Nigeria's central bank governor Lamido Sanusi has been suspended by the president for "financial recklessness and misconduct". Mr Sanusi caused shockwaves in Nigeria when he alleged that $20bn (£12bn) in oil revenue had gone missing. He said he would challenge his suspension in order to preserve the central bank's independence. Meanwhile, foreign exchange, bond and money markets have stopped trading because of uncertainty caused by the move. The president, however, does not have the power to sack the central bank governor - only the National Assembly can do this. Although his term in office was due to end in June, the decision to suspend him now is still highly significant. Many Nigerians will think the president has chosen to suspend the whistleblower rather than focus on stopping fraud.