Ice Fjord Research Articles

Temporal and spatial variability of sympagic metazoans in a high-Arctic fjord, Svalbard

Svalbard is one of the fastest warming regions in the Arctic including massive loss in fjord sea ice both in terms of area coverage, ice thickness and duration. Sea ice is a habitat for a wide variety of microscopic flora and fauna, and we know little about the impact of accelerated loss of sea ice on this unique sea ice community. Here, we present the first study on the seasonal progression and spatial distribution of the sympagic meiofauna community, in a Svalbard fjord. Further, the meiofauna community in sea ice versus the water column below were compared to investigate the link between the two habitats. In total, we found 12 taxa associated with the sea ice and 15 taxa in the water column below with 11 taxa occurring in both habitats. However, a Canonical-analysis (CA) showed that despite similarities in taxa the two mediums were distinctly different (potentially) due to the low abundance of ice nematodes and polychaete juveniles, in pelagic samples. Temporally, ice meiofauna abundances ranged from 9.7 to 25.3 x 103ind m-2from beginning of March to end of April, following the seasonal build-up of ice algal biomass from 0.02 to 15.99 mg Chlam-2during the same time span. For the transect stations, the lowest ice meiofauna abundance was recorded at the outermost station (VMF2) with 1.6 x 103ind m-2and the highest abundance at the mid-station MS with 25.3 x 103ind m-2. Our results indicate that fjord ice harbors most ice algae and sympagic meiofauna in its lower 10-cm with highest values in the lowermost 2-cm, at the sea ice water interface. Sympagic meiofauna communities were mostly dominated by nematodes or polychaete juveniles. We observed the phenology of ice nematodes through the maturation of females and hatching of juveniles from eggs. Polychaete larvae developed (quickly) into juveniles and grew morphological features indicative of readiness for settlement. Thus, we propose, that as with other parts of the Arctic, sea ice in Svalbard fjords plays an important role in the life cycle of ice nematodes and for accelerating the growth of polychaete larvae. Loss of coastal sea ice may therefore negatively impact coastal biodiversity and affect recruitment for some benthic infauna in Svalbard.

Environmental drivers of eukaryotic plankton and fish biodiversity in an Arctic fjord

Arctic fjords are experiencing rapid environmental shifts due to climate change, which may have significant impacts on marine biodiversity and ecosystem functioning. However, the impact of climate change on fjord biodiversity is difficult to quantify given the low accessibility and high cost to sample these areas. In this study, we sampled locations from inside to outside an Arctic fjord and used environmental DNA metabarcoding to assess how the biodiversity of fish and eukaryotic plankton communities relate with environmental conditions. We detected a total of 12 fish taxa and 872 MOTUs for eukaryotes and found marked gradients of temperature and salinity driven by the distance to the glacier at the terminal part of the fjord and depth. Eukaryotic richness was mainly associated with lower temperature and chlorophyll a. Moreover, co-inertia analyses showed a shared structure between eukaryotes assemblages and the environmental gradients. A partial association between eukaryote and fishes suggest a potential shared effect of environmental gradients among these taxa. Our findings provide a baseline for future studies to assess how these assemblages may be impacted by ongoing environmental changes and highlight how fjord ice loss and warming might shift environmental gradients and species distribution under climate change.

Learning from Alfred Wegener’s pioneering field observations in West Greenland after a century of climate change

