The research combined a survey of 216 metagenomes from profiles extending from 0 to 700 cm in four agroecosystems with a global synthesis of subsurface metagenomes. This work produced the Deep Soil Viral Resources Database, which contains 50,949 viral operational taxonomic units and 3,902 auxiliary metabolic genes, abbreviated as AMGs. Together, the two analytical components were used to examine how viral diversity, activity and encoded metabolic functions vary through soil profiles and how those patterns relate to carbon cycling at global scale.

Depth was associated with both increasing viral richness and a shift toward lysogeny. The deep-soil virome also carried AMGs and lysozymes involved in polymer degradation and cell endolysis. The AMGs were linked to facilitation of carbon scavenging by bacterial hosts, providing a potential mechanism through which viruses could affect microbial carbon acquisition when carbon availability is lower. This functional role was distinct from the observed global association: the survey data identified viral genetic functions and their relationship to host carbon use, whereas the global synthesis tested the broader relationship between viral abundance and soil organic carbon.

Viral endolysin provided a second mechanism in the proposed framework. The reported experiments found that viral endolysin significantly promoted necromass carbon accumulation, and that this contribution was associated with increases in mineral-associated organic carbon. These results connect virus-induced cellular breakdown with the transfer of microbial carbon into a pool associated with minerals. The authors therefore propose that viruses strengthen the microbial carbon pump in deep soils through two complementary processes: AMGs facilitate host carbon scavenging, while endolysin activity promotes necromass formation.

The global analysis provided evidence consistent with this framework. Across 138 soil profiles, viral abundance had a positive effect on soil organic carbon, while the depth-related patterns in microbial carbon utilization were examined as potential drivers of the virome. However, the broad synthesis demonstrates an association across soils rather than showing that viral abundance alone causes carbon retention. Likewise, the profile survey was conducted in four agroecosystems, so its mechanistic results may not represent every deep-soil environment. Within those limits, the study establishes viruses as important regulators of subsurface carbon cycling and offers a framework for assessing their contribution to deep-soil carbon persistence.

Subject of Research: Viral regulation of microbial carbon cycling in deep-soil profiles

Article Title: Soil viruses as key regulators of the microbial carbon pump in deep soils

Article References: Wu, X.-J., Han, W.-X., Liang, C., Chen, J., Nicol, G., Rillig, M. C., Zhu, D., Liu, B.-B., Wang, F.-H., Xiao, K.-Q., & Zhu, Y.-G. (2026). Soil viruses as key regulators of the microbial carbon pump in deep soils. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-026-03207-x

Image Credits: AI Generated

DOI: 10.1038/s41559-026-03207-x

Keywords: soil viruses, deep soils, microbial carbon pump, soil carbon cycling, auxiliary metabolic genes, viral endolysin, necromass carbon, mineral-associated organic carbon, metagenomics, Soil, viruses, regulators

The numbers behind the review are striking. Mangroves can hold up to 1,023 megagrams of carbon per hectare below ground, supported by anoxic, sulfate-reducing sediments and vertical accretion rates of 3 to 10 millimetres per year. Salt marshes sequester between 150 and 250 grams of carbon per square metre annually, while seagrass meadows bury 30 to 218 grams per square metre each year. Per unit area, these figures rival or exceed the sequestration rates of tropical rainforests, and salt marshes have been reported to store up to ten times more carbon per hectare than many terrestrial ecosystems. Because roughly half of all photosynthesis on Earth occurs in the ocean, the marine carbon cycle exerts a profound influence on atmospheric chemistry, and vegetated coastal habitats sit at the sharp end of that cycle.

The secret to mangrove carbon storage lies largely underground. Between 50 and 70 percent of the carbon in a mangrove forest resides in roots and soils, where prop roots, pneumatophores and fine root networks continuously deliver organic matter to the sediment. Waterlogged, oxygen-poor conditions suppress aerobic decomposition, forcing microbes down slower metabolic pathways such as fermentation and sulfate reduction. As a result, organic matter in mangrove soils breaks down three to ten times more slowly than in upland soils. The leaves and woody tissue of mangroves add another layer of defence, containing high concentrations of lignin, tannins and other polyphenolic compounds that resist microbial attack, extending the residence time of carbon in the sediment for centuries or even millennia.

