Vent Field
Where water circulates through hot rock or hydrocarbons leak up through sediment, a dense community grows on chemical energy. Each field is a few hundred feet across with miles of empty floor around it, and it lasts as long as the vent or seep does. Water leaving a black smoker is hot enough to melt a suit, and water three feet away is barely above freezing.
Crossing it
- Navigate
- DC 15
- Forage
- DC 10
- Notice
- DC 13
A few hundred feet of dense life, then nothing for miles.
Exposure
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Temperatures above about 100 degrees Fahrenheit in shade, or anywhere near a working vent.
CON save, DC 10, rising by 1 for each hour after the first. End of each hour. One level of exhaustion.
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Sealed and armored
A creature in medium or heavy armor, or in a sealed suit without active cooling, has disadvantage on the save.
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Water
A creature with its full water ration has advantage on the save. One without any fails automatically.
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Cooled
Active cooling, a Rift effect naming heat, or Resistance to fire damage removes the save.
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In play
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Plume
Water within 10 feet of an active smoker is superheated: 6d10 fire damage per round, and a pressure suit fails on the second round.
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Dense life
Biomass here is hundreds of times that of the surrounding floor. Creatures here depend on the field's energy and leave when it stops.
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Darkness
No light reaches the field. Creatures here navigate by chemistry and pressure, so an illusion that only looks right does not fool them.
Variations
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Black smoker
Volcanic. Superheated, mineral-loaded, and the chimney grows visibly over a season.
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Cold seep
Hydrocarbon leak through sediment. No heat, the same density of life, and it lasts far longer.
Worlds it occurs on
- Aquan A world that is liquid down to the core, with no land, no shelf and no solid surface to stand on.
- Magmatic A world with an unsettled surface: tidally heated, newly formed, or orbiting too close to its star.
- Terran (Oceanic) A world of ocean from pole to pole, with land only where a volcano has kept up.
- Terran (Verdant) A rocky world with liquid water, breathable air and a magnetic field to protect them, rare and the cause of most wars.
