Coastal marine ecosystems and biodiversity are changing rapidly under climate forcing, resource use, pollution and habitat modification. Monitoring these changes, and tracking progress across policy targets, remain constrained by uneven data coverage, fragmented observing networks and inconsistent measurement practices. International policy frameworks, most prominently the Kunming-Montreal Global Biodiversity Framework, alongside Sustainable Development Goal 14 and Regional Seas Agreements, rely on structured indicators to track biodiversity state, pressures, change and management outcomes. However, how well existing indicators align with current monitoring needs, data readiness, analytical maturity and recurring assessment pipelines has not been evaluated systematically. This review compiled and synthesised 145 operational marine biodiversity indicators and examined 223 marine-relevant online knowledge systems that were active and accessible in December 2025. Indicators were classified by analytical role within a state, pressure, response, benefit model, and assessed against their data sources, calculation transparency, update frequency and assessment applicability across depth zones and regions. Indicators describing biodiversity state and spatial pressure composites dominate current reporting and assessment use, particularly for coastal habitats and species-population trends. Fisheries sustainability indicators are comparatively well represented, while indicators tracking responses and biodiversity-linked benefits remain less mature, less standardised across measurement pipelines and less developed for offshore and areas beyond national jurisdiction. The current indicator overview shows expanding analytical capacity, but routine indicator production pipelines and integration of measured biological responses into recurring assessments remain limited relative to pressure mapping and species-level status reporting. The next phase of marine monitoring will likely be defined by recurring analytical production of indicators, greater comparability of measurements and stronger integration of observed biological patterns into routine assessment and policy tracking. Further development of indicators that can support management of pressures at a sector-level to support environmental impact assessment and area-based management or zoning of human activities remains a key direction for future analytical progress.

Abstract. A central tenet of Earth system science is that Earth's macroscopic environmental conditions reflect the co-evolution of the biosphere and the geosphere. Nevertheless, a universal theory of the biosphere's role in the Earth system remains elusive. This paper reviews the state of knowledge and reflects on future directions from the perspective of scientifically understanding Earth as an integrated whole. Four biosphere dimensions need to be considered in developing a theoretical foundation for the biosphere’s role in the Earth system: physical, i.e., physics-based influences of life on planetary state, such as through albedo, roughness length, and latent energy fluxes; chemical, i.e., the material operations of the biosphere as part of the planetary biogeochemical cycles, chemically linking biotic and abiotic components of the Earth system; biological, i.e., the genetic programme (biodiversity) and its derived structures required to operate the organisms of a functional biosphere performing the Earth system functions; and ecological, i.e., the formations of organisms into ecosystems and their biotically altered larger environments as conduits of life for exerting macro-scale influence on Earth as a whole, by performing Earth system functions as a biosphere that is more than the sum of its parts. Today, it is primarily the physical and chemical dimensions that are included in Earth system models and their biogeochemical submodels, while empirical studies on the biological dimension often focus on limited geographical areas and species enumeration, and only to a lesser extent on systemic effects. For studying the biosphere’s role in the Earth system, a comprehensive approach across scales is required. Owing to its shared genes and evolutionary history, we argue that the biosphere can be regarded as a single global entity. However, biosphere-geosphere interactions and their Earth system consequences differ geographically and between the marine and terrestrial realms, with the terrestrial biosphere generally influencing Earth conditions more directly and over shorter time scales than the marine. A better understanding (working towards the development of a more universal theory) of the biosphere’s role in the Earth system is needed to advance Earth system science and, not least, for developing better capacity for prediction of Earth’s responses to anthropogenic perturbations. More systematic collaboration than currently occurring is required between biogeophysics, biogeochemistry, biodiversity science (extending to traits and functions), ecosystem science, and land systems research.

