The dataset, called the History of Anthropogenic Phosphorus Inputs, or HaPi, was constructed by an international team led by Zihao Bian of Nanjing Normal University and Hanqin Tian of Boston College. It tracks human-driven phosphorus fluxes to the terrestrial biosphere from 1860 to 2020 at a spatial resolution of 5 arc-minutes, roughly 10 kilometers at the equator, with an annual time step. That combination of temporal depth and spatial detail is unprecedented for phosphorus. Where earlier datasets offered either coarse global totals for a few decades or fine-grained snapshots of a single year, HaPi stitches the entire industrial era into one harmonized, gridded record.

The headline finding is a nearly elevenfold increase in total phosphorus input to land. In the 1860s, human activities added about 3.8 teragrams of phosphorus per year to the terrestrial biosphere. By the 2010s, that figure had climbed to 41.0 teragrams per year. Mineral fertilizer and livestock manure contributed almost equally to the increase, accounting for 52 percent and 46 percent of the growth respectively. The steepest acceleration came between 1945 and 1989, the era of post-war agricultural intensification, when synthetic phosphate fertilizers, mechanized farming, and booming livestock herds transformed agriculture across the industrialized world.

The composition of phosphorus inputs shifted dramatically along the way. Before the 1980s, livestock manure accounted for more than half of all phosphorus reaching the land surface. By the 2010s, mineral fertilizer had overtaken manure as the largest single input for the first time in the record. Atmospheric phosphorus deposition, by contrast, tells a story of relative decline: although it rose modestly from 2.0 to 2.7 teragrams per year between the 1960s and 2010s, its share of the total collapsed from 50 percent in the 1860s to just 7 percent today, swamped by the sheer scale of deliberate fertilizer and manure applications.

The geography of phosphorus has also been redrawn. In the 1960s, Europe and the United States dominated, receiving 5.2 and 2.8 teragrams per year respectively and together consuming the majority of the world’s mineral fertilizer. In recent decades, China, South Asia, and Brazil have surged past them. By the 2010s, China alone accounted for 30 percent of global phosphorus fertilizer consumption and South Asia for 20 percent, while hotspots of high input emerged across eastern China, northern India, southern Brazil, and eastern Africa. Notably, China’s total inputs began to decline around 2010, and its fertilizer consumption has fallen since 2013, likely reflecting the exploitation of legacy phosphorus accumulated in soils over decades of heavy application.

Building such a dataset required reconciling an unruly collection of statistical and geospatial sources. National fertilizer consumption figures from the Food and Agriculture Organization, available only from 1961 onward, were split between cropland and pasture using observed nitrogen allocation patterns, then distributed across grid cells using land use maps, crop rotation data, and crop-specific application rates for 17 major crops. For the pre-1961 era, when guano and human excreta still mattered and phosphate rock had yet to be widely adopted, the team applied global change rates derived from historical estimates to back-cast the 1961 spatial pattern. Livestock manure inputs were generated by multiplying gridded manure nitrogen data from the team’s companion nitrogen dataset, HaNi, by annually varying, animal-number-weighted phosphorus-to-nitrogen ratios for eight livestock species.

Atmospheric deposition posed its own challenge. The researchers compiled a global phosphorus emission inventory spanning natural sources such as dust, sea salt, volcanic emissions, primary biological aerosol particles, and wildfires, together with anthropogenic emissions from the EDGAR database. This inventory fed the GEOS-Chem atmospheric chemistry model, driven by NASA meteorology, to simulate deposition from 2001 to 2019 at a coarse resolution. A machine-learning downscaling algorithm, trained separately for eight world regions against climate, vegetation, and aerosol variables, then sharpened the output to 0.1 degrees before it was resampled to match the rest of the dataset and extended back to 1900.

The scientific payoff is substantial. Because phosphorus is the limiting nutrient for phytoplankton in most freshwaters, runoff from over-fertilized fields drives eutrophication, algal blooms, and dead zones in rivers, lakes, and coastal oceans worldwide. Worse, legacy phosphorus banked in soils from historical applications continues to leach into waterways decades later, undermining conservation investments. HaPi’s explicit treatment of grasslands, which received over 70 percent of global manure phosphorus and more than 40 percent of total phosphorus inputs, is particularly valuable, since grasslands are often overlooked in nutrient budgets even as they face a negative phosphorus balance and contribute heavily to nutrient loading in systems such as the Gulf of Mexico.

