US Long-Term Ecological Research Network

Ammonia & Nitrate/Nitrite

NITRATE/NITRITE

This automated procedure for the determination of nitrate and nitrite utilizes the procedure whereby nitrate is reduced to nitrite by a copper-cadmium reductor column. The nitrite ion then reacts with sulfanilamide under acidic conditions to form a diazo compound. This compound then couples with N-1-napthylethylenediamine dihydrochloride to form a reddish-purple azo dye.

North Temperate Lakes LTER: Chemical Limnology of Primary Study Lakes: Nutrients, pH and Carbon 1981 - current

Abstract
Parameters characterizing the nutrient chemistry of the eleven primary lakes (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes, unnamed lakes 27-02 [Crystal Bog] and 12-15 [Trout Bog], Mendota, Monona, Wingra, and Fish) are measured at one station in the deepest part of each lake at the top and bottom of the epilimnion, mid-thermocline, and top, middle, and bottom of the hypolimnion. These parameters include total nitrogen, total dissolved nitrogen (only in the northern lakes), nitrate, ammonia, total phosphorus, total dissolved phosphorus (only in the northern lakes), dissolved reactive phosphorus (only in the southern lakes and not in Wingra and Fish after 2003), bicarbonite-reactive filtered and unfiltered silica (both discontinued in 2003), dissolved reactive silica, field pH, air equilibrated pH, total alkalinity, total inorganic carbon, dissolved inorganic carbon, total organic carbon, dissolved organic carbon, and total particulate matter (only in the northern lakes in this data set. Total particulate matter in southern lakes starting in 2000 is available in a separate dataset). Sampling Frequency: monthly during ice-free season - every 6 weeks during ice-covered season for the northern lakes. The southern lakes are similar except that sampling occurs monthly during the fall and typically only once during the winter (depending on ice conditions). Number of sites: 11
Dataset ID
1
Date Range
-
DOI
10.6073/pasta/cc6f0e4d317d29200234c7243471472a
Maintenance
ongoing
Metadata Provider
Methods
Inorganic and organic carbon: Samples for inorganic and organic carbon are collected together with a peristaltic pump and tubing and in-line filtered, if necessary, (through a 0.40 micron polycarbonate filter) into glass, 24 ml vials (that are compatible with the carbon analyzer autosampler), and capped with septa, leaving no head space. The samples are stored refrigerated at 4 degrees Celsius until analysis, which should occur within 2-3 weeks. The detection limit for inorganic carbon is 0.15 ppm, and the analytical range for the method is 60 ppm. The detection limit for organic carbon is 0.30 ppm and the analytical range for the method is 30 ppm. Method Log: Prior to May 2006 samples, inorganic carbon was analyzed by phosphoric acid addition on an OI Model 700 Carbon Analyzer. From May 2006 to present, inorganic carbon is still analyzed by phosphoric acid addition, but on a Shimadzu TOC-V-csh Total Organic Carbon Analyzer. Method Log: Prior to May 2006 samples, organic carbon was analyzed by heated persulfate digestion on an OI Model 700 Carbon Analyzer. From May 2006 to present, Organic carbon is analyzed by combustion, on a Shimadzu TOC-V-csh Total Organic Carbon Analyzer. Dissolved reactive silica Samples for silica are collected with a peristaltic pump and tubing and in-line filtered (through a 45 micron polycarbonate filter) into 120 ml LDPE bottles and acidified to a 1percent HCl matrix by adding 1 ml of ultra pure concentrated HCl to 100 mls of sample. For every sample acidification event, three acid blanks are created by adding the same acid used on the samples to 100 mls of ultra pure water supplied from the lab. Once acidified, the samples are stable at room temperature until analysis, which should occur within one year. Until acidification, the samples should be refrigerated at 4 degrees Celsius. Dissolved reactive silica is determined by the Heteropoly Blue Method and the absorption is measured at 820 nm. The detection limit for silica is 6 ppb and the analytical range is 15000 ppb. Method Log These determinations were performed manually using a Bausch and Lomb Spectrophotometer from the beginning of the project until April 1984. From 1984 through 2005, dissolved reactive silica was determined on a Technicon Auto Analyzer II. From January 2006 to present, samples are run on an Astoria-Pacific Astoria II Autoanalyzer. total and dissolved nitrogen and phosphorus Samples for total and dissolved nitrogen and phosphorus analysis are collected together with a peristaltic pump and tubing and in-line filtered, when necessary, (through a 45 micron polycarbonate filter) into 120 ml LDPE bottles and acidified to a 1percent HCl matrix by adding 1 mL of ultra pure concentrated HCl to 100 mls of sample. For every sample acidification event, three acid blanks are created by adding the same acid used on the samples to 100 mls of ultra pure water supplied from the lab. Once acidified, the samples are stable at room temperature until analysis, which should occur within one year. Until acidification, the samples should be refrigerated at 4 degrees Celsius. The samples must first be prepared for analysis by adding an NaOH–Persulfate digestion reagent and heated for an hour at 120 degrees C and 18-20 psi in an autoclave. The samples are analyzed for total nitrogen and total phosphorus simultaneously by automated colorimetric spectrophotometry, using a segmented flow autoanalyzer. Total nitrogen is determined by utilizing the automated cadmium reduction method, as described in Standard Methods, where the absorption is monitored at 520 nm. The detection limit for total and dissolved nitrogen is approximately 21 ppb and the analytical range for the method extends to 2500 ppb. The detection limit for total phosphorus is approximately 3 ppb and the analytical range for the method extends to 800 ppb. Method Log: Prior to January 2006 samples, total nitrogen was determined on a Technicon segmented flow autoanalyzer. From 2006 to present, total nitrogen is determined by an Astoria-Pacific Astoria II segmented flow autoanalyzer.
Short Name
NTLCH01
Version Number
52

