gov.noaa.nodc:0218895 eng utf8 dataset NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NOAA Contact Information Information for contacts at NCEI. information custodian 2025-12-14T19:41:16Z ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) Physical, chemical, and biological water quality data and CTD casts collected from NOAA R/V Shenehon in Saginaw Bay, Lake Huron in the Great Lakes region from 1991-04-12 to 1996-09-20 (NCEI Accession 0218895) 2020-09-16 publication 2020-08-24 creation NOAA National Centers for Environmental Information gov.noaa.nodc:0218895 NCEI Archive Management System 0218895 NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information publisher Lacey Mason NOAA Great Lakes Environmental Research Laboratory (GLERL) lacey.mason@noaa.gov http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information resourceProvider NOAA Great Lakes Environmental Research Laboratory (GLERL) http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information resourceProvider NOAA Great Lakes Environmental Research Laboratory (GLERL) NOAA GLERL Data Manager oar.glerl.data@noaa.gov http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information pointOfContact Lacey Mason NOAA Great Lakes Environmental Research Laboratory (GLERL) lacey.mason@noaa.gov http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information pointOfContact Reagan M. Errera NOAA Great Lakes Environmental Research Laboratory (GLERL) reagan.errera@noaa.gov http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information principalInvestigator Casey Godwin University of Michigan Cooperative Institute for Great Lakes Research (CIGLR) cgodwin@umich.edu https://ciglr.seas.umich.edu/ HTTPS University of Michigan Cooperative Institute for Great Lakes Research (CIGLR) website Institution web page information principalInvestigator Craig Stow NOAA Great Lakes Environmental Research Laboratory (GLERL) craig.stow@noaa.gov http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information principalInvestigator Nalepa, Thomas F. author Johengen, Thomas H. Cooperative Institute for Great Lakes Research, University of Michigan https://ciglr.seas.umich.edu/ HTTPS University of Michigan Cooperative Institute for Great Lakes Research (CIGLR) website Institution web page information author Fahnenstiel, Gary L. author McCormick, Michael J. author Lang, Gregory A. author Fanslow, David L. NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Cavaletto, Joann F. NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Goudy, Greg author Vanderploeg, Henry A. NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Agy, Megan A. author NOAA Great Lakes Environmental Research Laboratory (GLERL) http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information contributor tableDigital This dataset includes physical and chemical data collected in Saginaw Bay, Lake Huron from 1991 to 1996. All of these data were collected as part of a larger effort to monitor and assess the impacts of the zebra mussel (Dreissena polymorpha) on the Saginaw Bay ecosystem. Although mussels were found in the bay in 1990, the first large recruitment did not occur until the summer of 1991. Thus, the data presented herein reflect physical and chemical conditions, and subsequent changes, during the initial years of the mussel’s invasion into the bay. Soon after zebra mussels were discovered in the Great Lakes in 1988, Saginaw Bay was identified as an ideal location to assess ecological changes that might result from the filtering activities of this organism. Specific considerations that led to the decision to initiate a monitoring program in the bay were (1) at the time, the zebra mussel was not yet established in the bay, thus baseline conditions immediately prior to the mussel’s invasion could be documented; further, previous surveys of water quality parameters in 1974-80 (Smith et al., 1977; Bierman et al., 1984) could provide a longer term perspective to assess potential changes; (2) the bay had extensive areas of hard bottom, along with ideal temperature and food regimes, and thus large populations of mussels were expected to develop; (3) there existed an important commercial and sport fishery that could be affected; (4) with a natural gradient between the eutrophic inner bay and the more oligotrophic outer bay, the bay provided an opportunity to assess impacts over a wide range of trophic conditions, and; (5) the bay was an Area of Concern as designated by the International