The dataset also arrives at a geopolitically charged moment. Phosphate rock is a finite, unevenly distributed resource, and its concentration in a handful of countries creates vulnerabilities for global food systems. By quantifying where phosphorus has been applied, where it has accumulated, and where efficiency gains are possible, HaPi gives researchers and policymakers a common evidentiary foundation for managing nutrient resources, improving phosphorus use efficiency, and feeding Earth system models with consistent forcing data. The team is candid about limitations, including a fixed spatial baseline for fertilizer patterns, uncertainties of at least 20 percent inherited from national statistics, and the omission of minor historical sources such as guano and livestock bones. Even so, as an open, peer-reviewed record spanning 160 years, HaPi transforms our understanding of one of humanity’s most consequential geochemical interventions, and it will shape research on food security and water quality for years to come.

Subject of Research: Global anthropogenic phosphorus inputs to the terrestrial biosphere from 1860 to 2020

Article Title: History of anthropogenic Phosphorus inputs (HaPi) to the terrestrial biosphere from 1860 to 2020

Article References: Bian, Z., Shi, H., Li, R., Lun, F., Tubiello, F. N., Mueller, N. D., You, S., Hao, R., Ma, J., Li, L., Huang, C., He, B., Yao, Y., & Tian, H. (2026). History of anthropogenic Phosphorus inputs (HaPi) to the terrestrial biosphere from 1860 to 2020. Earth System Science Data, 18(10), 7125-7141. https://doi.org/10.5194/essd-18-7125-2026

Image Credits: AI Generated

DOI: 10.5194/essd-18-7125-2026

Keywords: phosphorus cycle, fertilizer, livestock manure, eutrophication, Earth system science, nutrient budgets, agriculture, biogeochemistry, water quality, legacy phosphorus, global dataset, planetary boundaries

The research, led by Bingkun Wang and Yapeng Wang of the Yellow Sea Fisheries Research Institute and Harbin Institute of Technology, together with colleagues in China and the United States, took an unusually long view of the problem. Rather than measuring how phytoplankton react to elevated carbon dioxide over days or weeks, the team followed experimental populations of the model diatom Thalassiosira pseudonana through more than 1,000 generations of evolution under high-CO2 conditions. This timescale matters, because it allowed the researchers to separate two very different biological phenomena: genuine evolutionary adaptation, in which genetic changes become heritable across lineages, and acclimation, the flexible physiological adjustments individual cells make to their immediate environment.

The results reveal a striking asymmetry. Long-term selection under elevated CO2 produced heritable increases in growth and carbon fixation that persisted regardless of how much phosphate was available to the cells. In other words, the diatoms’ carbon-side response to acidification appears to be locked in by evolution. But the phosphorus side of the story was entirely different. When the researchers measured particulate organic phosphorus — the phosphorus bound into living biomass — they found that ocean acidification drove it down under phosphate-limited conditions. Crucially, this decline was reversed when lineages were transferred back and forth between selection treatments, showing that the phosphorus response was not a fixed evolutionary outcome but a plastic, environment-dependent shift in how cells allocate their scarce phosphorus reserves.

To understand what was happening inside the cells, the team deployed a multi-omics arsenal, combining transcriptomics, proteomics and metabolite profiling across the long-term experiment. The picture that emerged was one of biochemical triage. Under the combined stress of acidification and phosphate scarcity, the diatoms depleted their cellular phosphorus reserves, including polyphosphate stores that normally serve as intracellular batteries of the nutrient. At the same time, they enriched their membranes with non-phosphorus lipids, swapping out the phospholipids that ordinarily form cellular boundaries for phosphorus-free substitutes. This membrane lipid remodeling is a well-documented survival strategy in phosphorus-starved phytoplankton, first described in landmark work on natural plankton communities, but the new study shows that acidification amplifies and reshapes the process, effectively squeezing phosphorus out of the structural fabric of the cells.

The laboratory findings did not stay confined to culture flasks. In coastal mesocosm experiments — large enclosures that contain natural plankton communities under controlled conditions — the researchers observed the same signature: reduced particulate organic phosphorus in natural phytoplankton assemblages at low-phosphate stations exposed to ocean acidification. This convergence between a decade-scale laboratory evolution experiment and real-world community responses is one of the study’s most persuasive elements, because it suggests the mechanism operates not just in a single cultivated diatom but across the messy diversity of wild plankton.