Earth’s climate is now departing from the stable conditions that supported human civilization for millennia. Crossing critical temperature thresholds may trigger self-reinforcing feedbacks and tipping dynamics that amplify warming and destabilize distant Earth system components. Uncertain tipping thresholds make precaution essential, as crossing them could commit the planet to a hothouse trajectory with long-lasting and potentially irreversible consequences.

A number of initiatives attempt to delimit the safe operating space (SOS) for human pressures on the Earth system, including the Planetary Boundaries framework. In some cases, data describing regional status are spatially aggregated to provide a global assessment. Several aggregation approaches can be observed, and the chosen approach may impact the conclusions. This study systematically reviews approaches of aggregating regional environmental boundaries and their state at the global level and uses a case study to compare them, aiming to highlight assumptions and implications and show how inconsistent approaches affect the accuracy and comparability of global boundary states. In the comprehensive literature review, 25 studies dealing with spatial aggregation of regional occupation of SOS and 43 associated regional boundary records were identified and categorized according to five spatial aggregation approaches and five types of adjustments that apply across approaches. These approaches were further classified as high- and low-risk approaches based on their assumptions and value judgments regarding precautionary levels and accepted regional transgressions. Notably, key publications dealing with multiple environmental boundaries use different aggregation approaches across the boundaries, potentially introducing biases. The application of these approaches to a case study revealed that the choice can influence the resulting aggregated occupation of SOS substantially, impacting conclusions as to whether or not a boundary is exceeded. To mitigate biases and inconsistencies, future estimates of spatially aggregated regional SOS should transparently communicate the assumptions underlying the chosen aggregation approach, address potential inconsistencies across boundaries, and advance our understanding of spatial propagation mechanisms.

In order to keep global warming below 2ºC, it is imperative not only to reduce future carbon dioxide (CO2) emissions but also to adopt negative emissions technologies (NETs) to remove approximately 600 Gt of CO2 from the atmosphere by the end of the twenty-first century. Among NETs, ocean alkalinity enhancement and ocean enrichment emerge as promising strategies for Carbon Dioxide Removal (CDR), leveraging the immense carbon-absorbing capacity of oceans. Glacial rock flour (GRF), an ultra fine-grained silicate mineral originating beneath the Greenland Ice Sheet, holds potential as a contributor to large-scale marine CO2 removal (mCDR). As it is transported into coastal waters, the dissolution of GRF in seawater naturally releases mineral components into the ocean. As a silicate-rich substance with micronutrients like iron and manganese, GRF has the dual capacity to enhance alkalinity and promote phytoplankton growth, presenting a viable avenue for mCDR. In a field study from the Kangerlussuaq fjord and glacier near the Greenland Ice Sheet (summer 2023) we observed that melt- and seawater contained an array of trace metals in high concentrations, including iron, manganese, zinc, copper, and cobalt, and the concentrations increased towards the fjord and away from the source. We explore the response to varying treatments with GRF, iron, manganese and zinc using laboratory incubation experiments with an Arctic phytoplankton diatom species (Coscinodiscus radiatus). We identify the relative mobilization rate of these trace metals in the GRF that can support phytoplankton growth and hypothesise that GRF can alleviate the co-limitation of iron and manganese on phytoplankton growth.

The planetary boundaries framework emerges from Earth system science and was developed to help guide the global community in its efforts to manage Anthroposphere interactions with the Earth’s bio-physical components. In the third iteration of the framework, PB3.0 (September 2023), six of the nine boundaries are found to be transgressed and anthropogenic pressure is increasing on all the boundaries earlier found to be exceeded. Metrics are, for the first time, proposed for all boundaries. Human Appropriation of Net Primary Production is proposed as the control variable for the function of the biosphere as photosynthesis represents the energy input supporting almost all life. The probability of achieving global climate goals is argued to be closely linked to the fate of global forests. Thus, the climate and biodiversity crises must be addressed together. Directions for the framework’s further development are discussed.

