Ward Hunt Island Research Articles

Mass-balance and ablation processes of a perennial polar ice patch on the northern coast of Ellesmere Island

AbstractIce patches have implications for landscape and ecosystem dynamics in polar deserts, however, the understanding of the driving factors that control their spatio-temporal variability is limited. This study aims to assess the seasonal and long-term evolution of ice patches on Ward Hunt Island (WHI; 83°N, Canadian High Arctic) based on field measurements of surface mass and energy balance. Results show that mass gains of the ice patch systems occur mostly through drifting snow, making them highly linked to the topography as well as the frequency and magnitude of wind events. Summer ablation is primarily driven by net radiation, but the short-term variability in melt rate is driven by sensible heat fluxes. The highest ablation rates occur during the passage of warm fronts that combine strong winds and mild temperatures. Conversely, foggy days reduce fluxes of solar radiation and sensible heat to the snow/ice surface, thereby suppressing ablation. Ice patches are less climate-sensitive than other cryospheric elements due to a feedback between snow accumulation and topography, however, summer ablation is strongly influenced by micrometeorology. Model projections of these factors suggest that conditions will become critical for preserving ice patches at WHI and along the northern coast of Ellesmere Island as early as in the next decades.

Properties and stratigraphy of polar ice patches in the Canadian High Arctic reveal their current resilience to warm summers

Ice patches are ubiquitous in polar regions and are a key element for landscape evolution. We present new insights into polar desert ice patch formation based on snow and ice properties at Ward Hunt Island (Canadian High Arctic, 83°N). Our results demonstrate that ice patches are composed of two distinct units. The upper unit is characterized by very fine granular and bubbly ice with a clear oblique layering. By contrast, the lower unit is strikingly different with coarse crystals, lower porosity, and a high frequency of fractures. For both units, superimposed ice formation at the base of the deep snowpack stands out as the primary ice aggradation process. The distinct properties of the lower unit likely result from a long period of kinetic ice crystal growth indicating a minimum age of several hundred years. A radiocarbon date of 3 487 ± 20 cal BP suggests that ice patches could potentially date back to the late Holocene. This old ice was recently truncated during warmer summers between 2008 and 2012, but the ice patch quickly recovered its volume during cooler summers. The old age of the ice patches and their rapid regeneration after melt events suggest their resilience to current warmer summers.

Effects of meteorology and soil moisture on the spatio-temporal evolution of the depth hoar layer in the polar desert snowpack

AbstractIn polar deserts, depth hoar (hereinafter: DH) growth is not systematic unlike on tundra and this is critical for snowpack properties. Here, we address the spatio-temporal variability of the DH layer in the polar desert at two sites in the Canadian High Arctic: Ward Hunt Island (83° N) and Resolute Bay (75° N). Our data show that, over humid areas, DH represented a larger fraction of the snowpack and was characterized by lower density and coarser crystals than over dry gravelly areas. Increased soil moisture extends the zero-curtain period during freeze-up, leading to stronger temperature gradients in the snowpack and greater kinetic metamorphism. Our results also demonstrate that the large inter-annual variability in DH is primarily driven by wind conditions in the fall since this key variable controls the initial snow density and snow onset date. These strong controls exerted by soil moisture and meteorological conditions on DH growth in polar deserts highlight the possibility of major changes in polar snowpacks physical properties in response to the rapid climate and environmental changes currently affecting these regions.

