Ilya Espino de Marotta takes over Monday as head of the Panama Canal Authority, facing a critical period for the waterway. Persistent low water levels caused by little rainfall are hindering the canal’s ability to meet shipping demand. The 50-mile route between the Pacific and Atlantic oceans carries 40% of U.S. containerized trade and has become part of a broader geopolitical struggle between the U.S. and China over control of global trade routes.