Just where are you finding these 'scattered reports' as I am unable to locate any reputable sources that would verify this. Other reports would seem to not only refute this idea but provide reasons for why it is unlikely. From http://rbth.com/defence/2015/11/30/only-in-the-event-of-war-can-turkey-close-the-straits_545995
""I don’t think that Turkey, even in these tense conditions with
Russia, will want to violate the Montreux Convention, because if Turkey
begins violating it, it will be very difficult to restore it. We can ask
the question: can Turkey close the straits to Russia? Theoretically,
yes. But to do so, it must declare war on Russia, since the Montreux
Convention states that only in the event of a war can Turkey close the
straits," said Buzhinsky.
First published in Russian in Gazeta.ru
The link to the Turkish straits website doesn't indicate what at infowars said it did and there is no indication that Russian ships are not passing as a quick look at the relevant pages shows that there are pilots on board (Pob) Russian ships and others as well as not Pob for Russian and others. If they weren't going to allow passage, I would expect a first indication would be all Russian-flagged ships with no Pob and others with.
I admit, I'm just guessing but it's hard to find any evidence at all of any blockade or closure. There are notices, one from November, or possibly March, and one for today or tomorrow but only for a short closure. At Istanbul: "TRAFFIC WILL CLOSE FROM SOUTH TO NORTH 03/11/2015 AT 13.30 HRS.. WILL BE OPEN FROM NORTH TO SOUTH 03/11/2015 AT 15.30 HRS .. -"
At Canakkale: >> TRAFFIC WILL BE SUSPENDED FOR SOUTHBOUND
VESSELS ON 01.12.2015 AT 04:45 HRS DUE TO NORTHBOUND UCC/ MSC BARI / LOA
365 M ENTERING 01.12.2015 AT 06:30 LT FROM MEHMETCIK. - ((UPDATE)) TRAFFIC WILL BE SUSPENDED FOR NORTHBOUND VESSELS ON 02.12.2015 AT 03:30 HRS DUE TO SOUTHBOUND LNG/C MOSTEFA BE BOULAID /
LOA 279 M ENTERING 02.12.2015 AT 06:45 LT FROM GELIBOLU.
None of this looks like a closure to Russian ships but if anyone can read this differently, please comment.