Zircon geochronology and geochemistry of the Ward Hunt pluton, Pearya terrane, Canadian High Arctic: Insights into its age, origin, and circum-Arctic Timanide connections

The northern margin of the Neoproterozoic Timanide Orogen is truncated by Paleozoic deformation of the Caledonian Orogen. Evidence for dispersion of terranes affected by the Timanide Orogen is documented through contemporaneous tectonothermal activity, and by detrital zircon in sedimentary rock from across the Arctic Ocean margins. However, directly tying these terranes to the Caledonide realm is hindered by the paucity of appropriate events in proximal terranes. The Ward Hunt Pluton, a previously undated syenite–monzodiorite intrusion located on Ward Hunt Island, northern Pearya terrane, yields a crystallization age of 542 ± 2 Ma. Trace-element data from the igneous zircon suggest that the pluton intruded older metasedimentary rocks of the terrane as part of a volcanic arc system, indicated by juvenile Hf isotopic signatures and trace-element data. The data support links between the Pearya terrane and other Neoproterozoic–Cambrian arc systems, such as those proposed in Arctic Alaska-Chukota and the Alexander terrane.

Soil moisture, wind speed and depth hoar formation in the Arctic snowpack

ABSTRACTBasal depth hoar that forms in Arctic snowpacks often has a low thermal conductivity, strongly contributing to the snowpack thermal insulance and impacting the permafrost thermal regime. At Ward Hunt Island (Canadian high Arctic, 83°05′N, 74°07′W) almost no depth hoar was observed in spring 2016 despite favorable thermal conditions. We hypothesize that depth hoar formation was impeded by the combination of two factors (1) strong winds in fall that formed hard dense wind slabs where water vapor transport was slow and (2) low soil moisture that led to rapid ground cooling with no zero-curtain period, which reduced soil temperature and the temperature gradient in the snowpack. Comparisons with detailed data from the subsequent winter at Ward Hunt and from Bylot Island (73°09′N, 80°00′W) and with data from Barrow and Alert indicate that both high wind speeds after snow onset and low soil moisture are necessary to prevent Arctic depth hoar formation. The role of convection to form depth hoar is discussed. A simple preliminary strategy to parameterize depth hoar thermal conductivity in snow schemes is proposed based on wind speed and soil moisture. Finally, warming-induced vegetation growth and soil moisture increase should reduce depth hoar thermal conductivity, potentially affecting permafrost temperature.

Hillslope water tracks in the High Arctic: Seasonal flow dynamics with changing water sources in preferential flow paths

AbstractPreferential subsurface flow paths known as water tracks are often the principal hydrological pathways of headwater catchments in permafrost areas, exerting an influence on slope physical and biogeochemical processes. In polar deserts, where water resources depend on snow redistribution, water tracks are mostly found in hydrologically active areas downslope from snowdrifts. Here, we measured the flow through seeping water track networks and at the front of a perennial snowdrift, at Ward Hunt Island in the Canadian High Arctic. We also used stable isotope analysis to determine the origin of this water, which ultimately discharges into Ward Hunt Lake. These measurements of water track hydrology indicated a glacio‐nival run‐off regime, with flow production mechanisms that included saturation overland flow (return flow) in a low sloping area, throughflow or pipe‐like flow in most seepage locations, and infiltration excess overland flow at the front of the snowdrift. Each mechanism delivered varying proportions of snowmelt and ground water, and isotopic compositions evolved during the melting season. Unaltered snowmelt water contributed to >90% of total flow from water track networks early in the season, and these values fell to <5% towards the end of the melting season. In contrast, infiltration excess overland flow from snowdrift consisted of a steady percentage of snowmelt water in July (mean of 69%) and August (71%). The water seeping at locations where no snow was left in August 2015 was isotopically enriched, indicating a contribution of the upper, ice‐rich layer of permafrost to late summer discharge during warmer years. Air temperature was the main driver of snowmelt, but the effect of slope aspect on solar radiation best explained the diurnal discharge variation at all sites. The water tracks in this polar desert are part of a patterned ground network, which increases connectivity between the principal water sources (snowdrifts) and the bottom of the slope. This would reduce soil–water interactions and solute release, thereby favouring the low nutrient status of the lake.

