Search

As the impacts of climate change grow, we need better ways to raise awareness and motivate action. Here we assess the effectiveness of an Arctic climate change card game in comparison with the more conventional approach of reading an illustrated article. In-person assessments with control/reading and treatment/game groups (N = 41), were followed four weeks later with a survey. The game was found to be as effective as the article in teaching content of the impacts of climate change over the short term, and was more effective than the article in long-term retention of new information. Game players also had higher levels of engagement and perceptions that they knew ways to help protect Arctic ecosystems. They were also more likely to recommend the game to friends or family than those in the control group were likely to recommend the article to friends or family. As we consider ways to broaden engagement with climate change, we should include games in our portfolio of approaches.

This first analysis of aggregated data from the Kahoot! game-based player response system demonstrates that it can provide assessments of overall US student polar knowledge and identifies differenc...

This Special Issue “Shaping Tomorrow’s Arctic” explores the past, present and future of Arctic sustainability [...]

The polar regions are experiencing dramatic and tangible impacts due to climate change (IPCC, 2014; USGCRP, 2018). The Arctic is the first region on the planet to experience a major abrupt climate ...

Climate change is a highly complex social-ecological problem characterized by system-type dynamics that are important to communicate in a variety of settings, ranging from formal education to decision makers to informal education of the general public. Educational games are one approach that may enhance systems thinking skills. This study used a randomized controlled experiment to compare the impact on the mental models of participants of an educational card game vs. an illustrated article about the Arctic social-ecological system. A total of 41 participants (game: n = 20; reading: n = 21) created pre- and post-intervention mental models of the system, based on a "fuzzy cognitive mapping" approach. Maps were analyzed using network statistics. Both reading the article and playing the game resulted in measurable increases in systems understanding. The group reading the article perceived a more complex system after the intervention, with overall learning gains approximately twice those of the game players. However, game players demonstrated similar learning gains as article readers regarding the climate system, actions both causing environmental problems and protecting the Arctic, as well as the importance of the base- and mid-levels of the food chain. These findings contribute to the growing evidence showing that games are important resources to include as strategies for building capacity to understand and steward sustainable social-ecological systems, in both formal and informal education.

The Sea Ice Tracking System (SITU), formerly known as the IceTracker or Lagrangian Ice Tracking System, has been expanded to include new functions facilitating a wide range of new applications (http://icemotion.labs.nsidc.org/SITU/). Ice motion vectors are calculated from an optimal interpolation of satellite-derived, free-drift and buoy drift estimates (Polar Pathfinder dataset, version 4, https://nsidc.org/data/nsidc-0116; International Arctic Buoy Program, http://iabp.apl.washington.edu/; NCEP/NCAR reanalysis, https://www.esrl.noaa.gov/). SITU now calculates forward and backward trajectories of Antarctic as well as Arctic sea ice from 1979 to 2018 and incorporates basin-wide contextual information including timeseries of bathymetry, ice concentration, ice age, ice motion, air temperature, pressure, and wind speed, along the tracks. A new animated background option allows users to visualize these basin-wide changing environmental conditions as the tracking progresses. SITU can be used by researchers, educators, local and indigenous communities, policy and planning professionals, and industries. For instance, geologists can use SITU to determine the provenance of sediment transported by sea-ice and deposited at an ocean core site; biologists can identify source region of biomass transported by sea-ice and seeding algal bloom in a given sea, or overlay bear and birds tracks over ice conditions or ice types animated in the background; coastal communities can backtrack ice to reveal age, origin and other factors that influence habitats of ice-associated species; people planning future expeditions can review recent ice conditions along potential cruise tracks, historians can compare current air temperatures, wind conditions, and ice concentration with past expeditions; students can learn about sea ice motion in the Arctic or compare recent ice drift (Tara or MOSAIC) with that of the epic expedition of Nansen. A new Eulerian option allows users to see changing conditions at one point over the full satellite record (1978 to present). This Eulerian depiction reveals variability as well as trends, and can provide context for data retrieved from a mooring, sediment trap, or sediment core. Publically hosted on the NSIDC Labs webpage, data can be downloaded graphically or in spreadsheet format for deeper analysis.