The cryosphere in Greenland is currently undergoing strong changes. While remote sensing improves our understanding of spatial and temporal changes across scales, particularly our knowledge of conditions during the pre-satellite era is fragmented. Therefore, high-quality field data from that period can be particularly valuable to better understand changes of the cryosphere in Greenland at climate time scales. At Graz University, the last work-place of Alfred Wegener we have access to the extensive expedition results from their epic 1929–1931 expedition to Greenland. The expedition coincides with the warmest phase of the Arctic early twentieth century warm period. We present an overview of the main findings of the Wegener expedition archive and set it into context with further monitoring activities that occurred since, as well as the results from reanalysis products and satellite imagery. We find that firn temperatures have increased significantly, while snow and firn densities and have remained similar or decreased since. Local conditions at the Qaamarujup Sermia have changed strongly, with a reduction in length of more than 2 km, in thickness by up to 120 m and a rise in terminus position of approximately 300 m. The elevation of the snow line of the years 1929 and 1930 was similar to the one from the extreme years 2012 and 2019. Compared to the satellite era, we find that during the time of the Wegener expedition fjord ice extent was smaller in early spring and larger in late spring. We demonstrate that a well-documented snapshot of archival data can provide a local and regional context for contemporary climate change and that it can serve as the basis for process-based studies on the atmospheric drivers of glacier changes.

Characteristics, recent evolution, and ongoing retreat of Hunt Fjord Ice Shelf, northern Greenland

AbstractArctic ice shelves have declined over the past several decades, one of many indications of a rapidly changing cryosphere. Here we use a collection of off-nadir Landsat 8 images, a 1978 digital orthophotograph and photogrammetrically derived DEM, satellite altimetry and other data to examine the causes of an Arctic ice-shelf retreat in northernmost Greenland, the Hunt Fjord Ice Shelf (HFIS). HFIS has several distinct provenance regions comprised of glacier-derived ice and corrugated multi-decadal fast ice, with varying ice thicknesses (5–64 m). Available imagery shows little change in HFIS between 1978 and 2012, after which several midsummer calving events occurred (2012, 2016 and 2019) that reduced the HFIS by 42.5 km2 (~56%). Shelf area losses began as the number of surface melt days on the adjacent ice sheet more than doubled relative to the 1980s. Recent calving events also occurred during open-water periods at the ice-shelf front. Prior to mid-2012, there were no calving events during similar open-water periods. HFIS tributary glaciers have thinned by 3–20 m near their grounding zones, and may have accelerated since the 1980s, likely due to increased basal melting from contact with warm Atlantic Water.

Evaluation of ICEYE Microsatellites Sensor for Surface Motion Detection—Jakobshavn Glacier Case Study

The marine-terminating glaciers are one of the biggest contributors to global sea-level rise. Research on this aspect of the effects of global climate change is developing nowadays in several directions. One of them is monitoring of glaciers movements, especially with satellite data. In addition to well-known analyzes based on radar data from available satellites, the possibility of studying glacier displacements from new sensors, the so-called microsatellites need to be studied. The main purpose of research was evaluation of the possibility of applying new high-resolution ICEYE radar data to observe glacier motion. Stripmap High mode were used to obtain velocities for the Jakobshavn glacier with an Offset-Tracking method. Obtained results were compared with displacements obtained from the Sentinel-1 data. The comparative analysis was performed on displacements in range and azimuth directions and for maximum velocity values. Moreover, correlation plots showed that in different parts of glaciers, a comparison of obtained velocities delivers different correlation coefficients (R2) in a range from 0.52 to 0.97. The analysis showed that the scale of movements is similar from both sensors. However, Sentinel-1 data present underestimation of velocities comparing to ICEYE data. The biggest deviations between results were observed around the maximum velocities, near the Kangia Ice Fjord Bay. In the analysis the amplitude information was used as well. This research presents that data from the ICEYE microsatellites can be successfully used for monitoring glacial areas and it allows for more precise observations of displacement velocity field.

