1.1. Emerging Arctic ecosystems and their potential for carbon sequestration

26 March 2025 | 13:30 - 15:30 (MDT)

Open Session - HYBRID

Room:  UMC Third Floor - 382

Organisers:  Claudia Elena Schmidt (Helmholtz-Zentrum Hereon); Helmuth Thomas (Helmholtz-Zentrum Hereon); Sarina Niedzwiedz (University of Bremen)

Session Description:

Novel ecosystems are emerging in Arctic regions as a result of retreating or thinning sea ice. Changes in the physical conditions (e.g. exposure to waves, light penetration, nutrient supply, stratification and oxygen content) allow for the poleward movement of species distributions with subsequent impact on biodiversity through changed primary production and reorganization of coastal, pelagic and benthic communities. At the same time, anthropogenic and climate change related stressors have the potential to change the functionality and productivity of these emerging ecosystems. Uncertainties arise whether these ecosystems actually generate a valuable negative feedback on climate change through carbon sequestration. It is within the context of these uncertainties, that we invite contributions that are planning or already conducting fundamental and applied research into carbon production, export and sequestration across the full range of existing and emerging Arctic ecosystems. We particularly welcome contributions focusing on observational studies (in situ, paleo-oceanography, or remote sensing) or modelling approaches that estimate carbon sequestration in the past, at the present-day and in the future. Here, we aim to focus on quantifying the carbon sequestration potential of novel Arctic ecosystems associated with sea ice retreat and marginal ice zones and compare it to the paleo-oceanographic records of past sedimentation, productivity, ice cover and other environmental factors in coastal, fjord, shelf sea and open ocean ecosystems.

The session is organized by the Horizon2023 project SEA-Quester (Grant Agreement No. 101136480), focusing on the causes and consequences of emerging polar ecosystems and their potential for carbon sequestration.

Oral Presentations: 

• unfold_moreParticle fluxes in the Chukchi Sea and adjacent Canada Basin: biological pump control or lateral tranport influence — Jianfang Chen

  Jianfang Chen
  Second Institute of Oceanography, MNR

  Format: Oral In-person
  

  Abstract:

  Arctic Ocean play a very important role in the carbon sequestration in the Global Ocean. Previous studies have already showed that the carbon uptake by the upper ocean physical or biological pump will increase because of the rapid retreat of sea ice. But how the upper ocean biological pump induce the carbon sequestraion to the deep Arctic Ocean still have not fully known. In this report will show that results from our 7 data set of long term time series sediment trap moorings which we started to deploy in Canada Basin and Chukchi Plateau since 2008. Our observation revealed that particle fluxes in this area were not only controlled by the upper ocean biological pump, but also deeply influenced by the lateral transportion of particulate matter from adjacent shelves, such as Chukchi Sea and East Siberian Sea. Sea ice edge variation, Beaufort Gyre shift or movement, Pacific inflow induced circulation change and mesoscale eddies were the main control factors for the particle fluxes in the Chukchi Plateau and adjacent Canada Basin.

• unfold_morePermafrost carbon modeling: refining emissions projections and addressing model limitations — Christina Schädel

  Christina Schädel ¹;  Brendan Rogers ¹;  Jon Wells ²;  William Riley ³;  Deborah Huntzinger ²;  Thomas Gasser ⁴;  Edward AG Schuur ²;  Susan Natali ^{1
  1} Woodwell Climate Research Center; ² Northern Arizona University; ³ Lawrence Berkeley National Laboratory; ⁴ International Institute for Applied Systems Analysis

  Format: Oral In-person

  Abstract:

  Permafrost is a critical component of Earth's climate system and yet many Earth System models do not adequately represent permafrost processes. Quantifying the potential of carbon sequestration or increased emissions from the permafrost region is of high urgency and requires innovative approaches for evaluating and improving model accuracy.

