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Diagenesis of hydrocarbon-seep carbonates: Common patterns, divergent pathways and conceptual pitfalls
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-07-04)Authigenic carbonates formed at marine hydrocarbon seeps are an important component of carbon cycling at continental margins. Ancient hydrocarbon-seep deposits serve as archives of the evolution of chemosynthesis-based ecosystems, past pore-water chemistry, and the tectonic architecture and geological history of their host sedimentary basins. However, while modern and ancient seep deposits share ... -
Western Greenland Ice Sheet-Land-Ocean Interactions: Near-Shore Dissolved Organic Carbon 14C Ages and Composition in Eastern Baffin Bay
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-07-11)Greenland's ongoing deglaciation and thawing permafrost, accompanied by an increase in ice sheet freshwater discharge and nutrient export, are significantly impacting the surrounding fjords and marine ecosystems. Understanding the geochemical linkages between ice, land, and marine environments is crucial for comprehending the effects of amplified cryosphere-biosphere interactions on marine ecosystems. ... -
Deep crustal deformation driven by reaction-induced weakening
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-07-11)Deep crustal shear zones, fundamental to the dynamics of terrestrial plate tectonics, exhibit complex processes of initiation and evolution that are yet to be comprehensively quantified across both long and short temporal scales. Conventionally, thermo–mechanical models posit that crustal rock behaviour is dominated by monomineralic aggregates undergoing processes like intracrystalline plastic ... -
Seasonal sea ice characterized the glacial Arctic-Atlantic gateway over the past 750,000 years
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-07-04)The past occurrence of an extreme ~1-kilometer–thick Arctic Ocean–Nordic Seas ice shelf has been inferred from submarine landscape features and geochemical records, although fundamental aspects of its characteristics, impacts, and timing remain highly debated. Here, we challenge this pan-Arctic glaciation hypothesis by investigating two sites from the Arctic-Atlantic gateway (AAG) and the Nordic ... -
Controls of sediment-bound and dissolved nutrient transport from a glacierised metasedimentary catchment in the high Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-06-16)Rapid warming in polar and alpine areas is causing significant glacier mass loss and resulting in increasing freshwater delivery to the oceans. Recent research indicates that higher meltwater water runoff is likely to increase solute and sediment transport, which will include nutrients, to downstream environments. This enhanced delivery may drive a negative feedback effect on atmospheric CO<sub>2</sub> ... -
Heavy potassium isotopes in carbonatites reveal oceanic crust subduction as the driver of deep carbon cycling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-06-13)Carbon cycling between surface and mantle reservoirs is pivotal in fostering habitability of Earth. A critical yet poorly constrained parameter is whether crustal carbon can “survive” devolatilization processes that accompany slab subduction and therefore influence deep carbon budgets. Carbonatites provide a key record to address this important topic. Here, we present high-precision potassium isotope ... -
Geology of critical mineral deposits of the Kuljuktau Mts., Central Kyzylkum (Uzbekistan)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-12-19)This article presents characteristics of geological and tectonic structures of the Kuljuktau Mountains, mineralogical and geochemical features of its volcanic and intrusive rocks and associated mineralisation of critical elements. The Taskazgan graphite, Shaidaraz lithium, and Tozbulak high-purity quartz deposits, and new prospects for rare earth mineralisation have been identified as the most ... -
Planktic calcifiers: from living assemblages to proxies in the Arctic Ocean
(Conference object; Konferansebidrag, 2025)Planktic foraminifers, pteropods, and coccolithophores are marine calcifiers, organisms living in the water column and found throughout all oceans, with shells made of calcium carbonate. Because of their shell, they play an important role in the carbon cycle exporting calcium carbonate from the upper ocean to the sea floor when they die and sink. If no dissolution occurs on the water column or within ... -
Sedimentary ancient DNA insights into foraminiferal diversity near the grounding line in the western Ross Sea, Antarctica
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-06-06)Foraminifera are important marine environmental indicators widely used in paleoceanography and paleoclimate studies. They are a dominant component of meiobenthic communities around the Antarctic continental shelf, including rarely studied locations below the ice shelves, close to the grounding line. In this study, we use high-throughput sequencing of sedimentary ancient DNA (sedaDNA) targeting ... -
Origin and composition of hydrothermally-influenced sediments at Aurora Vent Field, southwestern Gakkel Ridge (82.9°N)
(Journal article; Tidsskriftartikkel, 2025-05-21)Slow–ultraslow spreading ridges represent half of the total length of the global mid-ocean ridge system and have been recognized to host hydrothermal activity. Their role as a source versus sink of elements in the oceans remains poorly constrained. Here, we present the first sediment data from the Aurora Vent Field (~3900 m depth) on the ultraslow spreading Gakkel mid-ocean ridge and the northernmost ... -