Little Rock Lake Experiment at North Temperate Lakes LTER: Nutrients 1996 - 2000

Abstract
The Little Rock Acidification Experiment was a joint project involving the USEPA (Duluth Lab), University of Minnesota-Twin Cities, University of Wisconsin-Superior, University of Wisconsin-Madison, and the Wisconsin Department of Natural Resources. Little Rock Lake is a bi-lobed lake in Vilas County, Wisconsin, USA. In 1983 the lake was divided in half by an impermeable curtain and from 1984-1989 the northern basin of the lake was acidified with sulfuric acid in three two-year stages. The target pHs for 1984-5, 1986-7, and 1988-9 were 5.7, 5.2, and 4.7, respectively. Starting in 1990 the lake was allowed to recover naturally with the curtain still in place. Data were collected through 2000. The main objective was to understand the population, community, and ecosystem responses to whole-lake acidification. Funding for this project was provided by the USEPA and NSF. Parameters characterizing the nutrient chemistry of the treatment and reference basins of Little Rock Lake are measured at one station in the deepest part of each basin at the top and bottom of the epilimnion, mid-thermocline, and top, middle, and bottom of the hypolimnion. These parameters include total nitrogen, total dissolved nitrogen, nitrate, ammonia, total phosphorus, total dissolved phosphorus, dissolved reactive phosphorus, bicarbonite-reactive filtered and unfiltered silica, dissolved reactive silica, total inorganic carbon, dissolved inorganic carbon, total organic carbon, dissolved organic carbon, and total particulate matter. Sampling Frequency: varies - Number of sites: 2
Dataset ID
246
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Inorganic and organic carbonSamples for inorganic and organic carbon are collected together with a peristaltic pump and tubing and in-line filtered, if necessary, (through a 0.40 micron polycarbonate filter) into glass, 24 ml vials (that are compatible with the carbon analyzer autosampler), and capped with septa, leaving no head space. The samples are stored refrigerated at 4 degrees Celsius until analysis, which should occur within 2-3 weeks.The detection limit for inorganic carbon is 0.15 ppm, and the analytical range for the method is 60 ppm.The detection limit for organic carbon is 0.30 ppm and the analytical range for the method is 30 ppm.Method Log: Prior to May 2006 samples, inorganic carbon was analyzed by phosphoric acid addition on an OI Model 700 Carbon Analyzer. From May 2006 to present, inorganic carbon is still analyzed by phosphoric acid addition, but on a Shimadzu TOC-V-csh Total Organic Carbon Analyzer.Method Log: Prior to May 2006 samples, organic carbon was analyzed by heated persulfate digestion on an OI Model 700 Carbon Analyzer. From May 2006 to present, Organic carbon is analyzed by combustion, on a Shimadzu TOC-V-csh Total Organic Carbon Analyzer.Dissolved reactive siliconSamples for silicon are collected with a peristaltic pump and tubing and in-line filtered (through a 40 micron polycarbonate filter) into 120 ml LDPE bottles and acidified to a 1percent HCl matrix by adding 1 ml of ultra pure concentrated HCl to 100 mls of sample. For every sample acidification event, three acid blanks are created by adding the same acid used on the samples to 100 mls of ultra pure water supplied from the lab. Once acidified, the samples are stable at room temperature until analysis, which should occur within one year. Until acidification, the samples should be refrigerated at 4 degrees Celsius.Dissolved reactive silica is determined by the Heteropoly Blue Method and the absorption is measured at 820 nm.The detection limit for silicon is 6 ppb and the analytical range is 15000 ppb.Method Log These determinations were performed manually using a Bausch and Lomb Spectrophotometer from the beginning of the project until April 1984. From 1984 through 2005, dissolved reactive silicon was determined on a Technicon Auto Analyzer II. From January 2006 to present, samples are run on an Astoria-Pacific Astoria II Autoanalyzer.total and dissolved nitrogen and phosphorusSamples for total and dissolved nitrogen and phosphorus analysis are collected together with a peristaltic pump and tubing and in-line filtered, when necessary, (through a 40 micron polycarbonate filter) into 120 ml LDPE bottles and acidified to a 1percent HCl matrix by adding 1 mL of ultra pure concentrated HCl to 100 mls of sample. For every sample acidification event, three acid blanks are created by adding the same acid used on the samples to 100 mls of ultra pure water supplied from the lab. Once acidified, the samples are stable at room temperature until analysis, which should occur within one year. Until acidification, the samples should be refrigerated at 4 degrees Celsius.The samples must first be prepared for analysis by adding an NaOH–Persulfate digestion reagent and heated for an hour at 120 degrees C and 18-20 psi in an autoclave.The samples are analyzed for total nitrogen and total phosphorus simultaneously by automated colorimetric spectrophotometry, using a segmented flow autoanalyzer. Total nitrogen is determined by utilizing the automated cadmium reduction method, as described in Standard Methods, where the absorption is monitored at 520 nm.The detection limit for total and dissolved nitrogen is approximately 21 ppb and the analytical range for the method extends to 2500 ppb.The detection limit for total phosphorus is approximately 3 ppb and the analytical range for the method extends to 800 ppb.Method Log: Prior to January 2006 samples, total nitrogen was determined on a Technicon segmented flow autoanalyzer. From 2006 to present, total nitrogen is determined by an Astoria-Pacific Astoria II segmented flow autoanalyzer.
Short Name
LRNUTR1
Version Number
4

