Lost River

LRInfobox

Property	Value
Type	Cave
Depth Range	525 - 1065 meters
Temperature Range	3.3°C - 4.5°C
Biome ID	lostriver
Harvesting Nodes	Limestone Outcrop, Sandstone Outcrop, Shale Outcrop
Points of Interest	Inactive Lava Zone, Disease Research Facility, Lost River Laboratory Cache, Alien Arch Cache, Ancient Skeleton, Sea Dragon Leviathan Skeleton, Giant Cove Tree
Entrances	Northern Blood Kelp Zone, Deep Grand Reef, Mountains/Bulb Zone border, Blood Kelp Trench

"Terrain scans indicate this biome contains unusually high concentrations of organic and fossilized remains." ― PDA, Dialogue

The Lost River is a massive, frigid cave biome located deep under the surface and is further divided into seven distinct sub-biomes. It can be accessed through four entrances found in the Northern Blood Kelp Zone, the Deep Grand Reef, the border between the Mountains and the Bulb Zone, and the Blood Kelp Trench.

While the Cyclops and Prawn Suit are fully capable of exploring the entirety of the Lost River and the Inactive Lava Zone beyond it, there are some sections that are too deep for the Seamoth to explore, even with its strongest depth module.

Description

The Lost River is a vast and gloomy biome, its water possessing a distinct greenish tint due to the illuminating brine pools that cover a majority of the seabed. These pools are highly acidic, even to the Seamoth, and will damage the player if entered without the increased protection of the Prawn Suit. Wildlife in this area have become accustomed to the brine, meaning they can swim and grow in the pools without issue. Skeletons of immense, long-deceased fauna are a common sight in the Lost River, which, in conjunction with the biome's many native, spectral fauna, give the Lost River a uniquely eerie atmosphere.

One thousand years ago, the Lost River was a hub for Precursor activity, with the highly-important Disease Research Facility having been constructed between the Junction and Mountains Corridor sub-biomes. Further signs of their research can be found at the Lost River Laboratory Cache, and an Alien Arch Cache is hidden away in the Ghost Forest. All installations can be found using alien waymarkers ranging from small pylons to towering pillars.

The Lost River is one of the coldest biomes, with temperatures on the sea floor rarely rising above 10 degrees Celsius. Hence, thermal reactor modules do not work very well here, unless the vehicle is positioned near a thermal vent.

Lost River map, labeled by sub-biome

A Thermal Plant next to a thermal vent is one of the best ways to power a Seabase in this biome. It is advised to bring plenty of Titanium, since there are few large Titanium deposits to be found here. Any other resource can usually be acquired on the spot. Note that there are enough resources, like lead, in the Lost River for the player to build a nuclear reactor and nuclear reactor rods. Additionally, be conscious of the hull integrity so that the Seabase does not take any damage.

Bone Fields

"Bone Fields"

The Bone Fields is a vast cavern within the Lost River, centered on the Gargantuan Fossil which gives the Bone Fields its name. It is connected to the Blood Kelp Trench via the Lost River Corridor, and to the Deep Grand Reef via the Ghost Canyon, each of them having their own flora and particular landscapes.

The Ghost Leviathan Juvenile in this region is facing directly to the Ghost Canyon. One should be cautious when entering through there to here.

There are a few hydrothermal vents in this area. On these you can find Rubies, Lithium, Green Table Coral and sometimes Magnetite.

Large Resource Deposits are present mostly under the brine lake surrounding the colossal skeleton and the caves underneath. Rarer deposits can be found in the Bone Fields Caves on the ceiling, others around the cavern and deeper caverns under the brine.

The caves in the brine and ceiling contain a unique, unnamed kind of coral.

Resources

Diamond Gel Sack
Ghost Weed Seed
Gold
Large Gold Deposit
Large Lithium Deposit
Large Nickel Deposit
Large Silver Deposit
Large Titanium Deposit
Large Uraninite Deposit
Lead
Lithium
Magnetite
Mesmer Eggs
Nickel Ore
Quartz
Ruby
Silver Ore

Fauna

Flora

Crab Claw Kelp
Gel Sack
Ghost Weed
Green Table Coral

Gallery

A view of the Gargantuan Fossil

Smaller ribs located at the outskirts of the Bone Fields

A small cavern beneath the brine surface

Strange rock formations on the ceiling of the Bone Fields

The Bone Fields Caves above the Bone Fields

A view of the Large Skeletal Remains

Rear view of the skeletal remains

The Ghost Leviathan Juvenile found in this section of the biome

Corridor

"Corridor"

The Lost River Corridor is the area connecting the Bone Fields to the Blood Kelp Trench. Two brine rivers run through the full length of the corridor, frequently forming small brinefalls along the way. Rock formations overgrown with Pyrocoral dominate the area, adding to its unique appearance. Players passing through this entrance should be wary of the Crabsquids that roam here.

A good amount of Limestone Outcrops can be found on the seabed, with Shale Outcrops occasionally located on the walls and ceiling of the corridor. There is a group of hydrothermal vents at the end of the corridor, marking the entrance to the Bone Fields.

Gel Sacks can also be found in abundance scattered around the edge of the brine streams.