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Reconciling Models And Measurements Of Marsh Vulnerability To Sealevel Rise, Daniel J. Coleman, Mark Schuerch, (...), Matthew L. Kirwan
Reconciling Models And Measurements Of Marsh Vulnerability To Sealevel Rise, Daniel J. Coleman, Mark Schuerch, (...), Matthew L. Kirwan
VIMS Articles
Tidal marsh survival in the face of sea level rise (SLR) anddeclining sediment supply often depends on the ability ofmarshes to build soil vertically. However, numerical models typically predict survival under rates of SLR that farexceedfield-based measurements of vertical accretion. Here, we combine novel measurements from sevenU.S. Atlantic Coast marshes and data from 70 additional marshes from around the world to illustrate that—over con-tinental scales—70% of variability in marsh accretion rates can be explained by suspended sediment concentratin(SSC) and spring tidal range (TR). Apparent discrepancies between models and measurements can be explained bydiffering responses in high marshes and low marshes,the …
Sediment And Terrestrial Organic Carbon Budgets For The Offshore Ayeyarwady Delta, Myanmar: Establishing A Baseline For Future Change, Evan R. Flynn, S. Kuehl, Courtney K. Harris, Matthew J. Fair
Sediment And Terrestrial Organic Carbon Budgets For The Offshore Ayeyarwady Delta, Myanmar: Establishing A Baseline For Future Change, Evan R. Flynn, S. Kuehl, Courtney K. Harris, Matthew J. Fair
VIMS Articles
Large river deltas serve as globally important archives of terrestrial and shallow marine biogeochemical signatures and because of rapid sedimentation have the potential to impact global biogeochemical cycling. The Ayeyarwady Delta in Myanmar ranks as the world's third largest river delta in terms of sediment supply; however, modern increases in regional anthropogenic impacts risk severe alteration to sediment and TerrOC loads within this major system. By investigating modern sediment and terrestrial organic carbon (TerrOC) accumulation within the offshore Ayeyarwady Delta this study estimates baseline sediment and TerrOC budgets for this understudied mega-delta. Using 210Pb geochronology of 27 sediment cores collected …
Drivers And Seasonal Variability Of Redox-Sensitive Metal Chemistry In A Shallow Subterranean Estuary, Alison E. O'Connor, Elizabeth A. Canuel, Aaron J. Beck
Drivers And Seasonal Variability Of Redox-Sensitive Metal Chemistry In A Shallow Subterranean Estuary, Alison E. O'Connor, Elizabeth A. Canuel, Aaron J. Beck
VIMS Articles
The subterranean estuary (STE) has been historically defined in terms of the mixing of saline and fresh water, in an analogy to surface estuaries. However, redox gradients are also a defining characteristic of the STE and influence its role as a source or sink for metals in the environment. Approaching the STE from a redox-focused biogeochemical perspective (e.g., considering the role of microbial respiration and availability of organic matter) provides the ability to quantify drivers of metal transport across spatial and temporal scales. This study measured the groundwater composition of a shallow STE over 2 years and used multiple linear …
Benthic Biofilm Potential For Organic Carbon Accumulation In Salt Marsh Sediments, Kendall Valentine, Abbey Hotard, Tracy Elsey-Quirk, Giulio Mariotti
Benthic Biofilm Potential For Organic Carbon Accumulation In Salt Marsh Sediments, Kendall Valentine, Abbey Hotard, Tracy Elsey-Quirk, Giulio Mariotti
VIMS Articles
Coastal salt marshes are productive environments with high potential for carbon accumulation and storage. Even though organic carbon in salt marsh sediment is typically attributed to plant biomass, it can also be produced by benthic photosynthetic biofilms. These biofilms, generally composed of diatoms and their secretions, are known for their high primary productivity and contribution to the basal food web. The growth of biofilms and the preservation of carbon produced by biofilms depends on the amount of sedimentation; low sedimentation rates will favor decomposition, while high sedimentation rates could decrease biofilm productivity. In this study, we conducted laboratory experiments to …
Measuring Organization Of Large Surficial Clasts In Heterogeneous Gravel Beach Sediments, Dennis C. Lees, Christopher J. Hein, Duncan M. Fitzgerald
Measuring Organization Of Large Surficial Clasts In Heterogeneous Gravel Beach Sediments, Dennis C. Lees, Christopher J. Hein, Duncan M. Fitzgerald
