High Arctic Archipelago Of Svalbard Research Articles

On the terrestrial and freshwater invertebrate diversity of the High Arctic archipelago of Svalbard: a revised species inventory and synopsis of the community composition

On the terrestrial and freshwater invertebrate diversity of the High Arctic archipelago of Svalbard: a revised species inventory and synopsis of the community composition

Limited sensitivity of permafrost soils to heavy rainfall across Svalbard ecosystems

Together with warming air temperatures, Arctic ecosystems are expected to experience increases in heavy rainfall events. Recent studies report accelerated degradation of permafrost under heavy rainfall, which could put significant amounts of soil carbon and infrastructure at risk. However, controlled experimental evidence of rainfall effects on permafrost thaw is scarce. We experimentally tested the impact and legacy effect of heavy rainfall events in early and late summer for five sites varying in topography and soil type on the High Arctic archipelago of Svalbard. We found that effects of heavy rainfall on soil thermal regimes are small and limited to one season. Thaw rates increased under heavy rainfall in a loess terrace site, but not in polygonal tundra soils with higher organic matter content and water tables. End-of-season active layer thickness was not affected. Rainfall application did not affect soil temperature trends, which appeared driven by timing of snowmelt and organic layer thickness, particularly during early summer. Late summer rainfall was associated with slower freeze-up and colder soil temperatures the following winter. This implies that rainfall impacts on Svalbard permafrost are limited, locally variable and of short duration. Our findings diverge from earlier reports of sustained increases in permafrost thaw following extreme rainfall, but are consistent with observations that maritime permafrost regions such as Svalbard show lower rainfall sensitivity than continental regions. Based on our experiment, no substantial in-situ effects of heavy rainfall are anticipated for thawing of permafrost on Svalbard under future warming. However, further work is needed to quantify permafrost response to local redistribution of active layer flow under natural rainfall extremes. In addition, replication of experiments across variable Arctic regions as well as long-term monitoring of active layers, soil moisture and local climate will be essential to develop a panarctic perspective on rainfall sensitivity of permafrost.

Arctic plasmidome analysis reveals distinct relationships among associated antimicrobial resistance genes and virulence genes along anthropogenic gradients.

Polar regions are relatively isolated from human activity and thus could offer insight into anthropogenic and ecological drivers of the spread of antibiotic resistance. Plasmids are of particular interest in this context given the central role that they are thought to play in the dissemination of antibiotic resistance genes (ARGs). However, plasmidomes are challenging to profile in environmental samples. The objective of this study was to compare various aspects of the plasmidome associated with glacial ice and adjacent aquatic environments across the high Arctic archipelago of Svalbard, representing a gradient of anthropogenic inputs and specific treated and untreated wastewater outflows to the sea. We accessed plasmidomes by applying enrichment cultures, plasmid isolation and shotgun Illumina sequencing of environmental samples. We examined the abundance and diversity of ARGs and other stress-response genes that might be co/cross-selected or co-transported in these environments, including biocide resistance genes (BRGs), metal resistance genes (MRGs), virulence genes (VGs) and integrons. We found striking differences between glacial ice and aquatic environments in terms of the ARGs carried by plasmids. We found a strong correlation between MRGs and ARGs in plasmids in the wastewaters and fjords. Alternatively, in glacial ice, VGs and BRGs genes were dominant, suggesting that glacial ice may be a repository of pathogenic strains. Moreover, ARGs were not found within the cassettes of integrons carried by the plasmids, which is suggestive of unique adaptive features of the microbial communities to their extreme environment. This study provides insight into the role of plasmids in facilitating bacterial adaptation to Arctic ecosystems as well as in shaping corresponding resistomes. Increasing human activity, warming of Arctic regions and associated increases in the meltwater run-off from glaciers could contribute to the release and spread of plasmid-related genes from Svalbard to the broader pool of ARGs in the Arctic Ocean.