Joint Commission and the subject of remedial action by the State of Michigan. After a decade of little or no monitoring in the bay, surveys of selected physical and chemical variables not only provided information to assess changes induced by the zebra mussel, but they also provided information to assess the bay’s response to continued efforts to improve water quality. Funding Agency: Congressional appropriation through the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 Funding Agency: NOAA Great Lakes Environmental Research Laboratory completed historicalArchive NOAA National Centers for Environmental Information ncei.info@noaa.gov https://www.ncei.noaa.gov/contact HTTPS NCEI Contact Information Information for contacts at NCEI. information pointOfContact asNeeded https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:0218895 Preview graphic PNG 0218895 NCEI ACCESSION NUMBER 2020-06-26 publication AMMONIA (NH3) CHLOROPHYLL - EXTRACTED CHLOROPHYLL A CONDUCTIVITY DEPTH - OBSERVATION DISSOLVED ORGANIC CARBON DISSOLVED OXYGEN nitrate + nitrite content (concentration) PARTICULATE ORGANIC CARBON pH Secchi depth silica total alkalinity TOTAL PHOSPHORUS WATER TEMPERATURE theme NODC DATA TYPES THESAURUS CTD Secchi disk thermometer instrument NODC INSTRUMENT TYPES THESAURUS in situ laboratory analyses theme NODC OBSERVATION TYPES THESAURUS NOAA Great Lakes Environmental Research Laboratory dataCentre NODC COLLECTING INSTITUTION NAMES THESAURUS NOAA Great Lakes Environmental Research Laboratory dataCentre NODC SUBMITTING INSTITUTION NAMES THESAURUS Great Lakes place NODC SEA AREA NAMES THESAURUS oceanography theme WMO_CategoryCode 2012-09-15 publication DOC/NOAA/OAR/GLERL > Great Lakes Environmental Research Laboratory, OAR, NOAA, U.S. Department of Commerce dataCentre Global Change Master Directory (GCMD) Data Center Keywords 2026 revision 23 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian NOAA/GLERL PHYSICAL AND CHEMICAL VARIABLES OF SAGINAW BAY, LAKE HURON IN 1991-1996 project Provider Project Names EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > ALKALINITY EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > AMMONIA EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > CHLOROPHYLL EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NITRATE EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NITRITE EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > ORGANIC CARBON EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > OXYGEN EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > PH EARTH SCIENCE > OCEANS > OCEAN OPTICS > SECCHI DEPTH EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE EARTH SCIENCE > OCEANS > SALINITY/DENSITY > CONDUCTIVITY theme Global Change Master Directory (GCMD) Science Keywords 2026 revision 23 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Chlorophyll-a extracted beam attenuation chloride dissolved silica particulate silica soluble reactive phosphorus total dissolved phosphorus total suspended solids (TSS) theme Provider Keywords CTD > Conductivity, Temperature, Depth SECCHI DISKS > SECCHI DISKS THERMOMETERS > THERMOMETERS instrument Global Change Master Directory (GCMD) Instrument Keywords 2026 revision 23 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian LI-COR 193SB spherical (4 p) light sensor and LI-COR 1000 data logger Perkin Elmer (model 2400) CHN elemental analyzer Sea-Bird 19 CTD Shimadzu total organic carbon analyzer (model TOC-5000) Technicon Auto Analyzer II Turner 10AU filter pH meter instrument Provider Instruments R/V Shenehon platform Provider Platform Keywords CONTINENT > NORTH AMERICA > CANADA > GREAT LAKES, CANADA CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > GREAT LAKES place Global Change Master Directory (GCMD) Location Keywords 2026 revision 23 Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA) Greenbelt MD https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords HTTPS GCMD Keyword Forum Page Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords information custodian Lake Huron place Provider Place Names 5TWPHP Send2NCEI Submission Package ID accessLevel: public otherRestrictions Cite as: Nalepa, Thomas F.; Johengen, Thomas H.; Fahnenstiel, Gary L.; McCormick, Michael J.; Lang, Gregory A.; Fanslow, David L.; Cavaletto, Joann F.; Goudy, Greg; Vanderploeg, Henry A.; Agy, Megan A. (2020). Physical, chemical, and biological water quality data and CTD casts collected from NOAA R/V Shenehon in Saginaw Bay, Lake Huron in the Great Lakes region from 1991-04-12 to 1996-09-20 (NCEI Accession 0218895). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0218895. Accessed [date]. Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives. otherRestrictions Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose. Physical and chemical variables of Saginaw Bay, Lake Huron in 1991-93 1996-05-01 publication https://www.glerl.noaa.gov/pubs/tech_reports/glerl-091/tm-091.pdf HTTPS https://www.glerl.noaa.gov/pubs/tech_reports/glerl-091/tm-091.pdf NOAA Technical Memorandum GLERL-115 download Nalepa, Thomas NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Fahnenstiel, Gary NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author McCormick, Michael NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Johengen, Thomas Cooperative Institute for Limnology and Ecosystems Research, University of Michigan, Ann Arbor, Michigan author Lang, Gregory NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Cavaletto, Joann NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Goudy, Gregory Michigan Department of Natural Resources, Surface Water Quality Division, Lansing, Michigan author NOAA Great Lakes Environmental Research Laboratory (GLERL) http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information publisher documentDigital crossReference sciencePaper Physical and Chemical Variables of Saginaw Bay, Lake Huron in 1994-1996 2000-01-01 publication https://www.glerl.noaa.gov/pubs/tech_reports/glerl-115/tm-115.pdf HTTPS https://www.glerl.noaa.gov/pubs/tech_reports/glerl-115/tm-115.pdf NOAA Technical Memorandum GLERL-115 download Johengen, Thomas Cooperative Institute for Limnology and Ecosystems Research, University of Michigan, Ann Arbor, Michigan author Nalepa, Thomas NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Lang, Gregory NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Fanslow, David NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Vanderploeg, Henry NOAA Great Lakes Environmental Research Laboratory http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author Agy, Megan NOAA GLERL/University of Michigan http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information author NOAA Great Lakes Environmental Research Laboratory (GLERL) http://www.glerl.noaa.gov/ HTTP NOAA Great Lakes Environmental Research Laboratory (GLERL) website Institution web page information publisher documentDigital crossReference sciencePaper Fahnenstiel, G. L., Lang, G. A., Nalepa, T. F., & Johengen, T. H. (1995). Effects of Zebra Mussel ( Dreissena polymorpha ) Colonization on Water Quality Parameters in Saginaw Bay, Lake Huron. Journal of Great Lakes Research, 21(4), 435–448. https://doi.org/10.1016/s0380-1330(95)71057-7 1995 publication International DOI Foundation (IDF) https://doi.org/10.1016/s0380-1330(95)71057-7 https://doi.org/10.1016/s0380-1330(95)71057-7 HTTPS https://doi.org/10.1016/s0380-1330(95)71057-7 journal article information Fahnenstiel, Gary L. author Lang, Gregory A. author Nalepa, Thomas F. author Johengen, Thomas H. author Elsevier BV publisher documentDigital Journal of Great Lakes Research 21(4) ISSN 0380-1330, pp. 435-448 crossReference sciencePaper eng; USA utf8 environment oceans -83.9 -83 43.6 44.3 1991-04-11 1996-09-20 NOAA National Centers for Environmental Information +1-301-713-3277 ncei.info@noaa.gov pointOfContact In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media. Contact NCEI for other distribution options and instructions. Originator data format 2.948 https://www.ncei.noaa.gov/archive/accession/0218895 HTTPS Web browser NCEI Dataset Landing Page Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/oas/218895 HTTPS Web browser Descriptive Information Navigate directly to the URL for a descriptive web page with download links. information https://www.ncei.noaa.gov/archive/accession/download/218895 HTTPS Web browser HTTPS Navigate directly to the URL for data access and direct download. download ftp://ftp-oceans.ncei.noaa.gov/nodc/archive/arc0159/0218895/ FTP Any FTP client FTP These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). download dataset NCEI Accession 0218895 v1.1 was published. 