Physical processes reinforce the biological ones. Dense canopies and root mats slow water flow, trapping fine mineral and organic particles delivered by rivers, tides and waves. This promotes vertical accretion, allowing mangroves in sediment-rich regions to accumulate surface elevation at rates exceeding 10 millimetres per year, which helps them keep pace with moderate sea-level rise while continuously burying carbon. Salt marshes operate on similar principles, trapping suspended sediments and building elevation under favourable tidal conditions. Seagrass meadows, descended from land plants that returned to the sea roughly 100 million years ago, stabilise sediments with dense root and rhizome mats, and global syntheses indicate they can store roughly twice as much carbon per hectare as terrestrial forests. Nutrient supply through their roots allows seagrasses to keep accumulating carbon even in otherwise nutrient-poor waters.

Microbes and algae add further dimensions to the story. The review highlights the microbial carbon pump, a process by which marine bacteria convert labile organic matter into refractory dissolved organic carbon that resists degradation and persists in the ocean for long periods. Alongside the biological pump, which transports roughly 10 to 15 percent of ocean primary production into the deep sea, and microbially induced carbonate precipitation, these mechanisms extend carbon storage far beyond the coastal zone. Macroalgae contribute as well, with an estimated 90 percent of algal carbon sequestration exported to the deep sea and the remainder buried in coastal sediments. Microalgae, which fix carbon dioxide at rates up to ten times more efficient per unit of solar energy than terrestrial plants, are attracting attention as candidates for engineered carbon removal.

Yet the review is equally clear about the fragility of these systems. Disturbance can flip a blue carbon sink into a carbon source with alarming speed. Converting mangrove forests to aquaculture ponds can release carbon at rates up to 50 times higher than the sequestration achieved by intact forests, while deforestation and hydrological alteration raise emissions to levels 10 to 40 times above normal sequestration. Drainage and aeration of organic-rich soils accelerate decomposition, and sediment erosion exposes long-buried carbon to oxidation. Methane generation under shifting hydrological regimes adds another greenhouse gas pathway. The authors also flag bioturbation as a double-edged factor: crabs remove an average of 87 percent of daily mangrove litter fall in some Thai forests, and burrowing animals in marshes and seagrass beds alter sediment mixing, burial depth and porewater exchange in ways that can either aid or undermine carbon retention.

Environmental drivers complicate the picture further. Moderate sea-level rise can actually enhance carbon burial by encouraging sediment trapping and peat formation, but rapid rise can drown marshes and mangroves, releasing stored carbon and, in some conditions, promoting methane and nitrous oxide emissions. Elevated temperatures accelerate decomposition of tropical wetland soils, stronger storms erode seagrass meadows and their carbon reserves, and Mediterranean droughts have reduced primary production in Posidonia oceanica meadows. Hydrology matters enormously: tidal connection in mangroves raises sediment deposition from less than 2 millimetres per year in restricted systems to more than 10 millimetres per year in open tidal habitats, and carbon accumulation in salt marshes correlates strongly with tidal amplitude. Nutrients cut both ways, since moderate nitrogen and phosphorus inputs stimulate productivity while excessive loading from agriculture and wastewater drives algal blooms, reduces water clarity and accelerates greenhouse gas emissions.

The pollution control function of blue carbon ecosystems is one of the review’s most intriguing threads. Mangrove and salt marsh root systems slow water flow and promote deposition of suspended particles, immobilising heavy metals such as lead, cadmium and zinc, along with hydrocarbons and persistent organic pollutants, in anoxic soils. Seagrass canopies trap fine particles and microplastics, reducing their transport into coastal waters, while plant uptake and microbial denitrification remove excess nitrogen and improve water quality. Mangrove sediments have even been identified as major sinks for plastic burial. However, the authors caution that accumulating plastics impose physical stress on organisms, risk ingestion by invertebrates and fish, and may alter sediment structure and microbial activity in ways that could affect organic carbon burial and greenhouse gas fluxes, making the interaction between pollution and carbon storage a priority research area.

