Chlorophyll Collections and Analyses
September 21, 2006

Lake water was collected with a niskin bottle from the epilimnion, or epilimnion and hypolimnion, depending on the extent of stratification. Collections were done at night at selected transect stations and during a night cycle at selected diel stations in order to correlate discrete chlorophyll a sample values with derived values from the Plankton Survey System (PSS) fluorometer.

Duplicate chlorophyll samples were collected by filtering 100 mL aliquots through GF/F filters which were kept frozen in polypropylene tubes until analysis. Chlorophyll a was extracted from the filters with N, N-dimethylformamide (DMF) in a 65oC water bath for 15 minutes (Speziale et al. 1984). The extract was analyzed for chlorophyll a with a fluorometer (Turner Designs 10-AU-005-CE) using the acid correction method (Strickland and Parsons 1972).

Various IFYLE team members performed the water collections and filtrations. Chorophyll a analyses were done by Nancy Morehead. Mean, standard deviation (SD), and standard error (SE) of chlorophyll a for the duplicate samples are reported with units of µg/L. In events where a replicate was lost or duplicates were not taken, only one value is reported in the “mean” column with the “SD” and ”SE” columns blank. In a few cases, corrections to original sample labeling (i.e., station ID or date) were made based on the operations log.

References:

Speziale, B. J., S. P. Schreiner, P. A. Giammatteo, and J. E. Schindler. 1984. Comparison of N, N-dimethylformamide, dimethyl sulfoxide, and acetone for extraction of phytoplankton chlorophyll. Can. J. Fish. Aquat. Sci. 41: 1519-1522.

Strickland, J. D. H., and T. R. Parsons. 1972. A practical handbook of seawater analysis, 2nd ed., Bull. Fish. Res. Bd. Can. No. 167.

Contact Info

James R. Liebig
Great Lakes Environmental Research Laboratory
National Oceanic & Atmospheric Administration
U. S. Department of Commerce
2205 Commonwealth Blvd.
Ann Arbor, MI 48105-2945
Phone: 734-741-2177
Fax: 734-741-2055
email: