs of nutrients and organic matter from the Neuse watershed and Pamlico Sound (Figures 2-3a and b). The upper estuary responded strongly to the modeled watershed load reductions, ranging from 50% to 100% of the current loading, but was relatively unresponsive to reduction in the inputs from the Pamlico Sound (Figure 2-3a). The lower estuary responded to the modeled nutrient loading reductions from both sources, but more so to reductions in nutrients from the Pamlico Sound (Figure 2-3b). The implication of these modeled findings for installation managers at Marine Corps Air Station Cherry Point is that to eliminate hypoxia, reductions in local watershed nutrient loadings may not be enough to improve water quality in the estuary s lower reaches (Figure 2-3c), which also respond to inputs from external sources that are conveyed by tidal action into the estuary mouth and may be more difficult to control than loadings to the upper watershed. (a) (b) (c) Figure 2-3. Neuse River ESM temperature scenarios. The output of the Neuse River ESM under a series of temperature-warming scenarios relative to current conditions (CC). Figures a and b show the number of hypoxic days (days with a dissolved oxygen [DO] below 2 mg L -1 /L) in the upper and lower estuary, respectively, as a function of external loading (nutrients and total organic carbon) and temperature. Figure c shows the location of the Neuse River Estuary in relation to the New River Estuary. Lastly, the DCERP Team continues work on the system-wide impacts of the four climate factors that will result in many integrated assessments as the program enters the final synthesis phase. In 2016, the final climate futures will be available for modelers to use in developing climate change scenarios for process models (i.e., LANDIS-II, ESM, the Red-Cockaded Woodpecker [RCW] Decision-Support System [DSS], the Geospatial Marsh Model, and the Coastal Barrier Morphology Model). In addition, SERDP has provided installation-specific guidance about the sea level rise scenarios to be used by the Geospatial Marsh Model and the Coastal Barrier Morphology Model for MCBCL. DCERP2 Annual Report III 2-5 September 2016

18 2.2.2 Carbon Cycle Major focuses of DCERP2 are to develop an understanding of carbon cycling and exchanges between the estuary, marshes, coastal barrier, and the atmosphere and to explore terrestrial carbon dynamics resulting from different forest management practices. Quantifying carbon cycling in the estuarine/coastal landscape within MCBCL s boundaries hinges upon measuring intra-ecosystem carbon inventories and inter-ecosystem fluxes at the appropriate spatial and temporal scales. These results provide data for generating empirical carbon budgets and the mechanistic framework underlying the dynamic ESM and Geospatial Marsh Model used to gauge sensitivity of the carbon cycling processes to changing climate factors. The assessment of the terrestrial carbon budget focuses on modeling the effects of how different forestry management practices and climate change affect carbon storage in the managed forest lands of MCBCL so that in the future, Base managers can potentially offset anthropogenic carbon emissions. There is no direct linkage between the terrestrial and the estuarine/coastal carbon budgets; however, terrestrial lands are a source of carbon, nutrients, and sediment delivered from the watershed into tributary creeks and eventually the estuary. New River Estuary Carbon is delivered into the NRE through a combination of stormflow (soil-derived organic carbon) from the New River watershed and base flow from terrestrial (organic carbon) and freshwater (inorganic carbon) inputs. Estuarine-wide mapping of air water carbon dioxide (CO2) exchange shows that the NRE is a source of CO2 into the atmosphere, but at a baseline rate 10 times lower than previous estimates reported for similar estuaries. Overall there is a net release of CO2, since on average respiration is slightly higher than photosynthesis; however, large storm events can increase this release by an order of magnitude. Supplemental projects funded in 2015 will augment temporal and spatial resolution of our measurements. Calibrations among metabolism, water mass age, and CO2 fluxes and the determination of biological versus physical contributions to CO2 fluxes conducted in 2015 tighten the connection between field measurements and the model carbon budget produced by the ESM. Since 1900, carbon burial rates in the upper NRE have been highly variable, ranging over a factor of four and reflecting trends in sediment deposition and pulsed storm delivery. High rates of organic carbon burial associated with hurricanes resulted in peak carbon burial, showing that episodic events such as storms may be a major controlling factor for carbon sequestration in the estuary. Supplemental coring conducted in 2015 was essential for constraining the spatial extent of carbon burial, which was found to be highest in the middle estuary. This finding was used to revise the empirical carbon budget for the NRE. Biomarkers indicated that most of the carbon sequestered is from terrestrial sources, with only intermittent periods where internal carbon was sequestered. Tributary creeks are active conduits for carbon transport between watersheds and the estuary. Creeks draining all but the most developed watersheds (with the highest nutrients) removed carbon via net respiration. Carbon fluxes from the tributaries draining the MCBCL were land-use dependent, indicating that more land development results in less dissolved organic carbon (DOC) loading, but more particulate organic carbon (POC) loading. Because loads of DOC are much larger than POC, the net effect of watershed development is a reduction in carbon load into the DCERP2 Annual Report III 2-6 September 2016

