This dataset includes dissolved inorganic carbon (DIC), total alkalinity and partial pressure of carbon dioxide (pCO2), nutrients, dissolved oxygen, particulate organic carbon and nitrogen (POC and PON), pigment concentrations from discrete water samples and colored dissolved organic matter (CDOM) from the profiling sensor. Data were collected during the Atlantic Zone Monitoring Program (AZMP). The AZMP was implemented in 1998 with the aim of increasing Fisheries and Oceans Canada's (DFO) capacity to understand and forecast the state of the marine ecosystem and to quantify the changes in the ocean physical, chemical and biological properties. Ocean acidification program was implemented across the AZMP in 2014 funded by the Aquatic Climate Change Adaption Services Program (ACCASP). This submission covers measurements conducted by BIO (the Maritime region, DFO) in the Scotian Shelf, encompassing from the Cabot Strait to the Gulf of Maine, during the period from 2014-09-19 to 2021-10-03.

This U.S. Geological Survey (USGS) Data Release is focused on the geochemistry of wastewater (including flowback and produced water) samples, co-produced with natural gas, collected from the Marcellus Shale Energy and Environment Laboratory (MSEEL) site. MSEEL is a long-term field site and laboratory at the Northeast Natural Energy LLC (NNE) production facility, adjacent to the Monongahela River, located in western Monongalia County, West Virginia, USA. NNE began drilling two horizontal production wells, MIP (Morgantown Industrial Park) -5H and MIP-3H, in the Marcellus Shale in 2014. The wells were completed in December 2015. Large volumes of wastewater are generated with natural gas production. These wastewaters contain organic and inorganic chemical constituents from fracturing fluids used during drilling and stimulation of gas in host rocks/shale, as well as chemical compounds that are derived from formation water and the solid shale. Many of the organic and inorganic substances in the wastewater are potentially toxic and could pose an environmental risk if released due to spills, leaks, or unsafe disposal practices. Hydraulic fracturing fluid, field blanks, wastewater, and water from the Monongahela River stored in a lined holding pond adjacent to the MIP well pad, were collected from November 2015 through April 2019. The on-site storage tank was sampled from April 2017 through April 2019. Wastewater from the MIP-5H Separator Tank was collected daily at the beginning of the study to annually by the end of the study. One sample was collected from the MIP-3H Separator Tank in May 2018. This data release includes field measurements of temperature, specific conductance, total dissolved solids (TDS), and density; laboratory measurements of pH, non-volatile dissolved organic carbon (NVDOC), alkalinity, major ions, ammonia nitrogen, trace elements, low molecular weight organic acids (LMWOA), semi-volatile hydrocarbons, radium isotopes, and stable isotopes. There are seven files (*.xlsx and .csv) in this dataset: T1_DataDictionary, T2_RestonGeochemistry, T3_Mercury, T4_MenloGeochemistry, T5_pH_Buffers, T6_QAQC, and T7_Stable_Isotopes.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean from 1995-08-07 to 1995-10-05 and retrieved during cruise NH95-2 and PACIFICA_49HG19950807. These data include ALKALINITY, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Yutaka W. Watanabe of Hokkaido University and Ko Harada of (NIRE) National Institute for Resources and Environment (now AIST) as part of the PACIFICA_49HG19950807 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

