It had set a target of £5,000 to support the Buckley family with the costs of travelling and staying in Glasgow and the upkeep of their farm in Cork while police searched for Karen.
The page was set to be open to donations for 24 hours but closed early when £50,001 was raised.
A message on the Go Fund Me page by the organisers read: "This page has been set up by Karen's University of Limerick nursing classmates in the hope of raising funds to help Karen's family in any way possible during this difficult time.
"Please donate anything you can to assist with accommodation expenses, travel expenses and upkeep of their farm in Co Cork."
A thank you message was later posted on the site as the amount raised exceeded 10 times the target fund.
It said: "A huge thank you to everyone for your kind words and amazing donations - the response has been overwhelming.
"We hope that what has been raised will be of help in any way possible to Karen's family. Thank you all so much for your amazing generosity."
Some people asked for donations to be reopened so that they could contribute, Claire Agathe wrote: "Just tried to donate but it states this is now closed. I hope it opens again as I am sure a lot more people will want to help. RIP Karen x."
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