Water tracks in the High Arctic: a hydrological network dominated by rapid subsurface flow through patterned ground

Water tracks play a major role in the headwater basin hydrology of permafrost landscapes in Alaska and Antarctica, but less is known about these features in the High Arctic. We examined the physical and hydrological properties of water tracks on Ward Hunt Island, a polar desert site in the Canadian High Arctic, to evaluate their formation process and to compare with water tracks reported elsewhere. These High Arctic water tracks flowed through soils that possessed higher near-surface organic carbon concentrations, higher water content, and coarser material than the surrounding soils. The water track morphology suggested they were initiated by a combination of sorting, differential frost heaving, and eluviation. The resultant network of soil conduits, comparable to soil pipes, dominated the hydrology of the slope. The flow of cold water through these conduits slowed down the progression of the thawing front during summer, making the active layer consistently shallower relative to adjacent soils. Water tracks on Ward Hunt Island, and in polar desert catchments with these features elsewhere in the High Arctic, strongly influence slope hydrology and active-layer properties while also affecting vegetation distribution and the quality of runoff to the downstream lake.

Syngenetic dynamic of permafrost of a polar desert solifluction lobe, Ward Hunt Island, Nunavut

Repeated freeze–thaw cycles on slopes trigger sorting and solifluction mass movements, while subsequent displacement of material modifies the geomorphology of slopes as well as permafrost dynamics. This study focuses on the geomorphology and the cryostratigraphy of a polar desert stone-banked solifluction lobe with the objective to clarify the impact of slow mass movements on ground ice aggradation. The morphology of the solifluction lobe was characterized by peripheral ridges of coarse gravel, partially surrounding a depression filled with finer sediments saturated with water and covered by organics. Cryostratigraphic analysis demonstrated that the solifluction lobe’s formation led to the development of a syngenetic layer of permafrost with an ice content that varied according to the location in the lobe. The ice-rich cryofacies formed in the central depression of the lobe should act as a buffer to potential active layer deepening, slowing down its thawing, whereas the ice-poor cryofacies formed under the ridges is expected to thaw faster than the central depression under climate warming scenarios. Thawing of the ice-rich zone in the future will result in differential thaw subsidence between the ridges and the central depression of solifluction lobes, along with increased drainage through the ridges and subsequent changes in hydrology.

Total mercury and methyl-mercury contents and accumulation in polar microbial mats

Although polar regions are considered isolated and pristine areas, the organisms that inhabit these zones are exposed to global pollution. Heavy metals, such as mercury, are global pollutants and can reach almost any location on Earth. Mercury may come from natural, volcanic or geological sources, or result from anthropogenic sources, in particular industrial or mining activities. In this study, we have investigated one of the most prominent biological non-marine communities in both polar regions, microbial mats, in terms of their Hg and methyl-mercury (MeHg) concentrations and accumulation capacities. The main hypotheses posed argued on the importance of different factors, and to test them, we have measured Hg concentrations in microbial mats that were collected from 6 locations in different ecological situations. For this purpose, the direct anthropogenic impacts, volcanic influences, proximity to the seashore, latitudinal gradients and C contents were investigated. Our results show that, other than the direct anthropogenic influence, none of the other hypotheses alone satisfactorily explains the Hg content in microbial mats. In contrast, the MeHg contents were noticeably different between the investigated locations, with a higher proportion of MeHg on the McMurdo Ice Shelf (Antarctica) and a lower proportion on Ward Hunt Island (High Arctic). Furthermore, our results from in situ experiments indicated that the microbial mats from South Shetland Islands could quickly accumulate (48h) Hg when Hg dissolved salts were supplied. Over short-term periods, these mats do not transform Hg into MeHg under field conditions.