VIMS Articles
The natural stratification and interlocking “organization” of armored sediments in heterogeneous, coarse-grained, beaches provides protection and enhances habitat for borrowing sedentary megafauna and macrofauna such as hard-shelled clams. Here, we develop a novel metric for quantifying sediment organization of large surficial beach clasts through sedimentologic and photogrammetric analyses of 37 lower intertidal heterogeneous gravel beaches in western Prince William Sound, Alaska (USA). Grain size, photogrammetric, and Wolman Pebble Count clast-size data from 64, ~1-m2 study plots are combined into a clast-size-independent “Organization Metric” to quantify the degree of organization in the meshed arrangement of larger surficial sediments. This metric …
Variability In Marsh Migration Potential Determined By Topographicrather Than Anthropogenic Constraints In The Chesapeake Bay Region, Grace D. Molino, Joel A. Carr, Neil K. Ganju, Matthew L. Kirwan
Variability In Marsh Migration Potential Determined By Topographicrather Than Anthropogenic Constraints In The Chesapeake Bay Region, Grace D. Molino, Joel A. Carr, Neil K. Ganju, Matthew L. Kirwan
VIMS Articles
Sea level rise (SLR) and saltwater intrusion are driving inland shifts in coastal ecosystems. Here, we make high-resolution (1 m) predictions of land conversion under future SLR scenarios in 81 watersheds surrounding Chesapeake Bay, United States, a hotspot for accelerated SLR and saltwater intrusion. We find that 1050–3748 km2 of marsh could be created by 2100, largely at the expense of forested wetlands. Predicted marsh migration exceeds total current tidal marsh area and is about 4x greater than historical observations. Anthropogenic land use in marsh migration areas is concentrated within a few watersheds and minimally impacts calculated metrics of marsh …
Effects Of Shell Hash On Friction Angles Of Surficial Seafloor Sediments Near Oysters, Samuel T. Consolvo, Nina Stark, (...), Grace M. Massey
Effects Of Shell Hash On Friction Angles Of Surficial Seafloor Sediments Near Oysters, Samuel T. Consolvo, Nina Stark, (...), Grace M. Massey
VIMS Articles
Oysters are hypothesized to affect the shear strength of nearby surficial seafloor sediment as fragments of oyster shells (shell hash) are typically more angular relative to sand particles alone, among other differences. Resistance to shearing is well characterized by the friction angle, which is estimated in this study from vacuum triaxial laboratory and portable free-fall penetrometer field tests. Friction angles of sediment with shell hash were higher relative to those of sediment without shell hash (via hydrochloric acid treatment) on average by about 19% (36.0°–30.2°, respectively). Triaxial confining pressures ranged between 2.1 and 49.0 kPa to simulate subtidal and intertidal …
Nutrient Function Over Form: Organic And Inorganic Nitrogen Additions Have Similar Effects On Lake Phytoplankton Nutrient Limitation, Sabrina N. Volponi, Heather L. Wander, (...), Brian S. Kim, Et Al
Nutrient Function Over Form: Organic And Inorganic Nitrogen Additions Have Similar Effects On Lake Phytoplankton Nutrient Limitation, Sabrina N. Volponi, Heather L. Wander, (...), Brian S. Kim, Et Al
VIMS Articles
The concentration of dissolved organic nitrogen (DON) is increasing in many northern hemisphere lakes, yet its use by phytoplankton and fate in the environment seldom have been quantified. We conducted 1 week, insitu, microcosm incubations across 25 lakes in northeastern North America to understand how DON, dissolved norganic nitrogen (DIN), and dissolved inorganic phosphorus (P) affected phytoplankton biomass. In addition,we tested whether lakes were limited by single macronutrients (N or P) or colimited by both. Phytoplankton biomass in 80% of lakes responded similarly to DON and DIN additions. Of the lakes where N form produced differential responses, the majority of …
Leveraging The Interdependencies Between Barrier Islands And Backbarrier Saltmarshes To Enhance Resilience To Sea-Level Rise, Christopher J. Hein, Michael S. Fenster, Keryn B. Gedan, Jeff R. Tabar, Emily A. Hein, Todd Demunda
Leveraging The Interdependencies Between Barrier Islands And Backbarrier Saltmarshes To Enhance Resilience To Sea-Level Rise, Christopher J. Hein, Michael S. Fenster, Keryn B. Gedan, Jeff R. Tabar, Emily A. Hein, Todd Demunda
VIMS Articles