Driven by excessive anthropogenic nitrogen emissions, marine eutrophication poses a major threat to coastal ecosystems worldwide. Marine eutrophication and its most severe consequence, hypoxia, are expected to worsen due to both rising nitrogen emissions and climate change. This study employs an absolute environmental sustainability assessment (AESA) approach to project the future extent and severity of marine eutrophication under various climate scenarios. Parameterized under the five Shared Socioeconomic Pathways (SSPs), a characterization model for waterborne nitrogen emissions was developed to estimate the effects of climate change on the marine eutrophication impact pathway. Using state-of-the-art nitrogen projections, the model was then used to project future marine eutrophication impacts at a global scale. Our results indicate that marine eutrophication will intensify globally, placing more coastal waters at risk, with tropical regions being particularly affected. This worsening trend is largely influenced by shifts in the inland nitrogen cycle, which alter nutrient transport and exacerbate coastal eutrophication. Our findings highlight the urgent need for substantial nitrogen emission reductions to achieve environmental sustainability, even under low-carbon development pathways. Importantly, this study stresses that future climate change impacts must be explicitly considered when setting nitrogen reduction targets, as mitigation strategies based solely on current conditions may underestimate future risks. By addressing the compounded effects of nitrogen emissions and climate change, this study highlights the relevance of combining AESA methods with scenario analyses and provides valuable insights to policymakers in designing adequate nitrogen emission reduction targets.

Glacial rock flour (GRF) is a fine-grained silicate mineral formed below the Greenland Ice Sheet where the bedrock is abraded to a fine powder. GRF is transported by meltwater into fjords and coastal waters and its dissolution in seawater is part of the natural cycling of material between continents and the ocean. It is present in large sedimentary deposits along the coast of Greenland. However, due to the relatively small size distribution of GRF (d50 ~ 2-5 µm) it has a relatively long residence time in the coastal surface layers and significant amounts reach the open ocean as suspended particulate material. As a silicate-rich material, also containing substantial amounts of micronutrients (e.g., iron and manganese), dissolution of GRF has the potential to both increase alkalinity and support phytoplankton growth. Therefore, it may be considered a source for large-scale marine CO2 removal (mCDR). In this presentation we focus on its potential for supporting phytoplankton growth. We present results from incubation experiments in the field with natural phytoplankton communities and from climate-regulated laboratory experiments with a single-species phytoplankton culture. Field-incubations (6 days) with a subtropical phytoplankton community showed a significant increase in photosynthetic activity (Fv/Fm) in treatments with GRF. Similar field-experiments with natural communities from an Arctic fjord in Greenland, with a high natural background concentration of GRF, showed a modest or a neutral response to further addition of GRF. Long laboratory incubation experiments (3 weeks) with an Arctic green alga showed a significant increase in both growth rate and photosynthetic activity in treatments with GRF. The growth increased gradually with increasing concentrations of GRF until saturation was reached. This response was consistent with a simple model of trace-metal limited growth where micronutrients (e.g., iron) is biologically mobilized from GRF during the incubation period. These results show that substances in GRF, likely trace metals, can be biologically mobilized on timescales of days to weeks and thereby support growth of phytoplankton. Thus, GRF may be a source for large-scale mCDR due to its potential for increasing ocean productivity and strengthening the biological pump.