Interannual summer mixing processes in the Ilulissat Icefjord, Greenland

In the stratified water column inside the Ilulissat ice fjord, oceanic mixing processes can promote an upward transport of heat and salt from the subsurface to the surface mixed layer. Our objective was to map the temporal variation of vertical mixing inside the fjord by estimating the diapycnal mixing rates derived from oceanographic data collected during summer research cruises between 2009 and 2017. We applied the Thorpe scale method based on local density inversions. We found enhanced mixing in the deep water at 400 m sill depth inside the fjord, with diapycnal diffusivity reaching a maximum value of 1× 10 –3.5 m 2 s −1 . The strongest mixing rates in 2013, and the weakest during 2016, were mainly due to the Glacier's melting conditions and melange. The highest values of diapycnal diffusivity values occurred during years when low melange concentrations inside the ice fjord increased ventilation, which favored the intrusion of Polar and Irminger waters that perturbed the water structure. These years were also associated with a decrease in diffusive convection processes. Our results give insight into how the intrusion of waters from Disko Bay to the Ilulissat ice fjord may affect the stability of the Jakobshavn Isbræ Glacier. • · Water mixing interaction in the Ilulissat Ice Fjord, increase diapycnal diffusivities by more than one order of magnitude. • We used the Thorpe method to estimate mixing rates in the IIF system. • A warm water intrusion in 2013 lifted the isopycnals reducing the ice melange leading to the retreat of the glacier front.

On the potential of hand-held GPS tracking of fjord ice features for remote-sensing validation

ABSTRACTResearch on young thin sea ice is essential to understand the changes in the Arctic. But it is also the most challenging to investigate, both in situ and from satellites. If satellite remote-sensing techniques are developing rapidly, fieldwork remains crucial for the mandatory validation of such data. In April 2016, an Arctic fieldwork campaign was conducted at Kongsfjorden, Svalbard. This campaign provided an opportunity to combine various techniques to record the fjord ice properties ranging from local field sampling to broader ground-based and satellite radar remote sensing of the fjord. Tracking the boat used to access the field sites with hand-held GPS devices offered a good opportunity to map fjord ice and assess the limits of radar identification of small icebergs and thin ice. During 1 week, 17 icebergs and the thin ice edges in two different locations were mapped. The GPS tracks present a good agreement with the Radarsat-2 data analysis for one of the two ice edges. The second ice edge track only partly corresponds to the radar scene. Ice movement, recorded by a ground-based radar, is likely to explain this result. Grounded icebergs could be identified in both Radarsat-2 and ground-based radar.

Lake and Fjord Ice Imaging Using a Multifrequency Ground-Based Tomographic SAR System

The radar backscatter response of snow covered lake and fjord ice is investigated using a ground based multifrequency synthetic aperture radar system operated in a tomographic configuration. Direct imaging of the snow and ice layering is achieved by focusing the signal from a two-dimensional (2-D) synthetic array in the 3-D space. A mathematical derivation describing the propagation of electromagnetic waves across a dense and multilayered complex medium with arbitrary but finite number of layers is presented. It is used to estimate the depth and refractive indices of the snow and ice layers from the tomograms employing a simple least-square optimization scheme. The lake and fjord ice datasets are compared with respect to their vertical stratification and estimated refractive indices. The vertical structure of the reflectivity of the snow-covered lake ice is investigated and compared at two different frequencies, X -, and C -band. It is found that snow and ice volume responses at C -band are very low compared to the corresponding responses at X -band. At both frequencies, backscattering from surface and interface structures dominate volume contributions.

Tomographic Imaging of Fjord Ice Using a Very High Resolution Ground-Based SAR System

This paper presents new experimental results of 3-D imaging using tomographic techniques over a snow covered sea ice medium, sensed with an X-band radar system. The available data are from a ground-based synthetic aperture radar data collection campaign carried out over Kattfjord, Tromso, Norway. Direct imaging of the vertical structures of the radar reflectivity of the snow and sea ice layers is achieved by focusing the signal from a 2-D synthetic array in the 3-D space. The effect of a change in propagation velocity of the wave inside the considered medium is investigated in the focusing process, and the tomograms are effectively corrected for this effect. The distribution of the scattering contributions in the vertical direction reveals a strong response from the sea ice cover. Tomograms at two different polarizations are investigated and compared. The results and the interpretations are also supported by the simulated data from the same system.