The Arctic is undergoing a rapid transition toward a seasonal ice regime, with widespread implications for the polar ecosystem, human activities, as well as the global climate. Here we focus on how the changing ice cover impacts transborder exchange of sea ice between the exclusive economic zones of the Arctic states. We use the Sea Ice Tracking Utility, which follows ice floes from formation to melt, in conjunction with output diagnostics from two ensembles of the Community Earth System Model that follow different future emissions scenarios. The Community Earth System Model projects that by midcentury, transnational ice exchange will more than triple, with the largest increase in the amount of transnational ice originating from Russia and the Central Arctic. However, long‐distance ice transport pathways are predicted to diminish in favor of ice exchanged between neighboring countries. By the end of the 21st century, we see a large difference between the two future emissions scenarios considered: Consistent nearly ice‐free summers under the high emissions scenario act to reduce the total fraction of transnational ice exchange compared to midcentury, whereas the low emissions scenario continues to see an increase in the proportion of transnational ice. Under both scenarios, transit times are predicted to decrease to less than 2 yr by 2100, compared to a maximum of 6 yr under present‐day conditions and 2.5 yr by midcentury. These significant changes in ice exchange and transit time raise important concerns regarding risks associated with ice‐rafted contaminants.

In this perspective on the future of the Arctic, we explore actions taken to mitigate warming and adapt to change since the Paris agreement on the temperature threshold that should not be exceeded in order to avoid dangerous interference with the climate system. Although 5 years may seem too short a time for implementation of major interventions, it actually is a considerable time span given the urgency at which we must act if we want to avoid crossing the 1.5 to

The changing Arctic sea-ice cover is likely to impact the trans-border exchange of sea ice between the exclusive economic zones (EEZs) of the Arctic nations, affecting the risk of ice-rafted contamination. We apply the Lagrangian Ice Tracking System (LITS) to identify sea-ice formation events and track sea ice to its melt locations. Most ice (52%) melts within 100 km of where it is formed; ca. 21% escapes from its EEZ. Thus, most contaminants will be released within an ice parcel's originating EEZ, while material carried by over 1 00,000 km2 of ice—an area larger than France and Germany combined—will be released to other nations' waters. Between the periods 1988–1999 and 2000–2014, sea-ice formation increased by ∼17% (roughly 6 million km2 vs. 5 million km2 annually). Melting peaks earlier; freeze-up begins later; and the central Arctic Ocean is more prominent in both formation and melt in the later period. The total area of ice transported between EEZs increased, while transit times decreased: for example, Russian ice reached melt locations in other nations' EEZs an average of 46% faster while North American ice reached destinations in Eurasian waters an average of 37% faster. Increased trans-border exchange is mainly a result of increased speed (∼14% per decade), allowing first-year ice to escape the summer melt front, even as the front extends further north. Increased trans-border exchange over shorter times is bringing the EEZs of the Arctic nations closer together, which should be taken into account in policy development—including establishment of marine-protected areas. Plain Language Summary We use data from satellite images to identify the formation, drift tracks, and melt locations of sea ice in the Arctic. Most ice melts locally: only about 21% is exported from the exclusive economic zone (EEZ) in which it is formed. That export is nonetheless about 1,000,000 km2 each year. As the ice cover has thinned and the summer sea ice has retreated in a warming Arctic, formation and melt locations have moved further north, ice drifts have accelerated, and the area of ice formation and melt has increased. We looked at ice formation and transport between the EEZs of the Arctic nations, and broke the record into two periods: 1988–1999 and 2000–2014. As the Arctic warms, more ice is transported between EEZs and it is arriving at the receiving EEZ faster, than in the past. Between the two study periods: Sea ice velocity increased by about 14%/decade; Russian ice reached melt locations in other nations' EEZs 46% faster; and North American ice reached Eurasian destinations 37% faster. Exchanges of ice have increased as a result. For example, export of ice from Russia to Norway increased by 11% and export from Alaska to Russia by 16%.

Academic enterprises seeking to support society’s efforts to achieve global sustainability need to change their legacy reward systems. We need new structures to foster knowledge that is deeply integrated across disciplines and co-produced with non-academic stakeholders.

The patterns of sea ice retreat in the Arctic Ocean are investigated using two global climate models (GCMs) that have profound differences in their large-scale mean winter atmospheric circulation and sea ice drift patterns. The Community Earth System Model Large Ensemble (CESM-LE) presents a mean sea level pressure pattern that is in general agreement with observations for the late twentieth century. The Community Climate System Model, version 4 (CCSM4), exhibits a low bias in its mean sea level pressure over the Arctic region with a deeper Icelandic low. A dynamical mechanism is presented in which large-scale mean winter atmospheric circulation has significant effect on the following September sea ice extent anomaly by influencing ice divergence in specific areas. A Lagrangian model is used to backtrack the 80°N line from the approximate time of the melt onset to its prior positions throughout the previous winter and quantify the divergence across the Pacific and Eurasian sectors of the Arctic. It is found that CCSM4 simulates more sea ice divergence in the Beaufort and Chukchi Seas and less divergence in the Eurasian seas when compared to CESM-LE, leading to a Pacific-centric sea ice retreat. On the other hand, CESM-LE shows a more symmetrical retreat between the Pacific, Eurasian, and Atlantic sectors of the Arctic. Given that a positive trend in the Arctic Oscillation (AO) index, associated with low sea level pressure anomalies in the Arctic, is a robust feature of GCMs participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5), these results suggest that the sea ice retreat in the Pacific sector could be amplified during the transition to a seasonal ice cover.

