Last week, we talked about what I think will be a big investment theme for 2010, rising interest rates. This week, we take a look at the second installment in our series about the top 10 investment themes for 2010 -- currency upheaval.

Now, when I say currency upheaval, I am talking largely about the fortunes of the U.S. dollar. To be certain, the dollar has had a lot of upheaval in 2009. Just look at the chart below of the U.S. dollar index, a measure of the greenback compared to a basket of the most heavily traded foreign currencies.

After starting the year with a stout surge, the dollar’s fortunes turned tail in March. And with a few brief periods of sideways movement, the greenback plunged to record lows in late November.

Interestingly, the dollar has been on a sharp run higher since the first week of December. In fact, the dollar recently broke above its short-term, 50-day moving average (blue line), and now appears on route to break above its long-term, 200-day moving average (red line). If the greenback can breach this technical barrier, it could be the start of a protracted bull in the U.S. dollar vs. rival foreign currencies.

This is the kind of currency upheaval I expect will take place in 2010. As more and more countries try to keep the value of their currency low to help stimulate exports, we are likely to see more money move into dollars. Also, the rise in the dollar could mean a pullback in the price of gold.

The price of gold, as represented below in the chart of the SPDR Gold Shares (GLD), has been on a tear for most of the year. However, since the dollar’s December resurgence, the value of gold has declined precipitously.

I think that the currency upheaval we’re likely to see with the dollar -- and with other currencies around the globe -- will mean opportunities on both sides of the gold trade in 2010. It also will mean opportunities on both sides of the international equity market trade, and on both sides of the domestic market trade.

Just about any way you look at it, currency upheaval in 2010 will cause both dislocation and opportunity for investment capital. The trick, of course, is to know which is which, and to be on the right side of the trade.