Assessing Hydrocarbon presence in the waters of Port au Port bay, Newfoundland and Labrador, for AUV oil spill delineation tests

The waters adjacent to the Port au Port Peninsula, in Port au Port Bay, Newfoundland and Labrador, are known to be subject to release of hydrocarbons from natural oil seeps and old abandoned oil wells. An investigation was done to determine whether there were sufficient oil compounds present for planned autonomous underwater vehicle (AUV) test missions to develop adaptive sampling algorithms to delineate oil spills. Fluorometers were used in-situ to measure oil concentrations. Oil-and-water samples were taken at selected waypoints for chemical analysis in the laboratory to validate the sensor measurements and to provide a ground truth. Only one of the fluorometers was found to have a minimum detection level that was capable of sensing the hydrocarbons in the water column. The water sample results indicated hydrocarbon levels up to almost 30 ppm in the east side of the bay, just to the west of Shoal Point, but no detectable levels on the west side of the bay. It was concluded that it would be possible to operate an AUV on a planned fixed mission with a pre-programmed search path and record the levels of signal detected from fluorometers or other sensors. However, it would be difficult to implement an adaptive mission in this case because of the low levels of sensor signals resulting from the low concentrations of hydrocarbon present.