More than 50 Occupy Wall Street protesters were arrested Saturday while trying to take over a new public space in TriBeCa for their movement. Elsewhere, about 200 marchers made their way up Seventh Avenue under a heavy police presence. The arrests came during an all-day protest in city-owned Duarte Square to mark the three months since the movement started. The protesters want to set up camp in an adjacent fenced-in lot owned by Trinity Church.