Publications
Continuing subsidence and deformation of the Surtsey volcano, Iceland
Surtsey, a volcanic island formed off Iceland's coast between 1963 and 1967, continues to experience significant subsidence. Since its formation, the island has sunk by approximately 1 meter, with recent GPS surveys (2000–2023) revealing an average subsidence rate of 3.8 mm per year, totaling 9 cm over this period. About two-thirds of this subsidence is attributed to compaction of sedimentary and volcaniclastic material, thermal contraction, and palagonization, while the remaining third is due to the island's loading on the asthenosphere. The study also confirms that Surtsey moves horizontally with the Eurasian plate, providing insights into the dynamic processes shaping volcanic islands.
Flavobacterium aerium sp. nov., a bacterium isolated from the air of the Icelandic volcanic island Surtsey
Researchers have identified and characterized a novel bacterium, Flavobacterium aerium sp. nov., isolated from the air of Surtsey, a volcanic island in Iceland designated as a UNESCO World Heritage Site. This discovery was made using a polyphasic taxonomic approach, which included phylogenetic analysis based on 16S rRNA gene sequences, fatty acid profiling, and genomic sequencing. The bacterium, designated strain 19SA41, exhibits unique morphological and physiological traits, such as pale yellow-pigmented colonies, optimal growth at 22 °C and pH 7.5, and a genome with a G+C content of 33.2 mol%. Phylogenetic analysis revealed that F. aerium is most closely related to Flavobacterium xinjiangense, with a sequence similarity of 96.52%, supporting its classification as a novel species. This finding contributes to the understanding of microbial diversity in extreme environments and underscores the significance of UNESCO World Heritage Sites for scientific research.
Sinkholes observed at Vesturbunki, Surtsey
Researchers have identified and monitored sinkholes and fissures along the outer margin of Vesturbunki, one of Surtsey’s tuff cones, revealing a dynamic subsurface process. These features, first observed in 2015, were traced over nearly 500 meters and showed variability in their presence across multiple field visits (2017, 2019, 2025). The study suggests that these sinkholes are likely driven by a combination of island-wide subsidence, local compaction of volcanogenic material, and possibly triggered by seismicity. Surface temperature monitoring between 2008 and 2025 indicated Vesturbunki is consistently hotter (up to 100°C) compared to Austurbunki (up to 96°C), with fluctuations linked to subsurface heat flow. Seismic data from 2009–2024 showed low to moderate activity, though hypocenter locations remain uncertain due to sparse station coverage. The findings underscore the need for continued monitoring and installation of a local seismic station on Surtsey to better understand these processes.
Weather in Surtsey 2020-2024
A new maximum air temperature record of 22.6°C was set on Surtsey, Iceland's southernmost island, on 14 July 2025, breaking the previous record of 18.6°C from 11 July 2023. This study analyzes weather data from 2020 to 2024, highlighting significant variations, including a notably cloudy and cool summer in 2022 and a winter (2022–2023) marked by alternating warm/windy and cold/calm months. The research also identified extreme sea level pressure records of 1050.4 hPa and 932.3 hPa on 28 March 2020 and 15 February 2020, respectively. While temperature and wind data were robust, precipitation measurements faced considerable failures. The study aims to provide insights useful for understanding ecological processes on the island, which serves as a scientific laboratory for flora and fauna development.
Internal structure of the volcanic island of Surtsey and surroundings: Constraints from a dense aeromagnetic survey
A dense aeromagnetic survey of Surtsey, a young volcanic island off Iceland's south coast, reveals that the island lacks significant basaltic intrusions within its five vents, suggesting magma fragmentation dominated submarine eruptions from the onset. The study, using 2D spectral analysis and Euler deconvolution, identified a small magnetic anomaly over the submarine edifice of Surtla, hinting at preserved dykes during weak or moderate explosive activity in 1963–1964. Additionally, a 10–20 m thick pillow lava field, extending ~1 km south of Surtsey, was detected, indicating channelized intrusive flow during early effusive eruptions in May–July 1964. The survey also found indications of magnetized volcanic rocks predating the Surtsey eruption beneath Jólnir, an ephemeral island.
