Check out Jane’s interesting observation’s in today’s comment.
She has kept the ice open in both 2009 and 2010 winters.
Last year, no problem.
This year: amphibian mortalities.
I suspect the harsh weather is the problem here: the longer the ice cover, the more oxygen levels are reduced, until frogs simply run out of oxygen. The icy weather went on for much longer this year than last.
But we are still largely in the realm of speculation. For example, what, if any, is the role of ‘toxic gases’ in this. Do ice holes make any difference at all? Could they let air-breathing creatures get to the surface for a vital gasp of air? Are frogs running out of fat reserves before running out of oxygen? How are the other animals surviving all this? Would it be better just to run the pump, even in a wildlife pond?
All of these are hot questions with no definite answer yet.
And the differences between one pond to another are likely to be tremendously important too. There’s probably not going to be a one rule fits all answer.