2020-09-16T14:29:38Z NCEI Accession 0218895 v1.1 publication https://www.ncei.noaa.gov/archive/accession/0218895/1.1 HTTPS NCEI Accession 0218895 v1.1 published 2020-09-16T14:29:38Z download dataset Parameter or Variable: DEPTH - OBSERVATION (measured); Units: meter; Observation Category: in situ; Sampling Instrument: na; Sampling and Analyzing Method: na; Data Quality Method: expert review Parameter or Variable: SECCHI DEPTH (measured); Units: meter; Observation Category: in situ; Sampling Instrument: secchi disk; Sampling and Analyzing Method: Secchi-disk transparency was measured by lowering a white disk that was 25 cm in diameter.; Data Quality Method: expert review Parameter or Variable: WATER TEMPERATURE (measured); Units: degrees Celsius; Observation Category: in situ; Sampling Instrument: thermometer; Sampling and Analyzing Method: Water temperature was obtained by placing a thermometer in a portion of water collected in the Niskin bottle immediately after it was brought to the surface.; Data Quality Method: expert review Parameter or Variable: pH (measured); Units: pH; Observation Category: in situ; Sampling Instrument: pH meter; Sampling and Analyzing Method: pH was measured for collected water upon return to dock. Meter was calibrated daily.; Data Quality Method: expert review Parameter or Variable: CONDUCTIVITY (measured); Units: microsiemens per centimeter; Observation Category: in situ; Sampling Instrument: Sea-Bird 19; Sampling and Analyzing Method: A Sea-Bird CTD with a transmissometer (25-cm beam path) was slowly lowered from the surface to 1 m above the bottom. All data points were logged twice each second.; Data Quality Method: expert review Parameter or Variable: BEAM ATTENUATION (measured); Units: m^-1; Observation Category: in situ; Sampling Instrument: LI-COR 193SB spherical (4 p) light sensor and LI-COR 1000 data logger; Sampling and Analyzing Method: Photosynthetically active irradiation (PAR) was measured at a number of depths in the water column with a LI-COR 193SB spherical (4 p) light sensor and LI-COR 1000 data logger, from which the beam attenuation was calculated.; Data Quality Method: expert review Parameter or Variable: DISSOLVED OXYGEN (measured); Units: milligrams per liter; Observation Category: in situ; Sampling Instrument: Sea-Bird 19; Sampling and Analyzing Method: A Sea-Bird CTD was slowly lowered from the surface to 1 m above the bottom. All data points were logged twice each second.; Data Quality Method: expert review Parameter or Variable: CHLOROPHYLL-A - EXTRACTED (measured); Units: micrograms per liter; Observation Category: laboratory analysis; Sampling Instrument: Turner 10AU; Sampling and Analyzing Method: Chlorophyll (Chl) was measured in triplicate using the method of Strickland and Parsons (1972). Fifty or 100 mL of water was filtered through a 47-mm GF/F Whatman Glass Fiber filter. The filters were placed individually into amber vials containing 5 mL of cold acetone (90 %) and then stored in the freezer. W~thin 30 days, the filters were ground in cold acetone and then steeped for 24 h in the freezer. Samples were centrifuged, the extract poured into a 1-cm curvette, and readings taken with a Turner Design Fluorometer. After an initial reading, 2 drops of 1N HCL were added to the curvette and another reading taken.; Data Quality Method: expert review Parameter or Variable: TOTAL PHOSPHORUS (measured); Units: micrograms per liter; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Total phosphorus was determined after digesting 50 mL of unfiltered sample with potassium persulfate in an autoclave using the molybdate/ascorbic acid method.; Data Quality Method: expert review Parameter or Variable: Total Dissolved Phosphorus (measured); Units: micrograms per liter; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Total dissolved phosphorus was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter, digested with potassium persulfate in an autoclave and analyzed using the molybdate/ ascorbic acid method.; Data Quality Method: expert review Parameter or Variable: Soluble Reactive Phosphorus (measured); Units: micrograms per liter; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Soluble reactive phosphorus was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter and analyzed using the molybdate/ ascorbic acid method. The detection limit for this method is 0.1 µg P/L.; Data Quality Method: expert review Parameter or Variable: AMMONIA (NH3) (measured); Units: mi; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Ammonia was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter and analyzed using the Bertholet reaction.; Data Quality Method: expert review Parameter or Variable: nitrate + nitrite content (concentration) (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Nitrate+Nitrite