Restoration offers genuine grounds for optimism. Meta-analyses and long-term field studies indicate that restored mangroves, salt marshes and seagrass beds can recover 50 to 90 percent of depleted carbon stocks over several decades, with some planted mangroves regaining significant portions of ecosystem carbon in under 20 years. Restored seagrass meadows have achieved carbon accumulation rates of roughly 20 to 40 grams per square metre per year within a decade, and managed realignment of salt marshes has produced rapid carbon accumulation in its early years. Measurement techniques are advancing in parallel, with lidar remote sensing enabling precise biomass estimates in inaccessible terrain, sediment coring paired with radiometric dating revealing long-term storage, and GIS-based carbon budgeting scaling local measurements to regional estimates.

The policy implications are substantial. Mangroves alone are estimated to capture up to 42 million tons of carbon annually worldwide, and blue carbon offsetting is emerging as a mechanism for channelling finance into coastal conservation, with co-benefits spanning storm protection, fisheries support and biodiversity. The authors argue that realising this potential requires marine protected areas, hydrological restoration, catchment-level management of nutrient inputs, standardised monitoring protocols and integration of blue carbon into national climate strategies and carbon markets. The IPCC’s Sixth Assessment Report recognises ecosystem restoration as a significant natural option for boosting carbon burial and coastal resilience. As the review concludes, protecting intact mangroves, marshes and meadows is not merely a carbon accounting exercise; it is an investment in living infrastructure that filters pollutants, buffers storms and quietly performs one of the most valuable services on the planet, one gram of buried carbon at a time.

Subject of Research: Blue carbon sequestration mechanisms and pollution control in coastal ecosystems for climate change mitigation

Article Title: Mechanisms, processes, and implications of blue carbon sequestration and pollution control for climate change mitigation

Article References: Dinakarkumar, Y., Selvam, M. M., Inayathullah, N., Pavithra, K. S., Mallikarjuna, H. N., Indhusuvitha, S., Jebacani, M. J., Romauld, S. I., & Muthezhilan, R. (2026). Mechanisms, processes, and implications of blue carbon sequestration and pollution control for climate change mitigation. Discover Oceans, 3(1), Article 5. https://doi.org/10.1007/s44289-026-00118-4

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00118-4

Keywords: blue carbon, mangroves, salt marshes, seagrass meadows, carbon sequestration, climate change mitigation, coastal ecosystems, sediment carbon burial, pollution control, sea-level rise, ecosystem restoration, microbial carbon pump

For much of the history of soil science, researchers assumed that the slow decay of tough plant compounds such as lignin was the main route by which organic matter accumulated in soils. That view has been overturned in the past decade. Today, a growing body of evidence indicates that a large share of stable soil organic carbon is not plant material at all, but the residues of dead microorganisms, often called microbial necromass or microbial residue carbon. Microbes consume plant litter, build their own biomass, and when they die, their cell walls and other structural molecules bind to soil minerals and persist far longer than most raw plant debris. This pathway, sometimes described as the microbial carbon pump, effectively converts labile plant carbon into a more durable form. Understanding what controls the pump has become a central question for scientists trying to predict how soils will respond to climate change and shifting vegetation.

The research team set out to answer that question by comparing three types of forest stands: broadleaved forests, coniferous forests, and mixed forests. In each, they measured the chemical quality of the leaf litter, the total soil organic carbon content and its various fractions, and two powerful molecular fingerprints of carbon origin. Amino sugars served as markers for microbial residues, allowing the researchers to distinguish carbon left behind by bacteria from carbon left behind by fungi. Lignin phenols, meanwhile, acted as tracers of plant-derived carbon and revealed how far the lignin in the litter had been degraded. To probe the nutritional state of the microbial communities, the team applied an ecological stoichiometric approach, which evaluates whether microbes are limited more by carbon, nitrogen, or phosphorus based on the balance of these elements in their environment.

The results revealed a striking pattern. Broadleaved forest litter contained the lowest lignin content and the least carbon lability, meaning its carbon was less readily decomposable, but it boasted the highest levels of nitrogen, phosphorus, and cellulose, as well as the highest ratio of nitrogen to lignin. These stands also showed the greatest microbial nitrogen limitation, the highest total soil organic carbon, and, crucially, the largest accumulations of microbial residue carbon, including both bacterial residue carbon and fungal residue carbon. Lignin phenol concentrations and the degree of lignin degradation were likewise highest under broadleaved trees. In other words, the forests with the most nitrogen-rich, easily digestible litter were the ones where microbes were working hardest, dying in greatest numbers, and leaving the most residue behind.

