Exemplary embodiments provide autonomous surveillance systems for underwater environments. In one embodiment, a submerged node rests on a floor of a body of water, a module floats on the surface of the water, and a cable connects the submerged node to the floating module. The floating module collects sensor data and generates electricity, and provides both to the submerged node over the cable for storage by the submerged node. The submerged node receives a query for the sensor data from an antenna on the floating module. The submerged node identifies the sensor data based on the query, and transmits a response to the query for the sensor data using the antenna on the array.