The 2.1 Ma Clear Lake Volcanic Field (Donnelly-Nolan and others, 1981) and the 174 km2 Clear Lake are located ~150 km north of San Francisco, California. Sulphur Bank Mercury Mine (SBMM) is an abandoned mine located on the eastern shore of Clear Lake that was initially worked in 1865 for sulfur, then for mercury until it closed in 1957 (White and Roberson, 1962). The mine was declared a Superfund site by the U.S. Environmental Protection Agency in 1990 because of the presence of mercury-bearing mine waste and mercury bioaccumulation in fish within Clear Lake. SBMM is underlain by a localized, fault-controlled, liquid-dominated hydrothermal system (Goff and others, 1995). Hydrothermal gases are rich in CO2 with a high contribution of mantle-derived He (Goff and Janik, 1993). We carried out surveys of CO2 flux from ground and water surfaces using the accumulation chamber method to characterize the spatial distribution of and quantify hydrothermal CO2 emissions. In an initial reconnaissance survey on February 1-2, 2023, we made 180 CO2 flux measurements across SBMM and an adjacent area east of the mine. Measured CO2 fluxes ranged from <1 to 42,624 g/m2 d, with the highest values observed in and near mine pits. Four hundred thirty-one CO2 fluxes were measured in follow-on surveys on May 8-11 and June 21, 2023, and ranged from <1 to 93,215 g/m2 d. The CO2 flux data measured in the reconnaissance and follow-on surveys are saved in two spreadsheets in the *.csv format. References Donnelly-Nolan, J.M., B.C. Jr. Hearn, G.H. Curtis, R.E. Drake, 1981. Geochronology and evolution of the Clear Lake volcanics. In: Research in The Geysers-Clear Lake Geothermal Area, Northern California. U.S. Geological Survey Professional Paper 1141, 47–60. Goff, F.E., C.J. Janik, 1993. Gas geochemistry and guide for geothermal features in the Clear Lake region, California. In: Rytuba, J.J. (Ed.), Active Geothermal Systems and Gold-Mercury Deposits in the Sonoma-Clear Lake Volcanic Fields, California. Society Economic Geologists Guidebook Series, 16, 207–261. Goff, F.E., C.J. Janik, J.A. Stimac, 1995. Sulphur Bank mine, California: an example of a magmatic rather than metamorphic hydrothermal system? Proceedings of the World Geothermal Congress, Florence, Italy, 2, 1105–1110. White, D.E., C.E. Roberson, 1962. Sulphur Bank, California, a major hot-spring quicksilver deposit. Geological Society of America, Buddington Volume, 397-428.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean and South Pacific Ocean from 1992-08-07 to 1992-10-05 and retrieved during cruise NH92-2 and PACIFICA_49HG19920807. These data include ALKALINITY, AMMONIUM, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Yutaka W. Watanabe of Hokkaido University and Kimitoshi Ishikawa of (NIRE) National Institute for Resources and Environment (now AIST) as part of the PACIFICA_49HG19920807 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean from 1996-08-07 to 1996-10-03 and retrieved during cruise NH96-2 and PACIFICA_49HG19960807. These data include ALKALINITY, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Yutaka W. Watanabe of Hokkaido University and Ko Harada of (NIRE) National Institute for Resources and Environment (now AIST) as part of the PACIFICA_49HG19960807 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean and South Pacific Ocean from 1994-08-08 to 1994-10-06 and retrieved during cruise NH94-2 and PACIFICA_49HG19940808. These data include ALKALINITY, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Akira Nishimura of Geological Survey of Japan and Yutaka W. Watanabe of Hokkaido University as part of the PACIFICA_49HG19940808 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean and South Pacific Ocean from 1994-04-13 to 1994-06-11 and retrieved during cruise 49HG19940413 and NH94-1. These data include ALKALINITY, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Yutaka W. Watanabe of Hokkaido University and Ko Harada of (NIRE) National Institute for Resources and Environment (now AIST) as part of the PACIFICA_49HG19940413 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the South Pacific Ocean from 1996-04-12 to 1996-06-10 and retrieved during cruise NH96-1 and PACIFICA_49HG19960412. These data include ALKALINITY, Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Akira Nishimura of Geological Survey of Japan and Yutaka W. Watanabe of Hokkaido University as part of the PACIFICA_49HG19960412 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.

This dataset includes biological, chemical, discrete sample, physical and profile data collected from HAKUREI MARU in the North Pacific Ocean from 2001-08-13 to 2001-10-22 and retrieved during cruise 49HG20010813 and NH01. These data include ALKALINITY, CHLOROFLUOROCARBON-11 (CFC-11), CHLOROFLUOROCARBON-113 (CFC-113), CHLOROFLUOROCARBON-12 (CFC-12), Chlorophyll a, DISSOLVED INORGANIC CARBON, DISSOLVED ORGANIC CARBON, DISSOLVED OXYGEN, HYDROSTATIC PRESSURE, NITRATE + NITRITE CONTENT (CONCENTRATION), NITRITE, PHOSPHATE, SALINITY, SILICATE, SULFUR HEXAFLUORIDE (SF6), WATER TEMPERATURE and pH. The instruments used to collect these data include CTD, Coulometer for DIC measurement and bottle. These data were collected by Fumiyasu Nishibori of (KEEC) Kansai Environmental Engineering Center, Co., LTD. (now General Environmental Technos Co., LTD.) and Yutaka W. Watanabe of Hokkaido University as part of the PACIFICA_49HG20010813 dataset. PACIFICA (PACIFic ocean Interior CArbon) was an international collaborative project for the data synthesis of ocean interior carbon and its related parameters in the Pacific Ocean. The North Pacific Marine Science Organization (PICES), Section of Carbon and Climate (S-CC) supported the project.