Across all three stand types, the researchers observed that microbial residue carbon and plant residue carbon accumulated in step with total soil organic carbon, suggesting that both sources contribute synchronously to the growing carbon pool rather than one simply replacing the other. To identify which factors mattered most, the team used random forest analysis, a machine learning technique that ranks the influence of many variables simultaneously. The verdict was unambiguous: litter nitrogen emerged as the primary driver of microbial residue carbon accumulation, outweighing other litter characteristics such as lignin content or carbon lability.

But correlation alone does not establish mechanism, so the researchers turned to structural equation modeling, a statistical framework that allows scientists to test hypothesized chains of cause and effect. The model supported a compelling sequence. Higher litter nitrogen intensified the microbial nitrogen limitation, and that intensified limitation in turn promoted the accumulation of microbial residue carbon. This may seem counterintuitive at first glance: why would nitrogen limitation stimulate carbon storage? The likely explanation lies in microbial physiology. When nitrogen-rich litter raises the nitrogen supply relative to microbial demand, it spurs microbial growth and activity, and microbes constrained by nitrogen must invest more effort in acquiring it, processing more carbon in the process and building more biomass that eventually becomes residue. The nitrogen limitation detected by the stoichiometric analysis thus reflects a dynamic, growth-driven system in which abundant nitrogen fuels the microbial engine that converts plant carbon into persistent soil carbon.

The study also traced the consequences of this microbial activity for the composition and stability of the soil carbon pool. The accumulation of microbial residue carbon, and particularly bacterial residue carbon, increased the content of recalcitrant organic carbon, the fraction of soil organic carbon that resists decomposition. At the same time, this shift reduced the overall carbon lability of the soil, meaning a smaller proportion of the carbon pool was readily available for microbes to respire back into the atmosphere as carbon dioxide. In practical terms, nitrogen-rich broadleaved litter did not just add more carbon to the soil; it changed the character of that carbon, steering it toward a more stable, longer-lived form. This is a critical distinction, because the climate value of soil carbon depends not only on how much is stored but on how long it stays stored.

The implications extend well beyond forest ecology. As governments and land managers around the world pursue afforestation and reclamation programs to sequester carbon, the choice of tree species is often made on the basis of growth rates and timber value. This study suggests that litter chemistry deserves equal attention. Planting or encouraging nitrogen-rich broadleaved species could enhance the microbial carbon pump, boosting both the quantity and the stability of soil organic carbon. Conversely, stands dominated by conifers, whose litter is lignin-rich and nitrogen-poor, may build soil carbon more slowly and in a less stable form. In mixed forests, the researchers found intermediate patterns, hinting that species composition within a stand can be tuned to manage below-ground carbon dynamics. Such insights could inform everything from carbon credit accounting to the restoration of degraded soils.

The work also adds nuance to a long-running scientific debate about the role of nitrogen in decomposition. Nitrogen limitation of decay has been documented in many ecosystems, and some researchers have argued that it slows the breakdown of organic matter, potentially preserving soil carbon. The new findings suggest a more intricate picture: nitrogen availability shapes not only how fast litter decomposes but how effectively the products of decomposition are funneled into microbial biomass and, ultimately, into stable necromass. The microbial carbon pump, in this view, is throttled by the nitrogen supply in the litter, and managing that supply is a lever for managing soil carbon. As the authors conclude, shifts in stand type alter litter nitrogen, which primarily regulates soil organic carbon sequestration through this microbial pathway.

There remain open questions. The study was conducted across forest stands of different types, and future work will need to test whether the same relationships hold across climates, soil types, and timescales, and how disturbances such as fire, harvesting, or warming might disrupt the nitrogen-microbe-carbon chain. Data from the study will be made available on request, and the research was supported by funding from Chinese national and provincial science programs. For now, the message is clear and quietly profound: the fate of carbon in forest soils rests substantially on the shoulders of microscopic organisms, and what those organisms accomplish depends on the chemistry of the leaves that fall above them. A forest’s legacy in the soil, it turns out, is written as much in the nitrogen of its litter as in the wood of its trees.