Seasonal migration, vertical activity, and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides in West Greenland waters

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 508:211-222 (2014) - DOI: https://doi.org/10.3354/meps10874 Seasonal migration, vertical activity, and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides in West Greenland waters Jesper Boje1, Stefan Neuenfeldt1, Claus Reedtz Sparrevohn2, Ole Eigaard1, Jane W. Behrens1,* 1Technical University of Denmark, National Institute of Aquatic Resources, Kavalergaarden 6, 2920 Charlottenlund, Denmark 2Danish Pelagic Producers Organization, HC Andersens Boulevard 37, 1553 Copenhagen, Denmark *Corresponding author: jabeh@aqua.dtu.dk ABSTRACT: The deep-water flatfish Greenland halibut Reinhardtius hippoglossoides (Walbaum) is common along the West Greenland coast. In the northwestern fjords, Greenland halibut is an important socio-economic resource for the Greenland community, but due to the deep and partly ice-covered environment, very little is known about its behavior and habitat characteristics. We tagged adult Greenland halibut in the waters off Ilulissat with electronic data storage tags that collected information on depth, temperature, and time. Although clear differences between individuals in migration and vertical behavior were present, we discovered a consistent seasonal migration from the relatively shallow-water Disko Bay area into the deep waters of the Ilulissat Icefjord, where the fish resided in the winter months before returning to Disko Bay. Vertical activity was pronounced at both locations, with fish covering vertical distances of up to 100 m within 15 min. During the winter months, the fish experienced temperatures between ca. 0 and 4°C, with most experiencing temperatures of 2 to 3°C. Irrespective of year and quarter of the year, the fish experienced warmer water and a broader range of temperatures when resident in Disko Bay (mean range 2.6°C) than when resident in the ice fjord (mean range 1.4°C). Using the tagged halibut as a ‘live tool,’ we show that parts of the ice fjord are hundreds of meters deeper than previously thought. We also document the first seawater temperature measurements made beneath the Jakobshavn Isbræ outlet glacier, revealing a positive relationship between depth and temperature for the upper 600 m and a between-year variation in temperatures beneath the ice sheet in 2001, 2002, and 2003. KEY WORDS: Archival tags · Arctic · Behavior · Habitat · Seawater temperatures · Swimming speed Full text in pdf format PreviousNextCite this article as: Boje J, Neuenfeldt S, Sparrevohn CR, Eigaard O, Behrens JW (2014) Seasonal migration, vertical activity, and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides in West Greenland waters. Mar Ecol Prog Ser 508:211-222. https://doi.org/10.3354/meps10874 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 508. Online publication date: August 04, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Remote sensing of seawater and drifting ice in Svalbard fjords by compact Raman lidar

A compact Raman lidar system for remote sensing of sea and drifting ice was developed at the Wave Research Center at the Prokhorov General Physics Institute of the Russian Academy of Sciences. The developed system is based on a diode-pumped solid-state YVO(4):Nd laser combined with a compact spectrograph equipped with a gated detector. The system exhibits high sensitivity and can be used for mapping or depth profiling of different parameters within many oceanographic problems. Light weight (∼20 kg) and low power consumption (300 W) make it possible to install the device on any vehicle, including unmanned aircraft or submarine systems. The Raman lidar presented was used for study and analysis of the different influence of the open sea and glaciers on water properties in Svalbard fjords. Temperature, phytoplankton, and dissolved organic matter distributions in the seawater were studied in the Ice Fjord, Van Mijen Fjord, and Rinders Fjord. Drifting ice and seawater in the Rinders Fjord were characterized by the Raman spectroscopy and fluorescence. It was found that the Paula Glacier strongly influences the water temperature and chlorophyll distributions in the Van Mijen Fjord and Rinders Fjord. Possible applications of compact lidar systems for express monitoring of seawater in places with high concentrations of floating ice or near cold streams in the Arctic Ocean are discussed.