North Temperate Lakes LTER: Northern Highlands Stream Chemistry Survey 2006

Abstract
We compared regional patterns in lake and stream biogeochemistry in the Northern Highlands Lake District (NHLD), Wisconsin, USA to ask how regional biogeochemistry differs as a function of the type of ecosystem considered (i.e., lakes versus streams); if lake-stream comparisons reveal regional patterns and processes that are not apparent from studies of a single ecosystem type; and if characteristics of streams and lakes scale similarly. Fifty-two streams were sampled using a stratified random design to determine regional distribution of 21 water chemistry variables during summer baseflow conditions.Sampling Frequency: once per site Number of sites: 52
Contact
Core Areas
Dataset ID
254
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Site SelectionBecause lakes are a dominant feature of the region and stream characteristics could potentially differ based on their hydrologic connections to lakes, we classified streams into three categories as a function of their hydrologic connections to lakes. The first category was streams that had no lakes within the drainage network upstream of the sampling location. The second category was streams that originated from headwater lakes (i.e., no stream inlet but a stream outlet) and the headwater lake was the only lake in the drainage network above the sampling location. The final category had at least a single drainage lake (i.e., a lake with both stream inlet(s) and outlet) in the drainage network above the sampling location. We then used these categories to select sampling sites using a stratified random design for a variety of chemical and physical characteristics.All streams identified on 1:24,000 7.5 inch USGS topographical maps that crossed access points were selected as potential sampling locations and assigned to one of the three stream types. A stream could be classified by more than a single category depending on the sampling location within the drainage network. However, a single drainage network was never sampled more than once to ensure sample independence. Of the 500 possible sampling locations, 52 sites were selected and sampled.SamplingAll streams were sampled 7-10 channel widths upstream of an access point to minimize any influences caused by culverts and other features. Water samples were collected from the center of the channel using a peristaltic pump. Stream discharge was measured after Gore (2007) using cross sectional area and water velocity.Chemical AnalysesAll samples for both studies were collected and processed following the North Temperate Long Term Ecological Research (NTL-LTER) protocols (http://lter.limnology.wisc.edu). Filtering was done in the field using an in-line 0.45 μm membrane filter. All samples were stored on ice and returned to the laboratory where they were preserved according to NTL-LTER protocols. Acid neutralizing capacity (ANC) was determined by Gran titration (APHA 2005). DOC was measured on a Shimadzu TOC-V carbon analyzer. Total nitrogen and phosphorus (unfiltered, TN and TP; filtered, TDN and TDP), nitrate+nitrite (NO3-N), and ammonium (NH4-N) were quantified with an Astoria-Pacific segmented flow auto-analyzer. Soluble reactive phosphorus (SRP) in streams was measured colormetrically on a Beckman DU-800 spectrophotometer (APHA 2005). Anions (Cl- and SO4 2-) were measured using a Dionix DX-500 ion chromatograph and cations (Ca, Mg, Na, K, Fe, K, and Mn) on a Perkin Elmer ICP mass spectrometerDissolved inorganic carbon (DIC) and pH were quantified differently in the lakes and stream data sets. For the lakes data, DIC was determined with a Shimadzu TOC-V carbon analyzer, whereas DIC for the streams dataset was determined by headspace equilibration of acidified water samples in the field and direct measurement of carbon dioxide (CO2) gas on a Shimadzu gas chromatograph (Cole et al. 1994). pH measurements for the lakes dataset were quantified on non-air