MtDNA data reveal disparate population structures and High Arctic colonization patterns in three intertidal invertebrates with contrasting life history traits

IntroductionPost-glacial climate variation is known to have influenced the distribution of marine species in the North Atlantic. In particular, the Atlantic side of the Arctic has experienced strong fluctuations in both atmospheric and sea surface temperature, as well as seasonal ice coverage since the last glacial maximum (LGM). Here, we aim to unveil the phylogeography and historical demography of three rocky intertidal marine invertebrates showing a trans-Atlantic distribution and presently inhabiting the Arctic: Gammarus oceanicus, Littorina saxatilis and Semibalanus balanoides.MethodsWe used a large amount of mitochondrial DNA barcode data, both newly-obtained and stored in public databases. We performed phylogeographic and demographic analyses on 1119 G. oceanicus, 205 L. saxatilis, and 884 S. balanoides sequences.ResultsOur results show that all three of these boreal species have expanded their effective population sizes in the high Arctic Svalbard Archipelago since the LGM. Analyses investigating the origin of all these populations point to the eastern Atlantic.DiscussionBased on our results we conclude that the expansion of these boreal species to the Arctic possibly happened during an earlier warm cycle of the Holocene era, and is probably not the result of the recent ‘Atlantification’ of the Arctic. We also discuss the effects of dispersal potential on population structure as an important aspect of comparative biogeographical studies.

Svalbox Digital Model Database: A geoscientific window into the High Arctic

Abstract Digital outcrop models (DOMs) have revolutionized the way twenty-first century geoscientists work. DOMs are georeferenced three-dimensional (3-D) digital representations of outcrops that facilitate quantitative work on outcrops at various scales. Outcrop digitalization has been traditionally conducted using laser scanners, but in the past decade, it has seen an exponential growth because of efficient and consumer-friendly structure-from-motion (SfM) algorithms concurrent with the rapid development of cost-effective aerial drones with high-resolution onboard cameras. While DOMs are routinely used in geoscientific research, education, and industry, enhanced DOM usage is restricted because raw data (e.g., photographs) and metadata are often incomplete and/or unavailable. In this contribution, we present the Svalbox Digital Model Database (Svalbox DMDb), a database of metadata and openly available data packages for individual DOMs. The Svalbox DMDb is a regional DOM database geographically constrained to the Norwegian High Arctic archipelago of Svalbard at 74°N–81°N and 10°E–35°E. Svalbard offers exceptional-quality, vegetation-free outcrops with a wide range of lithologies and tectono-magmatic styles, including extension, compression, and magmatism. Data and metadata of the systematically digitalized outcrops across Svalbard are shared according to FAIR principles through the Svalbox DMDb. Fully open-access and downloadable DOMs include not just the DOMs themselves, but also the input data, processing reports and projects, and other data products such as footprints and orthomosaics. Rich metadata for each DOM include both the technical and geological parameters (metadata), enabling visualization and integration with regional geoscientific data available through the Norwegian Polar Institute and the Svalbox online portal. The current release of Svalbox DMDb, documented in this contribution, covers 135 DOMs cumulatively covering 114 km of Proterozoic to Cenozoic stratigraphy.

West Spitsbergen fold and thrust belt: A digital educational data package for teaching structural geology

The discipline of structural geology is taking an advantage of compiling observations from multiple field sites to comprehend the bigger picture and constrain the region's geological evolution. In this study we demonstrate how integration of a range of geospatial digital data sets that relate to the Paleogene fault and thrust belt exposed in the high Arctic Archipelago of Svalbard, is used in teaching in bachelor-level courses at the University Centre in Svalbard. This event led to the formation of the West Spitsbergen Fold and Thrust Belt and its associated foreland basin, the Central Spitsbergen Basin. Our digital educational data package builds on published literature from the past four decades augmented with recently acquired high-resolution digital outcrop models, and 360° imagery. All data are available as georeferenced data containers and included in a single geodatabase, freely available for educators and geoscientists around the world to complement their research and fieldwork with course components from Svalbard.

Science as Arbitrator on Arctic Land-Use Issues: а Historical Appraisal

The article offers a historical review of the practice of prioritizing scientific advice in land-use policies of the Arctic. It uses the high-arctic Svalbard archipelago as its main case study. It articulates the need for historians to contribute insights into the ways scientific communities have set much of the international agenda of Arctic and Antarctic matters over the last century. From a cultural heritage standpoint, today’s situation on Svalbard illustrates some problems of the currently widely accepted ideas of global (Arctic) governance. The author raises the question, according some points of view, whether the idea of Circumarctic, globally governed by scientific diplomacy, will not turn into something “sectorally” divided — a future that, as Arctic historians know, has a past in Arctic geopolitics from which lessons can be learned.

