Surface water samples were collected in the field by staff from the California Department of Water Resources and the U.S. Bureau of Reclamation at approximately 40 site locations once per month during calendar year 2023. Water isotope composition of each field sample was measured at the University of California Davis Stable Isotope Facility using GasBench-Isotope Ratio Mass Spectrometry techniques.

This dataset includes stable nitrogen-15 and carbon-13 isotope analysis data derived from freshwater aquatic and semi-aquatic primary producers, invertebrates, and fishes collected from five sampling sites (and one pilot site) within the Owens River Gorge, Mono and Inyo counties, CA, USA between 2017 and 2021. These sampling efforts were conducted in conjunction with the California Department of Fish and Wildlife’s fish population surveys and invertebrate monitoring. Fishes sampled were Owens Sucker (Catostomus fumeiventris (Miller, 1973)), hybrid Tui Chub (Siphateles bicolor snyderi (Miller, 1973) x Siphateles bicolor obesa (Girard 1856)), Rainbow Trout (Oncorhynchus mykiss (Walbaum, 1792)) and Brown Trout (Salmo trutta (Linnaeus, 1758)). Invertebrates sampled included 33 taxa and primary producers sampled consisted predominantly of stems and leaves of vascular macrophytes and non-vascular primary producers consisting of 22 taxa. This dataset includes all organism metadata (Dissection_Table.csv, Eye_Table.csv) and N15 and C13 stable isotope analysis data (Isotope_Table.csv) derived from the invertebrates, vegetation, and a representative subset of the fishes collected in this study. These data were collected to assess the effects of restoration flows on aquatic food webs and fish communities in the Owens River Gorge.

This dataset includes stable nitrogen-15 and carbon-13 isotope analysis data derived from freshwater aquatic and semi-aquatic primary producers, invertebrates, and fishes collected from five sampling sites (and one pilot site) within the Owens River Gorge, Mono and Inyo counties, CA, USA between 2017 and 2021. These sampling efforts were conducted in conjunction with the California Department of Fish and Wildlife’s fish population surveys and invertebrate monitoring. Fishes sampled were Owens Sucker (Catostomus fumeiventris (Miller, 1973)), hybrid Tui Chub (Siphateles bicolor snyderi (Miller, 1973) x Siphateles bicolor obesa (Girard 1856)), Rainbow Trout (Oncorhynchus mykiss (Walbaum, 1792)) and Brown Trout (Salmo trutta (Linnaeus, 1758)). Invertebrates sampled included 33 taxa and primary producers sampled consisted predominantly of stems and leaves of vascular macrophytes and non-vascular primary producers consisting of 22 taxa. This dataset includes all organism metadata (Dissection_Table.csv, Eye_Table.csv) and N15 and C13 stable isotope analysis data (Isotope_Table.csv) derived from the invertebrates, vegetation, and a representative subset of the fishes collected in this study. These data were collected to assess the effects of restoration flows on aquatic food webs and fish communities in the Owens River Gorge.

Stable isotope compositions (the ratios deuterium/hydrogen, oxygen-18/oxygen-16, and sulfur-34/sulfur-32) are reported for alunite, jarosite, kaolinite, silica, cinnabar, marcasite, and native sulfur from outcrops in and around the workings of the Sulphur Bank mercury mine, Lake County, California, and chemical compositions are reported, from electron microprobe analyses, for alunite and buddingtonite. Isotope analyses are given also for hydrogen sulfide gas from active fumaroles and for soluble sulfate in samples of mine waste. The waste results reflect fine grained material (particles less than 0.063 millimeter in diameter) that were taken from composites, each composite representing a particular waste pile that was active during a particular period of mining.

This dataset includes carbon-13 (d13C) and nitrogen-15 (d15N) stable isotope analysis from muscle, fin, and eye lens (laminae) tissues from Santa Ana sucker (Pantosteus santaanae) and arroyo chub (Gila orcutti) collected by the Riverside Corona Resource Conservation District (RCRCD) during a fish salvage effort in the Santa Ana River, near Colton, California, USA, on November 19, 2019. This data release includes all animal taxa and isotope values.