19 estuary. Areas where tributaries discharged into the estuary were hot spots for CO2 release from the estuary into the air. Coastal Marshes Determining the sediment history of MCBCL salt marshes is currently being conducted and will yield long-term marsh carbon burial rates for comparison to short-term rates. This information will be used to estimate the marsh carbon budget. In addition to understanding the carbon burial rates in marsh sediment, we need to understand the air marsh CO2 exchanges and lateral exchanges of dissolved carbon from the marsh into adjacent waters. Seasonal air marsh CO2 and methane fluxes being measured in chambers installed in the marshes are beginning to yield a picture of carbon exchange with the atmosphere. However, these chamber studies are only conducted during a few days each season. To improve our understanding of both daily and seasonal fluctuations in CO2 exchanges, CO2 monitoring equipment was installed on the marsh (Figure 2-4). When the marsh chamber studies are coupled with this continuous monitoring of CO2 exchanges in the marsh, we will be able to provide high-resolution temporal (daily 24- hour) coverage of the air marsh CO2 exchanges and responses to light, temperature, and tidal inundation. Quantification of the carbon exchanges between MCBCL marshes and adjacent surface waters is also ongoing. We have yet to determine how much of the lateral exchange of carbon constitutes new DOC or dissolved inorganic carbon (DIC) added by the marsh versus DOC + DIC contained in Figure 2-4. The monitoring water that has infiltrated the subsurface of the marsh, and equipment tower was deployed then is discharged laterally, thereby representing no new net in the Spartina marsh to capture additions of marsh carbon to adjacent waters via this air marsh CO2 exchanges. pathway. In addition, photo-oxidation and temperaturecontrolled experiments on marsh sediment decomposition revealed a robust and predictable temperature response that was further influenced by exposure of sediments to sunlight. Collectively, all of these findings help to understand carbon decomposition in a way that is suitable for making projections about the fate of marsh carbon that is released from the eroded edges of marshes that are keeping pace with sea level rise, as well as from those marshes that have drowned. Onslow Beach Backbarrier island salt marshes provide important ecosystem functions, which include the sequestration of atmospheric CO2 and below-ground carbon storage in the form of peat and organic-rich sediment. As the coastal barrier island moves landward and overwashes the backbarrier marshes in the southwestern portion of the island, this carbon is buried beneath the island for an unknown period of time before it becomes exposed by the ocean s hydrodynamic processes and is eroded and released on the beach front. DCERP2 Annual Report III 2-7 September 2016

20 Data collected in 2014 led to the creation of a carbon budget that balances the erosion of carbon at the shoreface and backbarrier marsh edge with the storage of carbon in the backbarrier marsh through vertical accretion. Unique mass balances were created for several cross-island transects. Revisiting those budgets after the passage of Hurricane Joaquin in 2015 revealed that geomorphic change is an important factor in coastal carbon budgets. In areas of high storminduced shoreface erosion and washover into the backbarrier marsh, the barrier island switched from being a net carbon sink to a net carbon source because of increased shoreface erosion of older peat and the complete loss of carbon burial capacity in the backbarrier marsh since it was overrun and covered by the washover fan. This switch was effectively instantaneous. The timescale over which the carbon budget will readjust as the marsh recolonizes and the rates of peat erosion remain at their new levels or revert to some other state as sea level rises remain unknown. Data from additional marsh sediment cores collected in 2016 should provide insights about this time scale. Terrestrial Carbon Results from terrestrial carbon modeling of forest management scenarios (using LANDIS-II) suggest that above-ground live carbon storage is highest in longleaf pine (Pinus palustris) forests compared to loblolly pine (Pinus taeda) forests and is lowest in pond pine (Pinus serotina) forests. The amount of above-ground live carbon stores depends on site conditions, stand development age, and variations and frequency of management practices (e.g., cutting interval and prescribed fire rotations). Model simulations of different forest management practices across MCBCL s landscape reinforced the findings that carbon storage was highest with management designed to promote the restoration of longleaf pine. This was