* S&P 500 turns negative for year
* S&P closes below 200-day moving average
* Global growth fears weigh on stocks
* Dow off 2.2 pct, S&P off 2.6 pct, Nasdaq 2.8 pct
* For up-to-the-minute market news see [STXNEWS/US] (Updates to close)
By Edward Krudy
NEW YORK, Aug 2 (Reuters) - The S&P 500 turned negative for the year on Tuesday as the wrangling over the U.S. debt ceiling faded and investors turned their attention to the stalling economy.
The broad-based index fell for a seventh day and crashed through the key 200-day moving average in an ominous sign for markets. The seven days of losses mark the longest losing streak since October 2008.