The submission took an unusual and deliberately democratic form. Rather than speaking with a single voice, AMI combined a survey reflecting the majority view of participating members with a detailed supporting document that sets out the scientific case for greater recognition of marine microorganisms in European ocean policy. The society’s central message is unambiguous: marine microbes must be explicitly recognised as fundamental components of ocean ecosystems, and their needs and contributions must be considered across biodiversity conservation, ecosystem management, ocean-climate policy and the assessment of overall marine health. In other words, an ocean act that only protects what can be seen with the naked eye is, in the view of these scientists, an act that protects only a fraction of what matters.

The scientific rationale for this position is compelling. Microorganisms, including phytoplankton, bacteria, archaea and viruses, drive many of the biological and chemical processes that regulate the ocean. They are responsible for recycling around half of global primary production, a staggering figure that underscores just how much of the planet’s carbon and nutrient throughput depends on organisms too small to see. Through the biological carbon pump, phytoplankton fix carbon dioxide at the surface and export it to the deep sea, while the microbial carbon pump converts dissolved organic matter into long-lived reservoirs that can keep carbon out of the atmosphere for centuries. Microbes also orchestrate the cycling of nitrogen, phosphorus and iron, elements that determine how productive marine food webs can be and how much carbon the ocean can ultimately sequester.

The urgency of this agenda is growing as the ocean changes. As marine waters warm, acidify and lose oxygen, microbial communities are being pushed into conditions they have not experienced on human timescales. Because microbes reproduce quickly and respond rapidly to shifting temperatures, pH levels and nutrient supplies, changes in their community composition and metabolic function often precede visible changes in larger organisms and habitats. Understanding how these communities respond to ocean warming, acidification and deoxygenation will therefore be increasingly important for predicting future shifts in ecosystem function, for anticipating how climate regulation services may weaken, and for designing interventions that support microbial processes capable of buffering environmental stress rather than amplifying it.

Beyond free-living microbes, AMI’s response draws attention to the intimate partnerships between microorganisms and larger marine life. Corals, sponges, seagrasses and fish all exist in close association with complex microbial communities that can influence nutrition, disease resistance and resilience to environmental stress. The coral microbiome, for example, can determine whether a reef survives a bleaching event, while the microbial partners of seagrasses are essential for nutrient uptake in the sediments that anchor these meadows. AMI argues that recognising these host-associated microbiomes could materially strengthen conservation and restoration efforts, by ensuring that the microscopic processes underpinning ecosystem health are not overlooked when protected areas are designated, when species are translocated, or when damaged habitats are actively restored.

There is also a powerful economic argument embedded in the society’s submission. Marine microbial communities represent a largely unexplored reservoir of genetic and biochemical diversity, a living library of molecules shaped by billions of years of evolution in some of the most extreme environments on Earth. Potential applications range from novel medicines and industrial enzymes to new biomaterials and biotechnological processes, with microbial enzymes from cold-adapted and pressure-tolerant species already finding uses in industry and research. AMI stresses that protecting marine microbial biodiversity is therefore not only an environmental priority but also an investment in future innovation, feeding directly into the ambitions of the European blue bioeconomy and the continent’s broader strategy for sustainable growth grounded in living resources.

Translating this science into law, AMI offers a series of concrete recommendations. First, the society calls for strengthening the definition and assessment of Good Environmental Status, the benchmark against which European seas are measured, so that it explicitly considers microbial diversity, community composition, functional diversity and the ecosystem services that microbes provide. Second, the submission urges that host-associated microbiomes be formally recognised wherever they are important to the health and resilience of protected species, habitats and ecosystems. These changes would mean that monitoring programmes, conservation targets and restoration criteria under the Ocean Act would no longer treat microbes as an afterthought but as measurable, reportable components of environmental quality in their own right.

