Filters: Tags: cesium-137 (X)
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Specific activities of cesium-137 (half life = 30.17 years), lead-210 (half life = 22.3 years), radium-226 (half life = 1,600 years), thorium-234 (half life = 24.1 days), and potassium-40 (half life = 1.277 billion years) in disintegrations per minute per gram (dpm/g) were determined for the Lake Lanier cores. The laboratory errors (plus or minus) and the critical levels are included for each sample.
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 represent a chronosequence of restoration occurring between 2001–10. Collected cores were up to 168 cm in length with dry bulk density ranging from 0.04 to 2.62 grams per cubic centimeter and carbon content 0.12 %...
Categories: Data;
Tags: Barnstable County (606927),
Bass Creek (617465),
Boat Meadow River (616844),
Cape Cod (606914),
Cape Cod Canal (619536),
Patrick Bayou, a section of the Houston Ship Channel near Deer Park, Texas, has accumulated permitted industrial wastewater discharges, municipal wastewater treatment plant effluent, and stormwater runoff from adjacent industrial facilities and nearby urban and residential areas. These discharges are suspected to be the primary sources of the sediment contamination in the Patrick Bayou section of the Houston Ship Channel near Deer Park, Texas. The U.S. Environmental Protection Agency (EPA) placed Patrick Bayou on the Superfund program’s National Priorities List because of sediment contamination detected in the wetlands bordering Patrick Bayou, posing a threat to downstream fisheries. The U.S. Geological Survey (USGS),...
The sustainability of coastal wetlands largely hinges on their ability to accrue elevation capital at a rate that equals or exceeds relative sea-level rise. A better understanding of these processes is needed to accurately assess the sustainability of these landscapes, and to predict their response to restoration measures such as sediment delivery through river diversions.
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Barataria basin,
Gulf of Mexico,
Louisiana,
USGS Science Data Catalog (SDC),
[u'Ecology',
This dataset contains vertical profiles of soil bulk density, percent organic matter, percent total carbon and cesium-137 activity from the surface down to 50-60 cm deep at 25 marsh locations across Breton Sound basin, Louisiana. These data will provide information related to rates of vertical accretion, organic and mineral accumulation and carbon burial in wetland soils across a large portion of the Mississippi River delta plain.
Categories: Data;
Tags: Breton Sound basin,
Gulf of Mexico,
Louisiana,
Soil Sciences,
USGS Science Data Catalog (SDC),
Strontium isotope (87Sr/86Sr) profiles in sediment cores collected from two subtidal harbor slips in the lower Hudson River estuary in October 2001 exhibit regular patterns of variability with depth. Using additional evidence from sediment Ca/Sr ratios, 137Cs activity and Al, carbonate (CaCO3), and organic carbon (OCsed) concentration profiles, it can be shown that the observed variability reflects differences in the relative input and trapping of fine-grained sediment from seaward sources vs. landward sources linked to seasonal-scale changes in freshwater flow. During high flow conditions, the geochemical data indicate that most of the fine-grained sediments trapped in the estuary are newly eroded basin materials....
Categories: Publication;
Types: Citation;
Tags: Cesium-137,
Hudson River estuary,
estuaries,
sediment
To parameterize accretion for SLR models, we measured historic rates of mineral and organic matter accumulation at each site by collecting deep soil cores with a Russian peat borer. At each site, we obtained cores in each of three vegetation zones: low, medium, and high marsh. Two replicate cores were sampled from each station for a total of 6 cores per site (except Coos Bay where 7 cores were taken). Coring locations were determined by RTK GPS elevation and tidal inundation data. Transects for core sampling were determined in ArcGIS, using a digitial elevation model and site-specific tidal datums to choose station locations below MHW (low), between MHW and MHHW (mid), and above MHHW (high). Sediment cores were...
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 elevations, at about 1.41 to 1.51 meters relative to the North American Vertical Datum of 1988, and similar salt marsh grass communities, dominated by Spartina patens, S. alterniflora, and Distichlis spicata. Permanently...
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