Common Murre - Iceland

In a prior post on the common murre, I noted that there are five subspecies and I featured Uria aalge inornata, the subspecies found in Alaskan waters which is also the largest of the subspecies. 

In Iceland, on a boat in the ocean outside of Reykjavik, we encountered a different subspecies, U. a. aalge, the nominate subspecies, found in eastern Canada, Greenland, Iceland, northern Ireland, Britain, and southern Norway. 

Those we saw were in the water and so the photos don't reveal as much of the bird as we saw in Alaska. Aside from size differential, I'm not sure what the differences are between these two subspecies.