Luquillo LTER

Stream water is collected weekly at the Luquillo Mountain sites listed below. These data sets begin as early as 1983; LTER sampling began in 1988.

Stream water samples are grab samples taken from the water/air interface at stream channel center on the sampling day (usually Tuesdays). A continuous record of stream stage (height) is recorded by a datalogger at all ongoing stream sampling sites. Average daily streamflows are available from the USGS and at other locations (Hydrology and Meteorology) on this site.

All samples are measured for pH and conductivity, and then filtered (pre-combusted Whatman GF/F glass fiber filter) prior to further analysis. From 1983-1994 samples were cooled and returned to the San Juan chemistry laboratory for analysis. During those years, samples for NH4 and NO3 analyses were refrigerated continuously until analysis. Subsamples for NH4 analysis were also preserved with 1 molar H2SO4. From 1994 on, samples for NH4 and NO3were frozen until analysis, were not acidified, and all analyses were conducted at the University of New Hampshire.

Stream water Sampling Sites
Descriptions of LTER LUQ stream water weekly sample chemistry data from 1988 onwards. Chemical concentrations are recorded as mg/L or mg/L as appropriate. Values below detection limits are recorded as 1/2 the detection limit.