Bazaruto is a sandy island located approximately 80 kilometers (50 miles) southeast of the mouth of the Save River, Mozambique. The warm, southward-flowing Mozambique Current seems to contribute to the increasing buildup of the sandy coastline. Because the water along this coastal area is very clear, much of the sub-surface channel pattern around the island is discernible. Several narrow lines of plankton bloom (barely visible in the photograph) parallel the shoreline. The coastal plains show numerous lakes and a swampy environment that appears to be karst topography. Underlying the area is limestone rock that has eroded into a pockmarked landscape, creating water-filled sinkholes. Rainfall in this humid subtropical climate amounts to between 50 and 100 centimeters (20 and 40 inches) annually.