Stratigraphic and Spatial Extent of HALIP Magmatism in Central Spitsbergen

AbstractRapid extensive magmatism may have a profound effect on global climate by liberating and releasing greenhouse gases to the atmosphere through contact metamorphism of lithologically heterogeneous host rocks and degassing of magma and associated lava flows. The high Arctic Archipelago of Svalbard offers accessible, superbly exposed outcrops revealing Early Cretaceous magmatism associated with the High Arctic Large Igneous Province (HALIP). In this contribution, we investigate the onshore‐offshore intrusive complex of central Spitsbergen formed due to HALIP activity, that is, the Diabasodden Suite. This is the most “data‐rich” part of Svalbard due to past petroleum exploration and research drilling. In this area, the predominantly dolerite intrusions are emplaced in a range of host rocks ranging from Permian carbonate‐dominated successions to organic‐rich shale‐dominated successions of Middle Triassic and Late Jurassic‐Early Cretaceous age. Two hundred sixty five individual igneous intrusions, covering 72 km2, are exposed onshore in the study area. This equates to approximately 0.14–2.5 km3 of emplaced magma. In addition, subsurface characterization using borehole, seismic and magnetic data indicates that an area of additional ca. 3,000 km2 is affected by magmatism (magma volume 3.2–195.2 km3). Wireline logs in boreholes characterize both intrusions and associated aureoles. Aureoles with very low resistivity indicate occurrence of organic‐rich shales suggesting past fluid circulation and de‐gassing. This study forms the foundation for quantifying HALIP‐related magmatism in the data‐poorer parts of Svalbard, and other circum‐Arctic basins.

Parasite–copepod interactions in Svalbard: diversity, host specificity, and seasonal patterns

Copepods of the genera Calanus and Pseudocalanus are important components of Arctic marine ecosystems. Despite the key roles of these zooplankters, little is known about the organisms they interact with most intimately, their parasites and symbionts. We applied metabarcode sequencing to uncover eukaryotic parasites present within these two copepod genera from three areas around the high Arctic archipelago of Svalbard. Ten distinct parasite groups were observed: four different Apostome ciliates, four different dinoflagellates (Chytriodinium sp., Ellobiopsis sp., Thalassomyces sp., and Hematodinium sp.), a Paradinium sp., and a trematode. Apostome ciliates closely related to Pseudocollinia spp. were the most commonly observed parasite, with overall infection rates of 21.5% in Calanus and 12.5% in Pseudocalanus. Infection by these ciliates varied seasonally, with no infections observed in early winter, but infection rates exceeding 75% in spring. Host specificity varied between parasites, with significant differences in infection rate between the two host copepod genera for four parasites (two ciliates, Chytriodinium, and a trematode). The diverse assemblage of parasites observed in these copepods, and the frequency of infection, with over one in five copepod individuals infected, suggest parasites may be playing a greater role in Arctic plankton communities than generally acknowledged.

As the Arctic becomes boreal: ongoing shifts in a high-Arctic seabird community.

The Arctic is currently experiencing the most rapid warming on Earth. Arctic species communities are expected to be restructured with species adapted to warmer conditions spreading poleward and, if already present, becoming more abundant. We tested this prediction using long-term monitoring data (2009-2018) from nine of the most common seabird species breeding in the High Arctic Svalbard archipelago. This region is characterized by rapidly warming ocean temperatures, declining sea-ice concentrations and an increasing influence of Atlantic waters. Concurrent with these environmental changes, we found a shift in the Svalbard seabird community, with an increase in abundance of boreal species (defined here as species breeding commonly in temperate environments) and a decline in Arctic species (species breeding predominantly in the Arctic). Combined with previous observations from lower trophic levels, our results confirmed that part of the Arctic fauna is moving from an arctic to a boreal (or north temperate) state, a process referred to as a "borealization." Spatial variations exist among colonies for some species, indicating that local conditions may affect the trajectories of specific populations and potentially counterbalance the consequences of large-scale climate warming.