The goal of this study was to develop a suite of inter-related water quality monitoring approaches capable of modeling and estimating the spatial and temporal gradients of particulate and dissolved total mercury (THg) concentration, and particulate and dissolved methyl mercury (MeHg), concentration, in surface waters across the Sacramento / San Joaquin River Delta (SSJRD). This suite of monitoring approaches included: a) data collection at fixed continuous monitoring stations (CMS) outfitted with in-situ sensors, b) spatial mapping using boat-mounted flow-through sensors, and c) satellite-based remote sensing. The focus of this specific Child Page is to present laboratory measured spectral data associated with discrete surface water samples collected as part of both the CMS and boat mapping sampling efforts. All laboratory-based measurement presented herein were conducted by the U.S. Geological Survey (USGS) Organic Matter Research Laboratory (OMRL) in Sacramento, Calif. The machine-readable (comma separated value, *.csv) files presented herein include spectral data collected using two different instruments: 1) Laboratory-based absorbance and fluorescence measurements on filtered water using an Aqualog (Hansen and others, 2018) and 2) Laboratory-based absorption measurements using a Varian Cary spectrophotometer on particulate samples collected on glass fiber filters (Kishino and others, 1985; Roesler, 1998). The reported spectral data includes: 1) fluorescence intensities across a wide range of excitation (240 to 800 nm) and emission (250 to 800 nm) wavelengths expressed as an excitation-emission matrix (EEM), 2) absorbance of light (from 239 nm to 800 nm) due to dissolved and colloidal substances, and 3) absorption coefficients (from 350 nm to 715 nm) for particulates using the quantitative filter technique (QFT).

Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC), located in the northern San Francisco Bay Delta (SFBD). Data was collected on 10/01/2014 for an approximate 4-hour period (10:30 – 14:30 h PST) while underway on the R/V Mary Landsteiner, a 26-foot USGS vessel. Sample water was pumped continuously through a pickup tube, passed through a 178 micron pre-filter, a de-bubbler, and diverted through a 0.2 micron filter and an unfiltered flow path to water quality instrumentation. The real-time data were recorded using a Campbell Scientific CR-6 data logger. Water isotopes (δ2H, δ18O) were logged to a separate CSV file in real-time. Methods of collection and instrumentation configuration are outlined in Downing et al. 2016. Water quality data was processed using a Microsoft Excel (v. 15.0) macro designed to remove outliers using a 20 second median, followed by a 30 second average. Isotope data was normalized to the VSMOW-SLAP scale using methods described in Downing et al. 2016. Data was merged into one Microsoft Excel file in MATLab. The data file includes: date, time, latitude, longitude, estimated boat distance, estimated boat speed, temperature, specific conductance, pH, dissolved oxygen, turbidity, fDOM, Chlorophyll-a, Phycocyanin, transmission and attenuation (670 nm), nitrate, water isotopes (δ2H, δ18O), calculated evaporation to inflow ratio, standard deviation of evaporation to inflow ratio, calculated water residence time, and standard deviation of water residence time. These data support the following publication: Using continuous underway isotope measurements to map water residence time in hydrodynamically complex tidal environments. Downing, B.D., Brian A. Bergamaschi, Carol Kendall, Tamara E.C. Kraus, Kate J. Dennis, Jeffery A. Carter, and Travis S. von Dessonneck. Environmental Science & Technology 2016 50 (24), 13387 – 133396. DOI: 10.1021/acs.est.6b05745.

Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC), located in the northern San Francisco Bay Delta (SFBD). Data was collected on 10/01/2014 for an approximate 4-hour period (10:30 – 14:30 h PST) while underway on the R/V Mary Landsteiner, a 26-foot USGS vessel. Sample water was pumped continuously through a pickup tube, passed through a 178 micron pre-filter, a de-bubbler, and diverted through a 0.2 micron filter and an unfiltered flow path to water quality instrumentation. The real-time data were recorded using a Campbell Scientific CR-6 data logger. Water isotopes (δ2H, δ18O) were logged to a separate CSV file in real-time. Methods of collection and instrumentation configuration are outlined in Downing et al. 2016. Water quality data was processed using a Microsoft Excel (v. 15.0) macro designed to remove outliers using a 20 second median, followed by a 30 second average. Isotope data was normalized to the VSMOW-SLAP scale using methods described in Downing et al. 2016. Data was merged into one Microsoft Excel file in MATLab. The data file includes: date, time, latitude, longitude, estimated boat distance, estimated boat speed, temperature, specific conductance, pH, dissolved oxygen, turbidity, fDOM, Chlorophyll-a, Phycocyanin, transmission and attenuation (670 nm), nitrate, water isotopes (δ2H, δ18O), calculated evaporation to inflow ratio, standard deviation of evaporation to inflow ratio, calculated water residence time, and standard deviation of water residence time. These data support the following publication: Using continuous underway isotope measurements to map water residence time in hydrodynamically complex tidal environments. Downing, B.D., Brian A. Bergamaschi, Carol Kendall, Tamara E.C. Kraus, Kate J. Dennis, Jeffery A. Carter, and Travis S. von Dessonneck. Environmental Science & Technology 2016 50 (24), 13387 – 133396. DOI: 10.1021/acs.est.6b05745.