Scientists have uncovered the genetic secrets behind a novel energy-use strategy that allows a deep-sea “giant” to survive without food for over five years, in one of nature’s most stunning survival stories.
Supergiant bathynomids, also known as giant isopods, present a bizarre biological paradox: they exhibit pronounced body gigantism as megafaunal species yet inhabit a deep-sea habitat with extremely sparse nutrient availability.
In a recent paper in Cell, researchers from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) revealed how these large deep-sea creatures subsist on such limited food, using a novel genetic strategy unique to bathynomids.
A Complex Genetic Approach
The IOCAS team employed a multi-omic strategy to address the problem, combining genomics with other disciplines, such as morphology, physiology, behaviorology, and metagenomics. Doing so led to a novel discovery: that supergiant bathynomids don’t have just one, but two techniques to manage their limited access to nutrients.
First, isopods have a massive stomach that can store vast amounts of nutrients for later use. Second, they have an exceptionally low basal metabolic rate (BMR), which is genetically driven.
To diversify their research, the team focused on two species that occupy different depths. At around 300 meters, the Bathynomus doederleini is the shallower of the two, while the Bathynomus jamesi is found at 898 meters. Despite the difference in depth, both are technically considered “deep-sea” inhabitants, as the boundary is defined at 200 meters.
A Powerful Stomach
Roughly two-thirds of a bathynomid’s body is stomach—a figure far beyond that of related intertidal and shallow water species. The contents of those enormous stomachs are also unusual, filled with a mud-like mixture of highly digested food. This finely ground nutrient sludge has a low proportion of digestive bacteria, but a high amount of lipid-storing Chlamydiae.
With a bacterial ratio leaning toward preservation rather than just digestion, this creates a food reserve that can be slowly digested and utilized as the creatures lower their BMR to endure long periods between feedings.
Genetic Findings
Another major finding was that bathynomids benefit not only from vertically transferred genes between parents and offspring, but from the horizontally transferred ND1 gene they acquired from an exogenous symbiotic bacterium. Intriguingly, the transfer defied typical horizontal transfer limitations, achieving an ultra-high level of expression in the bathynomid genome.
These isopods use epigenetic histone modifications to regulate energy-related gene expression, thereby improving efficiency, conservation, and control. An example of this is histone acetylation regulating ND1 expression at an ultra-high level, which the team investigated in a laboratory test. Researchers suspected this gene was essential to energy metabolism, as it is a component of Complex I in the electron transport chain.
ND1 Genetic Tests
Using zebrafish, nematodes, and human 293T cells, the IOCAS team tested the gene’s impact on energy usage. At normal temperatures, the team found that ND1 actually decreased starvation tolerance by increasing energy metabolism. Yet when the team lowered temperatures to reflect those found in a typical deep sea environment, they found the opposite effect, with ND1 decreasing mitochondrial activity and energy metabolism rates, to improve zebrafish starvation tolerance an astounding 37%.
The IOCAS team concluded that ND1 provides a solution to the long-standing paradox of bathynomid gigantism in the context of their nutrient-poor environment. By fine-tuning the degree of metabolic depression, the gene can adjust the mitochondrial metabolic network to preserve energy during extended periods without sustenance.
Never before has such a strategy for energy efficiency, combining horizontal gene transfer and epigenetic optimization, been identified in a deep-sea megafaunal species.
“Our work not only deciphers the mystery of ultra-long starvation tolerance in deep-sea isopods,” said lead author Yuan Jianbo, “but also provides an important paradigm for understanding how life balances growth and survival in extreme environments.”
The paper, “Deep-Sea Megafauna Co-Opts Microbial Energy Metabolism Genes to Withstand Ultra-Long Starvation,” appeared in Cell on June 5, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.