An apparatus. At least some illustrative embodiments are an apparatus comprising a sensor streamer. The sensor streamer includes at least one seismic streamer section and a first electrode adapter removably attached to the at least one seismic streamer section. The first electrode adapter includes a first electrode, wherein the first electrode is configured to couple to electrical circuitry configured to measure a potential difference between the first electrode at a first potential and a second potential. The conducting member forms a reference potential, wherein the conducting member is floating. The at least one seismic streamer section is without electromagnetic field-sensing components.