The U.S. Geological Survey (USGS) California Water Science Center (CAWSC) Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as proxies for more expensive and difficult to obtain measurements. These techniques are relatively rapid and inexpensive and allow for the comprehensive tracking of DOM dynamics in aquatic ecosystems ranging from rivers and lakes to estuaries to open marine systems. Laboratory fluorescence measurements collected on the Aqualog can provide validation or verification of field-based instrument fluorescence measurements where the sensor arrays are encompassed by the full Aqualog array (Booth and others, 2023). This approach may be superior to the other correction approaches where interferences are large, especially in cases where the field sensor measurements constitute less than 10% of the fully corrected value. For projects that already collect discrete samples during field sensor maintenance visits, the cost and effort is minimal for the data quality benefit. Data presented here were analyzed by the U.S Geological Survey California Water Science Center Organic Matter Research Lab, Sacramento CA. This release contains vectorized fluorescence data measured on the Aqualog ® fluorometer January-December 2022.

The USGS CAWSC Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as proxies for more expensive and difficult to obtain measurements. These techniques are relatively rapid and inexpensive and allow for the comprehensive tracking of DOM dynamics in aquatic ecosystems ranging from rivers and lakes to estuaries to open marine systems. Absorbance spectra and fluorescence matrices were simultaneously collected on filtered water samples at room temperature (21 °C) in an acid-cleaned 1 cm quartz cuvette using a spectrofluorometer equipped with a charge-coupled device (CCD) (Aqualog®, Horiba Instruments, New Jersey, U.S.A.). Excitation and absorbance scans were performed using a double-grating monochrometer, a 150 W Xenon arc lamp, a 5 nm bandpass, and a 1 s integration time at wavelengths of 240-800 nm. Emission spectra were collected with a CCD at approximately 2.3 nm (4 pixel) intervals at wavelengths of 245–800 nm. Excitation and absorbance wavelengths were scanned from low to high energy (i.e., VIS to UV) to reduce UV exposure of the sample, thus limiting the effects of photobleaching during analysis. Laboratory fluorescence measurements collected on the Aqualog can provide validation or verification of field-based instrument fluorescence measurements where the sensor arrays are encompassed by the full Aqualog array (Booth and others, 2023). This approach may be superior to the other correction approaches where interferences are large, especially in cases where the field sensor measurements constitute less than 10% of the fully corrected value. For projects that already collect discrete samples during field sensor maintenance visits, the cost and effort is minimal for the data quality benefit. Data presented here were analyzed by the U.S Geological Survey California Water Science Center Organic Matter Research Lab, Sacramento CA. This release contains vectorized fluorescence data measured on the Aqualog ® fluorometer January-December 2021.

The USGS CAWSC Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as proxies for more expensive and difficult to obtain measurements. These techniques are relatively rapid and inexpensive and allow for the comprehensive tracking of DOM dynamics in aquatic ecosystems ranging from rivers and lakes to estuaries to open marine systems. Absorbance spectra and fluorescence matrices were simultaneously collected on filtered water samples at room temperature (21 °C) in an acid-cleaned 1 cm quartz cuvette using a spectrofluorometer equipped with a charge-coupled device (CCD) (Aqualog®, Horiba Instruments, New Jersey, U.S.A.). Excitation and absorbance scans were performed using a double-grating monochrometer, a 150 W Xenon arc lamp, a 5 nm bandpass, and a 1 s integration time at wavelengths of 240-800 nm. Emission spectra were collected with a CCD at approximately 2.3 nm (4 pixel) intervals at wavelengths of 245–800 nm. Excitation and absorbance wavelengths were scanned from low to high energy (i.e., VIS to UV) to reduce UV exposure of the sample, thus limiting the effects of photobleaching during analysis. Laboratory fluorescence measurements collected on the Aqualog can provide validation or verification of field-based instrument fluorescence measurements where the sensor arrays are encompassed by the full Aqualog array (Booth and others, 2023). This approach may be superior to the other correction approaches where interferences are large, especially in cases where the field sensor measurements constitute less than 10% of the fully corrected value. For projects that already collect discrete samples during field sensor maintenance visits, the cost and effort is minimal for the data quality benefit. Data presented here were analyzed by the U.S Geological Survey California Water Science Center Organic Matter Research Lab, Sacramento CA. This release contains vectorized fluorescence data measured on the Aqualog ® fluorometer January-December 2021.

The U.S. Geological Survey (USGS) California Water Science Center (CAWSC) Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as proxies for more expensive and difficult to obtain measurements. These techniques are relatively rapid and inexpensive and allow for the comprehensive tracking of DOM dynamics in aquatic ecosystems ranging from rivers and lakes to estuaries to open marine systems. Data presented here were analyzed by the U.S Geological Survey California Water Science Center Organic Matter Research Lab, Sacramento CA. This release contains full spectra absorbance data measured on the Aqualog ® fluorometer January-December 2022.