Extreme ecosystems and geosystems in the Canadian High Arctic: Ward Hunt Island and vicinity

Global circulation models predict that the strongest and most rapid effects of global warming will take place at the highest latitudes of the Northern Hemisphere. Consistent with this prediction, the Ward Hunt Island region at the northern terrestrial limit of Arctic Canada is experiencing the onset of major environmental changes. This article provides a synthesis of research including new observations on the diverse geosystems/ecosystems of this coastal region of northern Ellesmere Island that extends to latitude 83.11° N (Cape Aldrich). The climate is extreme, with an average annual air temperature of -17.2 °C, similar to Antarctic regions such as the McMurdo Dry Valleys. The region is geologically distinct (the Pearya Terrane) and contains steep mountainous terrain intersected by deep fiords and fluvial valleys. Numerous glaciers flow into the valleys, fiords, and bays, and thick multi-year sea ice and ice shelves occur along the coast. These extreme ice features are currently undergoing rapid attrition. The polar desert landscape contains sparse, discontinuous patches of vegetation, including dense stands of the prostrate shrub Salix arctica (Artic willow) at some sites, and 37 species of vascular plants on Ward Hunt Island. Diverse aquatic ecosystems occur throughout the area, including meromictic, epishelf, and perennially ice-covered lakes. Many of these have responded strongly to climate shifts in the past and like other geosystems/ecosystems of the region are now sentinels of ongoing global climate change.

Microbes in High Arctic Snow and Implications for the Cold Biosphere

We applied molecular, microscopic, and culture techniques to characterize the microbial communities in snow and air at remote sites in the Canadian High Arctic (Ward Hunt Island, Ellesmere Island, and Cornwallis Island, latitudes 74 to 83(o)N). Members of the Bacteria and Eukarya were prevalent in the snow, and their small subunit (SSU) rRNA gene signatures indicated strong local aerial transport within the region over the preceding 8 months of winter snowpack accumulation. Many of the operational taxonomic units (OTUs) were similar to previously reported SSU rRNA gene sequences from the Arctic Ocean, suggesting the importance of local aerial transport processes for marine microbiota. More than 47% of the cyanobacterial OTUs in the snow have been previously found in microbial mats in the region, indicating that this group was also substantially derived from local sources. Viable cyanobacteria isolated from the snow indicated free exchange between the snow and adjacent mat communities. Other sequences were most similar to those found outside the Canadian Arctic but were from snow, lake and sea ice, glaciers and permafrost, alpine regions, Antarctica, and other regions of the Arctic, supporting the concept of global distribution of microbial ecotypes throughout the cold biosphere.

Arctic microbial ecosystems and impacts of extreme warming during the International Polar Year

As a contribution to the International Polar Year program MERGE (Microbiological and Ecological Responses to Global Environmental change in polar regions), studies were conducted on the terrestrial and aquatic microbial ecosystems of northern Canada (details at: http://www.cen.ulaval.ca/merge/). The habitats included permafrost soils, saline coldwater springs, supraglacial lakes on ice shelves, epishelf lakes in fjords, deep meromictic lakes, and shallow lakes, ponds and streams. Microbiological samples from each habitat were analysed by HPLC pigment assays, light and fluorescence microscopy, and DNA sequencing. The results show a remarkably diverse microflora of viruses, Archaea (including ammonium oxidisers and methanotrophs), Bacteria (including filamentous sulfur-oxidisers in a saline spring and benthic mats of Cyanobacteria in many waterbodies), and protists (including microbial eukaryotes in snowbanks and ciliates in ice-dammed lakes). In summer 2008, we recorded extreme warming at Ward Hunt Island and vicinity, the northern limit of the Canadian high Arctic, with air temperatures up to 20.5 °C. This was accompanied by pronounced changes in microbial habitats: deepening of the permafrost active layer; loss of perennial lake ice and sea ice; loss of ice-dammed freshwater lakes; and 23% loss of total ice shelf area, including complete break-up and loss of the Markham Ice Shelf cryo-ecosystem. These observations underscore the vulnerability of Arctic microbial ecosystems to ongoing climate change.

Comment on “Abrupt environmental change in Canada's northernmost lake inferred from fossil diatom and pigment stratigraphy” by Dermot Antoniades et al.