Subject of Research: The role of litter nitrogen in regulating soil organic carbon sequestration through microbial residue carbon accumulation in forest soils

Article Title: Litter nitrogen drives soil organic carbon sequestration by promoting microbial residue carbon accumulation

Article References: Zhang, M., Li, H., Wang, Y., Cui, Y., Gao, Y., Jia, Y., Yu, H., Dong, Q., Wang, Y., & Xu, Z. (2026). Litter nitrogen drives soil organic carbon sequestration by promoting microbial residue carbon accumulation. Plant and Soil. https://doi.org/10.1007/s11104-026-09109-y

Image Credits: AI Generated

DOI: 10.1007/s11104-026-09109-y

Keywords: soil organic carbon, microbial residue carbon, litter nitrogen, microbial carbon pump, forest soils, broadleaved forests, coniferous forests, lignin, amino sugars, ecological stoichiometry, carbon sequestration, microbial necromass

The core of the paradox lies in how seaweed handles carbon. As primary producers, macroalgae convert dissolved inorganic carbon into organic biomass through photosynthesis, drawing on both freely dissolved CO2, which diffuses across cell membranes, and bicarbonate, which is actively transported into cells via carbon-concentrating mechanisms. By lowering the partial pressure of CO2 in surface seawater, farms steepen the gradient that pulls atmospheric CO2 into the ocean. Based on carbon contents of roughly 20 to 35 percent of dry weight, China’s 2024 harvest alone removed an estimated 600,000 to 1,050,000 tonnes of carbon from seawater, while South Korea’s Porphyra industry removes about 80,000 to 140,000 tonnes annually. Photosynthesis also releases oxygen: large-scale cultivation can generate around 2.53 million tonnes of O2 per year, raising dissolved oxygen in the upper three metres of the water column by about 21 percent.

Carbon storage, however, depends on where the carbon ends up, not just how much is fixed. One pathway runs through the microbial carbon pump, in which bacteria transform the labile dissolved organic carbon released by seaweed into refractory dissolved organic carbon that resists degradation and can persist for long periods. The share of refractory material appears to grow as the cultivation season progresses, from as little as 3 to 4 percent of released dissolved organic carbon early in the cycle to estimates approaching 50 percent or more in long-term degradation experiments. Remarkably, the quantity of refractory carbon exported from farming areas to neighbouring waters appears comparable to the carbon removed in harvested biomass, underscoring how central microbial processing is to the seaweed carbon budget.

Sediments provide another sink. A recent global survey of 20 seaweed farms found a mean organic carbon burial rate of 1.87 plus or minus 0.73 tonnes of CO2-equivalent per hectare per year, roughly double the rate in adjacent non-farming areas. Aquaculture-derived sedimentary carbon accounts for less than 35 percent of total coastal stocks, but its millennial-scale residence time gives it outsized significance. Globally, about 90 percent of macroalgal-sequestered carbon is stored through deep-sea export, as detached fragments with buoyant pneumatocysts or structurally buoyant thalli drift with currents, sink through submarine canyons and reach deep sediments. Yet effective burial requires exchange with the open ocean, and many farms sit on shallow shelves in the Yellow, Bohai and East China Seas, where complex tides and circulation can resuspend carbon rather than lock it away.

The ecological benefits extend beyond carbon. Kelp forests and farms create structural habitat that supports juvenile fish, gastropods, limpets and crabs, and aquaculture infrastructure itself becomes a temporary biogenic reef for invertebrates and fish. In Gracilaria cultivation areas, plankton communities show significantly higher biodiversity at the peak of seaweed biomass than at nearby control sites, with elevated abundance, species richness and evenness. Macroalgal detritus also fertilizes low-productivity sandy habitats, feeding microbial and faunal communities through organic deposition. These habitat and food-web effects are a major part of the appeal of seaweed as a nature-based solution.