The team then scaled up to the planetary level. Mining global meta-transcriptomic datasets collected across the world ocean, they found widespread upregulation of genes involved in non-phosphorus membrane lipid synthesis in regions that combine high partial pressure of CO2 with low phosphate. These are precisely the conditions expected to expand as the ocean absorbs more anthropogenic carbon and as nutrient ratios shift. Independent observations have already documented declining phosphate relative to nitrate in upper ocean waters, and atmospheric nitrogen deposition continues to push many regions toward phosphorus limitation, making the overlap between acidification and phosphate stress a growing feature of the modern ocean rather than a rare corner case.

When the researchers fed these mechanisms into Earth system models, the projections were sobering. Under the intermediate Shared Socioeconomic Pathway SSP2-4.5, the models predict a 211 percent decline in particulate organic phosphorus by the year 2100, and under the high-emissions SSP5-8.5 scenario the projected decline reaches a staggering 2,185 percent. These are not marginal adjustments to the ocean’s elemental bookkeeping. Particulate organic phosphorus is the currency through which phosphorus enters marine food webs and is exported to the deep sea, so its collapse in phosphate-limited regions would ripple through ecosystem productivity, food web structure and the biological carbon pump that carries carbon away from the atmosphere.

The stoichiometric implications are profound. Since the era of Alfred Redfield, oceanographers have recognized that marine plankton maintain remarkably consistent ratios of carbon, nitrogen and phosphorus, and these ratios underpin much of how we model ocean biogeochemistry. Recent work has documented global-scale shifts in plankton elemental ratios over the past half-century, and the new study adds a mechanistic explanation for how acidification could accelerate that drift. If phytoplankton under future conditions carry systematically less phosphorus per unit of carbon, then the same amount of primary production would transfer less phosphorus to grazers, microbes and the deep ocean, intensifying nutrient imbalance throughout marine ecosystems. Models that assume static elemental ratios could therefore misjudge future carbon sequestration and nutrient cycling in ways that matter for climate projections.

There is also a subtler lesson in the study’s experimental design. By running reciprocal transfers between CO2 treatments, the researchers demonstrated that not all responses to ocean acidification are created equal. Carbon fixation gains can be genuinely heritable, meaning lineages evolved under high CO2 retain their enhanced performance even when returned to ambient conditions. Phosphorus allocation, by contrast, is reversible and context-dependent, which means it will track the environment the cells actually experience rather than the environment their ancestors evolved in. For forecasters, this distinction is critical: plastic responses can buffer populations in the short term but can also produce rapid, nonlinear shifts in biogeochemistry as conditions cross thresholds, without any evolutionary change being required.

As atmospheric CO2 continues to climb, the ocean will grow warmer, more acidic and, in many regions, more phosphorus-starved. This study makes clear that these stressors do not act independently; they converge inside the cells of phytoplankton, where a single nutrient must be rationed among DNA, RNA, energy metabolism and membrane construction. The diatoms that anchor marine food webs from coastal seas to the open ocean are already reorganizing their biochemistry in response, and the models suggest the reorganization will deepen dramatically by century’s end. What happens to phosphorus at the base of the ocean’s food web, the researchers conclude, may ultimately reshape the global phosphorus cycle itself — a reminder that climate change’s reach extends into the molecular plumbing of life in the sea.

Subject of Research: Effects of ocean acidification and phosphate limitation on phytoplankton phosphorus metabolism

Article Title: Ocean acidification reshapes phytoplankton phosphorus metabolism under phosphate-limited conditions

Article References: Wang, B., Wang, Y., Sun, Y., Huang, X., Yang, F., Wang, Z., Chi, H., Tong, S., Fan, X., Zhang, X., Sun, K., Fu, F., Wang, Y., Hutchins, D. A., Chen, G., Xu, D., & Ye, N. (2026). Ocean acidification reshapes phytoplankton phosphorus metabolism under phosphate-limited conditions. Nature Geoscience. https://doi.org/10.1038/s41561-026-02113-y

Image Credits: AI Generated

DOI: 10.1038/s41561-026-02113-y

Keywords: ocean acidification, phytoplankton, phosphorus cycle, phosphate limitation, diatoms, marine biogeochemistry, particulate organic phosphorus, membrane lipid remodeling, multi-omics, Earth system models, climate change, Thalassiosira pseudonana