Material and mechanical properties of young basalt in drill cores from the oceanic island of Surtsey, Iceland
Drill core samples from Surtsey, an oceanic island formed by eruptions between 1963 and 1967, reveal significant variability in the material and mechanical properties of young basalt deposits. These properties vary across subaerial, submarine, and subseafloor environments, with connected porosity ranging from 42% to 21%, permeability spanning six orders of magnitude, and uniaxial compressive strength varying between 10–70 MPa. Synchrotron X-ray microdiffraction analyses combined with geochemical data show that the initial alteration of fresh glass and incipient consolidation of a fine-ash matrix play crucial roles in modifying these properties. The study highlights how diverse cementing microstructures influence the physical characteristics of pyroclastic deposits, providing critical reference parameters for geophysical studies and understanding the stability and survival of oceanic islands over time.
Authigenic mineralization in Surtsey basaltic tuff deposits at 50 years after eruption
A study of Surtsey, a basaltic island in SW Iceland, reveals that authigenic mineralization processes in young pyroclastic deposits are influenced by thermal and hydrological factors, as well as the chemistry of original basaltic components. Researchers analyzed 50-year-old tuff samples from a borehole drilled in 2017 using petrographic studies, X-ray powder diffraction, and SEM-EDS imaging. They found multi-stage palagonitization processes and secondary mineral precipitation, including phillipsite, analcime, and Al-tobermorite, within basaltic pyroclasts. Temperature plays a significant role in controlling these reactions, but the chemistry of interstitial fluids also influences reaction pathways. This study provides a reference framework for understanding mineralogical evolution in Surtseyan-type volcanoes worldwide.
Comparison of Atmospheric and Lithospheric Culturable Bacterial Communities from Two Dissimilar Active Volcanic Sites, Surtsey Island and Fimmvörðuháls Mountain in Iceland
A comparative analysis of atmospheric and lithospheric bacterial communities at two distinct Icelandic volcanic sites—Surtsey Island and Fimmvörðuháls Mountain—revealed significant differences, with Surtsey's air hosting unique microbial populations. Using MALDI Biotyper analysis and 16S rRNA gene sequencing, researchers identified 72 species across 40 genera, including potential new species, predominantly from the Proteobacteria and Actinobacteria phyla. Back trajectory analysis suggested that 85% of isolates originated locally, while 15% traveled long distances. Taxonomic proportions mirrored the sites' environmental characteristics, offering insights into microbial dispersal dynamics in volcanic ecosystems.
Bryophytes of Surtsey, Iceland: Latest developments and a glimpse of the future
A recent study on Surtsey, Iceland—the youngest island in the Vestmannaeyjar archipelago—reveals that bryophyte species richness has increased from 43 to 59 taxa between 2008 and 2018. The research, conducted through systematic inventories in a grid of 100 m × 100 m quadrats, found that while some areas experienced expansion or contraction of earlier colonists, others showed significant increases in species richness, particularly in seabird-affected zones not overgrown by grassland. Additionally, the study compared bryophyte flora on Surtsey with that of Elliðaey, a 5,000-year-old island, identifying shared and unique taxa. The findings suggest that bryophyte diversity on Surtsey will continue to grow but may eventually decline as lava fields erode and grassland dominates. Continued monitoring is deemed essential for tracking these changes.
Characteristics of Sub-Aerially Emplaced Pyroclasts in the Surtsey Eruption Deposits: Implications for Diverse Surtseyan Eruptive Styles
A new analysis of the 1963–1967 Surtsey eruption deposits reveals diverse pyroclastic textures and microstructures, challenging previous assumptions about Surtseyan volcanism. The study identifies distinct subaerial cone-forming deposits—characterized by poorly sorted fines rich in sideromelane ash and composite bombs—and submarine edifice samples with fines-poor, vesicular coarse ash horizons. This diversity suggests a broader range of eruptive styles than previously recognized. Researchers examined archived samples from the Icelandic Natural History Museum, including material collected during the eruption and from the 1979 Surtsey core, alongside recent field samples. The findings imply that Surtseyan eruptions can produce varied volcanic products depending on vent conditions.
