The depth, surface area, and volume of the lagoon all vary depending on the configuration of the sand berm (high or low) and rainfall (wet or dry).

Since the Marin Headlands are often quite windy, it is not unusual to see Langmuir circulation form windrows of foam on the surface of the lagoon.

The bowl-shaped bathymetry of the lagoon traps this dense, salty water and prevents it from quickly draining back out in the ocean.

This annual algae bloom, because of its size and potential toxicity, is considered problematic for water quality and fish survival.

The lagoon is located within the geologically complex Marin Headlands and fills a valley drowned by recent sea level rise following the last glacial period.

[5] The bed of the lagoon is covered by viscous black mud that is high in organic content, except at the east and west ends, where non-organic sediment can be found.

However, the lagoon and surrounding area is an excellent place for wildlife viewing, particularly birding[7] and watching the playful river otters.