  In the Warming of Permafrost Model Intercomparison Project (WrPMIP), we use manipulative field‐based experiments to inform long‐term projections about the magnitude and underlying mechanisms of permafrost carbon dynamics in an emerging new Arctic. We conduct multi-model simulations at both pan-Arctic and site-specific scales, aligning with experimental perturbations and assessing the implications for scaling and forecasts. This work helps evaluate model performance and model coherence.

  To date, permafrost-enabled global-scale models primarily simulate gradual top-down thawing of the seasonally thawed soil layer. However, omitting carbon loss from abrupt thaw and fire-induced thaw can lead to inaccurate estimates of remaining carbon budgets consistent with global policy targets. We address this by expanding the compact Earth System Model OSCAR (v3.0) to account for carbon emissions from gradual thaw, abrupt thaw, and wildfire induced thaw. These first-order estimates show that remaining carbon budgets are reduced by up to 20% to avoid 1.5°C or up to 22% for 2.0°C.

  In conclusion, while full ESMs can provide information for carbon emissions from permafrost, many predictions are limited by missing processes such as abrupt thaw and fire-carbon interactions. Significant funding is needed to prioritize model development and reduce uncertainties, ensuring more accurate predictions of permafrost carbon dynamics.

• unfold_moreMarine underwater vegetation - a harbinger of Arctic change — Sarina Niedzwiedz

  Sarina Niedzwiedz ¹;  Kai Bischof ^{1
  1} University of Bremen

  Format: Oral In-person

  Abstract:

  Seaweeds act as ecosystem engineers on many polar rocky shore coastlines. The underwater light climate and temperature are the main drivers for their vertical and latitudinal distribution. With temperatures rising globally, an Arctic expansion of temperate seaweed species is expected. Glacial melt might result in newly available substratum for settlement, but also in a deteriorating light climate as consequence of increasing terrestrial run off. Combining data from pan-Arctic time-series of seaweed community structure, underwater light climate in response to glacier influence and species eco-physiology sheds light on the fate of Arctic fjord ecosystem functioning modulated by globally and locally acting drivers of environmental change. We observed reduced light intensities and a changed spectral composition in glacial meltwater plumes, potentially resulting in an upward shift of the lower depth limit of seaweeds, counteracting the predicted biomass increase in the Arctic. Furthermore, we studied temperature-related changes in light-use characteristics in different seaweed species. Ultimately, temperature induced changes in seaweed light-use characteristics might lead to shifts in species composition, at the expense of the rather cold-adapted species. We conclude that the deterioration of the underwater light climate in combination with temperature increase may drive substantial changes of the future Arctic underwater forest.

• unfold_moreThe impact of the melting Greenland ice sheet on the coastal zone — Lorenz Meire

  Lorenz Meire ¹;  John Mortensen ^{1
  1} Greenland Institute of Natural Resources

  Format: Oral In-person
  

  Abstract:

  The Greenland Ice Sheet is losing mass at an unprecedented rate, contributing to global mean sea level rise. Particularly at Greenland’s marine-terminating glaciers, discharge has increased significantly. Heat transport from the ocean to these glaciers has been identified as one of the critical processes for understanding future mass loss. In addition, there is increasing attention to the impact of meltwater discharge on fjord and its cascading impact on Greenland’s marine ecosystems. To resolve the effect on Greenland’s coastal zone, sampling was conducted and autonomous profiling floats were deployed in several fjords impacted by melting glaciers in Greenland. Physical, chemical and biological gradients were studied from close to the glaciers towards the open sea. Hydrographic and biogeochemical data from several fjord systems suggest that marine ecosystem productivity is very differently regulated in fjords influenced by either land-terminating or marine-terminating glaciers. Rising subsurface meltwater plumes originating from marine-terminating glaciers entrain large volumes of ambient deep water to the surface. The resulting upwelling of nutrient-rich deep water sustains a high phytoplankton productivity throughout summer in the fjord with marine-terminating glaciers. In contrast, fjords with only land-terminating glaciers lack this upwelling mechanism, and are characterized by lower productivity. These results suggest that a switch from marine-terminating to land-terminating glaciers can substantially alter the productivity in the coastal zone around Greenland with potentially large ecological and socio-economic implications requiring continious high resolution monitoring of Greenland's coastal zone.