Culturable Bacterial Diversity from the Basaltic Subsurface of the Young Volcanic Island of Surtsey, Iceland
Research on Surtsey, Iceland, reveals the subsurface of this young volcanic island hosts diverse and active microbial communities, with over 195 culturable bacterial strains identified. These belong to six phyla, including Firmicutes (40%) and Gammaproteobacteria (28.7%), with Bacillus being the dominant genus. Over 13% of the strains may represent novel species, closely related to those found in soil, seawater, and hydrothermal sites. The study used enrichment cultures under varying conditions, media, and temperatures, combined with MALDI-TOF MS analysis and 16S rRNA gene sequencing. While only five phyla were cultivated, they accounted for over 80% of the detected ASVs, underscoring the importance of both culture-dependent and -independent methods in exploring extreme volcanic environments.
Measurements of the inclination of the SE-03 Borehole on Surtsey Volcano
A precise measurement of the SE-03 borehole's inclination on Surtsey Volcano reveals that its average deviation from vertical is 33.4±0.2°, slightly less than the planned 35°. This minor discrepancy, corrected for in the study, confirms the location of a volcanic intrusion directly beneath the Surtur crater, identified as the feeder dyke for the 1966-67 eruption. The borehole's actual path was found to be 8 meters shorter and 4.7 meters deeper than designed, with a total vertical depth of 294.7±1.2 meters. These findings enhance the accuracy of stratigraphic interpretations derived from the SE-03 drill core, supporting the understanding of Surtsey's submarine structure and volcanic activity.
Rhodothermus bifroesti sp. nov., a thermophilic bacterium isolated from the basaltic subsurface of the volcanic island Surtsey
Scientists have discovered a novel thermophilic bacterium, Rhodothermus bifroesti sp. nov., in the basaltic subsurface of Surtsey, a volcanic island off Iceland's south coast. This Gram-negative, rod-shaped microorganism thrives at 70°C and exhibits distinct genetic traits, setting it apart from its closest relatives with only 17.6% digital DNA–DNA hybridization similarity to Rhodothermus marinus and 16.9% to Rhodothermus profundi. The bacterium was isolated from tephra core and borehole fluid samples collected below 70 meters depth, highlighting the unique microbial diversity in extreme environments. Comparative chemotaxonomic, genomic, and phylogenetic analyses confirmed its status as a new species within the genus Rhodothermus.
Systemic analysis of a developing plant community on the island of Surtsey
A volcanic island's plant community undergoes a complete adaptive cycle, transitioning from pioneer to grassland stages, driven primarily by nutrients deposited by breeding gulls. This finding emerges from a systemic analysis of Surtsey's vascular plants between 2000 and 2018, which also reveals deviations in the adaptive cycle due to environmental stressors like severe drought in 2012. The study employs a novel method to quantify adaptive cycles, offering insights into species' roles during ecological succession.
The development of the land-arthropod fauna on Surtsey, Iceland, during 1971-1976 with notes on terrestrial Oligochaeta
Surtsey, a volcanic island off Iceland's south coast, offers a unique laboratory for studying ecological succession. A 1973 study by Lindroth et al., analyzed terrestrial invertebrate data from Surtsey and its surroundings between 1964-1970, revealing the initial stages of colonization and adaptation in an extreme environment. The research identified key arthropod species that established themselves on the young volcanic terrain, highlighting the rapidity with which certain organisms can exploit new habitats. This study laid foundational knowledge for understanding ecological processes in primary succession, particularly focusing on how arthropods contribute to soil formation and ecosystem development. The findings underscore Surtsey's significance as a natural experiment for studying colonization dynamics, offering insights applicable to other newly formed terrestrial environments.
Vascular plant colonisation, distribution and vegetation development on Surtsey during 1965–2015
Between 1965 and 2015, Surtsey witnessed significant vascular plant colonization, with 74 species identified. Initial rapid colonization (1965–1979) stagnated until the establishment of a dense seagull colony in 1986, which drastically accelerated plant growth, peaking between 1992 and 1995. Six vegetation types emerged, ranging from sparse pioneer communities to lush, nutrient-rich grasslands influenced by seabird activity. Species richness increased from an average of 4.8 to 10.4 per hectare over the study period. Pioneering species like Honckenya peploides, Poa annua, and Silene uniflora led colonization, thriving on sandy lava and barren surfaces. Despite seabird impacts, most of Surtsey remains sparsely vegetated, offering insights into ecological succession in extreme environments.
Volcanic tremor associated with the Surtsey eruption of 1963–1967
The Surtsey eruption (1963–1967) revealed a complex relationship between volcanic tremor and magma flow, challenging conventional assumptions. Despite high magma discharge rates during initial explosive phases, seismic tremor was minimal, while later stages with reduced output exhibited significant tremor. Harmonic and spasmodic tremor frequencies varied from low (>3 Hz) to higher (3–5 Hz), with no clear link between tremor patterns and eruption style on short timescales. This study analyzed archival seismic data from two distant stations, demonstrating that even with limited modern monitoring, volcanic processes can be inferred through detailed seismogram analysis.
A model for wave abrasion on underwater bedrock, with an application to rapidly downwearing tephra cones adjacent to Surtsey Island in Iceland
Wave abrasion, a key process shaping shallow-water coastal bedrock, has been quantified through a predictive model linking erosion rates to wave-induced shear stress and bedrock resistivity. Applied to two tephra cones near Surtsey Island in Iceland—Jólnir (storm-exposed) and Syrtlingur (sheltered)—the model reveals distinct abrasion dynamics: Syrtlingur experiences 33% less deep-water wave energy but fourfold more efficient abrasion, with a shallower wave base (34.4 m vs. 51.5 m for Jólnir). The findings highlight how storm exposure and sheltering influence erosion patterns, offering insights into coastal bedrock evolution under varying hydrodynamic conditions.
Basalt-Hosted Microbial Communities in the Subsurface of the Young Volcanic Island of Surtsey, Iceland
Research on Surtsey, a volcanic island formed between 1963 and 1967, reveals diverse and distinct microbial communities thriving in its subsurface basaltic crust, including thermophilic species such as Thermaerobacter, BRH-c8a (Desulfallas-Sporotomaculum), Thioalkalimicrobium, and Sulfurospirillum. These findings, derived from 16S rRNA gene amplicon sequencing and scanning electron microscopy, highlight the island's potential as a model for studying microbial colonization in newly formed oceanic crust. The study also identifies uncharacterized taxonomic lineages, suggesting rich metabolic diversity. To distinguish endemic microbes from contaminants, rigorous methodological and computational strategies were employed during the International Continental Scientific Drilling Program expedition.
Availability of plant nutrients and pollutants in the young soils of Surtsey compared to the older Heimaey and Elliðaey volcanic islands
Nitrogen (N) is the most limiting nutrient for plant growth across sub-Arctic volcanic ecosystems, regardless of soil age or seabird presence. A study comparing young Surtsey (50 years old) to older Heimaey and Elliðaey (~1600 years) found that while seabird colonies enhance availability of most nutrients—including phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S), iron (Fe), manganese (Mn), and zinc (Zn)—N consistently constrained plant productivity. On Surtsey’s thinner tephra soils, low P availability may also contribute to co-limitation, warranting further investigation. No accumulation of cadmium (Cd) or lead (Pb) was detected in seabird colonies. The study used resin membranes incubated in topsoil (0–10 cm) to measure nutrient dynamics, revealing how time and biotic factors shape ecosystem development on unvegetated volcanic substrates.
