Central to this discovery is the phenomenon of “marine snow” — the continuous shower of organic particles descending from ocean surface waters. These aggregates consist of detritus such as dead algae, microbial cells, and other biogenic debris. Previous models treated these sinking particles chiefly as vehicles transporting carbon and nitrogen to the seafloor for burial, effectively removing organic matter from the active oceanic cycle for millennia. The SDU study introduces a paradigm shift by showing that intense hydrostatic pressures experienced between depths of 2 and 6 kilometers force these particles to leak substantial fractions of their organic content into the surrounding seawater, thus supplying microbes with an accessible and valuable nutrient source.

According to Peter Stief, Associate Professor and lead author, the immense pressure at these depths operates much like a colossal “juicer.” It mechanically compresses marine snow aggregates, extracting dissolved organic compounds such as proteins and carbohydrates. These leaked molecules represent a readily utilizable form of dissolved organic matter (DOM), which heterotrophic bacteria and other microbes in the deep ocean can immediately metabolize. This process effectively energizes deep-sea microbial communities that were previously thought to subsist on limiting resources.

Demonstrating this novel mechanism demanded meticulous laboratory recreation of pressure conditions approximating the deep ocean’s physical environment. The researchers cultivated synthetic marine snow from diatoms — microscopic, photosynthetic algae known to naturally coalesce in surface waters. These particles were then subjected to specially-designed, rotating pressure tanks capable of simulating the extreme hydrostatic pressures encountered thousands of meters below sea level. The rotation ensured particles remained suspended, accurately mimicking their natural descent through the water column without settling. Measurements revealed that up to 50% of the initial carbon and up to 63% of nitrogen content within these particles were released into surrounding waters as dissolved organic matter.

The chemical signature of these leakages confirmed a dominance of nitrogenous proteins and carbohydrates — compounds that fuel microbial metabolism efficiently. Correspondingly, incubation experiments demonstrated a rapid proliferation of bacterial abundance, soaring thirtyfold within just two days under pressurized conditions. Notably, bacterial respiration rates peaked simultaneously, signifying an energized microbial community swiftly capitalizing on this newly available carbon and nitrogen pool.

Beyond advancing microbiological understanding, this discovery has profound implications for global biogeochemical cycles. The conventional view holds that a major portion of sinking organic matter is sequestered in deep-sea sediments, where carbon is fossilized over millions of years and contributes to long-term climate regulation. The revelation that marine snow particles lose significant organic content midway through their descent implies that less carbon ultimately reaches the sediment floor. Instead, more dissolved carbon remains suspended within the deep ocean waters, exposed to complex circulation patterns that can retain it for centuries or millennia before eventual return to surface layers and the atmosphere.

This nuanced carbon leakage mechanism thus reshapes estimates of the ocean’s capacity to store carbon over different timescales, with critical consequences for predictive climate models. The longevity of dissolved organic carbon in abyssal waters alters feedback mechanisms between oceans and atmosphere, influencing how carbon fluxes respond to natural variability and anthropogenic pressures. Furthermore, since hydrocarbon deposits like oil and gas originated from ancient sedimented organic matter, understanding the efficiency of marine snow carbon burial enhances our knowledge of Earth’s fossil fuel genesis.

Intriguingly, the pressure-induced leakage of dissolved organic matter was consistent across multiple species of diatoms tested, suggesting this process is widespread rather than species-specific. Such ubiquity highlights a potentially universal role of hydrostatic pressure in modulating nutrient fluxes and microbial energetics throughout the global ocean. This challenges entrenched scientific dogmas and opens new avenues for research into deep-sea ecology and elemental cycling.

Next steps for the research team involve validating their laboratory findings in situ during an upcoming Arctic expedition aboard the German research vessel Polarstern. By collecting water samples spanning surface to abyssal depths, they aim to identify molecular fingerprints characteristic of leaked dissolved organic matter, verifying that this pressure-driven process occurs naturally in oceanic environments. Given the Arctic’s unique stratification and vulnerability to climate change, these observations could prove pivotal in understanding regional and global carbon budgets.

More broadly, the Danish Center for Hadal Research at SDU is committed to exploring life and biogeochemical dynamics in the ocean’s deepest trenches and hadal zones, where extreme pressures and unique ecological niches prevail. These investigations are crucial to integrate the deep ocean’s contributions into the Earth system perspective, ensuring comprehensive assessments of carbon cycling and climatic feedbacks in an era of rapid change.

This study represents a transformative stride in marine science, illuminating the hidden interplay between physical forces and biological processes shaping nutrient availability and carbon sequestration in the deep ocean. By unveiling how hydrostatic pressure effectively “juices” organic aggregates, it reshapes concepts of deep-sea microbial ecology and carbon fate, underscoring the ocean’s complexity and its central role in Earth’s climate system.

Subject of Research: Not applicable

Article Title: Hydrostatic pressure induces strong leakage of dissolved organic matter from ‘marine snow’ particles

News Publication Date: 4-Feb-2026

Web References: http://dx.doi.org/10.1126/sciadv.aef3182

References: Peter Stief, Jutta Niggemann, Margot Bligh, Hagen Buck-Wiese, Urban Wünsch, Michael Steinke, Jan-Hendrik Hehemann, Ronnie N. Glud. “Hydrostatic pressure induces strong leakage of dissolved organic matter from ‘marine snow’ particles.” Science Advances.

