Why would Turkey do that? They are a Russian ally?
“Turkey has closed access through the Bosphorus Straits.”
Why?
They have a longstanding International authority - the decision to restrict warships, a power given to Turkey by the Montreux Convention of 1936.
One of the likely reasons that Russia called its invasion a “Special Military Operation” and forbade the use of the word war to describe it, was to prevent NATO member Turkey from activating that closure. Turkey did it anyway - it is their call under the Convention.
The two heavy cruisers that Russia had brought nearby (Syria), will now not be able to participate in the hostilities around the Ukraine.
The opposite. That way the Russians cant reinforce he Black Sea Fleet.
No, Turkey is a member of NATO. Unfriendly.