Acoustic mapping of the Ilulissat Ice Fjord mouth, West Greenland

A ship-based acoustic mapping campaign was conducted at the exit of Ilulissat Ice Fjord of West Greenland and in the sedimentary basin of Disko Bay west of the fjord mouth. Submarine landscape and sediment distribution patterns represented by five acoustic facies types represent glaciomarine sediment facies types that are related to variations in the past position and relative motion of the glacier front. Asymmetric ridges on the shelf that form a curved entity and a large sill at the fjord mouth represent moraines that depict at least two relatively stable positions of the ice front in the Disko Bay and at the fjord mouth. Comparable ice-end features are not observed seaward of the East Greenland Kangerdlugssuaq Glacier, although both glaciers are comparable in their latitudinal position, present size and present role for the ice discharge from the Inland Ice sheet. Apparently, the retreat of the Greenland Inland Ice after the last maximum expansion was a more discontinuous process on the West Greenland Shelf than on the East Greenland Shelf. The Iceberg Bank, a prominent sill at the fjord exit appears to play an important role for the sedimentation after the retreat of the ice front from the shelf was completed. The retreat of the glacier behind the Iceberg Bank into the inner fjord is marked by a reorganization of sediment delivery in Disko Bay, as most of the till is now deposited within the fjord. Two linear clusters of pockmarks in the center of the sedimentary basin seem to be linked to methane release due to dissociation of gas hydrates, a process driven by fast crustal uplift of the Greenland Shelf. The orientation of these clusters appears to reflect a migration path that is defined by a buried structure which we could not resolve.

Ice stream influence on West Greenland Ice Sheet dynamics during the Last Glacial Maximum

AbstractThis paper investigates the processes governing bedrock bedform evolution in ice sheet and ice stream areas in central West Greenland, and explores the evidence for a cross‐shelf ice stream at the Last Glacial Maximum (LGM). To the east of Sisimiut the formation of streamlined bedforms with high elongation ratios and high bedform density has been controlled by geological structure and topography in slow‐flowing ice sheet areas. At the coast, the effects of regional flow convergence, caused by coastal fjord orientation, routed ice into the Sisimiut/Itilleq area where it formed an ice stream onset zone. This funnelled ice into an offshore trough (Holsteinsborg Dyb), resulting in a southwesterly regional ice flow direction and the formation of a topographically routed ice stream (Holsteinsborg Isbrae). To the south of this, striae and bedform evidence show that local valley glaciers initially flowed east to west across the coast, but were later redirected by the Itilleq Fjord ice which turned southwestward due to diffluent flow and deflection by Holsteinsborg Isbrae. Roches moutonnées in this area have low elongation ratios and high bedform density, but do not provide unequivocal support for ice streaming, as they are a product of both bedrock structure and changes in ice flow direction, rather than enhanced flow velocities. Cosmogenic surface exposure ages limit maximum ice sheet surface elevation to ca. 755–810 m above sea level in this region. Such ice thickness enabled Holsteinsborg Isbrae to reach the mid/outer continental shelf during the LGM, and to contribute to the formation of a trough mouth fan and the Outer Hellefisk moraines. Initial deglaciation across this region was driven by rising sea level and increasing air temperatures prior to the Bølling Interstadial at ca. 14.5 cal. ka BP. Between 12 and 10 cal. ka BP both increased air and ocean temperatures post the Younger Dryas, and peak sea‐level rise up to the marine limit, caused accelerated thinning and marginal retreat through calving, although dating evidence suggests ice streams remained along the inner shelf/coast boundary until at least ca. 10 cal. ka BP, their longevity maintained by increased ice thickness and ice discharge. Copyright © 2009 John Wiley & Sons, Ltd.