Barrier islands and their backbarrier saltmarshes have a reciprocal relationship: aeolian and storm processes transport sediment from the beaches and dunes to create and build marshes along the landward fringe of the island. In turn, these marshes exert a stabilizing influence on the barrier by widening the barrier system and forming a platform onto which the island migrates, consequently slowing landward barrier migration and inhibiting storm breaching. Here, we present a novel framework for applying these natural interdependencies to managing coastal systems and enhancing barrier-island resilience. Further, we detail application of these principles through a case study of the design …
Membrane Inlet Mass Spectrometry Method (Reox/Mims) To Measure 15n-Nitrate In Isotope-Enrichment Experiments, Xianbiao Lin, Kaijun Lu, Amber K. Hardison, Et Al
Membrane Inlet Mass Spectrometry Method (Reox/Mims) To Measure 15n-Nitrate In Isotope-Enrichment Experiments, Xianbiao Lin, Kaijun Lu, Amber K. Hardison, Et Al
VIMS Articles
Using 15N stable isotope as a tracer to quantify N transformation rates in isotope-enrichment experiments improves understanding of the N cycle in various ecosystems. However, measuring 15N-nitrate (15NO3−) in small volumes of water for these experiments is a major challenge due to the inconvenience of preparing samples by traditional techniques. We developed a “REOX/MIMS” method by applying membrane inlet mass spectrometry (MIMS) to determining 15NO3− concentrations in a small volumes of water from isotope-enrichment experiments after converting the dissolved inorganic N to N2. The nitrates (NO3− …
Vegetation Type And Decomposition Priming Mediate Brackish Marsh Carbon Accumulation Under Interacting Facets Of Global Change, Anthony J. Rietl, J. Patrick Megonigal, Ellen R. Herbert, Matthew L. Kirwan
Vegetation Type And Decomposition Priming Mediate Brackish Marsh Carbon Accumulation Under Interacting Facets Of Global Change, Anthony J. Rietl, J. Patrick Megonigal, Ellen R. Herbert, Matthew L. Kirwan
VIMS Articles
Coastal wetland carbon pools are globally important, but their response to interacting facets of global change remain unclear. Numerical models neglect species-specific vegetation responses to sea level rise (SLR) and elevated CO2 (eCO2) that are observed in field experiments, while field experiments cannot address the long-term feedbacks between flooding and soil growth that models show are important. Here, we present a novel numerical model of marsh carbon accumulation parameterized with empirical observations from a long-running eCO2 experiment in an organic rich, brackish marsh. Model results indicate that eCO2 and SLR interact …
The Geomorphic Impact Of Mangrove Encroachment In An Australian Salt Marsh, Daniel J. Coleman, Kerrylee Rogers, D. Reide Corbett, Christopher J. Owers, Matthew L. Kirwan
The Geomorphic Impact Of Mangrove Encroachment In An Australian Salt Marsh, Daniel J. Coleman, Kerrylee Rogers, D. Reide Corbett, Christopher J. Owers, Matthew L. Kirwan
VIMS Articles
Mangroves are encroaching into salt marshes throughout the world as a result of environmental change. Previous studies suggest mangroves trap sediment more efficiently than adjacent salt marshes, providing mangroves greater capacity to adapt to sea level rise; this may occur by displacing salt marshes. However, sediment transport in adjacent marsh-mangrove systems and its role in mangrove encroachment upon salt marsh remain poorly understood. Here we directly test the hypothesis that mangroves reduce the ability of adjacent marsh to adjust to sea level rise by measuring sediment transport across salt marsh platforms, with and without 6 m of fringing mangroves at …
Quantifying Thresholds Of Barrier Geomorphic Change In A Cross-Shore Sediment-Partitioning Model, Daniel J. Ciarletta, Jennifer L. Miselis, Justin L. Shawler, Christopher J. Hein
Quantifying Thresholds Of Barrier Geomorphic Change In A Cross-Shore Sediment-Partitioning Model, Daniel J. Ciarletta, Jennifer L. Miselis, Justin L. Shawler, Christopher J. Hein
VIMS Articles
