Cold seep

Marine habitats
Tube worms (Lamellibrachia luymesi pictured here) are among the dominant species in one of four cold seep community types in the Gulf of Mexico.
Coastal habitats
Littoral zone Intertidal zone Estuaries Mangrove forests Seagrass meadows Kelp forests Coral reefs Continental shelf Neritic zone
Ocean surface
Surface microlayer Epipelagic zone
Open ocean
Pelagic zone Oceanic zone
Sea floor
Seamounts Hydrothermal vents Cold seeps Demersal zone Benthic zone Marine sediment
v t e

A cold seep (sometimes called a cold vent) is an area of the ocean floor where seepage of fluids rich in hydrogen sulfide, methane, and other hydrocarbons occurs, often in the form of a brine pool. Cold does not mean that the temperature of the seepage is lower than that of the surrounding sea water; on the contrary, its temperature is often slightly higher.^[1] The "cold" is relative to the very warm (at least 60 °C or 140 °F) conditions of a hydrothermal vent. Cold seeps constitute a biome supporting several endemic species.

Cold seeps develop unique topography over time, where reactions between methane and seawater create carbonate rock formations and reefs. These reactions may also be dependent on bacterial activity. Ikaite, a hydrous calcium carbonate, can be associated with oxidizing methane at cold seeps.