The least harmful (but very expensive) method is to use a downbore video camera, the more traditional method is to drag a modified plankton net several times through the bore or sinkhole.
The more traditional method is to drag a modified plankton net several times through the bore or sinkhole. The least harmful (but very expensive) method is to use a downbore video camera.
The least harmful (but very expensive) method is to use a downbore video camera. The more traditional method is to drag a modified plankton net several times through the bore or sinkhole.
The least harmful (but very expensive) method is to use a downbore video camera. The more traditional method is to drag a modified plankton net several times through the bore or sinkhole.