• unfold_moreBenthic respiration and productivity in high Arctic fjord — Monika Kędra

  Monika Kędra ¹;  Marta Szczepanek ¹;  Katarzyna Koziorowska-Makuch ¹;  Joanna Stoń-Egiert ^{1
  1} Institute of Oceanology Polish Academy of Sciences

  Format: Oral In-person
  

  Abstract:

  Arctic fjords are among the most rapidly changing ecosystems in response to accelerating climate change. Fjords of Svalbard are experiencing a shift in environmental conditions related to increased inflow of Atlantic water, increasing temperatures and glaciers’ retreat. These results in changes in stratification, water turbidity and primary production patterns, which further cascades to the secondary production. Long-living benthic organisms are integrators of overlying water column processes, and thus can provide valuable information on the ongoing changes in the ecosystem.

  Here, we provide information on the sediment respiration rates and benthic secondary production from Woodfjorden, fjord located in the northern Spitsbergen. Ex-situ core incubation experiments were conducted at four contrasting stations: two areas near the glacier and close to the fjord ending, where cold water dominated, and two in the center and close to the mouth, where warmer waters prevailed. Sediment respiration rates and benthic secondary production were confronted to environmental information including sediment and water properties (granulometry, Total Organic Carbon and sediment pigments, and water chlorophyll a and Particulate Organic Carbon) and benthic community information (benthic species, biomass and abundance). Further, we discuss the benthic carbon sequestration potential in the deeper parts of the Arctic fjords. This study is a part of the Horizon2023 project SEA-Quester (Grant Agreement No. 101136480).

• unfold_moreQuantifying the carbon sequestration capacity of Arctic floodplains in response to permafrost thaw — Emily Geyman

  Emily Geyman ¹;  Yutian Ke ¹;  Joshua Anadu ¹;  John Magyar ¹;  Emily Seelen ²;  M. Isabel Smith ²;  Woodward Fischer ¹;  A. Joshua West ²;  Michael Lamb ^{1
  1} California Institute of Technology, Pasadena CA; ² University of Southern California, Los Angeles, California

  Format: Oral In-person
  

  Abstract:

  The vast accumulation of carbon in permafrost has been referred to as a ‘carbon bomb’ and ‘Pandora’s freezer’. These terms refer to the runaway feedback whereby thawing permafrost releases carbon dioxide and methane to the atmosphere, enhancing warming and driving further thaw. However, the timing, magnitude, and even directionality of carbon exchange between permafrost landscapes and the atmosphere depends not just on the intensity of atmospheric warming, but also on the response of the terrestrial biosphere. Here, we explore the extent to which the carbon emissions from permafrost soils may be offset by the formation of more carbon-rich forest canopies. We use river migration as a natural experiment to constrain timescales for forest succession and to estimate future above-ground carbon stocks in Arctic landscapes that are no longer underlain by permafrost. Arctic rivers provide an excellent case study because they carve out permafrost on their erosional banks and deposit unfrozen sands on their accreting banks. Thus, in the wake of the river’s path is a sequence of strips of land from young to old that archive the history of forest succession and permafrost regeneration. Using a combination of field vegetation surveys, permafrost observations, 14C-dating, and LiDAR data, we quantify the above-ground biomass density of three Arctic and sub-Arctic floodplain landscapes as a function of terrain age and permafrost content. We deconvolve the influences of forest succession and permafrost regeneration and show that unfrozen soils can support above-ground biomass stocks that are up to ten times larger than neighboring permafrost soils.