true for a variety of prescribed fire regimes. Carbon storage at MCBCL and through much of the Southeastern United States therefore can be increased through active management strategies for longleaf pine stands. Upcoming measurements of soil carbon storage, combined with measurements of below-ground carbon storage in pine root systems from other researchers, will help determine whether longleaf or loblolly pine forests store more below-ground carbon. The effects of possible alternative climate scenarios on carbon stored in MCBCL forests will also be determined in the context of different forest management and prescribed burning practices. These carbon storage values can be compared with the carbon storage capacity developed as part of the estuarine/coastal carbon budget Translating Science into Practice The goal of the translating science into practice theme is to ensure that the scientific knowledge generated by the DCERP2 Team is translated into practical tools and outcomes for DoD installation managers and other coastal managers. Efforts to also bring findings and information to the broader regional audience and to the scientific community are reflected in the number of presentations, publications, and engagements with stakeholders at the national, state, and local levels that are enumerated in the monitoring and research sections of this report. The TSP Module Team focused on enhancing the Interactive Mapping Application (imap) within the Data and Information Management System (DIMS) to create the most effective ways to visualize the data results and model outputs so they are useful to managers in making informed ecosystem-based management decisions. Early in 2015, imap was released to DCERP2 Annual Report III 2-8 September 2016

21 MCBCL users to review and evaluate those enhancements to further the utility of imap to end users. imap is now linked to research and monitoring data in the Monitoring and Research Data and Information System (MARDIS), which allows imap to pull in results data from MARDIS for analysis in imap rather than just showing the data spatially. imap also enables managers to consider the tradeoffs among different management decisions. 2.3 Ecosystem Module Level Findings The ecosystem-level findings are representative of the advancements made by each of the four DCERP2 ecosystem modules during 2015 and are focused on ecosystem structure, function, and response to stressors, such as various management decisions and/or climate change drivers. These findings help support our understanding of current conditions within and across the four MCBCL coastal ecosystems and our understanding of plausible conditions that may influence these ecosystems in the future Aquatic/Estuarine Ecosystem Estuaries are an important area along the land estuary ocean continuum where organic carbon and nutrients are processed and recycled within the food chain, resulting in high air seawater CO2 exchanges. Research and monitoring activities of the Aquatic/Estuarine Module examine the tidal reach of the NRE from the freshwater head of the estuary near Jacksonville, NC to the tidal inlet at Onslow Bay; and several tributary creek that discharge into the estuary. The NRE is a relatively small, shallow (2-m mean depth), Coastal Plain estuary, the majority of which is contained within MCBCL s boundaries. The NRE consists of a series of shallow lagoons and is confined by coastal barrier islands that restrict water exchange at the inlet with the Atlantic Ocean. The semi-lagoonal nature of the NRE plays a significant role in its sensitivity to nutrient inputs because long flushing times for water in the estuary allow more time for algae to take up nutrients, grow and reproduce, and allow more internal carbon and nutrient recycling to occur than in systems with rapid flushing times. The U.S. Geological Survey s gauging station data ( ) were used to conduct a statistical trend analysis, which did not reveal a long-term trend in the mean, median, or maximum daily freshwater flow at the Gum Branch station; however, there was an increasing trend in the 7-day minimum flow in the New River discharge. This result provides additional support for our earlier finding that revealed semi-diurnal tidal flow (first evident during low flow periods) has increased in magnitude at Gum Branch since the late 1980s. This finding is significant because changes in sea level affect exchanges of material to and from the estuary at both the upstream and downstream endpoints, including estuarine hydrodynamics, salinity, and physiology and distribution of important estuarine plant and animal species. Stream loadings of several types of carbon (DIC, DOC, and POC) were measured in five tributary streams at MCBCL from 2013 through The measured annual load of DIC in several streams was much higher than either DOC or POC, and there was a general pattern of increased DIC loading with increased land development. The ratio of DOC:DIC (Figure 2-5) was found to decrease as percent imperviousness increased with greater land development. The shift in the type of carbon (organic to inorganic carbon) as increasing land development occurs in coastal watersheds has implications for the DCERP2 Annual Report III 2-9 September 2016

