a) Polar echogram of plume “237 m” (lighter blue echoes in the darker blue field) located in the central part of the mapped area. See Figure 1 for echo locations. b) Polar echogram of plume “299 m” located in the northern part of the mapped area c) Along-track echogram of plume “355 m” located in the southern part of the mapped area. d) Polar echogram of plume “287 m” located in the southern part of the mapped area e) Along-track echogram of plume “1702 m” located in the southern part of the mapped area. f) Polar echogram of plume “1334 m” located in the southern part of the mapped area.