Antoniades et al. [2007; hereinafter referred to as A07] present an analysis of a 19‐cm lake sediment core from Ward Hunt Island from northern Canada. They conclude that a significant and abrupt change in the aquatic communities occurred in this lake during the past 2 centuries that was unusual with respect to the previous 8ka. In the paper, and especially in quotes to the press (e.g., http://www.cbc.ca; http://www.sciencedaily.com; http://scitizen.com) the authors conclude that their results, along with those from Smol et al. [2005] provide evidence for amplification of climates with latitude due to human caused global warming, an event unique in the past 8 ka. However, there are a number of problems in these data and flaws in the author's interpretations that render their results questionable. Their conclusions do not hold up to scrutiny as they do not concord with other information we have about climate variability in the Arctic. I have four major comments on the data, and several on the interpretation.

Robert L. Christie (1926-1999)

... Bob will be remembered for a broad range of geological achievements in western and Arctic Canada, as well as in Greenland, achievements documented by nearly 100 maps and reports published in scientific journals. ... Bob was undoubtedly the kindest and gentlest man I have ever known, and his family and friends were the special delights of his life. ... Bob discovered the Geological Survey of Canada (GSC) even before he went to the University of British Columbia (UBC) to study geology. ... He thrived in the outdoors, particularly in strenuous activities like rock climbing, mountain skiing, and backpacking. Moreover, he loved the beauty of nature, especially the mountains above tree line and the ocean. ... He was inventive and could fix anything: repairing a tent, a broken radio or compass, or a leaky boat was child's play to Bob. ... Bob's long career as an Arctic geologist began on northern Ellesmere Island in 1954, when he joined a team headed by Geoff Hattersley-Smith and jointly sponsored by the Defence Research Board of Canada and the United States Air Force Cambridge Research Centre. ... Using skis and a dog-hauled sledge, Bob made the first geological reconnaissance from Ward Hunt Island to Lands Lokk, where only a few early explorers had been before. In spite of severe weather and harsh travel conditions, Hattersley-Smith remembers Bob's cheerful stoicism, his tolerance, and his tact, but cannot recall a single cross word or disagreement for the entire six months. ... My most memorable and pleasant field seasons in the Arctic were in 1962, 1963, and 1966, when I served as Bob's assistant, mainly in fly camps. I remember the excitement of learning new things from Bob each day, about Arctic history, Inuit life, plants, animals, and astronomy, as well as geology. I hoped that the end of each field season could be delayed as long as possible. Each day would begin with Bob's favorite breakfast, his legendary raisin porridge, and it would end with his summarizing our scientific observations for the day with extensive, well-illustrated notes. ... In addition to being well prepared, well organized, and an outstanding but modest teacher in the field, he was always jovial. I can't remember a single cross word between us or a single day that we couldn't find something to laugh about. In addition to pursuing his own objectives in the field, Bob was always thinking about data that we might gather for colleagues interested in subjects beyond his own area of specialization. ... In the early 1980s, in addition to his Arctic work, Bob began to study the economic potential of phosphate rocks in Canada. Through extensive fieldwork in western and Arctic Canada and in the United States, he soon established himself as an authority on the subject. ... In recognition of Bob's scientific leadership and his broad knowledge of Arctic geology, he was assigned two other major projects in the 1980s both of which he completed with distinction. First, in 1984 and 1985, he updated the geology of Melville Island through incorporation and synthesis of new surface and subsurface geological and geophysical data to assist in the exploration for petroleum and minerals. Second, his compilation of the geology of Melville Island, with contributions from 16 other scientists, was published in 1994 as GSC Bulletin 450. ... Finally, Bob was seconded to the Polar Continental Shelf Project in 1990. ... Bob realized at that point that his Arctic career had come full circle: it had all started on the Ward Hunt Ice Shelf with Geoff Hattersley-Smith some 36 years earlier. ... For 38 years I have been warmed by the gift of Bob's friendship in my life. He has left a profound and indelible mark on all of us who knew him, and he has left an equally powerful imprint on the geology of the Arctic, a land he truly loved. ...