• unfold_moreThe impact of climate change on the timing of Arctic phytoplankton blooms — Courtney Payne

  Courtney Payne ^1,2;  Nicole Lovenduski ²;  Marika Holland ¹;  Kristen Krumhardt ¹;  Alice DuViver ^{1
  1} National Center for Atmospheric Research; ² University of Colorado Boulder

  Format: Oral In-person

  Abstract:

  In the Arctic Ocean, phytoplankton net primary production (NPP) has historically been constrained to a short, intense bloom in summer months that sustains both local and migrating fish, seabirds, and marine mammals. However, observed rapid sea ice loss and warming surface ocean temperatures attributed to climate change have altered Arctic phytoplankton NPP phenology (the seasonal and climate variations that affect the life cycles of plants and animals). We use a fully coupled Earth system model to evaluate changes in the timing, duration, and magnitude of the Arctic phytoplankton bloom between 1970, 2050, and 2100. While the phytoplankton bloom will shorten in many sub-Arctic seas by 2100, it lengthens by more than 30 days across much of the Arctic Ocean, driven largely by an earlier start to the bloom. We further find that future NPP will be more concentrated in the bloom in much of the Arctic Ocean. These results indicate that climate change will alter the timing of the Arctic phytoplankton bloom, likely impacting regional particulate organic carbon (POC) flux and the resulting benthic-pelagic coupling and potential for carbon storage.

• unfold_moreIntensification of organic matter remineralization in subsurface waters of southeastern Hudson Bay — Zakhar Kazmiruk

  Zakhar Kazmiruk ¹;  Eric Collins ¹;  Zou Zou Kuzyk ^{1
  1} University of Manitoba, Department of Environment and Geography, Centre for Earth Observation Science

  Format: Oral In-person
  

  Abstract:

  In order to understand remineralization of organic matter in subsurface waters of Hudson Bay, we have assessed spatial and temporal dynamics of apparent oxygen utilization (AOU) since the 1950s. AOU is a proxy for oxygen consumption due to aerobic heterotrophic oxidation of organic matter. We report that subsurface waters of southeastern Hudson Bay have relatively high AOU, which indicates that intermediate and deep waters in southeastern Hudson Bay were experiencing a much greater remineralization of organic matter than the equivalent water masses in the remainder of the bay. Moreover, the historical data shows that the high AOU signature was intensifying. We hypothesize that microbial degradation of the terrestrial organic matter delivered by the many rivers flowing into Hudson Bay plays a major role in the formation and intensification of the strong remineralization signal in subsurface waters of southeastern Hudson Bay. In order to test this hypothesis, we have assessed the sources of subsurface waters in Hudson Bay using temperature, salinity, and δ18O as the main tracer parameters. Additionally, we have performed a metagenomic analysis of the prokaryotic communities residing in southeastern Hudson Bay to gain an insight into the capability of microorganisms to remineralize terrestrial organic matter. The intensification of the high AOU signature is likely to continue as a result of the global warming induced increase in riverine input into Hudson Bay. As a result, an oxygen limited zone might develop in southeastern Hudson Bay in the near future.

• unfold_moreInteractions between plants, microbes, and minerals tilt the carbon balance in permafrost-affected soils: a holistic view developed across three priming experiments — Jessica Ernakovich

  Jessica Ernakovich ^1,2;  Fernando Montano Lopez ³;  Sean Schaefer ²;  Hannah Holland-Moritz ²;  Nathan Alexander ²;  Lukas Bernhardt ²;  Sarah Goldsmith ³;  Else Schlerman ²;  A. Stuart Grandy ^1,2;  Will Wieder ⁴;  Caitlin Hicks Pries ^{3
  1} Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH; ² Center of Soil Biogeochemistry and Microbial Ecology, University of New Hampshire, Durham, NH; ³ Department of Biological Sciences, Dartmouth College, Hanover, NH; ⁴ National Center for Atmospheric Research, Boulder, CO

