Isotopic analysis

Experimental determination of the proportion of a given isotope (or isotopes) in a sample.
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43 results listed by similarity [list alphabetically]
Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes on the South Shore of Cape Cod, Massachusetts, From 2013 Through 2014

The accretion history of fringing microtidal salt marshes located on the south shore of Cape Cod, Massachusetts, was reconstructed from sediment cores collected in low and high marsh vegetation zones. The location of these marshes within protected embayments and the absence of large rivers on Cape Cod result in minimal sediment supply and a dominance of organic matter contribution to sediment peat. Age models based on 210-lead and 137-cesium were constructed to evaluate how vertical accretion and carbon ...

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Collection, Analysis, and Age-Dating of Sediment Cores from Salt Marshes, Rhode Island, 2016

The accretion history of fringing salt marshes in Narragansett Bay, Rhode Island, was reconstructed from sediment cores. Age models, based on excess lead-210 and cesium-137 radionuclide analysis, were constructed to evaluate how vertical accretion and carbon burial rates have changed during the past century. The Constant Rate of Supply (CRS) age model was used to date six cores collected from three salt marshes. Both vertical accretion rates and carbon burial increased from 1900 to 2016, the year the data ...

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Geochemical analysis of seeps along the Queen Charlotte Fault

Geochemical analyses of authigenic carbonates, bivalves, and pore fluids were performed on samples collected from seep fields along the Queen Charlotte Fault, a right lateral transform boundary that separates the Pacific and North American tectonic plates. Samples were collected using grab samplers and piston cores, and were collected during three different research cruises in 2011, 2015, and 2017.

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Collection, analysis, and age-dating of sediment cores from Herring River wetlands and other nearby wetlands in Wellfleet, Massachusetts, 2015–17

The Herring River estuary in Wellfleet, Cape Cod, Massachusetts, has been tidally restricted for more than a century by a dike constructed near the mouth of the river. Upstream from the dike, the tidal restriction has caused the conversion of salt marsh wetlands to various other ecosystems including impounded freshwater marshes, flooded shrub land, drained forested upland, and brackish wetlands dominated by Phragmites australis. This estuary is now managed by the National Park Service, which plans to ...

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Collection, analysis, and age-dating of sediment cores from mangrove wetlands in San Juan Bay Estuary, Puerto Rico, 2016

The San Juan Bay Estuary, Puerto Rico, contains mangrove forests that store significant amounts of organic carbon in soils and biomass. There is a strong urbanization gradient across the estuary, from the highly urbanized and clogged Caño Martin Peña in the western part of the estuary, a series of lagoons in the center of the estuary, and a tropical forest reserve (Piñones) in the easternmost part with limited urbanization. We collected sediment cores to determine carbon burial rates and vertical ...

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Collection, analysis, and age-dating of sediment cores from a salt marsh platform and ponds, Rowley, Massachusetts, 2014-15

Sediment cores were collected from three sites within the Plum Island Ecosystems Long-Term Ecological Research (PIE-LTER) domain in Massachusetts to obtain estimates of long-term marsh decomposition and evaluate shifts in the composition and reactivity of sediment organic carbon in disturbed marsh environments. Paired sediment cores were collected from three sites on the marsh platform and from three ponds; these cores were about 100 and 50 centimeters in length, respectively. The marsh sites had similar ...

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Geochemical analysis of authigenic carbonates and chemosynthetic mussels at Atlantic Margin seeps (ver. 2.0, March 2019)

Isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus sp., was performed on samples collected from seep fields in the Baltimore and Norfolk Canyons on the north Atlantic margin. Samples were collected using remotely operated underwater vehicles (ROVs) during three different research cruises in 2012, 2013, and 2015. Analyses were performed by several different laboratories, and the results are presented in spreadsheet format.

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Collection, analysis, and age-dating of sediment cores from mangrove and salt marsh ecosystems in Tampa Bay, Florida, 2015

Coastal wetlands in Tampa Bay, Florida, are important ecosystems that deliver a variety of ecosystem services. Key to ecosystem functioning is wetland response to sea-level rise through accumulation of mineral and organic sediment. The organic sediment within coastal wetlands is composed of carbon sequestered over the time scale of the wetland’s existence. This study was conducted to provide information on soil accretion and carbon storage rates across a variety of coastal ecosystems that was utilized in ...

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Collection, analysis, and age-dating of sediment cores from natural and restored salt marshes on Cape Cod, Massachusetts, 2015-16

Nineteen sediment cores were collected from five salt marshes on the northern shore of Cape Cod where previously restricted tidal exchange was restored to part of the marshes. Cores were collected in duplicate from two locations within each marsh complex: one upstream and one downstream from the former tidal restriction (typically caused by an undersized culvert or a berm). The unaltered, natural downstream sites provide a comparison against the historically restricted upstream sites. The sampled cores ...