equilibrated samples in the lab with a Accumet 950 pH meter while direct measurements were taken in the field for the streams dataset using a hand-held Orion model 266 pH meter that was allowed to equilibrated about 20 min in the center for the stream channel.Several variables presented in this study were determined from calculations based on measured values. In streams, dissolved organic nitrogen and phosphorus (DON and DOP, respectively) were determined by the difference between inorganic nutrients and total dissolved nutrients (e.g., DOP = TDP-SRP). We were unable to determine DON in lakes due to the lack of inorganic nitrogen data. It was assumed that DOP approximately equals TDP in lakes because dissolved inorganic phosphorus concentrations in the region are typically below detection limits in the epilimnion during the summer months and consequently not quantified (NTL-LTER unpublished data).
Short Name
LOTTIG2
Version Number
19

Zooplankton of Small Lakes and Wetland Ponds in Wisconsin - North Temperate Lakes LTER 1996

Abstract
We sampled zooplankton communities from 54 small water bodies distributed throughout Wisconsin to evaluate whether a snap-shot of zooplankton community structure during early spring could be used for the purpose of differentiating lakes from wetlands. We collected a single set of zooplankton and water chemistry data during a one-month time window (synchronized from south to north across the state) from an open water site in each basin as a means to minimize and standardize sampling effort and to minimize cascading effects arising from predator-prey interactions with resident and immigrant aquatic insect communities. We identified 53 taxa of zooplankton from 54 sites sampled across Wisconsin. There was an average of 6.83 taxa per site. The zooplankton species were distributed with a great deal of independence. We did not detect significant correlations between number of taxa and geographic region or waterbody size. There was a significant inverse correlation between number of taxa and the concentration of calcium ion, alkalinity and conductivity. One pair of taxa, Lynceus brachyurus and Chaoborus americanus, showed a significant difference in average duration of sites of their respective occurrence. All other pairs of taxa had no significant difference in average latitude, waterbody surface area, total phosphorus, total Kjeldahl nitrogen, alkalinity, conductivity, calcium ion, sulfate, nitrate, silicate or chloride. Taxa were distributed at random among the sites - there were no statistically significant pairs of taxa occurring together or avoiding each other. Multivariate analysis of zooplankton associations showed no evidence of distinct associations that could be used to distinguish lakes from wetlands. Zooplankton community structure appears to be a poor tool for distinguishing between lakes and wetlands, especially at the relatively large scale of Wisconsin (dimension of about 500 km). The data suggest that a small body of water in Wisconsin could be classified as a wetland if it persists in the spring and summer for only about 4 months, and if it is inhabited by Lynceus brachyurus, Eubranchipus bundyi, and if Chaoborus americanus and Chydorus brevilabris are absent. Schell, Jeffery M., Carlos J. Santos-Flores, Paula E. Allen, Brian M. Hunker, Scott Kloehn, Aaron Michelson, Richard A. Lillie, and Stanley I. Dodson. 2001. Physical-chemical influences on vernal zooplankton community structure in small lakes and wetlands of Wisconsin, U.S.A. Hydrobiologia 445:37-50 Number of sites: 54
Creator
Dataset ID
224
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Schell, Jeffery M., Carlos J. Santos-Flores, Paula E. Allen, Brian M. Hunker, Scott Kloehn, Aaron Michelson, Richard A. Lillie, and Stanley I. Dodson. 2001. Physical-chemical influences on vernal zooplankton community structure in small lakes and wetlands of Wisconsin, U.S.A. Hydrobiologia 445:37-50
Short Name
DODSON3
Version Number
25