Recent trends and climate models suggest that the Arctic summer sea ice cover is likely to be lost before climate interventions can stabilize it. There are environmental, socioeconomic, and sociocultural arguments for, but also against, restoring and sustaining current conditions. Even if global warming can be reversed, some people will experience ice-free summers before perennial sea ice begins to return. We ask: How will future generations feel about bringing sea ice back where they have not experienced it before? How will conflicted interests in ice-covered vs. ice-free conditions be resolved? What role will science play in these debates?

Fewer than one in four Americans (23%) are currently in a formal educational setting—a school, college, or university (U.S. Census 2018). Many of the 77% who are not in school, have a distorted view of the Polar Regions—literally distorted as the typical Mercator projection stretches Antarctica into an enormous white band in the south, and Greenland looks larger than Africa in the north. As recently as 2008, climate change was not typically part of K-12 curriculum (Kastens and Turrin 2008). The greatest strides have been accomplished with the 2013 introduction of the Next Generation Science Standards and the inclusion of climate change in their Disciplinary Core Ideas for instruction (NGSS 2013), but this occurred well after most Americans graduated and NGSS has not been fully adopted by all 50 states. Taken together, these factors call for creative methods for delivering both polar and climate education to the broader public.

“Facilitating Interdisciplinary Scholars,” by Stephanie Pfirman and Paula J. S. Martin, explores approaches to interdisciplinary scholarship with comparison to disciplinary traditions in higher education. The authors investigate the particular challenges of interdisciplinary research, teaching, and service for scholars throughout different mileposts in a scholarly career. Ideas to support interdisciplinary faculty are presented, from the creation of the position, to the point of hire, and through a career timeline to tenure and posttenure review. As many institutions have barriers for scholars working between departments, frameworks to foster interdisciplinary collaboration are discussed. Special challenges in interdisciplinary scholarly productivity, scholarly recognition, evaluation, promotion, and funding are examined.

The need is urgent to build capacity in the environmental community, and the interdisciplinary approach is one of the most promising avenues to accomplish this. The environmental studies and sciences program movement can ably lead this effort. Based on a workshop at the second annual meeting of the Association for Environmental Studies and Sciences (AESS) in 2010, we look at barriers to interdisciplinarity in academia, including the cultural, historical, and institutional context of disciplinary scholarship. It is within this context that interdisciplinarians must fight for identity, recognition, roles, legitimacy, and standing. Teaching, research, service, publishing, competing for funding, and meeting reappointment/promotion/tenure evaluation criteria can all pose unique difficulties for interdisciplinary scholars. We offer advice to those seeking professional interdisciplinary education, including finding the right program and advisor, developing skills, designing and completing the dissertation, and establishing a professional network. We also offer advice on securing a job—setting the stage while still in graduate school and highlighting interdisciplinary strengths in the application and interview process. We also offer advice on career advancement, such as clarifying one’s expertise and its significance, setting and fulfilling tenure-track benchmarks, adapting the career trajectory to capitalize on an interdisciplinary career, clarifying with one’s institution the criteria for advancement, and preparing the tenure portfolio. Finally, we offer an introduction to interdisciplinarity as an explicit, systematic approach in concept and framework that rests on a higher order means of organizing knowledge and action, with a focus on integration. AESS is emerging as an organization to assist professionals by assembling a supportive community of environmental educators, researchers, and problem solvers, by clarifying and promoting standards for successful interdisciplinarity in the classroom and in the field, and by offering advice and support on career issues for both up-and-coming professionals and established faculty and practitioners.

