Wetlands in the Quaternary Project Completed
Wetlands accumulate organic-rich sediment or peat stratigraphically, making them great archives of past environmental change. Wetlands also act as hydrologic buffers on the landscape and are important to global biogeochemical cycling. This project uses wetland archives from a range of environments to better understand how vegetation, hydrology, and hydroclimate has changed on decadal to multi-millennial timescales, and how wetlands have responded to past perturbations, such as fire, sea-level rise, and permafrost degradation. We use a multi-proxy approach that includes pollen, plant macrofossils, stable isotope analysis, and radiometric dating. Study sites range from Florida and the Atlantic Coastal Plain to Alaska.
Project Lead: Miriam Jones
Project Team: Kristen Hoefke, Diana Carriker, Bailey Nash
Sea-level rise
Wetlands protect coastlines from sea-level rise, but wetland archives can also elucidate past change in rates and the responses of these coastal systems to those changes. By closely examining the layers laid down by wetland sediments and peat, we can use a combination of physical properties and radiometric dating to examine past rates of sea-level rise, while pollen, plant macrofossils, and stable isotopes, can provide insights into the depositional environment at the time of deposition. This project is currently examining Holocene rates of sea-level rise and mechanisms for inundation of formerly terrestrial environments in Florida Bay. We are also examining how tidal freshwater wetlands along the Atlantic Coastal Plain have shifted over the Holocene in response to changing rates of sea-level rise and the resilience of these riparian wetlands in the future.
Permafrost thaw
Permafrost, or permanently frozen ground, underlies vast swaths of the boreal and arctic zones. With thaw accelerating under current warming, wholesale ecological and hydrological changes are occurring, putting wildlife and infrastructure at risk. In permafrost peatlands, ice-rich permafrost thaw causes subsidence that can transform forested peatlands to wet herb and moss peatlands, resulting in large changes not only in the structure and function of these systems, but also in biogeochemical cycling. This project is examining the nature and rate of both permafrost aggradation and degradation on Holocene timescales to better understand trajectories of vegetation change and biogeochemical change upon thaw. Study sites include boreal peatlands in the discontinuous and sporadic permafrost zones of Alaska.
Land-use change
Human evidence of land-use change can be picked up to varying degrees in wetland records. In some cases, modifications are deliberate, such as ditching and draining of wetlands for harvesting of natural resources. In other cases, transformations to the larger landscape result in changes to neighboring wetlands and waterways, such as colonial land clearance that resulted in a large pulse of terrestrial sediment into riparian and coastal wetlands. This study is examining how a range of land-use changes have altered wetlands on decadal to centennial timescales, while also placing these changes into the greater context of natural variability by examining centennial to millennial-scale shifts. This project helps identify markers and impacts of land-use change and can also aid decision-makers and land managers plan for land restoration. Study sites include the Great Dismal Swamp, VA and tidal rivers on the Atlantic Coastal Plain.
Hydroclimate variability
Examining the range of hydroclimate variability from Holocene records can help contextualize recent observations. In some cases, hydroclimate variability is linked to long-term modes of climate variability, which can be linked to precipitation extremes and fisheries productivity. This study is examining Holocene hydroclimate variability using oxygen isotopes derived from peat cellulose across a the northern Gulf of Alaska and the Bering Sea to examine the timing and linkages to Aleutian Low variability and its connection to sea ice extent, ocean and atmosphere circulation, and teleconnections with northern hemisphere climate phenomena, such as El Nino Southern Oscillation, Arctic Oscillation, and the Pacific Decadal Oscillation.
Below are other science projects associated with this project.
Below are multimedia items associated with this project.
Below are publications associated with this project.
Sources and sinks of carbon in boreal ecosystems of interior Alaska: a review
Lateglacial and Holocene climate, disturbance and permafrost peatland dynamics on the Seward Peninsula, western Alaska
Characterizing post-drainage succession in Thermokarst Lake Basins on the Seward Peninsula, Alaska with TerraSAR-X Backscatter and Landsat-based NDVI data
Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska
Expansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes, northern Seward Peninsula, Alaska, USA
Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska
Below are partners associated with this project.
- Overview
Wetlands accumulate organic-rich sediment or peat stratigraphically, making them great archives of past environmental change. Wetlands also act as hydrologic buffers on the landscape and are important to global biogeochemical cycling. This project uses wetland archives from a range of environments to better understand how vegetation, hydrology, and hydroclimate has changed on decadal to multi-millennial timescales, and how wetlands have responded to past perturbations, such as fire, sea-level rise, and permafrost degradation. We use a multi-proxy approach that includes pollen, plant macrofossils, stable isotope analysis, and radiometric dating. Study sites range from Florida and the Atlantic Coastal Plain to Alaska.
Project Lead: Miriam Jones
Project Team: Kristen Hoefke, Diana Carriker, Bailey Nash
Sea-level rise
Wetlands protect coastlines from sea-level rise, but wetland archives can also elucidate past change in rates and the responses of these coastal systems to those changes. By closely examining the layers laid down by wetland sediments and peat, we can use a combination of physical properties and radiometric dating to examine past rates of sea-level rise, while pollen, plant macrofossils, and stable isotopes, can provide insights into the depositional environment at the time of deposition. This project is currently examining Holocene rates of sea-level rise and mechanisms for inundation of formerly terrestrial environments in Florida Bay. We are also examining how tidal freshwater wetlands along the Atlantic Coastal Plain have shifted over the Holocene in response to changing rates of sea-level rise and the resilience of these riparian wetlands in the future.
