Distribution of Vitamin B12 in waters of the central Great Barrier Reef

Updated: 2017-11-20

A highly sensitive and selective method was used to estimate concentrations of cyanocobalamin (Vitamin B12) in sea water along a transect of reefs across the central portion of the Great Barrier Reef. Water samples were collected from a depth of 0.5 m along each transect (moving from reef front to reef back) at Pandora, Rib and Myrmidon Reefs. Samples were also collected from Palm Passage at a depth of 10m. Analyses were based on clinical techniques of radioimmunoassay, combining the RIA method with preconcentration of Vitamin B12 by displacement liquid chromatography on C18 SEP-PAK columns. Analyses of the column eluate by radioassay proved sensitive to B12 at femtomolar concentrations (50-2400 pg B12/L seawater). The concentrations calculated from the radioassay translated directly into units of pg B12/L and ng folate/L seawater as a consequence of the concentration procedure. Concentrations above calibration range (2400 pg B 12; 24.0 ng folate) were determined by extrapolation. To determine changes in Vitamin B12 concentrations of sea water along a transect of reefs across the central portion of the Great Barrier Reef.