Emeritus Scientist
Email:
rstriegl@usgs.gov
Office Phone:
303-541-3091
ORCID:
0000-0002-8251-4659
|
A nested sampling network on the Colorado (CR) and Missouri Rivers (MR) provided data to assess impacts of large-scale reservoir systems and climate on carbon export. The Load Estimator (LOADEST) model was used to estimate both dissolved inorganic and organic carbon (DIC and DOC) fluxes for a total of 22 sites along the main stems of the CR and MR. Both the upper CR and MR DIC and DOC fluxes increased longitudinally, but the lower CR fluxes decreased while the lower MRs continued to increase. We examined multiple factors through space and time that help explain these flux patterns. Seasonal variability in precipitation and temperature, along with site-level concentration versus discharge relationships proved to...
|
Recent increases in the atmospheric concentrations of carbon dioxide and methane have emphasized the need for a more complete understanding of the processes that control carbon transfer among air, land, and water. Knowledge of the amount, rate and chemical form of carbon transfer across environmental interfaces, such as the land-air and water-air interfaces, is of particular importance. These fluxes are commonly controlled by a combination of physical, biological, and chemical processes at or near the interface. Isolation of the primary mechanisms that determine carbon transfer across the interface allows for development of process-based models that can be used for carbon mass transfer estimates at the ecosystem...
|
Areas along the Arctic coast are changing the fastest among all of Earth’s habitats due to climate change. The Arctic coast is a fragile ecosystem that provides habitat for migratory birds, endangered species, and species critical for local subsistence living. In this area, permafrost is thawing rapidly, changing how much and when water reaches rivers, ponds, lakes, wetlands and groundwater. In addition, there is also a growing interest in oil and gas resource exploration. With ongoing permafrost thaw, future warming, and interests in oil and gas extraction in the coastal plain (also known as the 1002 area) of the Arctic National Wildlife Refuge, it is urgent to improve the understanding of this area and its vulnerability...
Categories: Project;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: 2021,
Alaska,
Alaska,
Alaska CASC,
Alaska CASC, All tags...
Arctic,
Arctic,
Arctic,
CASC,
CASC,
Glaciers and Permafrost,
Glaciers and Permafrost,
Glaciers and Permafrost,
Landscapes,
Landscapes,
Landscapes,
Projects by Region,
Projects by Region,
Rivers, Streams and Lakes,
Rivers, Streams and Lakes,
Rivers, Streams and Lakes,
Sea-Level Rise and Coasts,
Sea-Level Rise and Coasts,
Water, Coasts and Ice,
Water, Coasts and Ice,
Water, Coasts and Ice, Fewer tags
|
The transport of dissolved organic matter (DOM) by rivers is an important component of the global carbon cycle, affects ecosystems and water quality, and reflects biogeochemical and hydrological processes in watersheds. Understanding the fundamental relationships between discharge and DOM concentration and composition reveals important information about watershed flow paths, soil flushing, connectivity to riparian zones, organic matter leaching, soil moisture, and climatic influences. Data to describe these processes - both magnitude and timing - is critical for modeling and predicting watershed DOM dynamics, particularly in light of land use and climate change . Despite several decades of data collection, a synthesis...
|
Recent studies have found insignificant or decreasing trends in time-series dissolved organic carbon (DOC) datasets, questioning the assumption that long-term DOC concentrations in surface waters are increasing in response to anthropogenic forcing, including climate change, land use, and atmospheric acid deposition. We used the Weighted Regressions on Time, Discharge, and Season (WRTDS) model to estimate annual flow-normalized (FN) concentrations and fluxes to determine if changes in DOC quantity and quality signal anthropogenic forcing at 10 locations in the Mississippi River Basin (MRB). Despite increases in agriculture and urban development throughout the basin, net increases in DOC concentration and flux were...
|
|