Deep chlorophyll maxima (DCMs) have long been studied in the northern hemisphere but have received less attention in the Southern Ocean. Their contribution to phytoplankton biomass and net primary productivity (NPP) is poorly resolved. Recently, the application of satellite NPP algorithms to biogeochemical (BGC)-Argo float data has improved vertically resolved NPP estimates. Using this approach on 12,700 BGC-Argo profiles south of 30 degrees S, we report (1) subsurface (below the mixed layer) estimates of NPP, (2) the contribution of subsurface NPP to total NPP, and (3) the influence of DCMs and deep biomass maxima (DBMs) on (1) and (2). When DCMs are present (n = 2,119 profiles), subsurface NPP is 217 +/- 106 mg C m(-2) day(-1) compared to 82 +/- 92 mg C m(-2) day(-1) for all profiles. We further compare observations across seasons in four water masses from nitrate-limited oligotrophic waters north of the subtropical front to iron-limited regions further south, including the sea ice zone. Low-latitude DCMs (i.e., 30-44 degrees S), show the highest contribution to column-integrated NPP. However, DCMs occur across all frontal zones and contribute significantly to total NPP when present. Rather than missing subsurface NPP associated with DCMs, the satellite Carbon-based Productivity Model (CbPM) tends to mistakenly assume DCMs below the mixed layer, overestimating NPP. This situation is somewhat ameliorated in the ferricline version of the CbPM due to better nutricline-euphotic depth alignment. Our results highlight the importance of understanding the vertical structure of phytoplankton stocks and productivity, with direct impacts on global NPP estimates and, ultimately, climate model projections.

Iceland was among the last large islands settled by humans, with colonization (Landnám) in the late 9th century CE (Common Era) and is often portrayed as an ecological disaster driven by the Norse settlers. Here, we revisit this narrative through environmental DNA (eDNA) and multiproxy analyses of sediment cores from Lake Tjörnin in central Reykjavík, one of Iceland’s earliest and longest-occupied settlements. Originally a marine embayment, Tjörnin became a freshwater lake around 660 CE. Our record reveals a human presence decades before the long-accepted arrival date of 877 CE, marked by the Landnám volcanic tephra. Early settlement brought livestock, barley cultivation, and other introduced taxa that enhanced nutrient cycling and unexpectedly increased local biodiversity. Contrary to the conventional view of rapid deforestation, eDNA shows that birch and willow expanded during the settlement period, likely supported by deliberate management. Pronounced ecological and land use shifts occurred after 1200 CE, but these were coeval with the Little Ice Age cooling, compounded by volcanic eruptions, storm surges, and plague, rather than anthropogenic degradation. Crop cultivation ceased, arboreal taxa retracted, and grazing pressure maintained open landscapes. Even more profound ecological changes came after c. 1750 CE with urbanization and industrialization, as wastewater discharge, heavy-metal pollution, and fossil fuel use reshaped Tjörnin’s ecosystem. These findings challenge the prevailing model of Norse-induced environmental collapse, revealing instead a dynamic human–environment relationship shaped by both cultural practices and external stressors. By applying eDNA to a long-occupied urban catchment, we demonstrate the power of genomic methods to refine settlement chronologies, reassess ecological baselines and changes, and integrate natural and cultural histories. This approach offers a model for revisiting human–environment interactions in urban centers worldwide. ### Competing Interest Statement The authors have declared no competing interest.

Mid-water column turbulence has been shown to cause elevated vertical nutrient flux at the shelf edge in the northeastern North Sea. Here, we demonstrate that phytoplankton communities in this region tend to be dominated by larger cells (estimated from percentage of chlorophyll captured on a 10 μm filter) than beyond the shelf edge. Fv/Fm (PSII electron transport capacity) corrected for photoinhibition in the surface layer correlated in this study with the percentage of chlorophyll captured on a 10 µm filter (assumed to be large cells), suggesting that the phytoplankton community was responding to increased nutrients in the euphotic zone by increasing photosynthetic efficiency and altering community composition. The greatest abundances of larger copepods and the highest rates of Centropages typicus egg production were also generally found at the shelf edge. These results suggested that impact from increased nutrient fluxes cascaded up the planktonic food web. As these regions of nutrient flux were very localised, this led to sub-mesoscale heterogeneity in plankton ecosystem structure. Reports of higher abundances of fish and mammals at the shelf edge are common and we hypothesise that their distributions are a response to the impact of mid-water column nutrient upwelling on the plankton food web in the region.

