Christopher Bernhardt, Ph.D.
Chris Bernhardt is the Center Director of the USGS Florence Bascom Geoscience Center.
Education and Certifications
University of Pennsylvania, Ph.D. (2009)
University of Akron, M.S. (2000)
Baldwin Wallace College, B.S. (1998)
Science and Products
Filter Total Items: 30
Coastal and wetland ecosystems of the Chesapeake Bay watershed: Applying palynology to understand impacts of changing climate, sea level, and land use
The mid-Atlantic region and Chesapeake Bay watershed have been influenced by fluctuations in climate and sea level since the Cretaceous, and human alteration of the landscape began ~12,000 years ago, with greatest impacts since colonial times. Efforts to devise sustainable management strategies that maximize ecosystem services are integrating data from a range of scientific disciplines to understa
Authors
Debra A. Willard, Christopher E. Bernhardt, Cliff R. Hupp, Wayne L. Newell
Pollen and spores of terrestrial plants
Pollen and spores are valuable tools in reconstructing past sea level and climate because of their ubiquity, abundance, and durability as well as their reciprocity with source vegetation to environmental change (Cronin, 1999; Traverse, 2007; Willard and Bernhardt, 2011). Pollan is found in many sedimentary environments, from freshwater to saltwater, terrestrial to marine. It can be abundant in a m
Authors
Christopher E. Bernhardt, Debra A. Willard
Late Holocene sea- and land-level change on the U.S. southeastern Atlantic Coast
Late Holocene relative sea-level (RSL) reconstructions can be used to estimate rates of land-level (subsidence or uplift) change and therefore to modify global sea-level projections for regional conditions. These reconstructions also provide the long-term benchmark against which modern trends are compared and an opportunity to understand the response of sea level to past climate variability. To ad
Authors
Andrew C. Kemp, Christopher E. Bernhardt, Benjamin P. Horton, Robert E. Kopp, Christopher H. Vane, W. Richard Peltier, Andrea D. Hawkes, Jeffrey P. Donnelly, Andrew C. Parnell, Niamh Cahill
Late Holocene vegetation, climate, and land-use impacts on carbon dynamics in the Florida Everglades
Tropical and subtropical peatlands are considered a significant carbon sink. The Florida Everglades includes 6000-km2 of peat-accumulating wetland; however, detailed carbon dynamics from different environments within the Everglades have not been extensively studied or compared. Here we present carbon accumulation rates from 13 cores and 4 different environments, including sawgrass ridges and sloug
Authors
Miriam C. Jones, Christopher E. Bernhardt, Debra A. Willard
Sea-level change during the last 2500 years in New Jersey, USA
Relative sea-level changes during the last ∼2500 years in New Jersey, USA were reconstructed to test if late Holocene sea level was stable or included persistent and distinctive phases of variability. Foraminifera and bulk-sediment δ13C values were combined to reconstruct paleomarsh elevation with decimeter precision from sequences of salt-marsh sediment at two sites using a multi-proxy approach.
Authors
Andrew C. Kemp, Benjamin P. Horton, Christopher H. Vane, Christopher E. Bernhardt, D. Reide Corbett, Simon E. Engelhart, Shimon C. Anisfeld, Andrew C. Parnell, Niamh Cahill
Reconstructing vegetation response to altered hydrology and its use for restoration, Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida
We present reconstructed hydrologic and vegetation trends of the last three centuries across the Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida in order to understand the effects of 20th century water management. We analyzed pollen assemblages from cores at marsh sites along three transects to document vegetation and infer hydroperiod and water depth both before and after human a
Authors
Christopher E. Bernhardt, Laura A. Brandt, Bryan D. Landacre, Marci E. Marot, Debra A. Willard
Chronology from sediment cores collected in southwestern Everglades National Park, Florida
Age model data are presented for 10 cores from the southwestern coastal mangrove zone of Everglades National Park, Florida, collected in Common Era (CE) 2004 and 2005 and used for paleoecological analysis. Carbon-14 (14C), lead-210 (210Pb), cesium-137 (137Cs), radium-226 (226Ra), and pollen biostratigraphic information is included, and age models were generated for 6 of the 10 cores. Age reversals
Authors
C.E. Bernhardt, G.L. Wingard, D. A. Willard, M. E. Marot, B. Landacre, C. W. Holmes
Nile Delta vegetation response to Holocene climate variability
A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this stud
Authors
Christopher E. Bernhardt, Benjamin P. Horton, Jean-Daniel Stanley
Recent and historic drivers of landscape change in the Everglades ridge, slough, and Tree Island mosaic
More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the hydrologic system.