Barrier coasts, including barrier islands, beach-ridge plains, and associated landforms, can assume a broad spectrum of morphologies over multi-decadal scales that reflect conditions of sediment availability, accommodation, and relative sea-level rise. However, the quantitative thresholds of these controls on barrier-system behavior remain largely unexplored, even as modern sea-level rise and anthropogenic modification of sediment availability increasingly reshape the world's sandy coastlines. In this study, we conceptualize barrier coasts as sediment-partitioning frameworks, distributing sand delivered from the shoreface to the subaqueous and subaerial components of the coastal system. Using an idealized morphodynamic model, we explore thresholds of behavioral and morphologic change …
Different Coastal Marsh Sites Reflect Similar Topographic Conditions Under Which Bare Patches And Vegetation Recovery Occur, Chen Wang, Lennert Schepers, Matthew L. Kirwan, Et Al
Different Coastal Marsh Sites Reflect Similar Topographic Conditions Under Which Bare Patches And Vegetation Recovery Occur, Chen Wang, Lennert Schepers, Matthew L. Kirwan, Et Al
VIMS Articles
The presence of bare patches within otherwise vegetated coastal marshes is sometimes considered to be a symptom of marsh dieback and the subsequent loss of important ecosystem services. Here we studied the topographical conditions determining the presence and revegetation of bare patches in three marsh sites with contrasting tidal range, sediment supply, and plant species: the Scheldt estuary (the Netherlands), Venice lagoon (Italy), and Blackwater marshes (Maryland, USA). Based on GIS (geographic information system) analyses of aerial photos and lidar imagery of high resolution (≤2×2 m pixels), we analyzed the topographic conditions under which bare patches occur, including their surface …
Coastal Forest Seawater Exposure Increases Stem Methane Concentration, Matthew J. Norwood, Nicholas Ward, (......), Matthew L. Kirwan, Anya Hopple, J. Patrick Megonigal
Coastal Forest Seawater Exposure Increases Stem Methane Concentration, Matthew J. Norwood, Nicholas Ward, (......), Matthew L. Kirwan, Anya Hopple, J. Patrick Megonigal
VIMS Articles
Methane (CH4) exchange between trees and the atmosphere has recently emerged as an important, but poorly quantified process regulating global climate. The sources (soil and/or tree) and mechanisms driving the increase of CH4 in trees and degassing to the atmosphere are inadequately understood, particularly for coastal forests facing increased exposure to seawater. We investigated the eco‐physiological relationship between tree stem wood density, soil and stem oxygen saturation (an indicator of redox state), soil and stem CH4 concentrations, soil and stem carbon dioxide (CO2) concentrations, and soil salinity in five forests along the United States …
Onset Of Runaway Fragmentation Of Salt Marshes, Orencio Duran Vinent, Ellen R. Herbert, Daniel J. Coleman, Joshua D. Himmelstein, Matthew L. Kirwan
Onset Of Runaway Fragmentation Of Salt Marshes, Orencio Duran Vinent, Ellen R. Herbert, Daniel J. Coleman, Joshua D. Himmelstein, Matthew L. Kirwan
VIMS Articles
Salt marshes are valuable but vulnerable coastal ecosystems that adapt to relative sea level rise (RSLR) by accumulating organic matter and inorganic sediment. The natural limit of these processes defines a threshold rate of RSLR beyond which marshes drown, resulting in ponding and conversion to open waters. We develop a simplified formulation for sediment transport across marshes to show that pond formation leads to runaway marsh fragmentation, a process characterized by a self-similar hierarchy of pond sizes with power-law distributions. We find the threshold for marsh fragmentation scales primarily with tidal range and that sediment supply is only relevant where …
Sea Level-Driven Marsh Migration Results In Rapid Net Loss Of Carbon, Alexander J. Smith, Matthew L. Kirwan
Sea Level-Driven Marsh Migration Results In Rapid Net Loss Of Carbon, Alexander J. Smith, Matthew L. Kirwan
VIMS Articles
Sea level rise alters coastal carbon cycling by driving the rapid migration of coastal ecosystems, salinization of freshwater systems, and replacement of terrestrial forests with tidal wetlands. Wetland soils accumulate carbon (C) at faster rates than terrestrial soils, implying that sea level rise may lead to enhanced carbon accumulation. Here, we show that carbon stored in tree biomass greatly exceeds carbon stored in adjacent marsh soils so that marsh migration reduces total carbon stocks by 50% in less than 100years. Continued marsh soil carbon accumulation may eventually offset forest carbon loss, but we estimate that the time for replacement is …