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Geochemical and isotopic compositions of stream sediment, parent rock, and nearshore sediment from southwest Puerto Rico, April 2017-June 2018

Geochemical and isotopic compositions were determined in stream sediment and parent rocks collected in April 2017 and June 2017 and in nearshore sediment collected bimonthly in sediment traps from May 2017 to June 2018 in the coastal zone and 12 drainages of southwest Puerto Rico: Rio Loco, Yauco, Guayanilla, Macana, Tallaboa, Matilde, Portugues, Bucana, Inabon, Jacaquas, Descalabrado, and Coamo. Geochemical compositional data include: a) total contents of major, minor, trace, and rare earth elements in the ...

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Mineralogy, rare earth elements, and strontium isotopic composition of phosphorites and phosphatized rocks from the Rio Grande Rise, south Atlantic Ocean

Phosphorites and phosphatized rocks from the summit of the Rio Grande Rise (RGR) in the south Atlantic Ocean were collected via dredge during the oceanographic research cruise RGR1 to the western RGR. The location (latitude, longitude, depth), mineralogy, concentrations of phosphorus and rare earth elements, and 87Sr/86Sr ratios of phosphorites and phosphatized FeMn crusts, ironstones, and carbonates from 10 dredge sites are presented here. These data were used to determine the presence of carbonate ...

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Radiocarbon dating of deep-sea black corals collected off the southeastern United States

Results of radiocarbon dating of deep-sea (500 m to 700 m) black corals are presented. These corals were collected off the southeastern United States as part of the Southeastern United States Deep-Sea Corals (SEADESC) Initiative.

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Census counts of benthic foraminifera, environmental parameters (temperature, salinity, and oxygen concentration), and radiocarbon measurements from cores obtained under and near a whale-fall off western Vancouver Island, British Columbia, Canada

This data release provides census counts of benthic foraminifera (in percent for the total fauna and as raw counts for just the living specimens) as well as environmental parameters (temperature, salinity, and oxygen concentration) at the sampling sites, and radiocarbon measurements from selected push core samples obtained under and near a whale-fall off western Vancouver Island, British Columbia, Canada.

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Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016

This data release is an archive of sedimentary field and laboratory analytical data collected in Grand Bay, Alabama/Mississippi from 2014-2016 by scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). This work, a component of the SPCMSC’s Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project, provides the necessary data to quantify sedimentation rates and sediment sources for the marsh and estuary. The SSIEES project ...

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Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016 (ver. 1.1, April 2020)

This data release is an archive of sedimentary field and laboratory analytical data collected in Grand Bay, Alabama/Mississippi from 2014-2016 by scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). This work, a component of the SPCMSC’s Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project, provides the necessary data to quantify sedimentation rates and sediment sources for the marsh and estuary. The SSIEES project ...

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Descriptive core logs, high-resolution images and derived data for Holocene reef cores collected from 1976 to 2017 along the Florida Keys reef tract

The USGS core archive (Reich and others, 2009; https://olga.er.usgs.gov/coreviewer/) houses an extensive collection of coral-reef cores that USGS researchers have collected from throughout the Florida Keys reef tract (FKRT). USGS scientists have compiled all available data on the 71 core records that recovered Holocene reef framework, including radiometric ages (radiocarbon and U-series), data on reef development (timing of reef initiation and senescence, reef accretion, and reef thickness) and geospatial ...

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Local radiocarbon reservoir age (Delta-R) variability from the nearshore and open-ocean environments of the Florida Keys reef tract during the Holocene and associated U-series and radiocarbon data (Marine13 Radiocarbon Calibration Curve)

Holocene-aged corals from reef cores collected throughout the Florida Keys reef tract (FKRT) were dated using a combination of U-series and radiocarbon techniques to quantify the millennial-scale variability in the local radiocarbon reservoir age (ΔR) of the shallow water environments of south Florida. ΔR provides a measure of the deviation of local radiocarbon concentrations of marine environments from the global average and can be used as a tracer of oceanic circulation and local hydrology. U.S. ...

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Local radiocarbon reservoir age (ΔR) variability from the nearshore and open-ocean environments of the Florida Keys reef tract during the Holocene and associated U-series and radiocarbon data (Marine20 Radiocarbon Calibration Curve)

68 Holocene-aged corals from reef cores collected throughout the Florida Keys reef tract (FKRT) were dated using a combination of U-series and radiocarbon techniques to quantify the millennial-scale variability in the local radiocarbon reservoir age (ΔR) of the shallow water environments of south Florida. ΔR provides a measure of the deviation of local radiocarbon concentrations of marine environments from the global average and can be used as a tracer of oceanic circulation and local hydrology. U.S. ...