was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter and analyzed using the cadmium reduction method. The detection limit for this method is 0.01 mg N/L.; Data Quality Method: expert review Parameter or Variable: particulate silica (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Particulate silica (PSI) was determined on 100 mL aliquots of water filtered through a 0.45-mm Nucleopore filter and then extracted with 0.2N NaOH at 95•C for 30 minutes (Krausse et al., 1983). The extract was neutralized with 1N H2SO4 and silica (SiO2) concentrations were determined by the heteropoly blue method.; Data Quality Method: expert review Parameter or Variable: dissolved silica (measured); Units: mil; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Dissolved silica was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter and analyzed using the heteropoly blue method.; Data Quality Method: expert review Parameter or Variable: chloride (measured); Units: milligram; Observation Category: laboratory analysis; Sampling Instrument: Technicon Auto Analyzer II; Sampling and Analyzing Method: Nutrient concentrations were determined using standard automated colorimetric techniques (APHA, 1990) on a Technicon Auto Analyzer II, as detailed in Davis and Simmons (1979). Dissolved silica was filtered through a pre-rinsed 0.2-µm HA Millipore filter or a 0.2-µm Nucleopore filter and analyzed using the mercuric thiocyanide/ferric ammonium sulfate method.; Data Quality Method: expert review Parameter or Variable: PARTICULATE ORGANIC CARBON (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: Perkin Elmer (model 2400) CHN elemental analyzer; Sampling and Analyzing Method: Samples for particulate organic carbon were processed in triplicate by filtering 50 or 100 mL of sample through pre-combusted GFF filters. Filters were frozen until analysis, then thawed, acidified with 10% HCl, and dried. Measurements were made with a Perkin Elmer (model 2400) CHN elemental analyzer.; Data Quality Method: expert review Parameter or Variable: DISSOLVED ORGANIC CARBON (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: Shimadzu total organic carbon analyzer (model TOC-5000); Sampling and Analyzing Method: Samples for dissolved organic carbon were processed in triplicate by filtering 50 or 100 mL of sample through pre-combusted GFF filters. The filtrate was acidified with HCl and sparged with air for 6 minutes to remove CO2. DOC was determined using a Shimadzu total organic carbon analyzer (model TOC-5000) fitted with an auto sampler.; Data Quality Method: expert review Parameter or Variable: Total Suspended Solids (TSS) (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: filter; Sampling and Analyzing Method: "Total suspended solids were determined by filtering between 500 and 2,000 mL of sample through a pre-dried, pre-weighed Whatman GFC 47-mm filter. The filters were then dried at 60•C for at least 48 h and reweighed."; Data Quality Method: expert review Parameter or Variable: total alkalinity (measured); Units: milligrams per liter; Observation Category: laboratory analysis; Sampling Instrument: pH meter; Sampling and Analyzing Method: Alkalinity was determined from the milk-equivalents of acid needed to bring the pH of the water sample below 4.0 (Davis and Simmons, 1979). Twenty mL of sample was pipetted with a volumetric buret into a chemically clean polyethylene bottle that contained 5 mL of 0.01 N HCL. Additional 1 mL aliquots of acid were added if the pH was above 4.0.; Data Quality Method: expert review asNeeded Metadata are developed, maintained and distributed by NCEI. Updates are performed as needed to maintain currentness. NOAA National Centers for Environmental Information custodian CTD CTD Conductivity-Temperature-Depth probe Secchi disk Secchi disk The Secchi disk (or Secchi disc), as created in 1865 by Angelo Secchi, is a plain white, circular disk 30 cm (12 in) in diameter used to measure water transparency or turbidity in bodies of water. The disc is mounted on a pole or line, and lowered slowly down in the water. The depth at which the disk is no longer visible is taken as a measure of the transparency of the water. This measure is known as the Secchi depth and is related to water turbidity. [Wikipedia, 2021-09-02] thermometer thermometer generic thermometer or reversing thermometer use thermometer when temperature is a data type, but the exact instrument used to measure temperature is unknown