The Effect Of Coastal Landform Development On Decadal-To Millennial-Scale Longshore Sediment Fluxes: Evidence From The Holocene Evolution Of The Central Mid-Atlantic Coast, Usa, Justin L. Shawler, Christopher J. Hein, Chloe A. Obara, Mahina G. Robbins, Sebastien Huot, Michael S. Fenster
The Effect Of Coastal Landform Development On Decadal-To Millennial-Scale Longshore Sediment Fluxes: Evidence From The Holocene Evolution Of The Central Mid-Atlantic Coast, Usa, Justin L. Shawler, Christopher J. Hein, Chloe A. Obara, Mahina G. Robbins, Sebastien Huot, Michael S. Fenster
VIMS Articles
The behavior of siliciclastic coastal systems is largely controlled by the interplay between accommodation creation and infilling. Factors responsible for altering sediment fluxes to and along open-ocean coasts include cross-shore mobilization of sediment primarily from tidal currents and storms as well as changes in alongshore transport rates moderated by changing wave conditions, river sediment inputs, artificial shoreline hardening and modification, and natural sediment trapping in updrift coastal landforms. This paper focuses on the latter relationships. To address understudied interactions between updrift coastal landforms and downdrift coastal behavior, we quantify the volume and fluxes of sediment trapped in the Assateague-Chincoteague-Wallops barrier-island …
Molluscan Aminostratigraphy Of The Us Mid-Atlantic Quaternary Coastal System: Implications For Onshore-Offshore Correlation, Paleochannel And Barrier Island Evolution, And Local Late Quaternary Sea-Level History, John F. Wehmiller, Laura L. Brothers, (...), Christopher J. Hein, Justin L. Shawler
Molluscan Aminostratigraphy Of The Us Mid-Atlantic Quaternary Coastal System: Implications For Onshore-Offshore Correlation, Paleochannel And Barrier Island Evolution, And Local Late Quaternary Sea-Level History, John F. Wehmiller, Laura L. Brothers, (...), Christopher J. Hein, Justin L. Shawler
VIMS Articles
The Quaternary record of the US Mid-Atlantic coastal system includes onshore emergent late Pleistocene shoreline deposits, offshore inner shelf and barrier island units, and paleovalleys formed during multiple glacial stage sea-level lowstands. The geochronology of this coastal system is based on uranium series, radiocarbon, amino acid racemization (AAR), and optically stimulated luminescence (OSL) methods. We report over 600 mollusk AAR results from 93 sites between northeastern North Carolina and the central New Jersey shelf, representing samples from both onshore cores or outcrops, sub-barrier and offshore cores, and transported shells from barrier island beaches. AAR age estimates are constrained by paired …
Mechanisms Of Pond Expansion In A Rapidly Submerging Marsh, Joshua Himmelstein, Orencio Duran Vinent, Stijn Temmerman, Matthew L. Kirwan
Mechanisms Of Pond Expansion In A Rapidly Submerging Marsh, Joshua Himmelstein, Orencio Duran Vinent, Stijn Temmerman, Matthew L. Kirwan
VIMS Articles
The development and expansion of ponds within otherwise vegetated coastal marshes is a primary driver of marsh loss throughout the world. Previous studies propose that large ponds expand through a wind wave-driven positive feedback, where pond edge erosion rates increase with pond size, whereas biochemical processes control the formation and expansion of smaller ponds. However, it remains unclear which mechanisms dominate at a given scale, and thus how, and how fast, ponds increase their size. Here, we use historical photographs and field measurements in a rapidly submerging microtidal marsh to quantify pond development and identify the processes involved. We find …
Biophysical Controls Of Marsh Soil Shear Strength Along An Estuarine Salinity Gradient, Megan N. Gillen, Tyler C. Messerschmidt, Matthew L. Kirwan
Biophysical Controls Of Marsh Soil Shear Strength Along An Estuarine Salinity Gradient, Megan N. Gillen, Tyler C. Messerschmidt, Matthew L. Kirwan
VIMS Articles
Sea-level rise, saltwater intrusion, and wave erosion threaten coastal marshes, but the influence of salinity on marsh erodibility remains poorly understood. We measured the shear strength of marsh soils along a salinity and biodiversity gradient in the York River estuary in Virginia to assess the direct and indirect im-pacts of salinity on potential marsh erodibility. We found that soil shear strength was higher in monospecific salt marshes (5–36 kPa) than in biodiverse freshwater marshes (4–8 kPa), likely driven by differences in below ground biomass. However, we also found that shear strength at the marsh edge was controlled by sediment characteristics, …
