Hi Abigail,
Interesting question to which, I'm afraid, there isn't a simple answer. Not only is the number ot those who died and were buried at sea in question but also the number of 'services' held on the
Carpathia - some sources state one and some as many as three, with the number of victims also varying.
Second Class passenger Lawrence Beesley wrote, in his book "The Loss of the SS Titanic":
"During the day, the bodies of eight of the crew were committed to the deep; four of them had been taken out of the boats dead and four died during the day."
Here's what I have found regarding this subject.
The four taken from the boats already dead were William Hoyt, Steward S. C. Siebert, Seaman W. H. Lyons, and possibly John Phillips, this according to the book "The Sinking of the Titanic and Other Sea Disasters" (the question of Phillips being one of the dead has been all but ruled out, however). The four who died during the day included Third Class Abraham Harmer (David Livshin), this according to this very website and the aforementioned book.
As to the number of services: According to the April 19 edition of the New York Herald, Fred Beachler (Carpathia passenger) stated that Hoyt, Harmer and Seibert were buried on the 15th and Lyons, who succumbed later, was buried the following morning. Also, in the same issue, Carpathia Assistant Saloon Steward William David was quoted as saying, "On Monday (April 15) five survivors died; on Tuesday, three; and on Wednesday, two. They were buried at sea."
Hope this is of some help.
Best regards,
Cook