Markets closed lower after falls in oil, copper and iron ore prices, following poor export data from China on Monday. Fears are rising around the growth trajectory for China, the world's largest emerging economy. Meanwhile, Ukraine tensions continue amid a gridlock in talks between Russia and the US. The Crimea will vote mid-March on whether to join Russia. Geopolitical threats are seen as the biggest risk to equities after five years of a bull market. Jane Searle speaks with Mark Newton at the NYSE.