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The absolute and relative composition of Holocene reef cores collected between 1976 and 2017 from the Florida Keys reef tract

This data release provides a summary of the absolute percent composition of all recovered material and relative percent composition of coral taxa in the Holocene-aged intervals of 61 coral-reef cores collected throughout the Florida Keys reef tract (FKRT) housed in the USGS Core Archive in St. Petersburg, FL (Estimated ages for distinct depths within each core are also provided; those ages were either measured by radiometric dating of coral samples at those depths or estimated by linear interpolation ...

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Radiometric ages and descriptive data for Holocene corals from southeast Florida

This data release compiles descriptive information (location, water depth, etc.) and radiometric ages from corals collected through the Southeast Florida Continental Reef Tract (SFCRT; Figure 1). The database includes data from studies published between 1977 and 2015 as well as previously unpublished data. The samples were originally collected using coral-reef coring or other geologic sampling methods. Many of the samples are presently stored in the U.S. Geological Survey (USGS) Core Archive at the St. ...

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South Florida Holocene coral sea-level database for samples collected from 1977 to 2017

Holocene-aged coral samples from the south Florida region were extensively characterized to create a new database of verified sea-level data. The samples were originally collected using coral-reef coring or other geologic sampling methods and were obtained by various researchers from published studies spanning the interval of 1977 to 2017. Many of these samples are presently stored in the U.S. Geological Survey (USGS) Core Archive at the St. Petersburg Coastal and Marine Science Center in St. Petersburg, ...

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Static chamber gas fluxes and carbon and nitrogen isotope content of age-dated sediment cores from a Phragmites wetland in Sage Lot Pond, Massachusetts, 2013-2015

Coastal wetlands are major global carbon sinks; however, quantification of carbon flux can be difficult in these heterogeneous and dynamic ecosystems. To characterize spatial and temporal variability in a New England salt marsh, static chamber measurements of greenhouse gas (GHG) fluxes were compared among major plant-defined zones (high marsh dominated by Distichlis spicata and a zone of invasive Phragmites australis) during 2013 and 2014 growing seasons. Two sediment cores were collected in 2015 from the ...

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Radiocarbon data from coastal wetlands on the Hawaiian islands of Kaua'i, O'ahu, and Hawai'i

This portion of the data release presents radiocarbon age data from 66 samples collected from Anahola Valley (Kaua'i), Kahana Valley (O'ahu), and Pololu Valley (Hawai'i). Sample ages were determined by the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. The data are provided in a comma-delimited spreadsheet (.csv).

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Location of radiocarbon age dates sampled from vibracores collected by the U.S. Geological Survey within Apalachicola Bay, Florida, 2007 (APP-07_AgeDates, points)

In 2007, the U.S. Geological Survey collected 24 vibracores within Apalachicola Bay, Florida. The vibracores were collected using a Rossfelder electric percussive (P-3) vibracore system during a cruise on the R/V Gilbert. Selection of the core sites was based on a geophysical survey that was conducted during 2005 and 2006 in collaboration with the National Oceanic and Atmospheric Administration’s (NOAA) Coastal Services Center (CSC) and the Apalachicola Bay National Estuarine Research Reserve. Available ...

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Radiocarbon age dates for sections of 19 sediment cores from offshore Puerto Rico and the U.S. Virgin Islands collected by the U.S. Geological Survey in 2008 and Lamont-Doherty Earth Observatory in the 1960's

In 2008, as a collaborative effort between Woods Hole Oceanographic Institution and the U.S. Geological Survey, 20 giant gravity cores were collected from areas surrounding Puerto Rico and the U.S. Virgin Islands. The regions sampled have had many large earthquake and landslide events, some of which are believed to have triggered tsunamis. The objective of this coring cruise, carried out aboard the National Oceanic and Atmospheric Administration research vessel Seward Johnson, was to determine the age of ...

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Globorotalia truncatulinoides Sediment Trap Data in the Gulf of Mexico

Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of Globorotalia truncatulinoides flux occurs in winter (January, February, and March), and that encrusted and non-encrusted individuals represent calcification in distinct depth habitats. Individual foraminiferal analysis (IFA) of G. ...