Responses of Microbial Communities in Arctic Sea Ice After Contamination by Crude Petroleum Oil

Microbial communities associated with Arctic fjord ice polluted with petroleum oils were investigated in this study. A winter field experiment was conducted in the Van Mijen Fjord (Svalbard) from February to June 2004, in which the ice was contaminated with a North Sea paraffinic oil. Holes were drilled in the ice and oil samples frozen into the ice at the start of the experiment. Samples, including cores of both oil-contaminated and clean ice, were collected from the field site 33, 74, and 112 days after oil application. The sampled cores were separated into three sections and processed for microbiological and chemical analyses. In the oil-contaminated cores, enumerations of total prokaryotic cells by fluorescence microscopy and colony-forming units (CFU) counts of heterotrophic prokaryotes both showed stimulation of microbial growth, while concentrations of oil-degrading prokaryotes remained at similar levels in contaminated and clean ice. Analysis of polymerase chain reaction (PCR)-amplified bacterial 16S rRNA gene fragments by denaturing gradient gel electrophoresis (DGGE) revealed that bacterial communities in oil-contaminated ice generated fewer bands than communities in clean ice, although banding patterns changed both in contaminated and clean ice during the experimental period. Microbial communities in unpolluted ice and in cores contaminated with the paraffinic oil were examined by cloning and sequence analysis. In the contaminated cores, the communities became predominated by Gammaproteobacteria related to the genera Colwellia, Marinomonas, and Glaciecola, while clean ice included more heterogeneous populations. Chemical analysis of the oil-contaminated ice cores with determinations of n-C17/Pristane and naphthalene/phenanthrene ratios indicated slow oil biodegradation in the ice, primarily in the deeper parts of the ice with low hydrocarbon concentrations.

Analysis of ERS Tandem SAR coherence from glaciers, valleys, and fjord ice on Svalbard

Interferometric satellite synthetic aperture radar (SAR) data was acquired from an area on Spitsbergen, Svalbard, during the European remote sensing satellite (ERS) Tandem mission in 1995-1996. Analyzing these data sets shows that the estimated SAR coherence is highly dependent on the satellite baseline length, and that corrections for this decorrelation effect is necessary if the baseline is a few hundred meters or more. Meteorological recordings are compared to SAR coherence estimates made at different seasons and surface categories: glaciers in motion, glacial forefields dominated by ice-cored moraines, lakes, rivers, and flat valleys with fine moraine materials like gravel and sand. It was found that temporal decorrelation effects are mainly due to changing surface conditions caused by precipitation and temperature variations around freezing, but that wind redistribution of snow also may play a role. Structures and cracks in the fjord ice as well as boundaries of lakes, rivers, and coastlines can be detected in SAR coherence images because of the contrast between high and low coherence areas. Low coherence is observed from those parts of moving glaciers that experience deformations shear, or zones of relative high velocity. The usefulness of 35-days interferometric SAR (e.g., the foreseen ENVISAT configuration) will be limited, even in sparsely vegetated areas like Svalbard, as compared to the ERS Tandem configuration.

Availability of suitable land-fast ice and predation as factors limiting ringed seal populations, Phoca hispida, in Svalbard

We examined the stability of fast ice areas in western and northern Spitsbergen, the area north of Nordaustlandet, the bays and sounds of Hinlopen Stretet and the large area in the northern part of Storfjorden. NOAA satellite imagery from 1974 and 1988 and NOAA (AVHRR) imagery from 1980-87 were used to determine the dates of freeze-up and break-up. The number of days of fast ice present before the nominal birth date of ringed seal pups were computed for all major bays and fjords. Ice thickness was then computed from these data. Known prime breeding habitat in Svalbard is found in areas near glacier fronts in protected fjords and bays, where densities of birth lairs are 5.46 km?2, corresponding to a ringed seal female density of 2.6 km?2. Most of the ringed seal breeding habitat in Svalbard, however, consists of flat fjord ice where snow accumulation is rarely deep enough to permit birth lair construction. In these areas pups are often born in the open. Based on breathing hole densities, the density of adult females in the flat ice areas in the breeding period was estimated to 0.98 km?2. A preliminary estimate is that approximately 19,500 pups could be born annually in the fast ice of Svalbard. Annual recruitment could be quite variable given the unpredictable nature of the fast ice areas and the high predation mortality on newborn pups. Discrepancies between our calculated ringed seal production and numbers of seals required to feed the large polar bear population in the area signal cause for management concern.