  Format: Oral In-person
  

  Abstract:

  Accurate predictions of permafrost–climate feedbacks require a systems-view recognizing that the pool of permafrost carbon (C) is affected not only by warming, but also complex feedbacks between plants, microbes, and minerals. One key aspect of plant–microbe–mineral interactions is priming, a process where plants reduce or stimulate decomposition of soil organic matter (SOM) via the addition of rhizodeposits (root exudates, fine roots). To probe how differences in mineralogy and changes in plant or microbial composition affect the accumulation and degradation of soil C following permafrost thaw, we performed three priming experiments where mineral permafrost from the North Slope of Alaska was amended with exudate C. These experiments isolate and combine the effects on priming of soil mineralogy, microbial communities, and plant roots. We found that plants and microbes affect how permafrost-derived OM interacts with the modern C cycle; permafrost incubated without additional amendments lost SOM-C (a positive feedback), while permafrost incubated with exudates often retained more SOM-C. However, if rhizosphere microorganisms were introduced to permafrost soils, SOM-C decomposition was again primed resulting in excess gaseous losses. Variation in mineralogy didn’t alter the direction and magnitude of the priming of permafrost-C except in the presence of living plants, which then exhibited differing temporal trends between mineral and plant combinations. These findings suggest that each component of the plant–microbe–mineral system plays a critical role in the permafrost–climate feedback, and that these interactions lead to different climate outcomes than would be expected by considering these components in isolation. 

• unfold_moreMegafires in sub-Arctic: satellite CO data for Canada and Siberia — Leonid Yurganov

  Leonid Yurganov 
  University of Maryland, Baltimore County

  Format: Oral Virtual
  

  Abstract:

  The influence of boreal forest fires on high-latitude Northern Hemisphere CO (HNH, above 30 N) has been monitored by several thermal IR sounders since the beginning of the 21st century. Solar radiation reflected from the surface and detected by TROPOMI since 2017 has improved the sensitivity to CO near the surface. The most severe fires ("megafires", e.g. 2002, 2003, 2012) pollute the troposphere even far beyond the burned area. In this report, we analyze the total CO column density over Canada and Russian Siberia in 2021 and 2023. In both cases, CO emissions were record high and the burned areas were in the northernmost parts of the hemisphere up to 70° N. The 2021 Siberian fires occurred in the permafrost zone and were responsible for 90% of the total fire CO emissions in Russia that year. Such high emissions in a low biomass area raise the question of the actual "fuel" being burned. At the same time, it is not clear whether the 2021 Siberian fire is really a "boreal fire". The key to further investigation may be the close coincidence of the fire locations with the Tunguska and Lena underground coal basins. These basins are the two largest reservoirs of black and brown coal in the world. Although coal burning itself is not the only explanation, coal deposits are known to contain methane. The idea of interaction of biomass, coal and methane as different fuels opens the way for further investigation.

• unfold_moreNitrogen fixation in different Arctic sea ice regimes is linked to primary production — Lisa W. von Friesen

  Lisa W. von Friesen ¹;  Hanna Farnelid ¹;  Wilken-Jon von Appen ²;  Mar Benavides ³;  Olivier Grosso ³;  Christien P. Laber ⁴;  Johanna Schüttler ⁵;  Marcus Sundbom ⁶;  Sinhué Torres-Valdés ²;  Stefan Bertilsson ⁷;  Ilka Peeken ²;  Pauline Snoeijs-Leijonmalm ⁶;  Lasse Riemann ^{8
  1} Linnaeus University; ² Alfred Wegener Institute; ³ Aix Marseille University; ⁴ Linnaeus University; ⁵ Max Planck Institute for Chemistry; ⁶ Stockholm University; ⁷ Swedish University of Agricultural Sciences; ⁸ University of Copenhagen

  Format: Oral Virtual
  

  Abstract:

  As the widely nitrogen-limited Arctic is undergoing rapid climate change resulting in withdrawing sea ice and often stimulated primary production, nitrogen may become an increasingly important determinant of productivity. Nitrogen fixation – the conversion of molecular nitrogen (N2) to bioavailable ammonia by a group of microorganisms called diazotrophs– was previously not thought to occur in the Arctic Ocean. Over the last decade, however, low but non-negligible nitrogen fixation rates have been measured in open waters of the Amerasian shelf and shelf-break. Still, data shortage from central and Eurasian regions impedes pan-Arctic understanding. Here, we investigate nitrogen fixation and diazotroph community composition and gene expression at the deep chlorophyll a maximum to discern eventual links to primary production. We covered different sea ice regimes from open Atlantic-influenced waters over the marginal ice zone in the western Eurasian Arctic to multiyear sea ice cover in the central Arctic Ocean. We report nitrogen fixation below multiyear ice in the central Arctic Ocean, occasionally limited by dissolved organic carbon, and sufficient to support up to 8.6% of in-situ net primary production via the provision of new nitrogen. Across the marginal ice zone, rates varied between days and with ice regime from below detection up to its maximum associated with an ice-edge phytoplankton bloom. Still, its support of in-situ net primary production was

 

Poster Presentations (during Poster Exhibit and Session on Wednesday 26 March): 

• unfold_moreSpatio-temporal shifts in sea ice microbial autotrophy and heterotrophy — Rosalie McKay

  Rosalie McKay ¹; Zoe Koenig ^1,2; Janina Osanen ³; Christine Michel ⁴; Brent Else ⁵; Karley Campbell ^{1
  1} UiT The Arctic University of Norway; ² Norwegian Polar Institute; ³ Norwegian Institute of Science and Technology; ⁴ Fisheries and Oceans Canada; ⁵ University of Calgary

  Format: Poster In-person
  

  Poster number: #407

  Abstract:

  Net community production (NCP) represents the balance between algal photosynthesis and microbial respiration; determining whether sea ice is considered a net autotrophic (CO2 uptake) or heterotrophic (CO2release) system. While existing measurements of NCP for the polar regions are limited, NCP is likely to mimic the inherent heterogenity of bottom-ice algal blooms across space and time. In this study, two locations of land-fast first-year sea ice were routinely sampled April - June, 2022, over a spring ice algal bloom near to the community of Cambridge Bay and the Canadian High Arctic Research Station (CHARS). Sample locations were selected for their differing sub-ice turbulence regimes that were likely to promote contrasting states of nutrient availability. We report higher algal abundance for most of the sampling period at the high turbulence site due to enhanced nitrogen supply. However, bloom termination was accelerated at this location as the greater sub-ice turbulence enhanced bottom-ice melt to the point of removing the algal-rich skeletal layer. Bacterial abundance, dissolved organic carbon (DOC) and particulate organic carbon (POC) were similar between the two sites, suggesting a decoupling of bacteria and organic carbon from the algal bloom. Furthermore, along with a relatively higher proportion of bacteria, our NCP measurements show that heterotrophy was prevalent at the low versus high turbulence site. Heterotrophic NCP conditions are also reported in the interior and upper sections of the ice column. Local conditions, such as turbulence-driven nutrient availability influenced by tidal cycles, can lead to a range of outcomes from stagnant growth to variable algal accumulation. These dynamics challenge the traditional understanding of ice algal bloom phenology, suggesting the need for its reevaluation to account for a broader range of local conditions.