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Parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and per- and polyfluoroalkyl substances (PFAS) in north San Francisco Bay, Napa River, and Sonoma Creek in 2018 and 2019

Sediment grain-size distributions, stable carbon isotope ratios (d13C), total carbon to total nitrogen ratios (C:N), short-lived radionuclides (Beryllium-7, Cesium-137, and Lead-210), concentrations of 76 parent and alkylated polycyclic aromatic hydrocarbons (PAHs) and concentrations of 33 per- and polyfluoroalkyl substances (PFAS) were measured in the northern reach of San Francisco Bay (San Pablo and Suisun Bays), and in stream beds of the lower reaches of Napa River and Sonoma Creek, 5 months and 20 ...

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Data and calculations to support the study of the sea-air flux of methane and carbon dioxide on the West Spitsbergen margin in June 2014

A critical question for assessing global greenhouse gas budgets is how much of the methane that escapes from seafloor cold seep sites to the overlying water column eventually crosses the sea-air interface and reaches the atmosphere. The issue is particularly important in Arctic Ocean waters since rapid warming there increases the likelihood that gas hydrate--an ice-like form of methane and water stable at particular pressure and temperature conditions within marine sediments--will break down and release its ...

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Comparison of methane concentration and stable carbon isotope data for natural samples analyzed by discrete sample introduction module - cavity ring down spectroscopy (DSIM-CRDS) and traditional methods

A discrete sample introduction module (DSIM) was developed and interfaced to a cavity ring-down spectrometer to enable measurements of methane and CO2 concentrations and 13C values with a commercially available cavity ring-down spectrometer (CRDS). The DSIM-CRDS system permits the analysis of limited volume (5 - 100-ml) samples ranging six orders-of-magnitude from 100% analyte to the lower limit of instrument detection (2 ppm). We demonstrate system performance for methane by comparing concentrations and ...

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Vertical chemical profiles collected across haloclines in the water column of the Ox Bel Ha cave network within the coastal aquifer of the Yucatan Peninsula in January 2015 and January 2016

Natural cave passages penetrating a coastal aquifer in the Yucatan Peninsula (Mexico) were accessed to test the hypothesis that chemoclines associated with salinity gradients (haloclines) within the flooded cave networks of the karst subterranean estuary are sites of methane oxidation. Two field trips were carried out to the fully-submerged cave system located 6.6 km inland from the coastline in January 2015 and January 2016. Vertical chemical profiles across the water column haloclines were obtained using ...

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Temporal hydrologic and chemical records from the Ox Bel Ha cave network within the coastal aquifer of the Yucatan Peninsula, from January 2015 to January 2016

Natural cave passages penetrating a coastal aquifer in the Yucatan Peninsula (Mexico) were accessed to investigate how regional meteorology and hydrology control methane dynamics in karst subterranean estuaries. Three field trips were carried out in January 2015, June 2015, and January 2016 to obtain year-long high-resolution temporal records of water chemistry and environmental parameters below and above the surface at a site (Cenote Bang) within the Ox Bel Ha cave network. These efforts resulted in ...

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Sediment and Radiochemical Characteristics from Shore-Perpendicular Estuarine and Marsh Transects in the Grand Bay National Estuarine Research Reserve, Mississippi

To examine sediment transport and provenance between a marsh and estuary, surface sediments were collected along two transects in the Grand Bay National Estuarine Research Reserve, Mississippi (GNDNERR). Each shore-perpendicular transect consisted of fifteen surface samples, collected every 2.5 meters (m) from 10-m out into the estuary to 25-m into the marsh from the shoreline. Sediment samples were analyzed for their physical and radiochemical properties or signatures. Sediment samples were collected ...

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Coastal Groundwater Chemical Data from the North and South Shores of Long Island, New York

Groundwater data were collected in the spring and fall of 2008 from three sites representing different geological settings and biogeochemical conditions within the surficial glacial aquifer of Long Island, NY. Investigations were designed to examine the extent to which average vadose zone thickness in contributing watersheds controlled biogeochemical conditions and processes, including dissolved oxygen concentration (DO), oxidation-reduction potential (Eh), dissolved organic carbon concentration (DOC), and ...

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Geochemistry of sediment and organic matter in drainages burned by the Altas and Nuns wildfires in October 2017 and of nearshore seabed sediment in north San Francisco Bay from March to April 2018

Fine-grained sediment was collected from the banks of Napa River, Sonoma Creek, and tributaries in March 2018 and from shallow nearshore areas of the northern reach of San Francisco Bay in April 2018. Bulk sediment was dated using activities of short-lived cosmogenic radionuclides (beryllium-7, cesium-137, and lead-210). Contents of potentially toxic metals and source-rock-indicative elements, including rare earth elements, were quantified in the fine fraction of sediment (particles less than 0.063 mm ...