On The Human Appropriation Of Wetland Primary Production, James E. Cloern, Samuel M. Safran, Lydia Smith Vaughn, (...), Elizabeth A. Canuel, J.Letitia Grenier
On The Human Appropriation Of Wetland Primary Production, James E. Cloern, Samuel M. Safran, Lydia Smith Vaughn, (...), Elizabeth A. Canuel, J.Letitia Grenier
VIMS Articles
Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and …
Global Blue Carbon Accumulation In Tidal Wetlands Increases With Climate Change, Faming Wang, Christian J. Sanders, (...), Matthew L. Kirwan, Et Al
Global Blue Carbon Accumulation In Tidal Wetlands Increases With Climate Change, Faming Wang, Christian J. Sanders, (...), Matthew L. Kirwan, Et Al
VIMS Articles
Coastal tidal wetlands produce and accumulate significant amounts of organic carbon (C) that help to mitigate climate change. However, previous data limitations have prevented a robust evaluation of the global rates and mechanisms driving C accumulation. Here, we go beyond recent soil C stock estimates to reveal global tidal wetland C accumulation and predict changes under relative sea level rise, temperature and precipitation. We use data from literature study sites and our new observations spanning wide latitudinal gradients and 20 countries. Globally, tidal wetlands accumulate 53.65 (95%CI: 48.52–59.01) Tg C yr−1, which is∼30% of the organic C buried on the …
How Old Are Marshes On The East Coast, Usa? Complex Patterns In Wetland Age Within And Among Regions, Anna E. Braswell, James B. Heffernan, Matthew L. Kirwan
How Old Are Marshes On The East Coast, Usa? Complex Patterns In Wetland Age Within And Among Regions, Anna E. Braswell, James B. Heffernan, Matthew L. Kirwan
VIMS Articles
Sea‐level dynamics, sediment availability, and marine energy are critical drivers of coastal wetland formation and persistence, but their roles as continental‐scale drivers remain unknown. We evaluated the timing and spatial variability of wetland formation from new and existing cores collected along the Atlantic and Gulf coasts of the United States. Most basal peat ages occurred after sea‐level rise slowed (after ~4,000 years before present), but predominance of sea‐level rise studies may skew age estimates toward older sites. Near‐coastal sites tended to be younger, indicating creation of wetlands through basin infilling and overwash events. Age distributions differed among regions, with younger …
Coastal Marsh Degradation Into Ponds Induces Irreversible Elevation Loss Relative To Sea Level In A Microtidal System, Lennert Schepers, Patrick Brennand, Matthew L. Kirwan, Glenn Guntenspergen, Stijn Temmerman
Coastal Marsh Degradation Into Ponds Induces Irreversible Elevation Loss Relative To Sea Level In A Microtidal System, Lennert Schepers, Patrick Brennand, Matthew L. Kirwan, Glenn Guntenspergen, Stijn Temmerman
VIMS Articles
Coastal marshes and their valuable ecosystem services are feared to be lost by sea level rise, yet the mechanisms of marsh degradation into ponds and potential recovery are poorly understood. We quantified and analyzed elevations of marsh surfaces and pond bottoms along a marsh loss gradient (Blackwater River, Maryland, USA). Our analyses show that ponds deepen with increasing tidal channel width connecting the ponds to the river, indicating a new feedback mechanism where channels lead to enhanced tidal export of pond bottom material. Pond elevations also decrease with increasing pond size, consistent with previous work identifying a positive feedback between …
Modeling Marsh‐Forest Boundary Transgression In Response To Storms And Sea‐Level Rise, J. Carr, G. Guntenspergen, Matthew L. Kirwan
Modeling Marsh‐Forest Boundary Transgression In Response To Storms And Sea‐Level Rise, J. Carr, G. Guntenspergen, Matthew L. Kirwan
VIMS Articles
The lateral extent and vertical stability of salt marshes experiencing rising sea levels depend on interacting drivers and feedbacks with potential for nonlinear behaviors. A two‐dimensional transect model was developed to examine changes in marsh and upland forest lateral extent and to explore controls on marsh inland transgression. Model behavior demonstrates limited and abrupt forest retreat with long‐term upland boundary migration rates controlled by slope, sea‐level rise (SLR), high water events, and biotic‐abiotic interactions. For low to moderate upland slopes the landward marsh edge is controlled by the interaction of these inundation events and forest recovery resulting in punctuated transgressive …