• unfold_morePlankton, Microbes & biogeochemical processes in the Arctic ecosystem, driven by glacial/sea-ice inputs and climate teleconnections — Rajani Kanta Mishra

  Rajani Kanta Mishra ¹; V. Venkataramana ¹; Melena A. Soares ^{1
  1} National Centre for Polar and Ocean Research, Goa, India

  Format:  Poster In-person
  

  Poster number: #569

  Abstract:

  The Arctic region shows the fastest warming on the Earth, so the changes in the Arctic climate significantly influence the superfluous Arctic regions. The proposed objective will focus on regional arctic warming leading to rapid sea ice/glacial meltwater varying in the different time periods and how it impacts the plankton (phytoplankton & zooplankton) biomass changes linked to microbial population, ecosystem which plays a more significant role in the biogeochemical cycle in the presence of nutrients dynamics. Further, the zooplankton is a consumer of the phytoplankton and microbial bacteria that interplay in the carbon cycle that govern by physical-chemical variables including sea ice/glacial inputs. The study would be ideal in these ecosystem due to the influence of the intrusion of waters from the Arctic and Atlantic, along with glacial melt and local winds, which are the key driving forces and are acting on the upper water masses in the Artic ecosystem. The available data on plankton microbial diversity, food web ecosystem, and their role in the biogeochemical cycle is obscure and further teleconnection to regional and global climate is very much dynamic. understanding such teleconnection is one of the essential factors in understanding the current climate variability and predicting its future and is further important in investigating the cause of extreme events in and out of the Arctic region and obtaining their future perspective.Therefore, the present study would understand the impact of sea ice/glacial input on the ecosystem function for the regional and global climate change and vice versa.

• unfold_moreHigh-altitude alpine ecosystems: vulnerability to climate change and potential for carbon sequestration — Federica D'Alò

  Federica D'Alò ¹; Olga Gavrichkova ^1,2; Carlotta Volterrani ^1,3; Maurizio Sarti ⁴; Alexandru Milcu ⁵; Sebastien Devidal ⁵; Enrico Brugnoli ¹; Angela Augusti ^{1
  1} Institute of Research on Terrestrial Ecosystems, National Research Council, Porano (TR), Italy; ² National Biodiversity Future Center (NBFC), Palermo, Italy; ³ Department of Environmental Sciences, Informatics and Statistics (DAIS), Cà Foscari University of Venice, Mestre (VE), Italy; ⁴ Consiglio Nazionale delle Ricerche; ⁵ Montpellier European Ecotron, Univ Montpellier, CNRS, Montferrier-Sur-Lez, France

  Format:  Poster Virtual
  

  Poster number: #321

  Abstract:

  High-altitude and high-latitude regions are particularly sensitive to climate change with current warming causing irreversible impacts. Climate change affects carbon cycle, altering the balance between carbon assimilation through photosynthesis and its release via respiration. High-altitude alpine ecosystems are increasingly viewed as analogous to Marginal Ice Zones (MIZ) due to similarity in species composition, sensitivity to warming and critical role in carbon dynamics. Like polar MIZ, which transition between sea ice and open ocean, high-altitude ecosystems form fragile boundaries between snow-covered and more pronounced vegetated landscapes. Both regions are experiencing rapid changes, impacting carbon dynamics. In this study, a site at 2500m was treated as an “emerging MIZ,” characterized by fluctuating snow cover and shifts in plant productivity. To investigate climate change effects on CO2 fluxes, alpine ecosystem monoliths (2500m a.s.l., Mont Blanc, Italy) were transferred to the Montpellier European Ecotron (France) for climate manipulation. Monoliths were exposed to current (~420ppm CO2) and future scenarios (~550ppm and ~800ppm CO2, according to RCP4.5 and RCP8.5, respectively) forecasted for 2070. Ecosystem respiration (Reco) and Net Ecosystem Exchange (NEE) were measured, and Gross Primary Productivity (GPP) was calculated. While differences between Control and RCP 4.5 were minimal, RCP 8.5 plots showed significantly higher GPP and increased Reco. Enhanced C allocation towards the green canopy allowed the system to maintain a positive carbon balance, acting as a carbon sink. In summary, alpine ecosystems, like MIZ, are highly responsive to future climate scenarios and could play a significant role in carbon sequestration under high-emission conditions.