But the same biology that sequesters carbon can destabilize coastal chemistry. During senescence and decay, macroalgae release large quantities of labile organic carbon that microbes rapidly remineralize, consuming dissolved oxygen and releasing CO2. In open coastal systems, tides flush these byproducts away within days. In semi-enclosed bays, however, prolonged water residence times turn the system into something like a bioreactor, allowing organic matter to decompose completely in place. Observations from China’s North Yellow Sea show that summer macroalgae cultivation induces coupled oxygen depletion and acidification in benthic zones, and the world’s largest seaweed farm has documented emergent seasonal hypoxia and acidification linked to polyculture operations.

The numbers are striking. Kelp can export up to 98 percent of its production as detritus, and in natural kelp ecosystems detrital production averages about 82 percent of annual primary productivity. Timing matters enormously: Norwegian Saccharina latissima farms that harvest in June lose only 8 to 13 percent of annual production to erosion, but if biomass is left in the water until August, cumulative losses can reach 49.4 percent as senescence intensifies. Decomposing detritus beneath farms creates microenvironments prone to hypoxia, particularly where low-energy hydrodynamics restrict oxygen renewal. Acidification follows a similar pattern, with decomposition-driven CO2 accumulation lowering pH in subsurface and bottom waters, and seasonal warming further shifting carbonate equilibria toward higher CO2 and lower pH late in the growing season.

Hydrodynamics emerge as the decisive variable separating success from harm. Sanggou Bay, a semi-enclosed farming region with short water-exchange times, maintains year-round carbon sink functionality and shows none of the acidification seen elsewhere, while Sansha Bay, where flushing is far weaker, records dissolved oxygen as low as 44 percent saturation and functions predominantly as a net carbon source on an annual scale despite brief seasonal sink periods. The authors also flag subtler risks: shading from farm infrastructure can cut light beneath farms by 75 to 90 percent, contributing to seagrass decline in Indonesia; non-native species such as Kappaphycus alvarezii raise invasion concerns in Brazil; and translocation of farmed algae can introduce pathogens, parasites and genetic introgression with wild populations, a phenomenon documented in coastal China and Japan.

The perspective outlines management tools that could tip the balance. Integrated multi-trophic aquaculture pairs seaweed with finfish and shellfish so that one species’ waste becomes another’s resource: macroalgal detritus feeds filter-feeding bivalves, while algae absorb the CO2 from shellfish respiration, and calcified shells create net carbon storage. Fish-seaweed polycultures produce fast-sinking fecal pellets that bypass water-column remineralization, though fish feed itself can worsen oxygen and pH conditions if poorly managed. Artificial upwelling, which pipes nutrient-rich deep water into the sunlit zone, has shown promise in field trials in Qiandao Lake and the East China Sea, but sudden nutrient injections risk triggering phytoplankton blooms and must be calibrated to local conditions.

The authors’ central demand is a comprehensive evaluation framework that treats water-exchange efficiency and biogeochemical vulnerability as first-order criteria, alongside carbon yields. Photosynthesis and remineralization may balance stoichiometrically over a full cycle, following the Redfield ratio, but their spatial and temporal decoupling means surface gains can coexist with subsurface oxygen deficits and pH declines. Current sustainability assessments that focus narrowly on harvested carbon, the paper warns, overlook the benthic-pelagic coupling that ultimately determines ecosystem resilience. The proposed answer is hydrodynamically guided site zoning combined with adaptive management of cultivation densities and harvest timing. Seaweed farming, the authors conclude, is a double-edged strategy: capable of meaningful carbon capture and coastal benefits, but only if placed and managed with the physics of each bay in mind.

Subject of Research: Climate mitigation potential and ecological risks of coastal seaweed farming

Article Title: Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming

Article References: Wu, Y., Liu, Y., & Qi, D. (2026). Reassessing the climate mitigation benefits and environmental risks of coastal seaweed farming. Discover Oceans, 3(1), Article 37. https://doi.org/10.1007/s44289-026-00144-2

Image Credits: AI Generated

DOI: 10.1007/s44289-026-00144-2

Keywords: seaweed farming, macroalgae, marine carbon dioxide removal, blue carbon, hypoxia, acidification, eutrophication, microbial carbon pump, hydrodynamics, aquaculture, coastal ecosystems, benthic-pelagic coupling

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