A5084006750- Geology and Paleoclimatology Research
- Coastal wetland ecosystem dynamics
- Geological formations and processes
- Geological Studies and Exploration
- Isotope Analysis in Ecology
- Botany, Ecology, and Taxonomy Studies
- Paleontology and Stratigraphy of Fossils
- Coastal and Marine Dynamics
- Methane Hydrates and Related Phenomena
- Aeolian processes and effects
- Peatlands and Wetlands Ecology
- Marine Biology and Ecology Research
- Plant Pathogens and Fungal Diseases
- Tree-ring climate responses
- Marine and environmental studies
- Hydrocarbon exploration and reservoir analysis
- Lichen and fungal ecology
- Archaeology and Natural History
- Plant Diversity and Evolution
- Marine and coastal plant biology
- Marine and fisheries research
- Archaeology and ancient environmental studies
- Climate variability and models
- Water Quality and Resources Studies
- Fire effects on ecosystems
United States Geological Survey
2013-2024
Florence Bascom Geoscience Center
2022-2024
Stockholm University
2023
University of Tartu
2023
University of Latvia
2023
Pacific Island Ecosystems Research Center
2023
Lomonosov Moscow State University
2023
Government of the United States of America
2022
National Park Service
2007
William & Mary
2007
Cores from Northwind Ridge, a high-standing continental fragment in the Chukchi borderland of oceanic Amerasia basin, Arctic Ocean, contain representatives every Phanerozoic system except Silurian and Devonian systems. Cambrian Ordovician shallow-water marine carbonates Ridge are similar to basement rocks beneath Sverdrup basin Canadian Archipelago. Upper Mississippian(?) Permian shelf carbonate spicularite Triassic turbidite lutite resemble coeval strata western Alaska (Hanna trough). These...
This evolutionary cladistic analysis of the arborescent (wood-producing) lycopsids, an exclusively fossil group vascular plants, is confined to strongest available data: anatomically preserved fossils that have been painstakingly reconstructed into conceptual whole plants. Ten Carboniferous genera are represented by 16 species: four pseudoherbs/«shrubs» and 12 arboreous (tree-sized) species epitomize Pennsylvanian coal swamps Euramerica. The 69 vegetative 46 reproductive characters described...
Early Eocene global climate was warmer than much of the Cenozoic and punctuated by a series transient warming events or 'hyperthermals' associated with carbon isotope excursions when temperature increased 4–8 °C. The Paleocene-Eocene Thermal Maximum (PETM, ~55 Ma) 2 (ETM2, 53.5 hyperthermals were short duration (<200 kyr) dramatically restructured terrestrial vegetation mammalian faunas at mid-latitudes. Data on character magnitude change in during after PETM ETM2 high northern latitudes,...
During the twentieth century, natural landscape of Florida peninsula was transformed extensively by agriculture, urbanization, and diversion surface water features. The purpose this paper is to present a numerical modeling study in which possible impacts transformation on warm season climate region were investigated. For three separate July‐August periods (1973, 1989, 1994), pair simulations performed with Regional Atmospheric Modeling System. Within each pair, differed only specification...
More than half of the original Everglades extent formed a patterned peat mosaic elevated ridges, lower and more open sloughs, tree islands aligned parallel to dominant flow direction. This ecologically important landscape structure remained in dynamic equilibrium for millennia prior rapid degradation over past century response human manipulation hydrologic system. Restoration is one primary objectives restoration effort. Recent research has revealed that three main drivers regulated...
Northern peatlands store globally-important amounts of carbon in the form partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency severity rapid loss atmosphere. However, our understanding patterns drivers peatland burning on an appropriate decadal millennial timescale relies heavily individual site-based reconstructions. For first time, we synthesise macrocharcoal records from across North America, Europe, Patagonia reveal...