Synoptic control on snow avalanche activity in central Spitsbergen

Abstract. Atmospheric circulation exerts an important control on a region's snow avalanche activity by broadly determining the mountain weather patterns that influence snowpack development and avalanche release. In central Spitsbergen, the largest island in the High Arctic Svalbard archipelago, avalanches are a common natural hazard throughout the winter months. Previous work has identified a unique snow climate reflecting the region's climatically dynamic environmental setting but has not specifically addressed the synoptic-scale control of atmospheric circulation on avalanche activity here. In this work, we investigate atmospheric circulation's control on snow avalanching in the Nordenskiöld Land region of central Spitsbergen by first constructing a four-season (2016/2017–2019/2020) regional avalanche activity record using observations available on a database used by the Norwegian Water Resources and Energy Directorate (NVE). We then analyze the synoptic atmospheric conditions on days with differing avalanche activity situations. Our results show atmospheric circulation conducive to elevated precipitation, wind speeds, and air temperatures near Svalbard are associated with increased avalanche activity in Nordenskiöld Land, but different synoptic signals exist for days characterized by dry, mixed, and wet avalanche activity. Differing upwind conditions help further explain differences in the frequency and nature of avalanche activity resulting from these various atmospheric circulation patterns. We further employ a daily atmospheric circulation calendar to help contextualize our results in the growing body of literature related to climate change in this location. This work helps expand our understanding of snow avalanches in Svalbard to a broader spatial scale and provides a basis for future work investigating the impacts of climate change on avalanche activity in Svalbard and other locations where avalanche regimes are impacted by changing climatic and synoptic conditions.

Evidence for circadian-based photoperiodic timekeeping in Svalbard ptarmigan, the northernmost resident bird

The high Arctic archipelago of Svalbard (74°-81° north) experiences extended periods of uninterrupted daylight in summer and uninterrupted night in winter, apparently relaxing the major driver for the evolution of circadian rhythmicity. Svalbard ptarmigan (Lagopus muta hyperborea) is the only year-round resident terrestrial bird species endemic to the high Arctic and is remarkably adapted to the extreme annual variation in environmental conditions.1 Here, we demonstrate that, although circadian control of behavior disappears rapidly upon transfer to constant light conditions, consistent with the loss of daily activity patterns observed during the polar summer and polar night, Svalbard ptarmigans nonetheless employ a circadian-based mechanism for photoperiodic timekeeping. First, we show the persistence of rhythmic clock gene expression under constant light within the mediobasal hypothalamus and pars tuberalis, the key tissues in the seasonal neuroendocrine cascade. We then employ a "sliding skeleton photoperiod" protocol, revealing that the driving force behind seasonal biology of the Svalbard ptarmigan is rhythmic sensitivity to light, a feature that depends on a functioning circadian rhythm. Hence, the unusual selective pressures of life in the high Arctic have favored decoupling of the circadian clock from organization of daily activity patterns, while preserving its importance for seasonal synchronization.

Seeing beyond the outcrop: Integration of ground-penetrating radar with digital outcrop models of a paleokarst system

Paleokarst breccias are a common feature of sedimentary rift basins. The Billefjorden Trough in the High Arctic archipelago of Svalbard is an example of such a rift. Here the Carboniferous stratigraphy exhibits intervals of paleokarst breccias formed by gypsum dissolution. In this study we integrate digital outcrop models (DOMs) with a 2D ground penetrating radar (GPR) survey to extrapolate external irregular paleokarst geometries beyond the 2D outcrops. DOMs are obtained through combining a series of overlapping photographs with structure-from-motion photogrammetry, to create mm- to dm-resolution georeferenced DOMs. GPR is typically used for surveying the shallow subsurface and relies on detecting the contrasts in electro-magnetic permittivity. We defined three geophysical facies based on their appearance in GPR. By integrating subsurface geophysical data with DOMs we were able to correlate reflection patterns in GPR with outcrop features. The chaotic nature of paleokarst breccias is seen both in outcrop and GPR. Key horizons in outcrop and the GPR profiles allow tying together observations between these methods. Furthermore, we show that this technique expands the two-dimensional outcrop surface into a three-dimensional domain, thus complementing, strengthening and extending outcrop interpretations.

Towards humble geographies

This paper outlines the potential for a more “humble geography.” Most of us have been awed in some way by the world, humbled, but how often is that reflected in our work as geographers? As a thinking tool, “humble geographies” can combine insights and ethics from posthuman and feminist philosophies, participatory action research, and situated knowledges. Humility could helpfully contribute in debates seeking to improve geographic research practice. Humility, a quiet virtue, has potential to inspire change in the ways we relate with others and our institutions. Drawing on research experiences in the high Arctic archipelago of Svalbard, I give some examples of humble geographies in practice that raise questions about the ideal balance between authority and humility. How can we be humble in the face of rising pressures to sell ourselves and our research as highly impactful and important – in short, anything but humble? My aim is to open a discussion as to how we can helpfully inject more humility into our work.