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Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016

This data release is an archive of sedimentary field and laboratory analytical data collected in Grand Bay, Alabama/Mississippi from 2014-2016 by scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). This work, a component of the SPCMSC’s Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project, provides the necessary data to quantify sedimentation rates and sediment sources for the marsh and estuary. The SSIEES project ...

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Sedimentary Data From Grand Bay, Alabama/Mississippi, 2014-2016

This data release is an archive of sedimentary field and laboratory analytical data collected in Grand Bay, Alabama/Mississippi from 2014-2016 by scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). This work, a component of the SPCMSC’s Sea-level and Storm Impacts on Estuarine Environments and Shorelines (SSIEES) project, provides the necessary data to quantify sedimentation rates and sediment sources for the marsh and estuary. The SSIEES project ...

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Sediment Radiochemical Data from Georgia, Massachusetts and Virginia Coastal Marshes

This data release is an archive of sedimentary laboratory analytical data produced by scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC) for sediment cores and surface samples collected from coastal marshes in Georgia (GA), Virginia (VA), and Massachusetts (MA). Collaborators from USGS Patuxent Wildlife Research Center (PWRC) and the Virginia Institute of Marine Science (VIMS) collected these samples in South Altamaha, GA, Mockhorn Island, VA, Goodwin ...

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Holocene evolution of sea-surface temperature and salinity in the Gulf of Mexico

Stable oxygen and carbon isotope composition (δ18O and δ13C) and magnesium-to-calcium (Mg/Ca) ratios were measured in the tests of planktic foraminiferal species, Globigerinoides ruber (white variety), in a northwestern Gulf of Mexico (GoM) sediment core 2010-GB2-GC1 collected from the Garrison Basin (26.67°N, 93.92°W) at a water depth of 1776 meters (m), aboard the R/V Cape Hatteras in April 2010. These measurements are used to generate sub-centennial-scale reconstructions of sea surface temperature ...

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Geochemical data supporting investigation of solute and particle cycling and fluxes from two tidal wetlands on the south shore of Cape Cod, Massachusetts, 2012-19

Assessment of geochemical cycling within tidal wetlands and measurement of fluxes of dissolved and particulate constituents between wetlands and coastal water bodies are critical to evaluating ecosystem function, service, and status. The U.S. Geological Survey and collaborators collected surface water and porewater geochemical data from a tidal wetland located on the eastern shore of Sage Lot Pond in Mashpee, Massachusetts, within the Waquoit Bay National Estuarine Research Reserve, between 2012 and 2019. ...

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Olowalu chronology and geochemistry time-series, West Maui

Chronology and time-series geochemistry data of a coral core collected from Olowalu, West Maui, Hawaii. The chronology is based on density banding, radiocarbon bomb-curve, and uranium thorium dating techniques. The geochemistry time-series data contains major and minor elements over the length of the coral life span, as measured from laser ablation inductively coupled mass spectrometry (LA-ICP-MS).

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Sediment trap and water column chemistry, Baltimore Canyon, U.S. Mid-Atlantic Bight

Time-series of sediment chemistry, including organic biomarker composition and bulk inorganic geochemical analytes, from samples collected over a one-year period in a sediment trap. The sediment traps were deployed at a depth between 603 m to 1318 m, and they were programmed to rotate a 250 mL sample bottle at 30 d intervals, delivering 12 samples during the 1-year deployment between August 2012 and June 2013. In addition, dissolved water column nutrient concentrations and water column trace element ...

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Geophysical properties, geochronologic, and geochemical data of sediment cores collected from San Pablo Bay, California, October 17-20, 2016

Geophysical properties (P-wave velocity, gamma ray density, and magnetic susceptibility), geochronologic (radiocarbon, excess Lead-210, and Cesium-137), and geochemical data (organic carbon content and 60 element contents) are reported for select vibracores collected aboard the S/V Retriever October 17-20, 2016, in San Pablo Bay, California. Geophysical properties were measured with a Geotek Multi-Sensor Core Logger (MSCL). Radiocarbon was measured by accelerator mass spectrometry (AMS). Excess Lead-210 and ...

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Geochemistry time series and growth parameters from Tutuila, American Samoa coral record

Geochemical analysis (including age-corrected radiocarbon stable isotopes, and elemental composition) and growth parameters (including calcification rate, density, and extension information) were measured from a coral core collected from a reef off the southern side of Tutuila, American Samoa. The core was collected near Matautuloa Point on 8 April 2012 in collaboration with the Ecosystem Sciences Division, Pacific Islands Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA), ...

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