Pond--in danger of becoming too acid?

[Panther]

My mother has a fish pond (12 ft long, 8 ft wide, 3 ft deep) with 7 medium sized goldfish and at least 4 or 5 good-sized Green Frogs. Unfortunately, the pond is next to a huge old spruce tree which appears to dying. It's seems to be shedding all of its needles--still green--directly into the pond. My mom is constantly fishing them out with a little skimmer net, but they just keep coming; she's becoming worried that the pine needles might wreak havoc on the pH, lowering it dramatically, and hurting her fish and frogs. Hopefully the pine will cut down soon, but until then, the pond continues to be covered with needles.

Is this a real threat, and if so, is there anything she can do?

 

[The-Wolf]

I suggest laying some polythene sheetint over the area where the needles are falling.
to be really sure you are doing everything you can, perform a 50% water change and vac the bottom(providing you have a pond vac of course).

the danger is going to come from the starches and sugars being released by the needles as they decompose.

 

[ryan]

Yes, there is a serious danger that the pond will be highly acidic affecting the pond life within it. As suggested above the best option is to perform a large water change and cover the pond to prevent the pine needles falling into the water.

 

[Panther]

It's going to be difficult to cover the pond, as the entire pond is subject to falling pine needles and yet it still needs to be accessible to the frogs. Considering the size of the pond coupled with its extremely cold temperatures (I think 50 is the highest it's reached so far) a 50% water change is a truly massive endeavor. If it's the decaying pine needles that is the problem, hopefully the constant straining of fallen pine needles from the pond will be enough for now, as they take quite a while to sink. Cross your fingers, anyway...