Keywords: Marine biology, Oceanography, Carbon cycle, Deep-sea microbiology, Hydrostatic pressure, Marine snow, Dissolved organic matter

The team meticulously analyzed human vascular tissue samples obtained from patients undergoing vascular surgeries. By employing advanced DNA sequencing technologies, they identified that a significant fraction of cells within the diseased arterial walls carried identical genetic alterations, tracing back to a common ancestral cell. This discovery points to a clonal proliferation within plaques, analogous to the rapid cellular divisions seen during tumorigenesis. Surprisingly, in some patients, more than ten percent of the arterial cells shared these mutations, amounting to hundreds of thousands of clonally expanded cells.

This revelation not only redefines the biological underpinnings of atherosclerosis but also suggests that cellular mutation and proliferation mechanisms may play an integral role in plaque development. Unlike cancer, however, the researchers emphasize that atherosclerosis should not be classified as a “blood vessel tumor.” The genetic mutations, though reminiscent of those driving malignancies, may act more subtly in influencing the behavior and progression of diseased vascular cells.

Historically, atherosclerosis has been characterized by the build-up of lipids and immune cells within arterial walls, leading to plaque formation and subsequent vessel narrowing. These plaques, which evolve through a complex interplay of cholesterol deposition and chronic inflammation, often culminate in life-threatening events such as heart attacks and strokes. Current clinical interventions primarily focus on managing cholesterol levels and blood pressure but do not directly target the diseased vessel tissue at the cellular or genetic level.

By identifying large clonal populations in plaque tissue, this study shines a light on a previously unappreciated layer of complexity within atherosclerosis. The presence of mutated cell clones suggests a potential mechanism by which plaques might expand or stabilize differently, influenced by the genetic “blueprint” carried by proliferating cells. The study’s lead researcher, Associate Professor Lasse Bach Steffensen, underlines that these findings open new pathways for research that could transform therapeutic strategies.

One of the study’s critical technical advancements was the comparison of mutated DNA from plaque cells with the patients’ blood DNA, enabling the identification of alterations specific to the diseased vessel wall. This approach minimized confounding factors and provided clear evidence of localized genetic changes potentially driving disease progression. The comprehensive sequencing data revealed mutations clustered in genes that plausibly impact cellular behavior, including proliferation, survival, and response to environmental stressors.

The implications of this clonal expansion are profound. If these mutated cell populations contribute actively to plaque growth or instability, understanding their genetic drivers could herald novel treatments aimed at halting or reversing disease progression. Such therapies might target pathways involved in cell division or mutation repair, areas currently explored extensively in oncology yet relatively unexplored in cardiovascular medicine.

Despite these exciting advancements, the researchers are cautious in their interpretation. The study, involving a limited patient cohort, requires validation in larger populations and experimental models to delineate causality. Furthermore, whether these genetic alterations are causative in plaque formation or secondary consequences of chronic disease remains to be established. Nonetheless, the evidence unmistakably points to the significance of clonal cellular behavior in atherosclerosis, reframing it as a dynamic and genetically influenced disease process.

This discovery also underscores the invaluable role of patient-donated tissue samples collected over more than a decade at Odense University Hospital. The meticulous collection, preservation, and analysis of these human samples have provided unparalleled insights that extend beyond traditional epidemiological or biochemical approaches. The collaboration between surgeons, laboratory scientists, and patients forms a solid foundation for future translational research poised to impact clinical practice.

Looking forward, the research team plans to expand their investigation to include a broader patient base and integrate clinical data correlating mutation burden with disease severity and outcomes. Such longitudinal studies could reveal whether the extent of clonal expansion predicts cardiovascular events or responsiveness to therapy. Moreover, advances in single-cell sequencing and spatial transcriptomics may enable detailed mapping of mutated cell populations within plaques, illuminating their interactions within the vascular microenvironment.

Notably, this study challenges the biomedical community to reassess the binary distinction between cancerous and non-cancerous proliferative diseases. The concept that atherosclerosis involves cellular proliferation driven by genetic mutations opens up a conceptual bridge linking cardiovascular pathology with oncogenic processes. This could inspire innovative interdisciplinary research blending oncology, genetics, and cardiovascular science to uncover shared molecular mechanisms and therapeutic targets.

In summary, the identification of clonal cell populations bearing shared genetic alterations in atherosclerotic plaques invites a transformative perspective on one of the world’s leading causes of death. By integrating genetic insights with classical risk factor paradigms, science edges closer to unraveling the complex biology of vascular disease. The prospect of genetically informed diagnostics and treatments offers hope for improved patient outcomes, representing a crucial step toward personalized cardiovascular medicine.

Subject of Research: Human tissue samples

Article Title: Mutational landscape of atherosclerotic plaques reveals large clonal cell populations

News Publication Date: 8-Apr-2025

Web References:
https://insight.jci.org/articles/view/188281
http://dx.doi.org/10.1172/jci.insight.188281

Image Credits: Lasse Bach Steffensen, University of Southern Denmark

Keywords: Atherosclerosis, genetic alterations, clonal expansion, vascular disease, DNA sequencing, plaque biology, cardiovascular genetics, cell proliferation, mutation, tumor biology analogy, personalized medicine, cardiovascular pathology