<p class="Body"><strong>Morphological ontogeny of <em>Fuscozetes coulsoni </em>sp. nov. (Acari: Oribatida: Ceratozetidae) from Svalbard, Norway</strong></p>

The morphological ontogeny of Fuscozetes coulsoni sp. nov. from the High Arctic archipelago of Svalbard (Norway) is described and illustrated. The adult of this species has medium sized translamella, similar to F. kamchatkicus Seniczak et al. 2016a and F. pini Dalenius, 1963, but in F. coulsoni, the lamellar cusp is clearly wider than in other species. The larva of F. coulsoni has a pygidial sclerite, which is unique to Fuscozetes Sellnick, 1928, in other species from this genus the gastronotal shield is uniform, divided in parts, or absent. The juveniles of F. coulsoni and F. kamchatkicus have several similar morphological characters which are rare in Fuscozetes (clavate bothridial seta, dark pigmented sclerite around opisthonotal gland opening, absence of microsclerites at some hysterosomal setae and humeral organ and humeral sclerite in larva), but which are common in Trichoribates Berlese, 1910, except for a humeral sclerite with seta c1 in nymphs, which is present in Fuscozetes and absent in Trichoribates.

Evidence of avian influenza virus in seabirds breeding on a Norwegian high-Arctic archipelago

BackgroundWild aquatic birds serve as the natural reservoir for avian influenza virus (AIV), a disease with significant implications for avian and mammalian health. Climate change is predicted to impact the dynamics of AIV, particularly in areas such as the Arctic, but the baseline data needed to detect these shifts is often unavailable. In this study, plasma from two species of gulls breeding on the high-Arctic Svalbard archipelago were screened for antibodies to AIV.ResultsAIV antibodies were found in black-legged kittiwake (Rissa tridactyla) samples from multiple years, as well as in glaucous gulls (Larus hyperboreous) samples.ConclusionsDespite small sample sizes, evidence of exposure to AIV was found among Svalbard gulls. A wider survey of Svalbard avian species is warranted to establish knowledge on the extent of AIV exposure on Svalbard and to determine whether active infections are present.

북극 스발바르 제도에 서식하는 관속식물의 국명

This study provides Korean names for the arctic vascular plants living in the High Arctic Svalbard archipelago. We applied the following naming rules to determine suitable Korean names for the Arctic plants. (1) Original Korean names were used for 42 species because they were already registered at Korean Plant Names Index (KPNI, http://www.nature.go.kr). (2) Korean names that were previously published in a paper (Lee et al., 2012) or in the book ‘Beautiful Arctic Tundra Plants’ were used for 56 species. (3) For a plant species without a Korean name, the scientific name of the species including subspecies or variation was translated into Korean; this was performed for 39 species. (4) When it was difficult to translate the scientific name, the English common name was translated into the Korean name; this occurred in 51 species. (5) When the scientific or common name referred to Arctic, the Korean word for Arctic, ‘Buk-geuk,’ was assigned. Even in cases where the scientific or common name did not refer to Arctic but the plant was distributed in the Arctic and subarctic, ‘Buk-geuk’ was used for the Korean name. Nine species were assigned ‘Buk-geuk’ in their Korean name. (6) When there is no Korean name for the genus, the scientific name of the genus was translated into the Korean genus name, or the Korean name of the type species for the genus was used for the Korean genus name. (7) If it was difficult to apply these rules to a certain species, the Korean word ‘Nado,’ which means ‘me too’ was added to the Korean name of a phylogenetically similar species. In this study, we listed 198 Korean names for vascular plants reported on the Svalbard archipelago, including two Lycopodiophytes, seven Pteridophytes, and 189 Magnoliophytes.