Authors
Laurel G. Larsen, Nicholas Aumen, Christopher E. Bernhardt, Vic Engel, Thomas J. Givnish, P McCormick S Hagerthey, Judson Harvey, Lynn Leonard, P. McCormick, Christopher McVoy, Gregory Noe, Martha K. Nungesser, K. Rutchey, Fred Sklar, Tiffany G. Troxler, John C. Volin, Debra A. Willard
Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context
We synthesize existing evidence on the ecological history of the Florida Everglades since its inception ~7 ka (calibrated kiloannum) and evaluate the relative impacts of sea level rise, climate variability, and human alteration of Everglades hydrology on wetland plant communities. Initial freshwater peat accumulation began between 6 and 7 ka on the platform underlying modern Florida Bay when sea l
Authors
D. A. Willard, C.E. Bernhardt
Development and application of a pollen-based paleohydrologic reconstruction from the lower Roanoke River Basin, North Carolina, USA
We used pollen assemblages to reconstruct late-Holocene paleohydrologic patterns in floodplain deposits from the lower Roanoke River basin (North Carolina, southeastern USA). Using 120 surface samples from 38 transects, we documented statistical relationships between pollen assemblages, vegetation, and landforms. Backswamp pollen assemblages (long hydroperiods) are dominated by Nyssa (tupelo) and
Authors
D. Willard, C. Bernhardt, R. Brown, B. Landacre, P. Townsend
Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use
The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ∼1200 km south of Manzala. Freshwater wetland plan
Authors
C.E. Bernhardt, J.-D. Stanley, B. P. Horton
Science and Products
Filter Total Items: 30
Coastal and wetland ecosystems of the Chesapeake Bay watershed: Applying palynology to understand impacts of changing climate, sea level, and land use
The mid-Atlantic region and Chesapeake Bay watershed have been influenced by fluctuations in climate and sea level since the Cretaceous, and human alteration of the landscape began ~12,000 years ago, with greatest impacts since colonial times. Efforts to devise sustainable management strategies that maximize ecosystem services are integrating data from a range of scientific disciplines to understa
Authors
Debra A. Willard, Christopher E. Bernhardt, Cliff R. Hupp, Wayne L. Newell
Pollen and spores of terrestrial plants
Pollen and spores are valuable tools in reconstructing past sea level and climate because of their ubiquity, abundance, and durability as well as their reciprocity with source vegetation to environmental change (Cronin, 1999; Traverse, 2007; Willard and Bernhardt, 2011). Pollan is found in many sedimentary environments, from freshwater to saltwater, terrestrial to marine. It can be abundant in a m
Authors
Christopher E. Bernhardt, Debra A. Willard
Late Holocene sea- and land-level change on the U.S. southeastern Atlantic Coast
Late Holocene relative sea-level (RSL) reconstructions can be used to estimate rates of land-level (subsidence or uplift) change and therefore to modify global sea-level projections for regional conditions. These reconstructions also provide the long-term benchmark against which modern trends are compared and an opportunity to understand the response of sea level to past climate variability. To ad
Authors
Andrew C. Kemp, Christopher E. Bernhardt, Benjamin P. Horton, Robert E. Kopp, Christopher H. Vane, W. Richard Peltier, Andrea D. Hawkes, Jeffrey P. Donnelly, Andrew C. Parnell, Niamh Cahill
Late Holocene vegetation, climate, and land-use impacts on carbon dynamics in the Florida Everglades
Tropical and subtropical peatlands are considered a significant carbon sink. The Florida Everglades includes 6000-km2 of peat-accumulating wetland; however, detailed carbon dynamics from different environments within the Everglades have not been extensively studied or compared. Here we present carbon accumulation rates from 13 cores and 4 different environments, including sawgrass ridges and sloug
Authors
Miriam C. Jones, Christopher E. Bernhardt, Debra A. Willard
Sea-level change during the last 2500 years in New Jersey, USA
Relative sea-level changes during the last ∼2500 years in New Jersey, USA were reconstructed to test if late Holocene sea level was stable or included persistent and distinctive phases of variability. Foraminifera and bulk-sediment δ13C values were combined to reconstruct paleomarsh elevation with decimeter precision from sequences of salt-marsh sediment at two sites using a multi-proxy approach.