The USGS CAWSC Organic Matter Research Laboratory (OMRL) provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy. Optical measurements such as absorbance and fluorescence are used to gain insight into dissolved organic matter (DOM) composition, and can also serve as proxies for more expensive and difficult to obtain measurements. These techniques are relatively rapid and inexpensive and allow for the comprehensive tracking of DOM dynamics in aquatic ecosystems ranging from rivers and lakes to estuaries to open marine systems. Absorbance spectra and fluorescence matrices were simultaneously collected on filtered water samples at room temperature (21 °C) in an acid-cleaned 1 cm quartz cuvette using a spectrofluorometer equipped with a charge-coupled device (CCD) (Aqualog®, Horiba Instruments, New Jersey, U.S.A.). Excitation and absorbance scans were performed using a double-grating monochrometer, a 150 W Xenon arc lamp, a 5 nm bandpass, and a 1 s integration time at wavelengths of 240-800 nm. Emission spectra were collected with a CCD at approximately 2.3 nm (4 pixel) intervals at wavelengths of 245–800 nm. Excitation and absorbance wavelengths were scanned from low to high energy (i.e., VIS to UV) to reduce UV exposure of the sample, thus limiting the effects of photobleaching during analysis. Data presented here were analyzed by the U.S Geological Survey California Water Science Center Organic Matter Research Lab, Sacramento CA. This release contains full spectra absorbance data measured on the Aqualog ® fluorometer January-December 2021.

Optical sensors measuring fluorescence of non-biological sources (e.g., dissolved organic matter, wastewater, hydrocarbons, fluorescent dyes, etc.; hereafter referred to as fDOM) are increasingly used in water quality studies because they provide proxy measurements for a variety of contaminants and constituents of concern including metals, wastewater effluent, and DOM (measured in the lab as dissolved organic carbon, (DOC)) concentrations. Similarly, sensors measuring biological (algal) fluorescence (hereafter referred to as chlorophyll (fChl) and phycocyanin (fPC), have gained popularity to measure phytoplankton concentration, biomass, and even primary productivity. As additional sensors are coupled with ongoing field monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e., pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field, allowing for the standardization of United States Geological Survey (USGS) measurements across the entire agency. Here, we present the results of testing a multiparameter field standard (MPFS), an experimental mixed standard solution capable of simultaneously verifying calibrations for multiple fluorescence sensors (fDOM, fChl, and fPC).

Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various approaches. As additional sensors are grouped for in situ monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e. pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field to standardize USGS measurements among sensors and across the landscape. Here, we present the results of a mixed standard solution capable of simultaneously verifying calibrations for multiple sensors including fluorescence of dissolved organic matter (fDOM) and fluorescence of chlorophyll-a (fChl).

Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various approaches. As additional sensors are grouped for in situ monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e. pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field to standardize USGS measurements among sensors and across the landscape. Here, we present the results of a mixed standard solution capable of simultaneously verifying calibrations for multiple sensors including fluorescence of dissolved organic matter (fDOM) and fluorescence of chlorophyll-a (fChl).

Optical sensors measuring fluorescent dissolved organic matter (fDOM) are increasingly being used in water quality studies because they provide proxy measurements for dissolved organic matter concentrations (DOC). Similarly, chlorophyll-a (chl-a) fluorescence sensors have gained popularity as a means to measure phytoplankton concentration, biomass, and even primary productivity using various approaches. As additional sensors are grouped for in situ monitoring, field calibration checks are becoming quite time consuming for even the basic set of sensors (i.e. pH, specific conductivity, turbidity) that require ongoing verification over timescales ranging from weekly to semi-annual intervals. As such, there is a critical need to establish a means to verify calibrations using a simple, fast, and efficient method in the field to standardize USGS measurements among sensors and across the landscape. Here, we present the results of a mixed standard solution capable of simultaneously verifying calibrations for multiple sensors including fluorescence of dissolved organic matter (fDOM) and fluorescence of chlorophyll-a (fChl).

Here we report optical data collected as part of a collaborative study between USGS Pennsylvania Water Science Center, Pennsylvania Department of Environmental Protection and Water Mission Area Proxies Project. The optical measurements reported here were collected to aide in the characterization of water sources and mixtures and establish proxies (surrogates) for per- and poly-fluorinated alkyl substances within the Neshaminy Creek basin. Data are compiled into three tables: 1) full fluorescence spectra in vectorized format, 2) full absorbance spectra, and 3) summary file of commonly extracted optical indicators and field-based sensor arrays.