Filters: Tags: biogeochemical cycles (X)
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This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 This dataset is a single comma-delimited text file (.csv). Data include the name of lakes where samples were obtained, the historical dynamics of that lake, the sampled community type, and the dry mass of annual new growth. Shrub community measurements are a combination of understory mass from quadrat harvests and shrub stem mass derived from published allometric equations.
This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 This dataset is a single comma-delimited text file (.csv). Data include the name of lakes where samples were obtained, soil pH, electrical conductivity (EC), water content (VWC), and bulk density (BD) of soil core samples within organic soil horizon in lake-margin wetland plant communities.
This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 Total and organic carbon values from soil samples taken from the Yukon River Basin, Alaska. These samples were used to create a relationship between total carbon and organic carbon for samples which were only run for total carbon.
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/2014GL060199/abstract): While recent work demonstrates that glacial meltwater provides a substantial and relatively labile flux of the micronutrient iron to oceans, the role of high-latitude estuary environments as a potential sink of glacial iron is unknown. Here we present the first quantitative description of iron removal in a meltwater-dominated estuary. We find that 85% of “dissolved” Fe is removed in the low-salinity region of the estuary along with 41% of “total dissolvable” iron associated with glacial flour. We couple these findings with hydrologic and geochemical data from Gulf of Alaska (GoA) glacierized catchments to calculate meltwater-derived...
Categories: Publication;
Types: Citation;
Tags: Biogeochemistry,
Geochemical cycles,
Glaciers and Permafrost,
National CASC,
Rivers, Streams and Lakes,
This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 This dataset is a single comma-delimited text file (.csv). Data include the name of lakes where samples were obtained, soil core dimensions, bulk density, and carbon/nitrogen content of soil core samples within the organic soil horizon in lake-margin wetland plant communities.
We identified nine study site locations, representing three mature vegetation communities [Atlantic White Cedar (desired community), tall pine pocosin (desired community), and red maple/black gum mixed (undesired community)] with typical water depth within each vegetation type. All measurements were replicated three times (3 vegetation types x 3 replicates = 9 sites total). We installed four flux chambers at each site to collect GHG fluxes from all nine sites. We measured CO2 and CH4 using a Los Gatos Research Ultra Portable Greenhouse Gas Analyzer and two-part 760 cm2 flux chambers (chamber base remained in situ; chamber top was placed on the bottom only when sampling). We checked the gas fluxes on a monthly time-table...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Ecology,
Geochemistry,
Great Dismal Swamp National Wildlife Refuge,
Land Use Change,
Soil Sciences,
Scientific research on the global carbon cycle has emerged as a high priority in biogeochemistry, climate studies, and global change policy. The emission of carbon dioxide (CO2) from fossil fuel combustion is a dominant driver of the current net carbon fluxes between the land, the oceans, and the atmosphere, and it is a key contributor to the rise in modern radiative forcing. Contrary to a commonly held perception, our quantitative knowledge about these emissions is insufficient to satisfy current scientific and policy needs. A more highly spatially and temporally resolved quantification of the social and economic drivers of fossil fuel combustion, and the resulting CO2 emissions, is essential to supporting scientific...
Categories: Publication;
Types: Citation;
Tags: Carbon cycling,
Science polic,
biogeochemical cycles
This data release includes six child items of soil and vegetation data from lake margin soils of the Yukon Flats National Wildlife Refuge, Alaska. Data includes multiple lakes that are defined as either stable or drying. Lake margin vegetation communities include graminoid, shrub, and forest. Sols are separated into organic and mineral layers. Microbial data includes different phospholipid fatty acids and soil enzyme activity data for multiple enzymes involved in C,N, and P cycling. Data also includes information on respiration rate constants (k) and labile substrate pool (Ao) from soil incubations. Other soil chemical attributes such as soil pH, electrical conductivity, percent C and percent N are also included....
There is currently have a very poor understanding of how climate change will affect food web structure and mercury accumulation in lakes on the Arctic Coastal Plain of Alaska. In this study, researchers are addressing this knowledge gap by adopting a space-for-time approach. Fish and food web ecology, and mercury accumulation patterns, are being investigated in several lakes that represent a gradient in temperature/ice phenology of up to two ice-free weeks and 10°C. They are also comparing food web structure and rates of mercury biomagnification among the lakes, and relating these to several climate variables. Finally, they are relating past trends in mercury accumulation in lake sediments to indices of lake productivity...