Effects of sea birds and soil development on plant and soil nutritional parameters after 50 years of succession on Surtsey
Research on Surtsey, a volcanic island formed during submarine eruptions from 1963 to 1967, reveals that seabird colonies play a pivotal role in shaping soil nutritional characteristics and plant productivity. A study conducted in 2013 found that the presence of seagulls significantly increased nitrogen (N) and phosphorus (P) concentrations in tephra soils, with δ15N analyses confirming the transfer of N from bird waste to plants. Despite the high P availability in volcanic soils and substantial N input by birds—47 kg N ha-1 yr-1—vegetation on Surtsey remains nitrogen-limited due to the extreme imbalance between N and P. The study highlights the critical impact of seabird colonies on the nutritional ecology of young, nutrient-poor ecosystems like Surtsey.
Erosion and sedimentation in Surtsey island quantified from new DEMs
A photogrammetric study of Surtsey, an Icelandic UNESCO World Heritage Site, reveals that coastal wave erosion has removed approximately 28 million cubic meters of lava fields since 1967, with a current rate of loss at 0.4 million cubic meters per year. Tuff cones, though more resistant, have also eroded significantly, losing about 1.6 million cubic meters, primarily due to wind deflation and runoff. The study used three new digital elevation models (DEMs) derived from aerial images (1967, 1974) and high-resolution close-range imagery (2019) to quantify these changes. Erosion rates were initially much higher post-eruption but have since stabilized, with projections suggesting the island may become a tuff crag within the next century.
Hydrozoan colonization and succession in the tidal and subtidal zones in Surtsey during the period 1967 to 1984
By 1984, Surtsey’s intertidal and subtidal rocky bottoms hosted 37 hydrozoan species, making them one of the most diverse marine invertebrate groups on the island. This steady increase in species diversity over 17 years suggests that colonization continues even two decades after the formation of rocky shores. The study highlights the importance of both planktonic medusa dispersal and rafting of polyps on floating debris as key mechanisms for hydrozoan establishment. Conducted between 1967 and 1984, the research involved sampling in intertidal zones and subtidal depths down to 40 meters, documenting eight species previously unrecorded in Iceland.
Lithofacies from the 1963-1967 Surtsey eruption in SUSTAIN drill cores SE-2a, SE-2b and SE-03
A comprehensive analysis of drill cores from Surtsey, collected during the 2017 SUSTAIN project, reveals significant insights into the volcanic activity that shaped the island between 1963 and 1967. The study identified armoured lapilli tuff and lapilli tuff, primarily formed by explosive eruptions at Surtur, with notable intervals of coherent basalt likely representing intrusions that fed later lava flows. These findings challenge previous understandings, as the 2017 drill cores did not intersect a thick basalt interval found in earlier drilling, suggesting complex volcanic processes. The research also highlights extensive hydrothermal alteration and cement deposition, indicating the dynamic interaction between volcanic materials and seawater. Additionally, the angled drill hole SE-03 provided evidence that Surtur's eruptions excavated the pre-eruption sea floor to depths of several tens of meters.
Observations on the structure of Surtsey
New insights into the subsurface structure of Surtsey, an Icelandic volcanic island, challenge previous understandings of its geothermal dynamics. Analysis of 2017 cored boreholes reveals that near-surface layering dips westerly, indicating the boreholes are within the Surtur crater, and suggests a broad diatreme underlies the vent. Temperature measurements in these boreholes show peak temperatures of 124–127 °C at depths of 105–115 meters below the surface, with residual heat detected up to 290 meters depth, implying a broad, warm substrate rather than localized intrusions. This challenges the earlier hypothesis of a nearby intrusion as the source of the heat anomaly and instead supports a model where heat was conducted from a hot lava shield into a diatreme, creating a vapor-dominated system below sea level.
Petrograpic and material observations of basaltic lapilli tuff, 1979 and 2017 Surtsey drill cores, Iceland
A comparative petrographic analysis of basaltic lapilli tuff from Surtsey's 1979 and 2017 drill cores reveals evidence of rapid microbial activity, with tubular microstructures suggesting growth rates up to 30 µm in approximately 15 years. The study also identifies differential alteration processes in the volcano's structural and hydrothermal zones over time, while long-term storage significantly impacts glass stability. Narrow ash rims on pyroclasts indicate complex eruptive and depositional dynamics. Material measurements show varying oven-dry densities correlating with porosity and water absorption. This foundational work advances understanding of tephra alteration in volcanic and curatorial environments.