The response also argues that an ecosystem-based approach to ocean management must move beyond a focus on visible organisms and iconic habitats. Microorganisms drive the processes that make marine ecosystems possible, including nutrient cycling, carbon sequestration, primary productivity and decomposition. Their rapid responses to environmental change could provide early-warning indicators of ecosystem condition and recovery, offering policymakers near-real-time signals of stress long before fish stocks decline or habitats collapse. Incorporating microbial indicators into routine monitoring would give regulators a finer-grained, more responsive picture of ocean health, and could reveal whether management measures are actually working at the functional level where the ocean’s essential chemistry is performed.

By bringing together the expertise and perspectives of its global membership, AMI is advocating for an Ocean Act that recognises the full biological complexity of marine ecosystems and puts microbiology firmly within Europe’s vision for a healthy, resilient and sustainable ocean. The society, the oldest microbiology society in the United Kingdom with more than half of its members based outside the country, publishes The Microbiologist magazine and three internationally recognised journals in partnership with Oxford University Press, and it frames this intervention as part of its wider mission to amplify the collective influence of applied microbiologists in evidence-based decision making. The consultation response makes clear that the microbes drifting in every litre of seawater are not a footnote to ocean policy; they are its scientific foundation, and the legislation that will govern European seas for decades should say so explicitly.

Subject of Research: The role of marine microorganisms in European ocean policy and the proposed EU Ocean Act

Article Title: AMI calls for marine microbes to be at the heart of Europe’s future ocean policy

Article References: AMI calls for marine microbes to be at the heart of Europe’s future ocean policy. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: marine microbes, EU Ocean Act, Applied Microbiology International, ocean policy, microbial carbon pump, Good Environmental Status, blue bioeconomy, host-associated microbiomes, ocean acidification, biodiversity conservation, ecosystem monitoring, phytoplankton

The study, led by Dr. Jiaqi Li of Northeastern University under the supervision of Professors Dake Xu and Derek R. Lovley, examined the interaction between titanium and the marine bacterium Shewanella algae. The organism belongs to a group of bacteria known for extracellular electron transfer, a process that allows cells to move electrons beyond their outer membranes and interact with minerals, metals and other solid surfaces. The researchers found that this ability can have serious consequences for titanium. By changing the electronic and chemical state of the metal’s passive film, bacterial communities can gradually destabilize the very layer that normally prevents corrosion. The finding offers a new explanation for a longstanding scientific puzzle: how microorganisms can damage titanium even though titanium dioxide is considered nearly electrically insulating under many environmental conditions.

The process begins inside a biofilm, the slimy community that bacteria form on submerged surfaces. Although the surrounding seawater may contain abundant dissolved oxygen, dense biofilms consume oxygen rapidly as they grow and metabolize nutrients. This creates microscopic oxygen-depleted zones immediately next to the titanium surface. The result is a chemically complex environment in which conditions at the metal may differ dramatically from those in the surrounding water. These localized anaerobic or oxygen-poor regions provide an opportunity for S. algae to use extracellular electron transfer pathways. Rather than relying exclusively on oxygen as a terminal electron acceptor, the bacteria can direct electrons toward materials outside the cell. In this case, the passive titanium oxide film becomes an unexpected target for bacterial metabolism.

The crucial agents in this process are flavins, small redox-active molecules naturally produced by Shewanella bacteria. Flavins can exist in different oxidation states, allowing them to accept and donate electrons. In the biofilm, reduced flavins act as mobile electron shuttles. They collect electrons generated during bacterial metabolism and carry them through the biofilm toward the titanium surface. Once they reach the oxide layer, the flavins can transfer those electrons into the passive film. This reaction does not dissolve titanium in the same way that a strong acid would. Instead, it changes the oxidation state of titanium within the protective oxide. Stable titanium dioxide contains titanium in a highly oxidized state, but electron addition can convert portions of the film into lower oxidation-state titanium oxides.

That reduction has important consequences for the structure and function of the passive layer. Titanium’s resistance to corrosion depends not only on the presence of an oxide coating but also on the coating’s chemical stability, electronic properties and ability to repair itself when damaged. When bacterial electron transfer converts titanium dioxide into less stable forms, the film can become thinner and develop defects. These defects may provide pathways through which ions, water and electrons move more easily. As the passive layer loses uniformity, localized corrosion becomes more likely, particularly in the chemically uneven environment beneath a biofilm. The metal is therefore not attacked in a single dramatic event. Instead, its defense is progressively weakened at the nanoscale until the underlying titanium becomes increasingly vulnerable.