Authors
Andrew C. Kemp, Benjamin P. Horton, Christopher H. Vane, Christopher E. Bernhardt, D. Reide Corbett, Simon E. Engelhart, Shimon C. Anisfeld, Andrew C. Parnell, Niamh Cahill
Reconstructing vegetation response to altered hydrology and its use for restoration, Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida
We present reconstructed hydrologic and vegetation trends of the last three centuries across the Arthur R. Marshall Loxahatchee National Wildlife Refuge, Florida in order to understand the effects of 20th century water management. We analyzed pollen assemblages from cores at marsh sites along three transects to document vegetation and infer hydroperiod and water depth both before and after human a
Authors
Christopher E. Bernhardt, Laura A. Brandt, Bryan D. Landacre, Marci E. Marot, Debra A. Willard
Chronology from sediment cores collected in southwestern Everglades National Park, Florida
Age model data are presented for 10 cores from the southwestern coastal mangrove zone of Everglades National Park, Florida, collected in Common Era (CE) 2004 and 2005 and used for paleoecological analysis. Carbon-14 (14C), lead-210 (210Pb), cesium-137 (137Cs), radium-226 (226Ra), and pollen biostratigraphic information is included, and age models were generated for 6 of the 10 cores. Age reversals
Authors
C.E. Bernhardt, G.L. Wingard, D. A. Willard, M. E. Marot, B. Landacre, C. W. Holmes
Nile Delta vegetation response to Holocene climate variability
A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this stud
Authors
Christopher E. Bernhardt, Benjamin P. Horton, Jean-Daniel Stanley
Recent and historic drivers of landscape change in the Everglades ridge, slough, and Tree Island mosaic
More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past century in response to human manipulation of the hydrologic system.
Authors
Laurel G. Larsen, Nicholas Aumen, Christopher E. Bernhardt, Vic Engel, Thomas J. Givnish, P McCormick S Hagerthey, Judson Harvey, Lynn Leonard, P. McCormick, Christopher McVoy, Gregory Noe, Martha K. Nungesser, K. Rutchey, Fred Sklar, Tiffany G. Troxler, John C. Volin, Debra A. Willard
Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context
We synthesize existing evidence on the ecological history of the Florida Everglades since its inception ~7 ka (calibrated kiloannum) and evaluate the relative impacts of sea level rise, climate variability, and human alteration of Everglades hydrology on wetland plant communities. Initial freshwater peat accumulation began between 6 and 7 ka on the platform underlying modern Florida Bay when sea l
Authors
D. A. Willard, C.E. Bernhardt
Development and application of a pollen-based paleohydrologic reconstruction from the lower Roanoke River Basin, North Carolina, USA
We used pollen assemblages to reconstruct late-Holocene paleohydrologic patterns in floodplain deposits from the lower Roanoke River basin (North Carolina, southeastern USA). Using 120 surface samples from 38 transects, we documented statistical relationships between pollen assemblages, vegetation, and landforms. Backswamp pollen assemblages (long hydroperiods) are dominated by Nyssa (tupelo) and
Authors
D. Willard, C. Bernhardt, R. Brown, B. Landacre, P. Townsend
Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use
The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ∼1200 km south of Manzala. Freshwater wetland plan
Authors
C.E. Bernhardt, J.-D. Stanley, B. P. Horton