22 estuarine carbon budget and could create conditions in the estuary that are more favorable to algal blooms. The range of CO2 releases and uptakes (water atmosphere net CO2 flux) was highest in the upper estuary and became increasingly smaller with distance down-estuary. In the lower estuary, the CO2 flux was near zero. CO2 fluxes measured every two months in both the channel and shoal (July 2013 July 2015) were very similar throughout the estuary; however, measurements made in different areas of the estuary (i.e., Figure 2-5. The relationship between the ratio of DOC to DIC loading and watershed imperviousness (an indicator of land development). upper, middle, and lower) were very different. The large CO2 releases in the upper estuary suggest that high concentrations of DIC/CO2 may have been transported from the New River at the head of the estuary. The largest CO2 releases occurred after rain events or at high temperatures, whereas uptakes of CO2 were highest during phytoplankton blooms. The significance of this finding is that air-water exchanges of CO2 in the New River estuary are regulated primarily by temperature, fresh water discharge, and phytoplankton bloom events. The annual fluxes of CO2 from the NRE are lower than from many temperate European estuaries, which are larger, deeper, and more eutrophic than the NRE (Chen et al., 2013; Frankignoulle et al., 1998). NRE CO2 fluxes are more similar in magnitude to other estuaries of similar size and characteristics in Australia, West Africa, and the Southeast and Gulf Coast regions of the United States (Koné et al., 2009; Maher and Eyre, 2012). Carbon burial in the NRE sediments is relatively high in the upper and middle estuary in part because these areas are more protected from direct wave and tidal energy than the lower estuary. Mean carbon burial rates appeared to be spatially uniform in the upper estuary sediments (119 g C m -2 yr -1 ); spatially variable in the middle estuary, but nearly three times higher overall than the upper estuary sediments (375 g C m -2 yr -1 ); and were negligible in the lower estuary s predominantly sandy sediments (Figure 2-6). Station NRE4 (middle estuary) is apparently the hotspot for sediment deposition in the NRE, trapping carbon inputs from terrestrial runoff of sediments and being protected from disturbances from waves and tides. DCERP2 Annual Report III 2-10 September 2016

23 Estuary Region Stations Carbon Burial Rates NRE1 150 Upper NRE2 100 NRE3 125 NRE4 550 Middle NRE5 10 NRE6 200 Lower NRE7 0 Figure 2-6. Sediment coring stations in the NRE and associated mean carbon burial rates (C m -2 yr -1 ) Coastal Wetlands Ecosystem Coastal marshes are a vital component of the estuarine landscape and link terrestrial and freshwater habitats with the ocean. In the intertidal zone, marshes help to stabilize sediments and minimize erosion. Wetlands also improve water quality by acting as nutrient transformers and nutrient sinks and by trapping sediment. Salt marshes are known to play an important role in the global carbon cycle. Even though marshes account for only a small percentage of the total land area, they sequester large amounts of CO2 from the atmosphere and provide carbon storage by acting as a carbon sink, equivalent to other major terrestrial habitats, including temperate, tropical, and boreal forests. The coastal wetlands of MCBCL are defined as the vegetated intertidal habitat in salt and brackish waters and encompass the salt marshes along the lower estuarine shoreline and Intracoastal Waterway (ICW), as well as the brackish marshes along the middle estuarine shoreline and tributaries of the NRE. The salt marshes in the lower NRE and ICW are typically dominated by smooth cordgrass (Spartina alterniflora), and the brackish marshes in the middle NRE are dominated by black needle rush (Juncus roemerianus). Coastal salt marshes must increase in elevation at a rate equal to or greater than the rate of sea level rise in order to maintain their intertidal position. Studies were conducted to determine whether fertilization of marshes was a viable management strategy since surface elevation increase is positively correlated with total standing biomass (aboveground stem growth plus below-ground root growth). After 1 year of fertilization, stem DCERP2 Annual Report III 2-11 September 2016

24 growth in marshes dominated by Spartina increased by a factor of 2 to 4, but stem growth in marshes dominated by Juncus did not increase. This finding has important implications for the potential use of fertilization as an adaptive management tool to enhance surface elevation increases for Spartina marshes, but may not be useful at Juncus-dominated sites. To develop models of marsh response to sea level rise, we need to understand the spatial patterns of sediment transport in water moving from the tidal creek across the marsh where sediment deposition occurs on a daily tidal cycle. A decrease in suspended sediment concentrations (SSC) was expected as creek water moved across the marsh; however, the SSC remained fairly constant even 160 feet (50 m) from the creek. In the field, a large amount of fine sediment was observed floating on the water s surface, and this sediment was not captured in standard SSC sampling. Therefore, a new sampling method was designed, and the results found that fine sediment trapped