Skip to main content
U.S. flag

An official website of the United States government

Publications

Filter Total Items: 822

The presence of denitrifiers in bacterial communities of urban stormwater best management practices (BMPs)

Stormwater best management practices (BMPs) are engineered structures that attempt to mitigate the impacts of stormwater, which can include nitrogen inputs from the surrounding drainage area. The goal of this study was to assess bacterial community composition in different types of stormwater BMP soils to establish whether a particular BMP type harbors more denitrification potential. Soil sampling
Authors
Natalie Hall, Masoumeh Sikaroodi, Dianna M. Hogan, R. Christian Jones, Patrick Gillevet

Review of ESA SYMP 7: A dynamic perspective on ecosystem restoration–establishing temporal connectivity at the intersection between paleoecology and restoration ecology

Landscape connectivity is vital not only spatially, but also temporally; as ecosystems change, it is important to be aware of past, present, and future variables that may impact ecosystem function and biodiversity. As climate and environments continue to change, choosing appropriate restoration targets is becoming more challenging. By considering the paleoecological and paleoenvironmental record f
Authors
Rachel Reid, Jenny McGuire, Jens-Christiane Svenning, G. Lynn Wingard, David Moreno-Mateos

Calcareous plankton biostratigraphic fidelity and species richness during the last 10 m.y. of the Cretaceous at Blake Plateau, subtropical North Atlantic

Species distributions of well-preserved and diverse assemblages of planktonic foraminifera and calcareous nannofossils spanning the last 10 m.y. of the Cretaceous (middle Campanian through Maastrichtian) are analyzed from samples taken across a 1400 m depth transect at Blake Nose in the western subtropical North Atlantic (Ocean Drilling Program Sites 1049, 1050 and 1052). Age models constructed by
Authors
Brian T. Huber, Nataliya A. Tur, Jean Self-Trail, Kenneth G. MacLeod

The Yorktown Formation: Improved stratigraphy, chronology and paleoclimate interpretations from the U.S. mid-Atlantic Coastal Plain

The Yorktown Formation records paleoclimate conditions along the mid-Atlantic Coastal Plain during the mid-Piacenzian Warm Period (3.264 to 3.025 Ma), a climate interval of the Pliocene in some ways analogous to near future climate projections. To gain insight into potential near future changes, we investigated Yorktown Formation outcrops and cores in southeastern Virginia, refining the stratigrap
Authors
Harry J. Dowsett, Marci M. Robinson, Kevin M. Foley, Timothy D. Herbert

A practical solution: The Anthropocene is a geological event, not a formal epoch

The Anthropocene has yet to be defined in a way that is functional both to the international geological community and to the broader fields of environmental and social sciences. Formally defining the Anthropocene as a chronostratigraphical series and geochronological epoch with a precise global start date would drastically reduce the Anthropocene’s utility across disciplines. Instead, we propose t
Authors
Philip Gibbard, Andrew M Bauer, Matthew Edgeworth, William F Ruddiman, Jacquelyn L. Gill, Merritts. Dorothy J, Stanley C. Finney, Lucy E. Edwards, Michael J.C. Walker, Mark Maslin, Erle C Ellis

Proportions, timing, and re-equilibration progress during the 1959 Summit Eruption of Kīlauea: An example of magma mixing processes operating during OIB petrogenesis

Petrographic and chemical analysis of scoria samples collected during the 1959 Kīlauea summit eruption illustrates the progress of thermal and chemical homogenization of the melts, and the gradual growth and/or re-equilibration of olivine phenocrysts, over the course of the eruption. Glass compositions show that thermal equilibration was largely complete within the span of the eruption, whereas ch
Authors
Rosalind L. Helz

PlioMIP: The Pliocene Model Intercomparison Project

PlioMIP is a network of paleoclimate modelers and geoscientists who, through the study of the mid-Pliocene Warm Period (mPWP ~3.3–3.0 million years ago), seek to understand the sensitivity of the climate system to forcings and examine how well models reproduce past climate change.
Authors
A. M. Haywood, Harry J. Dowsett

Postcards from the field

My research focuses on pre-20th century conditions in the Greater Everglades Ecosystem of south Florida to provide the context for resource managers to set targets for restoration. A primary goal of Everglades restoration is to re-establish more natural delivery of freshwater to the wetlands and estuaries in the region. By analyzing biotic assemblages from sediment cores collected from Florida B
Authors
G. Lynn Wingard

Diagenetic barite-pyrite-wurtzite formation and redox signatures in Triassic mudstone, Brooks Range, northern Alaska

Mineralogical and geochemical studies of interbedded black and gray mudstones in the Triassic part of the Triassic-Jurassic Otuk Formation (northern Alaska) document locally abundant barite and pyrite plus diverse redox signatures. These strata, deposited in an outer shelf setting at paleolatitudes of ~45 to 60°N, show widespread sedimentological evidence for bioturbation. Barite occurs preferenti
Authors
John F. Slack, Ryan J. McAleer, Wayne (Pat) Shanks, Julie A. Dumoulin

Influence of permafrost type and site history on losses of permafrost carbon after thaw

We quantified permafrost peat plateau and post-thaw carbon (C) stocks across a chronosequence in Interior Alaska to evaluate the amount of C lost with thaw. Macrofossil reconstructions revealed three stratigraphic layers of peat: (1) a base layer of fen/marsh peat, (2) peat from a forested peat plateau (with permafrost) and, (3) collapse-scar bog peat (at sites where permafrost thaw has occurred).
Authors
Kristen L. Manies, Miriam C. Jones, Mark Waldrop, Mary-Catherine Leewis, Christopher C. Fuller, Robert S. Cornman, Kristen Hoefke

Formation of miarolitic-class, segregation-type pegmatites in the Taishanmiao batholith, China: The role of pressure fluctuations and volatile exsolution during pegmatite formation in a closed, isochoric system

The Taishanmiao granitic batholith, located in the Eastern Qinling Orogen in Henan Province, China, contains numerous small (mostly tens of centimeters in maximum dimension) bodies exhibiting textures and mineralogy characteristics of simple quartz and alkali feldspar pegmatites. Analysis of melt inclusions (MI) and fluid inclusions (FI) in pegmatitic quartz, combined with Rhyolite-MELTS modeling
Authors
Yabin Yuan, Lowell Moore, Ryan J. McAleer, Shunda Yuan, Hegen Ouyang, Harvey E. Belkin, Jingwen Mao, Matthew D. Sublett Jr., Robert J. Bodnar

Paleozoic and Mesozoic tectonic events west of the Waterbury Dome: Results of new mapping in the western Connecticut Highlands

This field trip highlights the results of recent U.S. Geological Survey (USGS) bedrock geologic mapping in four 7.5 min quadrangles in the western Connecticut highlands near Southbury, Connecticut, USA. The rocks are broadly within what Rodgers (1985) called the Hartland and Gneiss Dome belts of the Connecticut Valley Synclinorium (Rodgers, 1985; Fig. 1), the latter of which is now known as the Co
Authors
William C. Burton, William J. Devlin