LOG NUMBER Dimensionless A unique internal sample identifier

CRUISE CODE Dimensionless Name of cruise when sample was taken

SAMPLE DATE MM/DD/YY Date sample was taken from lake

STATION Dimensionless Station occupied when sample was taken In normal conditions, samples are taken within 1/2 mi of the lat/long corresponding to the station location.

DEPTH m Depth sample was taken. Depth indicated on CTD when Niskin bottle was fired. Depth sensor is 0.9 m below midpoint of vertical Niskin bottle; depths given here are not corrected for that difference.

FRACTION m * 10-6 Pore size of filter used to fractionate before sample collection. Water taken from Niskin, transferred into carboy, then fractionated as indicated. "W" or "whole" are unfractionated whole water. From "80" to "20" water has been passed through Nitex of that mesh size. "10" may be Nitex or 47 mm polycarbonate filter. Smaller than 10, water is first prefiltered through 10 um, then "2" is a polycarbonate filter of varying diameter. "0.7" is 47mm Whatman GF/F. "0.2" is 47 mm polycarbonate filter.

STORAGE Dimensionless Method of sample preservation Frozen = stored at approx. -4 C with liquid samples in HDPE bottles; fridge = stored at approx 4 C.

VOL FILT Ml Volume of sample filtered.
This volume used to calculate particulate concentration in the lake.
REP Dimensionless Integer value, replicate number.
Normally replicates are from the same Niskin bottle.
SAMPLE_TYPE Dimensionless Type of sample (sed/core/water) "Water" samples are taken from the water column."Sediment" means a mud sample, taken from the ponar or a subsample from the mulitcorer and analyzed.  "Core" samples refer to water samples from the headspace above sediment cores taken with the multicorer.

DIC mg/L Dissolved inorganic carbon. Using Shimadzu VCSH. Contains carbonates and CO2.
DOC mg/L Dissolved organic carbon Using Shimadzu VCSH. Post acification to pH of 2 and sparging with purified air. Organic carbon present in a sample in a nonvolatile form.
TN mg/L Total nitrogen Using Shimadzu VCSH with TNM-1 attachment.

TDN mg/L Total dissolved nitrogen. Using Shimadzu VCSH with TNM-1 attachment. High detection for nitrates, nitrites and ammonia and the majority of other organic N compounds. Low detection for hydrazines, pyrazolones and azide.
POC ug/L Particulate Organic Carbon Sample collected on ashed GF/F filter. Frozen, dried at 60C. Run on Perkin Elmer 2400 CHN analyzer.

PON ug/L Particulate Organic Nitrogen Sample collected on ashed GF/F filter. Frozen, dried at 60C. Run on Perkin Elmer 2400 CHN analyzer.

Probe pH Dimensionless Hydrogen ion activity

SRSi mg/L Soluble reactive silica Metol-sulphate/molybdate reaction.

Chl-a ug/L Chlorophyll A Sample filtered onto 25 mm 0.2 um cellulose nitrate filter and frozen. Extracted with 90% Acetone in the refrigerator for 20-24 h (no grinding of filer). Then measured on a Turner 10-AU using narrow band width filters per Welschmeyer xxxx. Once every 4 y, Turner Design liquid standard is used for recalibration. Solid standard used in between.

PP uM Particulate phosphorus Sample filtered onto 25 mm acid-rinsed (~10mL 1% HCl, followed by 50 mL nanopure, rinsed on filter tower) precombusted GF/F filter. Frozen. Dried at 60 C. Analyzed using persulfate then ammonium molybdate reaction.

NH4 uM Ammoniuum GF/F filtered sample is frozen. Thawed samples are added to an OPA working reagent per Taylor et al. 2007, using a combination of Holmes et 1. 1999 Methods A and B. Standard addition series done on all samples. Background fluorescence measured after adding working reagent and reading immediately.

NO3 uM Nitrate Unfiltered sample is frozen. Thawed sample is run using Cd-reduction protocol on a Lachat flow injection analyzer.