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| Velji, M; Albright, L. |
| A technique has been investigated for dispersing adhered marine bacteria from various surfaces prior to direct counting. The bacterial cells were initially preserved and strengthened by use of 3.7% formaldehyde (v/v final concentration). Seawater samples were then treated with 0.001 M of tetrasodium pyrophosphate (final concentration), a sequestering and deflocculating agent. Surface sediment and kelp disc samples were treated with 0.01 M tetrasodium pyrophosphate (final concentration) after having been suspended in 0.44 M sodium chloride solution. These samples were incubated for 15-30 min. Subsequently, the samples were treated with ultrasound (100 W) for 30 to 45 s. This technique resulted in an even dispersion of most bacterial cells in the samples.... |
| Tipo: Text |
Palavras-chave: Bacteria; Microbiological analysis; Flocculation; Ultrasonics; Bacterial counters. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-968.pdf |
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| Wilson, M; Acolas, M; Begout, Marie-laure; Madsen, P; Wahlberg, M. |
| Most fish cannot hear frequencies above 3 kHz, but a few species belonging to the subfamily Alosinae (family Clupeidae) can detect intense ultrasound. The response of adult specimens of the European allis shad (Alosa alosa) to sinusoidal ultrasonic pulses at 70 and 120 kHz is tested. The fish showed an intensity-graded response to the ultrasonic pulses with a response threshold between 161 and 167 dB re 1 mu Pa (pp) for both frequencies. These response thresholds are similar to thresholds derived from juvenile American shad (Alosa sapidissima) in previous studies, supporting the suggestion that these members of Alosinae have evolved a dedicated ultrasound detector adapted to detect and respond to approaching echolocating toothed whales. (C) 2008 Acoustical... |
| Tipo: Text |
Palavras-chave: Zoology; Ultrasonics; Biocommunications; Bioacoustics. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6118.pdf |
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