The terrestrial invertebrate fauna of Edge\xf8ya, Svalbard: Arctic landscape community composition reflects biogeography patterns

Colonisation and immigration history is often neglected as a factor when investigating community or species distribution patterns. However, for dynamic systems that are still reacting to large-scale environmental change, such as the retreat of the ice since the last glacial maximum, colonisation history may explain a large amount of the variation between geographically distinct communities. The High Arctic archipelago of Svalbard presents an opportunity to test whether it is possible to observe the effects of large-scale biogeographical patterns on species distribution at landscape scales. Svalbard has one of the best described inventories of the invertebrate fauna in the Arctic. Nonetheless, the majority of the species records originate from the more accessible west coast and the invertebrate fauna of the whole eastern region, including Edgeøya, is virtually unknown. Edgeøya is located at the eastern fringe of the archipelago on the boundary between Palaearctic and Nearctic faunas. It was expected that post-colonisation dispersal within Edgeøya would conceal routes to the archipelago. Samples were obtained from six locations along the coast of Edgeøya between 2009 and 2010. 140 invertebrate species were identified belonging to 69 different genera of which 16 are new records for Svalbard. Most new species present an eastern Palaearctic distribution. Habitat variables (percentage cover of moss, lichen, vascular plant, or bare soil) fail to explain 35.5% of the differences among sites. However, cluster analysis reveals a clear east–west distribution pattern across the island suggesting that pan-Arctic dispersal routes can be identified even at relatively short geographical scales.

Feasibility of hyperspectral vegetation indices for the detection of chlorophyll concentration in three high Arctic plants: Salix polaris, Bistorta vivipara, and Dryas octopetala

Remote sensing, which is based on a reflected electromagnetic spectrum, offers a wide range of research methods. It allows for the identification of plant properties, e.g., chlorophyll, but a registered signal not only comes from green parts but also from dry shoots, soil, and other objects located next to the plants. It is, thus, important to identify the most applicable remote-acquired indices for chlorophyll detection in polar regions, which play a primary role in global monitoring systems but consist of areas with high and low accessibility. This study focuses on an analysis of in situ-acquired hyperspectral properties, which was verified by simultaneously measuring the chlorophyll concentration in three representative arctic plant species, i.e., the prostrate deciduous shrub <em>Salix polaris</em>, the herb <em>Bistorta vivipara</em>, and the prostrate semievergreen shrub <em>Dryas octopetala</em>. This study was conducted at the high Arctic archipelago of Svalbard, Norway. Of the 23 analyzed candidate vegetation and chlorophyll indices, the following showed the best statistical correlations with the optical measurements of chlorophyll concentration: Vogelmann red edge index 1, 2, 3 (VOG 1, 2, 3), Zarco-Tejada and Miller index (ZMI), modified normalized difference vegetation index 705 (mNDVI 705), modified normalized difference index (mND), red edge normalized difference vegetation index (NDVI 705), and Gitelson and Merzlyak index 2 (GM 2). An assessment of the results from this analysis indicates that <em>S. polaris</em> and <em>B. vivipara</em> were in good health, while the health status of <em>D. octopetala</em> was reduced. This is consistent with other studies from the same area. There were also differences between study sites, probably as a result of local variation in environmental conditions. All these indices may be extracted from future satellite missions like EnMAP (Environmental Mapping and Analysis Program) and FLEX (Fluorescence Explorer), thus, enabling the efficient monitoring of vegetation condition in vast and inaccessible polar areas.

A new NDVI measure that overcomes data sparsity in cloud-covered regions predicts annual variation in ground-based estimates of high arctic plant productivity

Efforts to estimate plant productivity using satellite data can be frustrated by the presence of cloud cover. We developed a new method to overcome this problem, focussing on the high-arctic archipelago of Svalbard where extensive cloud cover during the growing season can prevent plant productivity from being estimated over large areas. We used a field-based time-series (2000−2009) of live aboveground vascular plant biomass data and a recently processed cloud-free MODIS-Normalised Difference Vegetation Index (NDVI) data set (2000−2014) to estimate, on a pixel-by-pixel basis, the onset of plant growth. We then summed NDVI values from onset of spring to the average time of peak NDVI to give an estimate of annual plant productivity. This remotely sensed productivity measure was then compared, at two different spatial scales, with the peak plant biomass field data. At both the local scale, surrounding the field data site, and the larger regional scale, our NDVI measure was found to predict plant biomass (adjusted R2 = 0.51 and 0.44, respectively). The commonly used ‘maximum NDVI’ plant productivity index showed no relationship with plant biomass, likely due to some years having very few cloud-free images available during the peak plant growing season. Thus, we propose this new summed NDVI from onset of spring to time of peak NDVI as a proxy of large-scale plant productivity for regions such as the Arctic where climatic conditions restrict the availability of cloud-free images.