Anhydrobiosis is the remarkable ability of certain organisms to survive almost complete dehydration. Explore what happens inside cells as water disappears and why some organisms survive while others do not.
Anhydrobiosis — from the Greek "life without water" — is the ability of certain organisms to survive almost complete dehydration. Most cells can only survive losing a small fraction of their water. Anhydrobiotic organisms are the exception — they can lose more than 95% of their body water, halt visible metabolism almost entirely, and remain in that suspended state indefinitely, only "waking up" once water becomes available again.
So far, most of what biology knows about how cells work comes from studying fully hydrated systems. Much less is known about how cells function in the absence of water. The Water and Life Interface Institute (WALII) studies how life interacts with water from the molecular to the whole organism level.
This webpage is built around WALII research themes and explores the cellular and molecular biology of anhydrobiosis via interactive modules and illustrations, aiming to translate complex mechanisms into an accessible visual narrative.
Image credit: rukanoga / Depositphotos.com
From microscopic animals to drought-resistant plants, evolution has produced remarkable solutions across all kingdoms of life.
Tardigrades, also known as water bears, are microscopic eight-legged, segmented animals. They can survive extended periods without water by entering a reversible state of suspended metabolism called cryptobiosis. During desiccation, tardigrades retract their legs and contract their bodies into a compact "tun" shape, allowing them to withstand extreme dehydration until water becomes available again.
The same species used in bread and beer survives drying as a single cell by accumulating protective molecules and remodeling its membrane — making it one of the simplest systems for studying the minimal toolkit anhydrobiosis requires.
Many crop and wild plant seeds naturally dry into a stable glassy state during maturation, allowing them to remain viable for years or even decades in storage. In this dormant state, they can preserve cellular structures until water returns. However, RNA within the seed gradually degrades over time, and this decay predicts the eventual loss of germination potential.
Resurrection plants are plants that can survive extreme dehydration — losing up to 95% of their leaf water. They are rare but are found across nearly every major group of plants, except for gymnosperms. During desiccation, they shut down photosynthesis and appear dry and lifeless. When water returns, they rapidly resume metabolism, restore photosynthesis, and regain their green appearance within hours to days.
Most cells can't tolerate losing more than a fraction of their water before their membranes rupture and their proteins unfold irreversibly. Anhydrobiotes are the exception: they cross a threshold that ordinary cells never survive. Drag the water bar from right to left to simulate progressive water loss. The cellular response changes at each hydration level.
Dehydration is dangerous because water is essential for maintaining membrane structure, protein mobility, and biochemical reactions. Desiccation-tolerant organisms use multiple protective strategies.
Understanding how life survives without water could help address challenges in medicine, agriculture, biotechnology, and space exploration.
Develop strategies for preserving biological materials and improving stability during storage.
Learn from natural desiccation tolerance to improve agricultural resilience.
Use protective strategies to stabilize cells, proteins, and biological products.
Explore how biological systems might survive extreme environmental stress during long-duration missions.