Antarctic glaciers export carbon-stabilised iron(II)-rich particles to the surface Southern Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-05-30)Iron is an essential micronutrient for phytoplankton and plays an integral role in the marine carbon cycle. The supply and bioavailability of iron are therefore important modulators of climate over glacial-interglacial cycles. Inputs of iron from the Antarctic continental shelf alleviate iron limitation in the Southern Ocean, driving hotspots of productivity. Glacial meltwater fluxes can deliver ... -
The Role of Ballasting, Seawater Viscosity and Oxygen-Dependent Remineralization for Export and Transfer Efficiencies in the Global Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-05-05)The particulate organic carbon (POC) flux from the euphotic zone to the deep ocean is central to the biological carbon pump. It is typically evaluated using “export efficiency” and “transfer efficiency,” which reflect POC formation and sinking and carbon sequestration efficiency in the ocean's interior, respectively. Since observations of these metrics are limited, biogeochemical models can elucidate ... -
Southern Ocean Carbon Export Revealed by Backscatter and Oxygen Measurements From BGC-Argo Floats
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-04-28)The Southern Ocean (south of 30°S) contributes significantly to global ocean carbon uptake through the solubility, physical and biological pumps. Many studies have estimated carbon export to the deep ocean, but very few have attempted a basin-scale perspective, or accounted for the sea-ice zone (SIZ). In this study, we use an extensive array of BGC-Argo floats to improve previous estimates of carbon ... -
Arctic fjord ecosystem adaptation to cryosphere meltdown over the past 14,000 years
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-04-25)The Arctic cryosphere is the epicentre of acute global change impact, with abrupt warming and amplification driving rapid sea ice decline and irreversible glacial ice loss. A key challenge is understanding how the cryosphere meltdown will impact Arctic marine carbon cycles and ecosystems. Here, we use organic geochemical biomarkers to trace the contribution of different planktonic groups to organic ... -
A constellation of mud volcanoes originated from a buried Arctic mega-slide, Southwestern Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-04-30)Global estimates on the number of submarine mud volcanoes are highly uncertain, as well as their role in the deep-sea biosphere and methane budgets. Here, we report the discovery of ten Arctic mud volcanoes in the Barents Sea (440–480 m depth), where only two had been previously known. The new mud volcanoes form flat-topped mounds on the seafloor and are connected to seismic chimneys rooted within ... -
Glacier releases of heavy metals in Kongsfjorden: What are the ecosystem impacts?
(Conference object; Konferansebidrag, 2025-01)While climate change is of global concern, its impacts are especially rapid and pronounced in Arctic ecosystems. Arctic glaciers have been particularly impacted, with increasing melt and retreat in conjunction with shifts in riverine freshwater and sediment discharge. Arctic fjords are the ultimate recipients of glacial discharge and a plethora of heavy metals released from glacial environments. ... -
Geology of Svalbard: Deep-time and Deep-Earth (SVALGEOL)
(Chapter; Bokkapittel, 2025-01-20)Geology is omnipresent in Svalbard, defining among other parameters the location of all major settlements. The SVALGEOL chapter provides an overview of the geology of Svalbard, and how it influences local and global society. We briefly describe the history of geological exploration and mapping of Svalbard, before outlining the various data sets geoscientists use in their work. We then focus on two ... -
Insights into silicon cycling from ice sheet to coastal ocean from isotope geochemistry
(Journal article; Tidsskriftartikkel; Peer reviewed, 2025-04-19)The polar regions are biologically productive and play a critical role in regional and global biogeochemical cycling. A key nutrient is dissolved silicon, required for the growth of siliceous phytoplankton, diatoms, which form an important component of polar ecosystems. Glacial weathering is thought to be an important dissolved silicon source to coastal waters, especially critical in regions ... -
Methane in Svalbard (SvalGaSess)
(Research report; Forskningsrapport, 2025-01-20)Methane is a powerful greenhouse gas whose emission into the atmosphere from Arctic environments is increasing in response to climate change. At present, the increase in atmospheric methane concentrations recorded at Ny-Ålesund and globally threatens the Paris Agreement goal of limiting warming to 2 degrees, preferably 1.5 degrees, by increasing the need for abatements. However, our understanding ... -
The Atlantification process in Svalbard: a broad view from the SIOS Marine Infrastructure network (ARiS)
(Chapter; Bokkapittel, 2025-01-20)Arctic marine systems are vital to the Earth’s ecological and climatic balance and harbour a unique biodiversity adapted to extreme conditions. However, they are under unprecedented threat from climate change, in particular from “Atlantification”, i.e., the loss of sea ice and the increasing influence of Atlantic Water (AW) in this region. Long-term observatories are crucial to detect even small ...
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