The main strait (Great Belt) connecting the North Sea and the Baltic Sea constitutes a quasi-stationary front and exposes phytoplankton to various degrees of water column mixing. Here, we examine phytoplankton community distributions (using the cell abundance of 4 readily identifiable diatoms) and estimate new production along the strait during early spring. Vertical turbulent mixing was similar to 10 times greater at stations in the strait compared to stations outside the strait. New production in the strait was on average similar to 50 mg C m(-2) d(-1), i.e. 8% of the average total primary production, and could explain the increase in chlorophyll observed along the strait. A non-metric multidimensional scaling analysis of phytoplankton community composition showed significant spatial groupings. However, variation of species abundances could not be explained by the general transport, where the abundance of the largest species decreased during the passage of the strait. A relatively small species (Guinardia delicatula) showed an increasing dominance in and above the subsurface chlorophyll maximum along the strait, and the bottom layer was also correspondingly dominated by a relatively small species (Skeletonema marinoi). This phytoplankton composition could be explained by photosynthetic traits associated with more efficient light usage of small cells together with increased nutrient supply in the strait.

The planetary boundaries framework emerges from Earth system science and was developed to help guide the global community in its efforts to manage Anthroposphere interactions with the Earth’s bio-physical components. In the third iteration of the framework, PB3.0 (September 2023), six of the nine boundaries are found to be transgressed and anthropogenic pressure is increasing on all the boundaries earlier found to be exceeded. Metrics are, for the first time, proposed for all boundaries. Human Appropriation of Net Primary Production is proposed as the control variable for the function of the biosphere as photosynthesis represents the energy input supporting almost all life. The probability of achieving global climate goals is argued to be closely linked to the fate of global forests. Thus, the climate and biodiversity crises must be addressed together. Directions for the framework’s further development are discussed.

The Anthropocene signifies the start of a no-analogue trajectory of the Earth system that is fundamentally different from the Holocene. This new trajectory is characterized by rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. We urgently need a new global approach to safeguard critical Earth system regulating functions more effectively and comprehensively. The global commons framework is the closest example of an existing approach with the aim of governing biophysical systems on Earth upon which the world collectively depends. Derived during stable Holocene conditions, the global commons framework must now evolve in the light of new Anthropocene dynamics. This requires a fundamental shift from a focus only on governing shared resources beyond national jurisdiction, to one that secures critical functions of the Earth system irrespective of national boundaries. We propose a new framework—the planetary commons—which differs from the global commons framework by including not only globally shared geographic regions but also critical biophysical systems that regulate the resilience and state, and therefore livability, on Earth. The new planetary commons should articulate and create comprehensive stewardship obligations through Earth system governance aimed at restoring and strengthening planetary resilience and justice.

Human pressures have pushed the Earth system deep into the Anthropocene, threatening its stability, resilience and functioning. The Planetary Boundaries (PB) framework emerged against these threats, setting safe levels to the biophysical systems and processes that, with high likelihood, ensure life-supporting Holocene-like conditions. In this Review, we synthesize PB advancements, detailing its emergence and mainstreaming across scientific disciplines and society. The nine PBs capture the key functions regulating the Earth system. The safe operating space has been transgressed for six of these. PB science is essential to prevent further Earth system risks and has sparked new research on the precision of safe boundaries. Human development within planetary boundaries defines sustainable development, informing advances in social sciences. Each PB translates to a finite budget that the world must operate within, requiring strengthened global governance. The PB framework has been adopted by businesses and informed policy across the world, informing new thinking about fundamental justice concerns, and has inspired, among other concepts, the planetary commons, planetary health and doughnut economics. Future work must increase the precision and frequency of PB analyses, and, together with Earth observation data analytics, produce a high-resolution and real-time state of planetary health. The Planetary Boundary (PB) framework — which provides guardrails to maintain the safe operating space for humanity — has received widespread scientific and societal interest. This Review outlines the emergence and mainstreaming of PB thinking, including relevance to Earth system science, justice, governance, economics and sustainability.

