| Summary: | <h2>Bacteria Abundance, Biomass and Chlorophyll: Water Column Samples<em>a</em></h2> <p><strong>BG 235 - Methods used for chlorophyll <em>a</em> (chla) analysis and bacteria biomass determination</strong></p> <p><strong>Core Sampling techniques:</strong></p> <p>Sampling methods for recovery of chlorophyll <em>a</em> and bacteria from sea ice cores follows those described in <br /> Garrison and Buck (1986)</p> <p>Recommendations for reporting were used as outlined by: Horner, R. et al.,(1992)</p> <p><strong>Analytic Techniques:</strong></p> <p>Chla (mg m<sup>-3</sup>):</p> <ul> <li>determined fluorometrically (Turner Designs 10AU Fluorometer) following extraction in 90% acetone (Parsons <em>et al</em>., 1984)</li> <li>ice core chla corrected to account for chla in filtered sea water (FSW) added to core sections during melting</li> </ul> <p>Bacteria cell abundance (cells m<sup>-3</sup>) and biomass (mg C m<sup>-3</sup>):</p> <p><strong>LMG 0106</strong></p> <ul> <li>preserved (0.5% glutaraldehyde) samples stained with 4',6-diamidino-2-phenylindole (DAPI; 0.1 to 0.3% final concentration), filtered through 0.2 mm black, polycarbonate membrane filters, and mounted onto glass microscope slides on the ship (within 24 hours following collection)</li> <li>bacteria enumerated using epifluorescence microscopy and sized using digital images taken with Image Pro Plus</li> <li>bacteria biomass determined using cell abundance, cell biovolume (BV; mm<sup>3</sup>; as determined from mean length and width measurements), and an allometric conversion factor for bacterial carbon per volume specific for DAPI-stained bacteria (cellular carbon = 218 X BV<sup>0.86</sup>; Loferer-Krossbacher <em>et al.</em>, 1998).</li> <li>ice core samples corrected for FSW dilution</li> </ul> <p><strong>NBP 0104</strong></p> <ul> <li>preserved (0.5% glutaraldehyde) samples stained with SYBR Gold (0.01% final concentration), filtered through 0.2 mm Anodisc filters (Whatman), and mounted onto glass microscope slides at home institution (~1-2 months following collection)</li> <li>bacteria enumerated using epifluorescence microscopy and sized using digital images taken with Image Pro Plus</li> <li>bacteria biomass determined using cell abundance, cell biovolume (BV; mm<sup>3</sup>), and an allometric conversion factor for bacterial carbon per volume specific for Acridine Orange-stained bacteria (cellular carbon = 89.9 X BV<sup>0.59</sup>; Simon and Azam, 1989). Note: an AO-specific carbon per volume conversion factor was used in calculating biomass in SYBR Gold-stained samples because both AO and SYBR Gold stain bacteria cells similarly relative to DAPI (unpublished data).</li> <li>ice core samples corrected for FSW dilution</li> </ul> <p>Data from <strong>LMG0106</strong> (July-August, 2001) added in June 2002.</p> <p><em>Updated: April 21, 2006</em></p>
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