Ecology , Coastal New Orleans

The original City of New Orleans is founded on naturally occurring river levees on the Mississippi River in the lower delta. It was surrounded by lower swampy delta land in a hot subtropical climate and would seem to be a foolish place to put a city. And yet history indicates that the have been compelling reasons for one of the more iconic cities in North America.
Question: How has marine shipping impacted the development and environment of New Orleans? But sure to understand the impact of the Panama Canal expansion. Also be sure to explain MR-GO.