The Ward Hunt Ice Shelf, Spring 1982

In order to improve the understanding of arctic ice shelf evolution, ice coring and water sampling were undertaken and observations made on the Ward Hunt Ice Shelf and surrounding area during spring 1982. A total of 74 m of 7.6 cm diameter ice core was obtained from seven locations including Ward Hunt Ice Shelf, Ayles Fiord and Milne Ice Shelf. Water sampling of Lake 'A' and Disraeli Fiord indicated that these water bodies remain stratified. Observations of ice conditions between Ward Hunt Island and Cape Evans revealed the following: accretion of multi-year ice along the front of Ward Hunt and Milne Ice Shelf; grounding and/or loss of approximately 40 square km of ice shelf near Cape Discovery; possible development of rolls in multi-year ice in Ayles Fiord; and evidence of former ice tongues in Milne Fiord.

A Note on the Holocene History of a Portion of Northernmost Ellesmere Island

Three points raised in Lyons and Mielke's paper on the history of a portion of northernmost Ellesmere warrant further discussion. ... The points to be discussed deal with: 1) the Holocene chronology, 2) the interpretation of postglacial uplift, and 3) the form of the postglacial uplift curve on northern Ellesmere Island. ... Lyons and Mielke place the Pleistocene/Holocene boundary on northern Ellesmere Island at 10,000-13,000 BP. This boundary is based on inference from the Greenland ice core, since the authors state that is no reliable information on northernmost Ellesmere Island which closely fixes the transition from the Pleistocene to the Holocene. ... It seems clear that the estimated time profile through the Greenland ice core is particularly subject to question and should not be assumed to be free of error or without the need of being clarified by the radiocarbon-dated terrestrial record (not vice versa). ... Terasmae has described the time-transgressive nature of the late glacial/postglacial boundary in southeastern Canada (ca. 10,000 BP), and hence, similar time-transgressive problems might be expected in the arctic events. ... The terrestrial record from northern Ellesmere Island, therefore, should be accepted on its own merit .... The present writer suggests, therefore, that the local Pleistocene/Holocene boundary on northern Ellesmere Island occurred between 7500-8100 BP rather than 10,000-13,000 BP. This is also the case indicated by the majority of radiocarbon dates from raised marine deposits in Archer Fiord/Lady Franklin Bay. ... Lyons and Mielke also infer that the observed postglacial uplift on Ward Hunt Island is a product of the maximum Pleistocene ice thicknesses in this area. ... There is, however, no stratigraphic evidence that the maximum Pleistocene ice thickness in this area caused this Holocene uplift (7755 ±150 BP ...). It is equally possible that this postglacial emergence on Ward Hunt Island (only 38 m. a.s.l.) could have been produced beyond a restricted inland ice margin entirely independent of this most extensive ice advance. The present author has modelled the postglacial uplift over northeastern Ellesmere Island and northwestern Greenland using relatively small ice advances during the last glaciation, and the resulting uplift is consistent with the observed isobases over this area. ... Hence, there is no apparent need for the maximum Pleistocene ice load in this area to produce this moderate amount of postglacial uplift - in fact, these are very possibly two discrete events separated by an unknown amount of time. Evidence from northwestern Greenland and from eastern Baffin Island suggests that the maximum Pleistocene glaciations in these areas are much older than the last glaciation. ... The postglacial uplift curve constructed by Lyons and Mielkel is quite steep showing >70 per cent of the postglacial uplift occurring in the first two thousand years following deglaciation. ... On the curve of Lyons and Mielke postglacial uplift has almost completely flattened-off by ca. 5000 BP. Whether this is an accurate representation of the postglacial uplift process in this area or whether it is a problem of stratigraphy is not clear. ... Before such steep curves are assumed to accurately represent post-glacial uplift on northern Ellesmere Island, many more stratigraphically-controlled shell and driftwood samples must be obtained and dated. Also it needs to be determined whether the north coast of the island is undergoing a renewed submergence which could distort the real form of the uplift curve, particularly in its lower elevations. It is clear that Lyons and Mielke have made a valuable contribution to the Holocene history of northern Ellesmere Island, particularly around the evolution of the Ward Hunt Ice Shelf. However, the local data on the Pleistocene/Holocene boundary must be evaluated on their own merit, and caution should be exercised in making correlations with such data as the Greenland ice core which must, in return, be clarified by the land record provided by glacial geology.