Categories: Data,
Project;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Academics & scientific researchers,
BIOGEOCHEMICAL CYCLES,
BIOGEOCHEMICAL CYCLES,
CONTAMINANTS,
CONTAMINANTS,
These are data from cruises carried out in April, May and July 2010 from the Copper River (AK) mouth to beyond the shelf break, approximately 150 km from shore. The focus of the dataset is the iron (Fe) data, intended to help infer the processes controlling concentrations of Fe. The data include concentrations of total dissolvable Fe (TDFe), dissolved Fe (dFe), nitrate, and salinity, temperature and fluorescence data (CTD) as background. This also includes sea surface height deviation data for a two month interval when a Yakutat eddy passed by the sampling site. Also included is a simple 1-dimensional numerical model used to simulate the the April DFe data assuming a DFe flux from shelf sediments, horizontal transport...
The episodic nature of water availability in arid and semiarid ecosystems has significant consequences on belowground carbon and nutrient cycling. Pulsed water events directly control belowground processes through soil wet-dry cycles. Rapid soil microbial response to incident moisture availability often results in almost instantaneous C and N mineralization, followed by shifts in C/N of microbially available substrate, and an offset in the balance between nutrient immobilization and mineralization. Nitrogen inputs from biological soil crusts are also highly sensitive to pulsed rain events, and nitrogen losses, particularly gaseous losses due to denitrification and nitrate leaching, are tightly linked to pulses of...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Oecologia,
Springer Berlin / Heidelberg,
biogeochemical cycles,
carbon cycling,
nitrogen mineralization,
This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 This dataset includes soil properties and microbial data from lake margin soils throughout the Yukon Flats National Wildlife Refuge. Data include multiple lakes that are defined as either stable or drying. Lake margin vegetation communities include graminoid, shrub, and forest. Sols are separated into organic and mineral layers. Microbial data includes different phospholipid fatty acids and soil enzyme activity data for multiple enzymes involved in C,N, and P cycling. Data also includes information on respiration rate constants (k) and labile substrate pool (Ao) from soil incubations.
This is a child item of the USGS Data Release: https://doi.org/10.5066/P9QF8RR5 The file contains ocular percent cover estimates for eight plant functional types occurring in lake-margin wetland plant communities in the Yukon River floodplain within the Yukon Flats National Wildlife Refuge. Observations were collected along up to four 100-meter linear transects oriented perpendicular to the lakeshore. Eight cover classes were used, and the median % cover for each cover class is shown in the dataset. Separate percent cover observations were recorded for each of eight distinct plant community encountered along each transect. Community types were associated with one of three aggregate community types (Grass/Sedge,...
Climate change and climate variability, population growth, and land use change drive the need for new hydrologic knowledge and understanding. In the mountainous West and other similar areas worldwide, three pressing hydrologic needs stand out: first, to better understand the processes controlling the partitioning of energy and water fluxes within and out from these systems; second, to better understand feedbacks between hydrological fluxes and biogeochemical and ecological processes; and, third, to enhance our physical and empirical understanding with integrated measurement strategies and information systems. We envision an integrative approach to monitoring, modeling, and sensing the mountain environment that will...
Categories: Publication;
Types: Citation;
Tags: biogeochemical cycles,
energy balance,
global change
We identified nine study site locations, representing three mature vegetation communities [Atlantic White Cedar (desired community), tall pine pocosin (desired community), and red maple/black gum mixed (undesired community)] with typical water depth within each vegetation type. All measurements were replicated three times (3 vegetation types x 3 replicates = 9 sites total). We installed four flux chambers at each site to collect GHG fluxes from all nine sites. We measured CO2 and CH4 using a Los Gatos Research Ultra Portable Greenhouse Gas Analyzer and two-part 760 cm2 flux chambers (chamber base remained in situ; chamber top was placed on the bottom only when sampling). We checked the gas fluxes on a monthly time-table...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Ecology,
Geochemistry,
Great Dismal Swamp National Wildlife Refuge,
Land Use Change,
Soil Sciences,
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