Nitrogen emissions from human activities are contributing to elevated levels of eutrophication in coastal ecosystems. Mechanisms involved in marine eutrophication show strong geographical variation. Existing life cycle impact assessment (LCIA) and absolute environmental sustainability assessment (AESA) methods for marine eutrophication do not adequately represent this variability, do not have a full global coverage, and suffer from other limitations, such as poor estimation of coastal residence times. This study aims to advance LCIA and AESA for marine eutrophication. We aligned and combined recent advancements in marine eutrophication LCIA and AESA methods into one method. By re-running models underlying the combined methods and incorporating additional data sources, we included marine regions missing in previous methods and improved fate modeling, with the inclusion of denitrification and plant uptake in the air emission-terrestrial deposition pathway. To demonstrate and validate our method, we applied it in a case study. The developed method allows the assessment of marine eutrophication impacts from emissions to soil, freshwater, and air at high resolution (0.083° and 2° × 2.5° for inland and air emissions, respectively) and spatial coverage (all ice-free global continents). In the case study, we demonstrate the added value of our method by showing that the now quantified spatial variability within spatial units, e.g., river basins, can be large and have a strong influence on the modeled marine eutrophication from the case study. Compared to existing methods, our method identifies larger occupations of safe operating space for marine eutrophication, mainly due to the high resolution of the coastal compartment, reflecting a more realistic areal extent of marine eutrophication impacts. Although limited by factors such as simulations based on a single reference year for modeling inland and air fate, our method is readily applicable to assess the marine eutrophication impact of nitrogen emitted to any environmental compartment and relate it to the safe operating space. With substantial advancement of existing approaches, our method improves the basis for decision-making for managing nitrogen and reducing emissions to levels within the safe operating space.

Glacial rock flour (GRF) is a felsic, silicate sediment that originates below the Greenland Ice Sheet, where the ice abrades basement rocks to a very fine powder. This is then transported by meltwater rivers or subglacial discharge into fjords and coastal waters. Thus, GRF is a naturally occurring component of the oceans around Greenland. The grain size of GRF typically ranges <1 - 100 µm with a median of 2-5 µm. The material behaves colloidally in water and distributions in fjords and coastal waters show that it has a residence time in the surface layer of up to several weeks. Glacial rock flour deposits are voluminous and common along the coast of Greenland and therefore it has the potential to be applied in geoengineering efforts on a global scale. The potential alkalinization from conservative cation release is estimated to be ~5,000 moles of alkalinity produced per ton of dissolved GRF. Additionally, GRF contains silica and phosphate that may contribute with macronutrients for phytoplankton growth together with various trace metals, e.g., iron and manganese. Hence, adding GRF to ocean surface waters has the potential to influence phytoplankton growth and, at the same time, increase alkalinity. However, the physical and chemical cycling of GRF in the water column, its implications for ecosystem services, and the chemical impact on the carbonate system are not well understood. The first results from incubation experiments with GRF in the field and from controlled laboratory experiments are presented here. Incubation experiments of GRF added to seawater collected in the Canary Current system showed a significant increase in photosynthetic activity during short term (~1 week) incubations. The positive influence from GRF on phytoplankton biomass and photosynthetic activity is also found in incubation experiments with a monoculture of a green planktonic alga and shows that trace metals mobilized within a few weeks have a significant positive effect on phytoplankton growth. Laboratory experiments of the settling rate of GRF show that the residence time is relatively long but also that flocculation of GRF particles, caused by salinity increases, may be an important process to consider in future field studies. Our results show that GRF has significant potential for increasing alkalinity, and that trace metals are mobilized from GRF in seawater, which can stimulate photosynthesis. We propose that GRF has the potential to impact ecosystem structure and increase biological productivity when applied to the ocean.

Earth system scientist with passion for people and planet.