Seabirds and seals as drivers of plant succession on Surtsey
Seabirds and seals are key drivers of plant succession on Surtsey, accelerating vegetation development through nutrient transfer from sea to land. Since 1965, 75 vascular plant species have colonized the island, with 40 establishing viable populations. Recent decades show slowed colonization, but dense vegetation (2 ha in 2018) has emerged on the northern spit due to seagull breeding and grey seal haul-outs. A 2019 survey revealed overlapping seal distribution and dense vegetation, suggesting seals contribute 9-13 kg N/ha annually, comparable to seagulls' 5-30 kg N/ha input. Plant biomass measurements indicate the spit's development mirrors that of an older gull colony in the south, highlighting the combined role of seabirds and seals in shaping Surtsey's ecosystem. Further research is recommended to quantify seal impacts on nutrient cycling.
The climate of Surtsey
Surtsey, an Icelandic volcanic island, experiences a mild yet windy climate with no monthly mean temperatures below freezing and sustained winds exceeding 20 m/s on average 30 days annually. A comprehensive analysis of meteorological data, collected continuously since 2009, reveals that Surtsey's climate closely resembles that of nearby Vestmannaeyjar stations—Vestmannaeyjabær and Stórhöfði—though wind speeds vary due to local sheltering effects. Precipitation patterns indicate drier summers and the most variable, wettest conditions in October. This study provides the first detailed characterization of Surtsey's climate, leveraging long-term automatic measurements to compare microclimatic differences within the archipelago.
Vascular plant colonisation of Surtsey Island (1965-1990) - a dataset
A comprehensive dataset of vascular plant occurrences on Surtsey Island, Iceland, documents the early stages of primary succession from 1965 to 1990. This rare record of unperturbed colonization over three decades provides an invaluable baseline for studying ecological processes in pristine conditions. The dataset includes 10,094 georeferenced plant observations, offering a unique opportunity for comparative research on plant dynamics and succession. Surtsey's isolation and early protection efforts minimize human disturbance, making it an ideal natural laboratory for tracking ecosystem development on new volcanic substrates.
The Surtsey Magma Series
Research on the Surtsey Magma Series reveals that the chemical composition of lavas from this iconic phreatomagmatic eruption evolved progressively, becoming more primitive over time. This variation is best explained by mixing different proportions of depleted ridge-like basalt and ponded, enriched alkalic basalt, similar to those found in Iceland's Eastern Volcanic Zone. However, the study also identifies a systematic offset in Nb/Zr ratios, suggesting that the end members used for this explanation are not fully represented in existing literature. The findings highlight processes occurring in ephemeral magma bodies on the extreme leading edge of a propagating off-axis rift near the Iceland plume, providing new insights into volcanic activity at the southwestern-most volcano in the Vestmannaeyjar.
Plant colonization, succession and ecosystem development on Surtsey with reference to neighbouring islands
Seabirds, particularly seagulls and puffins, play a pivotal role in the development of volcanic island ecosystems by transferring nutrients from sea to land, significantly accelerating plant colonization, soil formation, and biodiversity. A study on Surtsey, a volcanic island formed in 1963, revealed that seabird colonies led to the establishment of dense grasslands with higher species richness, diversity, biomass, and soil carbon compared to low-impact areas. By 2013, Surtsey hosted 69 vascular plant species, more than twice as many as neighboring islands, with bird dispersal becoming the dominant pathway after 1985. However, long-term impacts of seabirds result in species-poor grasslands, similar to those found on older neighboring islands like Elliðaey and Heimaey. The research compared permanent plots on Surtsey, Elliðaey (puffin colony), and Heimaey (no seabirds) to assess plant succession, soil formation, and invertebrate communities, highlighting the contrasting effects of nutrient input on ecosystem development.
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