BLUE-WATER SCUBA COLLECTION OF PLANKTONIC FORAMINIFERA

• Main Authors: Brian T. Huber, Jelle Bijma, Howard J. Spero
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Planktonic foraminifera
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.527.3526; http://www.si.edu/dive/pdfs/huber.pdf

The best way to collect free-floating planktonic foraminifera for laboratory study and experimentation is to capture them in glass jars held by scuba divers at 3 to 5 m depth in open-ocean conditions. This blue water diving method is preferred over collection with a plankton net because it minimizes trauma and enhances the survival of taxa that are easily damaged or killed when they come into contact with the mesh of a plankton net. Planktonic foraminifera can be discriminated from other groups of marine plankton (e.g., radiolaria, acantharia) by focusing from 50 to 80 cm distance, whereas species-level identification is best accomplished at a range of 20 to 50 cm. One fine-mesh collection bag containing wide-mouthed collection jars (~130 ml) that are each filled with seawater is hung onto a 25 m length vertical down-line that is passed through a float and tethered to the dive boat. An empty collection bag is also attached to the line to receive jars with captured specimens. Divers are tethered to the down-line through a safety-diver monitored trapeze to ensure continuous contact with the diving platform. Foraminifera are collected by gently rotating the jar around a specimen as the lid is slowly lowered onto the jar top. After the lid is firmly replaced the jar is put into the receiving sack. Using this method, as many as 60 to 80 specimens/hr can be collected depending on planktonic foraminifera abundance. Upon return to the laboratory the collected specimens are transferred to culture vessels using a wide-mouthed pipette. At this point, the researcher is ready to initiate a desired experiment.