Early Holocene morainal bank sedimentology and marine ecology, Skjoldungebrae gorge, North Scoresby Land, East Greenland

Abstract Skjoldungebrae gorge sections have allowed a reconstruction of changing sedimentological and palaeoecological environments during the early Holocene in the Kap Petersen area of North Scoresby Land. There is evidence for a former morainal bank and associated glacimarine environments at the grounding line of the early Holocene tidewater Skjoldungebrae. The sequence has been subdivided into: bergstone/suspension, laminite, proximal morainal bank avalanche, distal submarine fan and proximal submarine fan glacimarine facies. There are three molluscan and three foraminiferal assemblages present which indicate likely palaeotemperatures, salinities and water depths. Evidence suggests that sea level fell from 105 m to 77.5 m and as it did so modified the tidewater glacimarine sequence. A readvance of Kong Oscar Fjord ice reworked part of the glacimarine sequence and deposited a basal till over the lower slopes of the Kap Petersen area and in lower Skeldal. Criteria used to distinguish between till and various diamictons are discussed.

North Greenland ice islands

AbstractLarge tabular icebergs derived from the glaciers which drain the north fringe of Greenland's Inland Iceoccur in many North Greenland fjords. Many have undulating surface topography resembling that of the ice islands calved from Ellesmere Island ice shelves. Semi-permanent sea ice in North Greenland fjords often prevents the escape of bergs, except in exceptional summers several decades apart, when the fjord ice melts completely and some bergs may reach the Arctic Ocean. Other possible sources for ice islands are small ice shelves and local glaciers along the north coast of Greenland.

X.—Geological Notes on the Stubendorff Mountains, West Spitsbergen

The Cambridge Spitsbergen Expedition, 1938 (Polar Record No. 17, p. 4), was led by L. H. McCabe for intensive geomorphological work in the Campbell Range at the head of Billen Bay, Ice Fjord. The principal work on nivation and corrie erosion (McCabe, 1939) was supplemented by topographical and geological survey, while some detailed investigations were made on the raised beaches and “soil polygons.” During this work a party of three crossed the ice divide by sledge to East Fjord, Wijde Bay, and spent ten days working from the northern side of the Stubendorff Glacier. The Stubendorff Mountains in this region were chosen for comparison of corrie erosion on account of their contrasting geological constitution. They are carved out of tough folded metamorphic rocks while the Campbell Range is formed of softer horizontal Carboniferous rocks.

The Vegetation of Cape Napier, Spitsbergen

THE work here described was done during the month 21 July-19 August 1936, while the party of which I was a member was centred at Bruce City, Klaas Billen Bay, a branch of Ice Fjord, West Spitsbergen, in lat. 78? 39' N., long. 16? 45' E. This district has been visited several times by Oxford University Expeditions, and descriptions of the vegetation are to be found in papers by J. Walton (1922) and Summerhayes & Elton (1928). In addition, A. M. Acock has been carrying on, during 1936 and 1937, an investigation at Bruce City of wider scope. Arctic studies limited to a single summer visit are necessarily incomplete and likely to be of small value if they remain isolated. The aim has been in this paper to build upon foundations already laid by reinvestigating a small and readily identifiable area in the high Arctic, of which the vegetation has been described before, sufficiently long ago to allow of changes having occurred. For this reason the work has been limited to the area lying close behind Cape Napier, which was mapped by Walton in 1921 with a view to reinvestigation by some future observer. The chief objects of the paper are therefore: (1) To record any changes which may have occurred in the intervening fifteen years, (2) To provide a more detailed description for the benefit of later observers.