Note that contours for methane and ethane look completely different in surface from bottom water. Also note regular line of high C1 and C2 anomalies running from the center bottom toward the northeast in bottom water. Pattern is still present, but not as strongly in mid water.
Pattern goes away in the surface water.
We propose that these bottom water anomalies are diagnostic of hydrocarbon seepage into bottom water. However, we have no 3-D seismic data in appropriate region to test this hypothesis. Therefore, anyone with 3-D seismic data should be able to overlay their data on this data with minimal difficulty.