After the diver got into difficulties, the alarm was raised at around 9am on Tuesday (17 October).
The man, who has not been named, was taken ashore by Coastguard teams from the Orkney bases of Kirkwall and Stromness, but reportedly died on his way to hospital.
Police Scotland are submitting a report to the Procurator Fiscal, but stated that there were no suspicious circumstances.
Another diver, a 64-year-old Scottish man, died after a Scapa wreck-dive on 6 October. He was found after being reported missing from a position north-east of the island of Cava, as reported on Divernet.
The Markgraf also lies just north of Cava.
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