Palaeoclimate records from late-Holocene sediments in Chesapeake Bay, the largest estuary USA, provide evidence that both decadal to centennial climate variability and European colonization had severe impacts on watershed estuary. Using pollen dinoflagellate cysts as proxies for mid-Atlantic regional precipitation, estuarine salinity dissolved oxygen (DO) during last 2300 years, we identified four dry intervals, centred ad 50 (P1/D1), 1000 (P2/D2), 1400 (P3) 1600 (P4). Two centennial-scale...
An illustrated, descriptive atlas of pollen and spores from wetland plants the Florida Everglades was compiled to facilitate identification dispersed palynomorphs in sediments. The includes 121 species characteristic eleven plant associations including sloughs, sawgrass marshes, tree islands, wet prairies, cypress domes, mangrove forests, salt ridges, beach/dune communities, pine flatwoods/dry disturbed/developed sites. We include light micrographs detailed descriptions species, 110 genera,...
Drilling results from the Integrated Ocean Program's Arctic Coring Expedition (ACEX) to Lomonosov Ridge (LR) document a 26 million year hiatus that separates freshwater‐influenced biosilica‐rich deposits of middle Eocene fossil‐poor glaciomarine silty clays early Miocene. Detailed micropaleontological and sedimentological data sediments surrounding this mid‐Cenozoic describe shallow water setting for LR, finding conflicts with predrilling seismic predictions an initial postcruise assessment...
Research Article| February 01, 1989 Origin of the Pennsylvanian coal-bearing cyclothems North America George deV. Klein; Klein 1Department Geology, University Illinois at Urbana-Champaign, 245 Natural History Building, 1301 West Green Street, Urbana, 61801-2999 Search for other works by this author on: GSW Google Scholar Debra A. Willard 2Department Plant Biology, 289 Morrill Hall, 505 South Goodwin 61801-3793 Author and Article Information Publisher: Geological Society First Online: 02 Jun...
The ridge and slough landscape of the Florida Everglades consists a mosaic linear sawgrass ridges separated by deeper-water sloughs with tree islands interspersed throughout landscape. We used pollen assemblages from transects sediment cores spanning ridges, sloughs, ridge-slough transition zones to determine timing formation evaluate response components climate variability 20th-century water management. These data indicate that have been vegetationally distinct one another since initiation...
The largest abrupt climatic reversal of the Holocene interglacial, cooling event 8.6–8.2 thousand years ago (ka), was probably caused by catastrophic release glacial Lake Agassiz‐Ojibway, which slowed Atlantic meridional overturning circulation (AMOC) and cooled global climate. Geophysical surveys sediment cores from Chesapeake Bay reveal pattern sea level rise during this event. Sea rose ∼14 m between 9.5 to 7.5 ka, a consistent with coral records ICE‐5G glacio‐isostatic adjustment model....
The Cenozoic record of the Lomonosov Ridge (central Arctic Ocean) recovered during Integrated Ocean Drilling Program (IODP) Expedition 302 revealed an unexpected 26 Ma hiatus, separating middle Eocene (∼44.4 Ma) from lower Miocene sediments (∼18.2 Ma). To elucidate nature this unconformity, we performed a multiproxy palynological (dinoflagellate cysts, pollen, and spores), micropaleontological (siliceous microfossils), inorganic, organic (Tetra Ether Index lipids with 86 carbon atoms (TEX )...
Abstract Radiocarbon-dated sediment cores from the Champlain Valley (northeastern USA) contain stratigraphic and micropaleontologic evidence for multiple, high-magnitude, freshwater discharges North American proglacial lakes to Atlantic. Of particular interest are two large, closely spaced outflows that entered Atlantic Ocean via St. Lawrence estuary about 13,200–12,900 cal yr BP, near beginning of Younger Dryas cold event. We estimate varve chronology, sedimentation rates lake volumes...
Abstract. Quaternary records provide an opportunity to examine the nature of vegetation and fire responses rapid past climate changes comparable in velocity magnitude those expected 21st-century. The best documented examples change are warming events associated with Dansgaard–Oeschger (D–O) cycles during last glacial period, which were sufficiently large have had a potential feedback through albedo greenhouse gas emissions on climate. Previous reconstructions D–O used independently...