To establish that electron transfer was responsible, the research team used several complementary techniques. Advanced electron microscopy allowed the scientists to examine changes in the surface and thickness of the oxide film. Surface chemical analyses identified shifts in the oxidation state and composition of titanium-containing compounds. Electrochemical measurements provided information about the film’s protective behavior and the ease with which charge could move across the metal–biofilm interface. The researchers also used genetic engineering to alter bacterial flavin production. Strains engineered to produce larger quantities of flavins caused more extensive reduction of the passive film and more severe corrosion than strains with lower flavin output. First-principles calculations supported the experimental observations by showing how electron injection could alter the energetics and stability of titanium oxide structures.

The results challenge a widely held assumption about microbiologically influenced corrosion of titanium. Conventional explanations have often focused on acidic metabolites, sulfide compounds or other chemicals released by microorganisms. Such substances can certainly alter metal surfaces, but they do not fully explain every case of titanium corrosion in marine and biological environments. The new work points to a different category of mechanism in which microorganisms directly modify a passive material through electrical interactions. The bacteria are not simply creating a more aggressive chemical solution around the metal. They are using a biological electron-transfer network to change the oxide film itself. This distinction is significant because it links microbial metabolism with the electronic structure of a solid protective coating.

The discovery also broadens the scientific understanding of extracellular electron transfer. Previous research has shown that Shewanella species can transfer electrons to insoluble minerals and metal-containing compounds outside their cells. The new findings indicate that a passive oxide layer, even one that is highly resistant to electron transport, can participate in this process when a biofilm creates the right local conditions. Flavins may help overcome the limitations imposed by the oxide’s low conductivity by repeatedly shuttling electrons between bacterial cells and reactive sites on the surface. Local defects, chemical heterogeneity and oxygen depletion could further concentrate the reaction in specific areas, helping explain why corrosion may appear as localized damage rather than uniform surface deterioration.

The practical implications extend across several sectors that depend on titanium’s long-term stability. Marine transportation and offshore infrastructure may be exposed to biofilms containing electron-transferring bacteria for years or decades. Titanium components in energy systems could face similar risks in seawater or biologically active process environments. Medical implants introduce an additional concern because biofilms can form on implanted materials, where even limited surface degradation may affect performance or biological compatibility. Preventing microbial attachment will remain important, but the study suggests that it may not be enough. Future corrosion-resistant titanium alloys and coatings could be designed to reduce the ability of surface biofilms to exchange electrons with the passive film. Engineers may also seek outer layers that are more electrically insulating, chemically resistant or less receptive to flavin-mediated reduction.

By revealing a direct bioelectrochemical route to passive-film destabilization, the research changes the way scientists may evaluate titanium in microbe-rich environments. The metal’s protective oxide layer is not an entirely inert barrier; under the right conditions, it can become part of a microbial electron-transfer circuit. The work does not mean that titanium will rapidly corrode whenever bacteria are present, nor does it diminish titanium’s substantial resistance compared with many other metals. Instead, it identifies a previously unrecognized vulnerability that may help explain gradual, localized failures in demanding environments. The researchers’ findings provide a foundation for developing materials, surface treatments and monitoring strategies capable of interrupting the electron pathway before bacterial activity compromises titanium’s protective armor.

Subject of Research: Bioelectrochemical corrosion of titanium by marine bacteria through flavin-mediated extracellular electron transfer

Article Title: Marine Bacteria Weaken Titanium’s Protective Oxide Layer Through Electron Transfer

Web References: https://doi.org/10.1093/nsr/nwag426

References: National Science Review, DOI: 10.1093/nsr/nwag426

Image Credits: © Science China Press

Keywords: titanium corrosion, microbiologically influenced corrosion, Shewanella algae, marine bacteria, biofilms, extracellular electron transfer, flavins, titanium dioxide, passive oxide film, marine engineering, biomedical implants, bioelectrochemistry