Historical Birge - Juday Lake Survey 1900 - 1943

Abstract
Data collected by Birge, Juday, and collaborators, mostly in north-central Wisconsin, from 1900 through 1943; generally one sampling event per lake during the summer, but on some lakes, especially around Trout Lake Station, several sampling events for several successive years. This data set contains both surface data (depth of zero) and multi-depth data. Note that not all variables were measured on all lakes. Documentation: Johnson, M.D. (1984) Documentation and quality assurance of the computer files of historical water chemistry data from the Wisconsin Northern Highland Lake District (the Birge and Juday data).Wisconsin DNR Technical Report. Note: Values of -99999 in water quality data indicate trace amount of parameter was present. Number of sites: 663 (generally one sampling point per lake; occasionally, several sampling points per lake on multibasin, large lakes).<u> Note:</u> This data set was updated in 2013 to include multi-depth and additional surface data for a large subset of lakes. These additions expanded the number of sites from 605 to 663, and expanded the date range from 1925-1942 to 1900-1943 . Furthermore, 14 lakes in Minnesota were added to the data set contributing additional surface and multi-depth data. Another dataset was added in 2013 collected by Wisconsin limnologists Chauncey Juday and Edward Birge, this data set contains variables that are still commonly used in research. For example, temperature, dissolved carbon dioxide, color, pH, secchi disk, plankton, and silica. However, the data set also includes variables that are not commonly used, for example, crude protein, non-amino nitrogen, ether extract, and total organic and inorganic material. These data are characteristic of water chemistry analysis from the time in which they were compiled (5/31/1915 - 8/29/1938). The data set features data from 586 different lakes, primarily lakes in the Northern Highland Lakes District of Wisconsin. However, there is also data from lakes in southeastern and southcentral Wisconsin. Furthermore, there is a minimal amount of data from lakes in Minnesota, Ohio,New York, Alaska, the Philippines, and the United Kingdom. Documentation:Birge, E.A., and Juday, C. 1922. The inland lakes of Wisconsin. The Plankton I. Its quantity and chemical composition. Bulletin, Wis. Geol. and Nat. Hist. Survey No. 64: (Scientific series 13), ix-222.
Core Areas
Dataset ID
106
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Johnson, M.D. (1984) Documentation and quality assurance of the computer files of historical water chemistry data from the Wisconsin Northern Highland Lake District (the Birge and Juday data).Wisconsin DNR Technical Report.Methods not included in Johnson (1984):Nitrite Nitrogen- Sulphanilic acid procedure. Standard methods for the examination of water and sewage, Pub. Health Assn., New York, 5th edition, 1923, 13. Other Documentation: Domogalla, B.P., Juday, C., and Peterson, W.H. 1925. The forms of nitrogen found in certain lake waters. Jour. Biol. Chem. 63: 269-285.Ferric Ion- First calculated by subtracting ferrous ion from total iron measurements. Standard methods of water analysis. 1936. Amer. Pub. Health Assoc. P. 309. New York. Procedure was modified to determine ferric ion by acidifying samples by adding 1 milliliter of 3 N HCL to 50mL of lake water. With the iron samples in readiness, add 5 ml of the thiocyanate solution to the sample and to the standards, mix and compare immediately. (Standard Methods, Amer. Public Health Assoc. 8th ed., p. 75, 1936). Other documentation: Domogalla, B.P., Juday, C., and Peterson, W.H. 1925. The forms of nitrogen found in certain lake waters. Jour. Biol. Chem. 63: 269-285.Ferrous Ion- First calculated by ferricyanide method. Procedure was modified to determine ferrous ion by subtracting ferric ion from total iron. Documentation: Domogalla, B.P., Juday, C., and Peterson, W.H. 1925. The forms of nitrogen found in certain lake waters. Jour. Biol. Chem. 63: 269-285.Manganese- Determined by the persulfate method using the procedure described in Standard Methods of Water Analysis, Amer. Public Health Assoc., p. 84, 1936.Chlorophyll-a- A photometric method was used, in which the color of the light was confined to the wave-length 6200-6800 A which are absorbed by chlorophyll. Water samples of 5 to 15 liters (18 liters in the case of very low plankton content) were taken from different depths by using a hand operated vacuum pump), the water was the centrifuged at 25,000 rpm (for about 30 minutes). Residue was then washed with 98percent acetone, and CaCO3 was added to neutralize organic acids. This residue-acetone mixture was ground to extract the chlorophyll. The acetone extract was then filtered through filter paper into a flask, the residue being thoroughly washed with pure acetone. The light absorption of the extract was then measured. Procedure was carried out in a single day, under minimal light. Documentation: Kemmerer, G.I., and Hallett, L.T. 1938. Amount and distribution of the chlorophyll in some lakes of northeastern Wisconsin. Trans. Wisconsin Acad. Sci. 31: 411-438.Phosphate- Ceruleomolybdic method employed. Documentation: Juday, C., Birge, E.A., Kemmerer, G.I., Robinson, R.J. 1927. Phosphorus content of lake waters of northeastern Wisconsin. Trans. Wisconsin. Acad. Sci. 23: 233-248. Other Documentation: Robinson, R.J., Kemmerer, G.I. 1930. Determination of organic phosphorus in lake waters. Trans. Wisconsin. Acad. Sci. 25: 117-121.Redox Potential- Determined in situ on a given sampling date by use of a bright platinum electrode. Eh readings were made in millivolts. Documentation: Allgeier, R.J., Hafford, B.C., and Juday, C. 1941. Oxidation-reduction potentials and pH of lake waters and lake sediments. Trans. Wisconsin Acad. Sci. 33: 115-133.Note: The methodology used to determine copper, alumnium, boron, and hydrogen sulfide could not be determined.
Short Name
RGBIJD
Version Number
18

