It's long been a given that high levels of fecal indicator bacteria (FIB) in the Malibu lagoon are a result of our fair city's aging septic systems. But according to a new study by the USGS, the culprit actually may be the kelp. From the press release:

Tests show that FIB concentrations routinely exceed U.S. Environmental Protection Agency public health standards for marine recreational water in Malibu Lagoon and occasionally exceed those standards at several Malibu beaches.

According to preliminary results of the study, scientists suspect possible sources of FIB to the ocean are kelp accumulated on the beach, discharge from Malibu Lagoon to the ocean, or movement of water from the lagoon through the sand berm separating the lagoon from the ocean. Scientists hope to know the exact source of the FIB to the near-shore ocean and the Malibu Lagoon once the study is complete.

More studies and more testing are on the way. For the full report, look here.