The Mosses of Northern Ellesmere Island, Arctic Canada. II. Annotated List of the Taxa

One hundred and fifty-one species and four varieties of Musci are documented from northern Ellesmere Island, Arctic Canada. My studies have added 39 species and four varieties to the northern Ellesmere moss flora. The annotations include comments on distribution and abundance, habitats, altitudinal range, and fertility of each taxon on northern Ellesmere. Where appropriate, morphological variation and taxonomy are discussed. A new variety, Splachnum vasculosum var. heterophyllum, is proposed to accommodate arctic specimens of S. vasculosum. Cyrtomnium hymenophylloides, Distichium hagenii, Fissidens arcticus, and Polytrichum hyperboreum are illustrated. New data and observations on the taxonomy of the following taxa are presented: Aulacomnium acuminatum, Brachythecium groenlandicum, B. turgidum, Fissidens arcticus, Funaria arctica, Grimmia apocarpa var. nigrescens, Splachnum vasculosum, Voitia hyperborea, and V. nivalis. The following annotated list of northern Ellesmere Island mosses is arranged in the taxonomic order of Crum, Steere, and Anderson (1965), which is also used as the nomenclatural base. I have generally followed their taxonomic concepts, but where mine differ I state the reasons. Taxa whose names are enclosed in square brackets are provisionally excluded from the northern Ellesmere moss flora. Important synonyms are cited, in parentheses, following the names of certain taxa. After the name of each taxon I have listed the localities from which it is known. The localities and their abbreviations as used in the checklist are as follows: AF, Ayles Fiord; AL, Alert; BP, Barbeau Peak; cM, Clements Markham Inlet; DB, Doidge Bay; FC, Fort Conger; GG, Gilman Glacier; GI, Garlic Island (tentative name); HL, Heintzelman Lake; JL, Jasper Lakes (tentative name); LB, Lincoln Bay; LH, Lake Hazen; OF, Otto Fiord; 1 Part of a doctoral dissertation submitted to the University of Ottawa, Canada. Financial assistance for the field studies came from the National Museum of Natural Sciences, Canada, the National Research Council of Canada (grant A730 to R. E. Beschel), and the New York Botanical Garden (National Science Foundation grant GB-1313 to W. C. Steere). The Defence Research Board of Canada provided logistic support during all three field seasons. I thank the members of Operation Tanquary, especially Dr. Royce Longton, my companion in 1967. I am greatly indebted to the bryologists who willingly identified or verified specimens for me: Dr. Howard Crum and Dr. W. C. Steere, both of whom examined many specimens, Dr. Kjeld Holmen, Dr. A. Crundwell, and Mr. Harry Williams. The curators and staffs of the following herbaria allowed me full use of their facilities and collections: National Museum of Natural Sciences (CANM), New York Botanical Garden (NY), Plant Research Institute, Ottawa (DAO), Queen's University (QK). 2 Department of Biology, University of Ottawa, Ottawa, Canada. Present address: Department of Biology, Memorial University, St. John's, Newfoundland, Canada. This content downloaded from 207.46.13.111 on Tue, 09 Aug 2016 05:20:17 UTC All use subject to http://about.jstor.org/terms 1971] BRASSARD: NORTHERN ELLESMERE ISLAND MOSSES II 283 TF, Tanquary Fiord; TI, Taconite Inlet; VH, Van Hauen Pass; wB, Wrangle Bay; wH, Ward Hunt Island; YB, Yelverton Bay. Each locality abbreviation is followed by collection numbers in italics (which are mine unless otherwise preceded by a name); an asterisk (*) indicates a specimen with sporophytes and an exclamation point (!) denotes specimens which I have examined but which were not collected by me. A name and date in parentheses, e.g., (Steere, 1959), is a published report based on specimens which I have been unable to study. A fire at Van Hauen Pass in 1967 destroyed many of my moss specimens, and a few species which I had definitely identified in the field but of which no specimens remain are cited as sight record. After the list of localities and specimens for each taxon I have added annotations about its biology and ecology on northern Ellesmere. Where appropriate I have also included comments on taxonomy, morphological variation, illustrations, or keys. The following list comprises 71 genera, 151 species, and four varieties of Musci. I expect that future investigations on northern Ellesmere will raise its known moss flora to at least 160 species, and will in addition provide more material of rare species.

