Visual assessment of the respiring microorganisms associated with burrow structures of Capitella sp.I in seawater soft-agar microcosms

• Published in: Plankton & benthos research Vol. 1; no. 1; pp. 54 - 58
• Main Authors: Wada, Minoru, Wu, Shiow-Shyan, Tsutsumi, Hiroaki, Kita-Tsukamoto, Kumiko, Do, Hyung-Ki, Nomura, Hideaki, Ohwada, Kouichi, Kogure, Kazuhiro
• Format: Journal Article
• Language: English
• Published: 01.01.2006
• Subjects: Capitella
• ISSN: 1880-8247; 1882-627X

Some benthic organisms make burrows that may stimulate bacterial activity by introducing oxygen-rich overlying water. In order to assess this effect quantitatively, it is necessary to establish a suitable method to observe both behavior of the animal and bacterial activities. Here we developed a soft-agar microcosms in which Capitella sp. I successfully created borrows. Bacterial respiratory activity in the microcosm was visualized by using tetrazolium salt, 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT), which is converted to red insoluble form (INT-for-mazan) after reduction. Formazan was then extracted and quantified spectrophotometrically. Within a couple of hours after adding INT into overlying water, the red color due to formazan precipitation became apparent in the water column and on the soft agar surface. With incubation time, the red color zone extended to deeper layers along with burrows, indicating the aerobic bacterial respiration on the burrow lining. The newly developed microcosm system composed of seawater soft-agar and INT staining will provide a unique opportunity for visual observation of both benthic organisms and bacterial metabolic activities under various experimental conditions.