Permafrost thaw
Permafrost, or permanently frozen ground, underlies vast swaths of the boreal and arctic zones. With thaw accelerating under current warming, wholesale ecological and hydrological changes are occurring, putting wildlife and infrastructure at risk. In permafrost peatlands, ice-rich permafrost thaw causes subsidence that can transform forested peatlands to wet herb and moss peatlands, resulting in large changes not only in the structure and function of these systems, but also in biogeochemical cycling. This project is examining the nature and rate of both permafrost aggradation and degradation on Holocene timescales to better understand trajectories of vegetation change and biogeochemical change upon thaw. Study sites include boreal peatlands in the discontinuous and sporadic permafrost zones of Alaska.
Land-use change
Human evidence of land-use change can be picked up to varying degrees in wetland records. In some cases, modifications are deliberate, such as ditching and draining of wetlands for harvesting of natural resources. In other cases, transformations to the larger landscape result in changes to neighboring wetlands and waterways, such as colonial land clearance that resulted in a large pulse of terrestrial sediment into riparian and coastal wetlands. This study is examining how a range of land-use changes have altered wetlands on decadal to centennial timescales, while also placing these changes into the greater context of natural variability by examining centennial to millennial-scale shifts. This project helps identify markers and impacts of land-use change and can also aid decision-makers and land managers plan for land restoration. Study sites include the Great Dismal Swamp, VA and tidal rivers on the Atlantic Coastal Plain.
Hydroclimate variability
Examining the range of hydroclimate variability from Holocene records can help contextualize recent observations. In some cases, hydroclimate variability is linked to long-term modes of climate variability, which can be linked to precipitation extremes and fisheries productivity. This study is examining Holocene hydroclimate variability using oxygen isotopes derived from peat cellulose across a the northern Gulf of Alaska and the Bering Sea to examine the timing and linkages to Aleutian Low variability and its connection to sea ice extent, ocean and atmosphere circulation, and teleconnections with northern hemisphere climate phenomena, such as El Nino Southern Oscillation, Arctic Oscillation, and the Pacific Decadal Oscillation.
- Science
Below are other science projects associated with this project.
- Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 18Sources and sinks of carbon in boreal ecosystems of interior Alaska: a review
Boreal regions store large quantities of carbon but are increasingly vulnerable to carbon loss due to disturbance and climate warming. The boreal region, underlain by discontinuous permafrost, presents a challenging landscape for itemizing current and potential carbon sources and sinks in the boreal soil and vegetation. The roles of fire, forest succession, and the presence (or absence) of permafrAuthorsThomas A. Douglas, Miriam C. Jones, Christopher A. HiemstraLateglacial and Holocene climate, disturbance and permafrost peatland dynamics on the Seward Peninsula, western Alaska
Northern peatlands have accumulated large carbon (C) stocks, acting as a long-term atmospheric C sink since the last deglaciation. How these C-rich ecosystems will respond to future climate change, however, is still poorly understood. Furthermore, many northern peatlands exist in regions underlain by permafrost, adding to the challenge of projecting C balance under changing climate and permafrostAuthorsStephanie D. Hunt, Zicheng Yu, Miriam C. JonesCharacterizing post-drainage succession in Thermokarst Lake Basins on the Seward Peninsula, Alaska with TerraSAR-X Backscatter and Landsat-based NDVI data
Drained thermokarst lake basins accumulate significant amounts of soil organic carbon in the form of peat, which is of interest to understanding carbon cycling and climate change feedbacks associated with thermokarst in the Arctic. Remote sensing is a tool useful for understanding temporal and spatial dynamics of drained basins. In this study, we tested the application of high-resolution X-band SyAuthorsPrajna Regmi, Guido Grosse, Miriam C. Jones, Benjamin M. Jones, Katey Walter AnthonyPeat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward Peninsula, Alaska
Thermokarst lakes and peat-accumulating drained lake basins cover a substantial portion of Arctic lowland landscapes, yet the role of thermokarst lake drainage and ensuing peat formation in landscape-scale carbon (C) budgets remains understudied. Here we use measurements of terrestrial peat thickness, bulk density, organic matter content, and basal radiocarbon age from permafrost cores, soil pits,AuthorsMiriam C. Jones, Guido Grosse, Benjamin M. Jones, Katey Walter AnthonyExpansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes, northern Seward Peninsula, Alaska, USA
Investigations on the northern Seward Peninsula in Alaska identified zones of recent (<50 years) permafrost collapse that led to the formation of floating vegetation mats along thermokarst lake margins. The occurrence of floating vegetation mat features indicates rapid degradation of near‐surface permafrost and lake expansion. This paper reports on the recent expansion of these collapse features aAuthorsA.D. Parsekian, Benjamin M. Jones, M. Jones, G. Grosse, Anthony K.M. Walter, L. SlaterModern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska
Quantifying changes in thermokarst lake extent is of importance for understanding the permafrost-related carbon budget, including the potential release of carbon via lake expansion or sequestration as peat in drained lake basins. We used high spatial resolution remotely sensed imagery from 1950/51, 1978, and 2006/07 to quantify changes in thermokarst lakes for a 700 km2 area on the northern SewardAuthorsBenjamin M. Jones, G. Grosse, C.D. Arp, M.C. Jones, Anthony K.M. Walter, V.E. Romanovsky - Partners
Below are partners associated with this project.