Observations on Ice Regions of the Arctic Ocean

Reports 7 Mar - 20 Apr observations made by a physician and a high school geography teacher, members of a six-man nonscientific field party of the Plaisted Polar Expedition 1968, which traversed the pack ice from Ward Hunt Island to the geographic North Pole to be evacuated by air. Logistics, using four Bombardier Skidoo snowmobiles to tow 8-ft sleds, weather, and positioning are briefly described. The west wind was so constant that a northerly heading was maintained on overcast days by crossing tightly packed snow drifts or sastrugi at right angles. Surface features of three zones are described, a so-called shatter zone extending out about 25 mi where pack ice meets shelf ice; another with a highly variable surface, broad, old floes being the basic feature, separated by areas of extensive fragmentation; the third zone has an enormous lead at its southern limit and contains large-sized and old floes. These log-book notes give many details on pressure ridges, leads, floe sizes, orientation of upended ice fragments, etc.

Navigating to the North Pole-A Surface Traverse

ON APRIL 20~1-1, 1968 a small group of men on snowmobiles completed a t,raverse across the frozen surface of the Arctic Ocean from Ward Hunt Island to the geographical north pole. This paper goes into detail on the navigation problems encountered and the procedures used. The sun, visible 24 hours a day for the last month of the trip, was used almost exclusively for maintaining direction and determining position. Although several special techniques were used, the basic approach was a straightforward sun-line exercise. At one period of the trip the moon was visible and in an appropriate position for sightings in combination with the sun. However, during the most critical period, the last few days within 89 degrees north latitude, only the sun was available. Achieving a reasonable accurate fix using only one celestial body requires repeated sightings at lengthy time intervals. During the last phase of the expedition our party stopped for two days at one campsight that I estimated to be approximately 10 miles from the goal. During this period hourly sightings were made unt,il a sufficient number of LOPS were plotted to give us the accuracy in position necessary to set out on the final leg to the north pole. We received our “moment of truth” when the planned-for Air Force weather reconnaisance flight, LARK-47, overflew our position confirming the fact that we had achieved the north pole.

Studies of Ice Movements on the Ward Hunt Ice Shelf by Means of Triangulation-Trilateration

Ward Hunt Island is surrounded by more than 2000 sq km of ice shelf. In 1964 and 1965 the University of New Brunswick Department of Surveying Engineering made a survey of the ice shelf in which geodimeter distance measurements and angular theodolite measurements were combined in a system of triangulation-trilateration in the form of a chain of quadrilaterals to achieve relative positioning accuracies of ± 2 cm for the survey markers. Shelf ice movements of 30 cm with respect to solid ground occurred between 1964 and 1965. The relative position change between the markers on shelf ice was < 4 cm.