| Summary: | <h2>Bacteria Abundance, Biomass and Chlorophyll <em>a</em> in Ice Cores</h2> <p><strong>NOTES:</strong><br /> NBP0104: Cores labelled with \"DNA\" were collected for DNA analysis.</p> <pre> <strong>Contributor:</strong> Dr. Christian Fritsen University and Community College System of Nevada Desert Research Institute Div. of Earth and Ecosystem Sciences 2215 Raggio Parkway Reno, NV 89512 Office: 775/673-7487 </pre> <h3>BG 235 - Methods used for chlorophyll <em>a</em> (chla) analysis and bacteria biomass determination</h3> <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, D.L. and K.R. Buck(1986), Organism losses during ice melting: a serious bias in sea ice community studies. <em>Polar Biol.</em>, <strong>6</strong>:237-239.</p> <p>Recommendations for reporting were used as outlined by:<br /> Horner, R. <em>et al.</em>,(1992), Ecology of Sea Ice Biota. I: Habitat, Terminology and Methodology. <em> Polar Biol.</em> <strong>12</strong>:417-427</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>LMG 0106</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-Kribacher <em>et al.</em>, 1998).</li> <li>ice core samples corrected for FSW dilution</li> </ul> <p>NBP 0104</p> <ul> <li>preserved (0.5% glutaraldehyde) samples stained with Sybri 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 Sybri Gold-stained samples because both AO and Sybri Gold stain bacteria cells similarly relative to DAPI (unpublished data).</li> <li>ice core samples corrected for FSW dilution</li> </ul> <p>Loferer-Kribacher, M., Klima, J., and R. Psenner. 1998. Determination of bacterial cell dry mass by transmission electron microscopy and densitometric image analysis. Applied and Environmental Microbiology. 64:688-694.</p> <p>Parsons,T.R., Maita, Y., and C.M. Lalli. 1984. A manual of chemical and biological methods for seawater analysis. Pergamon Press. Elmsford, New York.</p> <p>Simon, M., and F. Azam. 1989. Protein content and protein synthesis rates of planktonic marine bacteria. Marine Ecology Progress Series. 51, 201-213.</p> <p><em>updated: April 20, 2006</em></p>
|
|---|