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.

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 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. 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. 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.

Carbon (C) and nitrogen (N) extracted from soil with water are associated with available plant nutrients and microbial activity, but information about how C and N have changed over time in the U.S. Great Plains is sparse. Optical measurements of absorbance and fluorescence were used to compare dissolved organic matter (DOM) extracted from historic (1947) and contemporary (2018) soil samples collected from Moccasin, MT, Akron, CO, and Big Spring, TX. Extracts were prepared at two temperatures (20 and 80 degrees Celsius) associated with different DOM pools to evaluate changes to soil DOM composition after 71 years of dryland farming practices. Together, water extracts and subsequent optical methods can produce insights into long term patterns of soil change while conserving limited and irreplaceable physical samples of archived soil.

This dataset, “AquaMatch Dissolved Organic Carbon Data from Water Quality Portal ~1970-2024”, is a component of a forthcoming update to AquaSat (Ross et al., 2019), AquaSat version 2 (“V2”). The overarching purpose of AquaSat V2 is to emphasize the individual parts of the AquaSat pipeline that make-up the matchups between satellite and in-situ measurements. As such, we have greatly expanded and improved upon the AquaSat dissolved organic carbon dataset in two ways: First, we have incorporated additional recent in situ data beyond what was available at the publication of AquaSat. Second, we have created a data quality tiering system to provide end-users with more guidance on data usage. In this schema we have three tiers: restrictive data that are verifiably self-similar across organizations and time-periods and can be considered highly reliable; narrowed data that we have good reason to believe are self-similar, but for which we cannot verify full compatibility across data providers; and inclusive data, which are assumed to be reliable and are harmonized to our best ability given the information available from the data provider. We have also added flag columns to help users understand complexities of the available depth and field sampling data. This dataset is a derived data product created using records downloaded from the Water Quality Portal (WQP) spanning January 5, 1970, to June 27, 2024. The WQP is a data warehouse for water-related data measured or observed within the United States and US territories managed by the Environmental Protection Agency, United States Geological Survey, and the National Water Quality Monitoring Council. The dataset does not contain remote sensing matchups but can be paired with Landsat surface reflectances using the pipeline presented in Ross et al. (2019). Ross, M. R. V., Topp, S. N., Appling, A. P., Yang, X., Kuhn, C., Butman, D. et al. (2019). AquaSat: A data set to enable remote sensing of water quality for inland waters. Water Resources Research, 55, 10012–10025. https://doi.org/10.1029/2019WR024883

This dataset, “AquaMatch Dissolved Organic Carbon Data from Water Quality Portal ~1970-2024”, is a component of a forthcoming update to AquaSat (Ross et al., 2019), AquaSat version 2 (“V2”). The overarching purpose of AquaSat V2 is to emphasize the individual parts of the AquaSat pipeline that make-up the matchups between satellite and in-situ measurements. As such, we have greatly expanded and improved upon the AquaSat dissolved organic carbon dataset in two ways: First, we have incorporated additional recent in situ data beyond what was available at the publication of AquaSat. Second, we have created a data quality tiering system to provide end-users with more guidance on data usage. In this schema we have three tiers: restrictive data that are verifiably self-similar across organizations and time-periods and can be considered highly reliable; narrowed data that we have good reason to believe are self-similar, but for which we cannot verify full compatibility across data providers; and inclusive data, which are assumed to be reliable and are harmonized to our best ability given the information available from the data provider. We have also added flag columns to help users understand complexities of the available depth and field sampling data. This dataset is a derived data product created using records downloaded from the Water Quality Portal (WQP) spanning January 5, 1970, to June 27, 2024. The WQP is a data warehouse for water-related data measured or observed within the United States and US territories managed by the Environmental Protection Agency, United States Geological Survey, and the National Water Quality Monitoring Council. The dataset does not contain remote sensing matchups but can be paired with Landsat surface reflectances using the pipeline presented in Ross et al. (2019). Ross, M. R. V., Topp, S. N., Appling, A. P., Yang, X., Kuhn, C., Butman, D. et al. (2019). AquaSat: A data set to enable remote sensing of water quality for inland waters. Water Resources Research, 55, 10012–10025. https://doi.org/10.1029/2019WR024883

Moderate Resolution Imaging Spectroradiometer on Aqua (MODISA) Level-3 Standard Mapped Image