Do Blanding's Turtles die of old age?

Question

I have recently found articles and various claims that turtles (Blanding's turtles as an exact example) could possibly live indefinitely. http://discovermagazine.com/2002/jun/featturtle

This is said to be due to the fact that they

don't senesce— deteriorate physically— as they grow old

I am highly skeptical of that claim, and on the other side are links such as this http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/indiana/journeywithnature/blandings-turtles.xml which say they can live up to 70 years (though in the actual article it says 70+)

I realize in the wild that predation, disease, and other causes other than old age could kill turtles, but my question is:

Can blandings turtles die of old age? If so, around what age would this be?

Answer 1

It looks like as in fishes, the lack of an intrinsic cause of death in turtles in general is seen:

Like in fishes, the reptiles appear to show three types of senescence. The African skink, Mabuya buettneri, shows rapid senescence similar to death at mating observed in Salmon and marsupial mouse. Most of the lizards and snakes undergo gradual senescence comparable to the pattern exhibited by a majority of vertebrates. On the other hand, turtles, tortoises and crocodiles continue to grow throughout life and are thus credited with slow or negligible senescence. Patnaik 1994 Gerontology 40(2–4):200–20.

The main article by Congdon, the researcher who the Discover article profiles, also seems to be fairly definitive about this lack of senescence (or negative senescence?) in Blanding's Turtles specifically:

Survivorship, reproductive frequency and size-adjusted mean clutch size were all higher in the Oldest age group compared to the younger age groups. Congdon et al 2001 Experimental Gerontology 36(4–6): 813–827