EPA Eastern Lake Survey original data for the Upper Midwest Region 1984

Abstract
Overton, W. S., P. Kanciruk, L. A. Hook, J. M. Eilers, D. H. Landers, D. F. BRAKKE, R. A. Linthurst, and M. D. DeHaan. 1986. Characteristics of lakes in the Eastern United States. Vol. 2. Lakes sampled and descriptive statistics for physical and chemical variables. US EPA 600/4-86/007B. 369 p. The Eastern Lake Survey-Phase I (ELS-I), conducted in the fall of 1984, was the first part of a long-term effort by the U.S. Environmental Protection Agency known as the National Surface Water Survey. It was designed to synoptically quantify the acid-base status of surface waters in the United States in areas expected to exhibit low buffering capacity. The effort was in support of the National Acid Precipitation Assessment Program (NAPAP). The survey involved a three-month field effort in which 1612 probability sample lakes and 186 special interest lakes in the northeast, southeast, and upper midwest regions of the United States were sampled. This dataset includes data on 592 lakes in Michigan, Minnesota and Wisconsin. Number of sites: 592
Core Areas
Creator
Dataset ID
107
Date Range
-
Maintenance
completed
Metadata Provider
Methods
please see methods description in abstract
Short Name
RGELS
Version Number
19

Environmental Research Lab-Duluth Chemical Lake Survey 1979 - 1982

Abstract
Chemical survey of 832 lakes in Minnesota, Michigan, Wisconsin and Ontario conducted by ERL-Duluth and UMD between 1979 and 1982 for evaluation of trophic state and sensitivity to acid deposition Glass, G.E. and Sorenson, J.A. (1994) USEPA ERLD-UMD acid deposition gradient-susceptibility database. U.S. EPA Environmental Research Laboratory - Duluth and University of Minnesota at Duluth, MN. Number of sites: 856 within 832 lakes
Core Areas
Dataset ID
101
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Methods are published in Glass, G.E. and Sorenson, J.A. (1994) USEPA ERLD-UMD acid deposition gradient-susceptibility database. U.S. EPA Environmental Research Laboratory - Duluth and University of Minnesota at Duluth, MN.
Short Name
RGERLD
Version Number
23
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