You have to use the heatmap and fly down to a light blue area. (You can filter the signals in the DSS mode) Then you just have to skim low near the surface to spot the flora/bacteria. There are no POI's that you can target for them anymore and they won't show in the nav panel.
As a side note, the two signals now just means there are two types of bio life on the surface and has no relation to how many places they exist on a planet.