in this surface microlayer was concentrated enough to slowly sink, thereby concealing the decrease in SSC as creek flood water moved across the marsh. The substantial amount of fine sediment contained in the surface microlayer decreased over time through settling out over the marsh surface, thus supporting the expected results and revealing an important sediment transport pathway. This surface microlayer transport pathway was estimated to redistribute more sediment in the marsh over every tidal cycle than entered the creek from the watershed during one of the largest flood events. In 2014, a correlation between SSC and tidal creek structure was discovered. In 2015, SSC in tidal creeks of varying structures on MCBCL were compared to other North Carolina tidal creeks. Tidal creeks with wide, bay-like mouths have only half the SSC of narrow, winding tidal creeks. This correlation is useful because it allows us to make general predictions of median SSC in tidal creeks from aerial imagery alone instead of having to collect marsh water samples, and this will help increase the accuracy of broadscale, high-resolution marsh modeling efforts. Marshes in the lower estuary appear to be transitioning from Juncus-dominated to Spartina-dominated. When J. roemerianus declined in 2012, S. alterniflora biomass began a 4-year increase. This trend is consistent with other monitoring parameters, including the percentage of plots containing each species, species percent cover, and stem density. Increases in salinity and/or more frequent inundation under sea level rise conditions would be expected to favor Spartina over Juncus, and the data suggest that changes in response to these climate-related factors may already be underway Coastal Barrier Ecosystem The coastal barrier ecosystem at MCBCL encompasses the shoreface, tidal inlet, backshore beach, dune, shrub zone, maritime forest, and washover fan sand habitats. Onslow Beach is a southwest to northeast-oriented coastal barrier island whose southwest end is vulnerable to overwash by rising sea level, and this portion of the island is moving toward the mainland. Washover fans in the central and southwestern portions of Onslow Beach indicate that storms are an important driver shaping changes in the physical landscape of the island over time. Frequent overwash during storms forms new washover fans in the southwestern portion of the island, and sediment transport across the island via wind-driven processes is more efficient because of the DCERP2 Annual Report III 2-12 September 2016

25 reduction in vegetation density. In contrast, the continuous high-elevation dune ridge in the northeastern portion of the island backed by the well-developed maritime forest protects the backbarrier area from beach overwash processes, even during severe storms. Onslow Beach is also prime habitat for loggerhead sea turtles, which are a federally protected species. MCBCL must monitor and manage this barrier island to ensure sustainability of their nesting habitat. Therefore, Base managers must understand how future processes of sea level rise, shoreline erosion, and overwash may reduce prime nesting areas. Overwash occurs when storm-driven waves exceed the height of a dune and sand-laden water is transported over the top of the dune and is deposited inland. This current model of overwash assumes that sand deposition is associated with a single event, such as a hurricane, and subsequent recovery of the dune line occurs rapidly (within 1 year) as vegetation recolonizes the overwashed area, trapping wind-blown sand. Research results show that this conceptual model is not applicable to narrow portions of a barrier island where backbarrier elevation is low. Eighty-one separate overwash events were documented between August 2012 and August 2015 at one site where a washover fan continued to increase in area and volume (Figure 2-7). These results highlight that overwash during fair-weather conditions is an important process for transporting sand across a barrier island. Results indicate that more sand was transported across the island by overwash after storms than during storm events. Area = 3,300 m 2 Area = 29,000 m 2 Area = 37,300 m 2 Volume = 2,200 m 3 Volume =16,700 m 3 Volume = 24,100 m 3 Figure Volume and area changes in the washover fan at Site 2 over time. In 2015, an average of 60% of the loggerhead sea turtle (Caretta caretta) eggs laid in the nests across Onslow Beach produced hatchlings that emerged onto the beach. This rate of hatching success at Onslow Beach is typical, which can range from 40 80%. It is clear that the MCBCL s practice of digging up nests shortly after the first emergence of the hatched turtles is detected and releasing live, hatchlings that did not emerge from the nest increases the mean emergence success rate (ESR) by more than 10% every year. Given the relatively high proportion of sea turtle nests that are relocated at MCBCL each year (between 20 45%), the data were assessed to determine whether moving nests negatively impacted nest success. Comparing annual means from 2007 through 2014, there were no significant differences for either nest incubation interval or mean ESR between undisturbed and relocated nests. The annual mean ESR for relocated nests DCERP2 Annual Report III 2-13 September 2016