Sediment Delivery To A Tidal Marsh Platform Is Minimized By Source Decoupling And Flux Convergence, Daniel J. Coleman, Neil K. Ganju, Matthew L. Kirwan
Sediment Delivery To A Tidal Marsh Platform Is Minimized By Source Decoupling And Flux Convergence, Daniel J. Coleman, Neil K. Ganju, Matthew L. Kirwan
VIMS Articles
Sediment supply is a primary factor in determining marsh response to sea level rise and is typically approximated through high‐resolution measurements of suspended sediment concentrations (SSCs) from adjacent tidal channels. However, understanding sediment transport across the marsh itself remains limited by discontinuous measurements of SSC over individual tidal cycles. Here, we use an array of optical turbidity sensors to build a long‐term, continuous record of SSC across a marsh platform and adjacent tidal channel. We find that channel and marsh concentrations are correlated (i.e., coupled) within tidal cycles but are largely decoupled over longer time scales. We also find that …
Impacts Of Seagrass Dynamics On The Coupled Long‐Term Evolution Of Barrier‐Marsh‐Bay Systems, I.R.B. Reeves, L. J. Moore, E. B. Goldstein, A. B. Murray, Matthew L. Kirwan
Impacts Of Seagrass Dynamics On The Coupled Long‐Term Evolution Of Barrier‐Marsh‐Bay Systems, I.R.B. Reeves, L. J. Moore, E. B. Goldstein, A. B. Murray, Matthew L. Kirwan
VIMS Articles
Seagrass provides a wide range of economically and ecologically valuable ecosystem services, with shoreline erosion control often listed as a key service, but can also alter the sediment dynamics and waves within back‐barrier bays. Here we incorporate seagrass dynamics into an existing barrier‐marsh exploratory model, GEOMBEST++, to examine the coupled interactions of the back‐barrier bay with both adjacent (marsh) and nonadjacent (barrier island) subsystems. While seagrass reduces marsh edge erosion rates and increases progradation rates in many of our 288 model simulations, seagrass surprisingly increases marsh edge erosion rates when sediment export from the back‐barrier basin is negligible because the …
Role Of Delta-Front Erosion In Sustaining Salt Marshes Under Sea-Level Rise And Fluvial Sediment Decline, Shi Lun Yang, Xiangxin Luo, Stijn Temmerman, Matthew L. Kirwan, Et Al
Role Of Delta-Front Erosion In Sustaining Salt Marshes Under Sea-Level Rise And Fluvial Sediment Decline, Shi Lun Yang, Xiangxin Luo, Stijn Temmerman, Matthew L. Kirwan, Et Al
VIMS Articles
Accelerating sea-level rise and decreasing riverine sediment supply are widely considered to lead to global losses of deltaic marshes and their valuable ecosystem services. However, little is known about the degree to which the related erosion of the seaward delta front can provide sediments to sustain salt marshes. Here, we present dataf rom the mesomacrotidal Yangtze Delta demonstrating that marshes have continued to accrete vertically and laterally, despite rapid relative sea-level rise (approx.10 mm yr−1) and a > 70% decrease in the Yangtze River sediment supply. Marsh progradation has decelerated at a lower rate than fluvial sediment reduction, suggesting an additional …
Impacts Of Muddy Bed Aggregates On Sediment Transport And Management In The Tidal James River, Va, David W. Perkey, S. Jarrell Smith, Kelsey A. Fall, Grace M. Massey, Carl T. Friedrichs, Emmalynn M. Hicks
Impacts Of Muddy Bed Aggregates On Sediment Transport And Management In The Tidal James River, Va, David W. Perkey, S. Jarrell Smith, Kelsey A. Fall, Grace M. Massey, Carl T. Friedrichs, Emmalynn M. Hicks
VIMS Articles
Aggregation state significantly influences the size, density and transport characteristics of fine sediment. Understanding sediment transport and deposition processes in the nation’s navigable waterways is a primary mission for the US Army Corps of Engineers (USACE), particularly when it comes to infilling of navigation channels. In this study, a newly developed camera system was used to evaluate the aggregation state of eroded sediment from cores collected in the tidal James River, VA. Results showed that bed sediments were composed mostly of mud, but that erosion predominately occurred in the form of aggregates with median sizes 50-270x larger than the disaggregated …