Angela Hansen
Biography
My research focuses on source and cycling of organic carbon in aquatic environments. Much of my current work involves the investigation of organic matter optical properties–as measured by absorbance and fluorescence–to demonstrate the utility of these measurements as proxies for organic compounds (i.e. DBPs, oil/gas, wastewater, Hg, etc.). I also supervise our group’s Organic Matter Research Laboratory.
Science and Products
Biogeochemistry Group
The Biogeochemistry (BGC) Group uses an interdisciplinary approach to address surface water quality issues and food web dynamics throughout California, particularly in the Sacramento-San Joaquin Delta and San Francisco Bay.
Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys
California’s Sacramento-San Joaquin River Delta (Delta) provides drinking water to about 30 million people and irrigation water to the agriculturally rich Central Valley. The Delta is also home to numerous threatened and endangered native species. The health of the Delta's aquatic ecosystems, and fish in particular, have long been in a state of decline. This is associated with decreasing...
Table of Analysis Methods
The OMRL provides a variety of laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy along with standard measurement of total dissolved organic carbon and nitrogen concentration (DOC and TDN, respectively).
Laboratory DQOs
The OMRL monitors laboratory performance though the use of QC data. Our laboratory QC data is reviewed daily and compiled in a manner that allows reviewers to compare the QC results to the Data Quality Objectives (DQOs) listed here.
An initial comparison of pesticides and amphibian pathogens between natural and created wetlands in the New Jersey Pinelands, 2014–16
A study conducted by the U.S. Geological Survey, in cooperation with the New Jersey Pinelands Commission and Montclair State University, was designed to compare pesticide concentrations and the presence and prevalence of amphibian pathogens between natural ponds and two types of created wetlands, excavated ponds and stormwater basins, throughout...
Smalling, Kelly L.; Bunnell, John F.; Cohl, Jonathan; Romanok, Kristin M.; Hazard, Lisa; Monsen, Kirsten; Akob, Denise M.; Hansen, Angela M.; Hladik, Michelle L.; Abdallah, Nicole; Ahmed, Quratulain; Assan, Araba; De Parsia, Matthew; Griggs, Amaryl; McWayne-Holmes, Megan; Patel, Naisargi; Sanders, Corey; Shrestha, Yesha; Stout, Sean M.; Williams, Brianna
Procedures for using the Horiba Scientific Aqualog® fluorometer to measure absorbance and fluorescence from dissolved organic matter
Advances in spectroscopic techniques have led to an increase in the use of optical measurements (absorbance and fluorescence) to assess dissolved organic matter composition and infer sources and processing. Although optical measurements are easy to make, they can be affected by many variables rendering them less comparable, including by...
Hansen, Angela M.; Fleck, Jacob; Kraus, Tamara E. C.; Downing, Bryan D.; von Dessonneck, Travis; Bergamaschi, Brian
Wetlands receiving water treated with coagulants improve water quality by removing dissolved organic carbon and disinfection byproduct precursors
Constructed wetlands are used worldwide to improve water quality while also providing critical wetland habitat. However, wetlands have the potential to negatively impact drinking water quality by exporting dissolved organic carbon (DOC) that upon disinfection can form disinfection byproducts (DBPs) like trihalomethanes (...
Hansen, Angela M.; Kraus, Tamara E. C.; Bachand, Sandra M.; Horwath, William R.; Bachand, Philip A.M. Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation
Advances in spectroscopic techniques have led to an increase in the use of optical properties (absorbance and fluorescence) to assess dissolved organic matter (DOM) composition and infer sources and processing. However, little information is available to assess the impact of biological and photolytic processing on the optical properties of...
Hansen, Angela; Kraus, Tamara E. C.; Pellerin, Brian; Fleck, Jacob; Downing, Bryan D.; Bergamaschi, Brian
Mercury, monomethyl mercury, and dissolved organic carbon concentrations in surface water entering and exiting constructed wetlands treated with metal-based coagulants, Twitchell Island, California
Coagulation with metal-based salts is a practice commonly employed by drinking-water utilities to decrease particle and dissolved organic carbon concentrations in water. In addition to decreasing dissolved organic carbon concentrations, the effectiveness of iron- and aluminum-based coagulants for decreasing dissolved concentrations both of...
Stumpner, Elizabeth B.; Kraus, Tamara E.C.; Fleck, Jacob A.; Hansen, Angela M.; Bachand, Sandra M.; Horwath, William R.; DeWild, John F.; Krabbenhoft, David P.; Bachand, Philip A.M.
Scientists Launch Two-Pronged Approach to Map Cyanotoxins in Bay-Delta
Over the last few decades the Sacramento-San Joaquin River Delta has experienced declines in phytoplankton productivity and a shift in species composition resulting in observed increases in harmful algal blooms (HABs).