US Long-Term Ecological Research Network

Parameter: Inorganic 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.

Importance of Biological Processing Hotspots in Water Bodies

Emerging research shows that hot spots for biological processing of elements such as nitrogen and phosphorus can be important in water bodies. We are exploring the importance of potential hot spots as well as cold spots for biological processing of these nutrients. The north temperate lakes (NTL) LTER has immediate access to diverse water bodies, including not only lakes but also abundant streams, rivers, and wetlands of various sizes and shapes. We are studying these habitats to answer questions related to ecosystem structure, functioning, hydrology, and biogeochemistry, with an emphasis on habitats ...

Linking Nutrient Cycling to Cyanobacterial Community Structure and Succession in Lakes

Lake Mendota is an eutrophic lake that harbors an abundant and diverse array of bloom-forming cyanobacteria (also called blue-green algae). The cyanobacterial community is highly variable, contains numerous nitrogen (N2) fixing and non-N2 fixing genera, and has multiple genotypes capable of forming ephemeral, and possibly toxic, blooms. Nutrients play an integral role in structuring the cyanobacterial community, but it is unclear how phosphorus (P), nitrogen (N), and trace metal limitation might influence seasonal to decadal community dynamics ...

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

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 major ions 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 chloride, sulfate, calcium, magnesium, sodium, potassium, iron, and manganese Sampling Frequency: varies - Number of sites: 2
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Chloride, SulfateSamples for chloride and sulfate are collected together with a peristaltic pump and tubing and in-line filtered (through a 0.40 micron polycarbonate filter) into new, 20 ml HDPE plastic containers with conical caps. The samples are stored refrigerated at 4 degrees Celsius until analysis, which should occur within 6 months. The samples are analyzed for chloride (and sulfate) simultaneously by Ion Chromatography, using a hydroxide eluent.The detection limit for chloride is approximately 0.01 ppm and the analytical range for the method extends to 100 ppm.The detection limit for sulfate is approximately 0.01 ppm and the analytical range for the method extends to 60 ppm.Method Log: Prior to January 1998 samples, chloride was determined on a Dionex DX10 Ion Chromatograph, using a chemical fiber suppressor. From 1998 to 2011, chloride was determined by a Dionex model DX500, using an electro-chemical suppressor. From January 2011 until present, chloride is determined by a Dionex model ICS 2100 using an electro-chemical suppressor.
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