Arctic sea ice can incorporate sediment and associated chemical species during its formation in shallow shelf environments and can also intercept atmospherically transported material during transit. Release of this material in ice ablation areas (e.g. the Fram Strait) enhances fluxes of both sediments and associated species in such areas. We have used a suite of natural ( 7 Be, 210 Pb) and anthropogenic ( 137 Cs, 239 Pu, 240 Pu) radionuclides in sea ice, sea-ice sediments (SIS), sediment trap material and bottom sediments from the Fram Strait to estimate transit times of sea ice from source to ablation areas, calculate radionuclide fluxes to the Fram Strait and investigate the role of sea-ice entrained sediments in sedimentation processes. Sea ice intercepts and transports the atmospherically supplied radionuclides 7 Be and 210 Pb, which are carried in the ice and are scavenged by any entrained SIS. All of the 7 Be and most of the excess 210 Pb measured in SIS collected in the Fram Strait are added to the ice during transit through the Arctic Ocean, and we use these radionuclides as chronometers to calculate ice transit times for individual ice floes. Transit times estimated from the 210 Pb inventories in two ice cores are 1–3 years. Values estimated from the 7 Be/ 210 Pb excess activity ratio of SIS are about 3–5 years. Finally, equilibrium values of the activity ratio of 210 Pb to its granddaughter 210 Po in the ice cores indicate transit times of at least 2 years. These transit times are consistent with back-trajectory analyses of the ice floes. The latter, as well as the clay-mineral assemblage of the SIS (low smectite and high illite content), suggest that the sampled sea-ice floes originated from the eastern Siberian Arctic shelf seas such as the eastern Laptev Sea and the East Siberian Sea. This result is in agreement with the relatively low activities of 239,240 Pu and 137 Cs and the 240 Pu/ 239 Pu atom ratios (∼0.18, equivalent to that in global fallout) in SIS, indicating that prior global atmospheric fallout, rather than nuclear fuel reprocessing facilities, forms the main source of these anthropogenic radionuclides reaching the western Fram Strait at the time of sampling (1999). Transport of radionuclides by sea ice through the Arctic Ocean, either associated with entrained SIS or dissolved in the ice, accounts for a significant flux in ablation areas such as the Fram Strait, up to several times larger than the current atmospheric flux in the area. Calculated fluxes derived from sea-ice melting compare well to fluxes obtained from sediment traps deployed in the Fram Strait and are consistent with inventories in bottom sediments. 240 Pu/ 239 Pu atomic ratios lower than 0.18 in bottom sediments from the Fram Strait provide evidence that plutonium from a source other than atmospheric fallout has reached the area. Most likely sources of this Pu include tropospheric fallout from atomic weapons testing of the former Soviet Union prior to 1963 and Pu released from nuclear reprocessing facilities, intercepted and transported by sea ice to the ablation areas. Future work is envisaged to more thoroughly understand the actual mechanisms by which radionuclides are incorporated in sea ice, focusing on the quantification of the efficiency of scavenging by SIS and the effect of melting and refreezing processes over the course of several years during transit.

For at least a decade, U.S. funding agencies and university campuses have promoted the expansion of interdisciplinary research. At the same time, federal and local programs have sought to increase the participation of women and minorities in science, mathematics, and engineering. Research has focused on each of these trends independently, but very few studies have considered their interaction by asking how intellectual preferences for and professional consequences of interdisciplinary science might be influenced by gender, race, and/or ethnicity. Focused specifically on gender, this paper considers the expectation that women will be more drawn to interdisciplinary research, and explores the learning styles, work preferences, and career behaviors that might anticipate and/or explicate gender differences in interdisciplinary science. Principal mechanisms by which researchers engage in interdisciplinarity – cross-fertilization, team-collaboration, field-creation, and problem-orientation – are tested for evidence of gendering using preliminary empirical data from three studies. The results of this exploratory analysis offer clues about possible tendencies and raise questions about the potential costs and benefits for those who adopt them.

Ice-rafted sediments of Eurasian and North American origin are found consistently in the upper part (13 Ma BP to present) of the Arctic Coring Expedition (ACEX) ocean core from the Lomonosov Ridge, near the North Pole (≈88° N). Based on modern sea-ice drift trajectories and speeds, this has been taken as evidence of the presence of a perennial sea-ice cover in the Arctic Ocean from the middle Miocene onwards (Krylov et al. 2008 Paleoceanography 23, PA1S06. ( doi:10.1029/2007PA001497 ); Darby 2008 Paleoceanography 23, PA1S07. ( doi:10.1029/2007PA001479 )). However, other high latitude land and marine records indicate a long-term trend towards cooling broken by periods of extensive warming suggestive of a seasonally ice-free Arctic between the Miocene and the present (Polyak et al. 2010 Quaternary Science Reviews 29, 1757–1778. ( doi:10.1016/j.quascirev.2010.02.010 )). We use a coupled sea-ice slab-ocean model including sediment transport tracers to map the spatial distribution of ice-rafted deposits in the Arctic Ocean. We use 6 hourly wind forcing and surface heat fluxes for two different climates: one with a perennial sea-ice cover similar to that of the present day and one with seasonally ice-free conditions, similar to that simulated in future projections. Model results confirm that in the present-day climate, sea ice takes more than 1 year to transport sediment from all its peripheral seas to the North Pole. However, in a warmer climate, sea-ice speeds are significantly faster (for the same wind forcing) and can deposit sediments of Laptev, East Siberian and perhaps also Beaufort Sea origin at the North Pole. This is primarily because of the fact that sea-ice interactions are much weaker with a thinner ice cover and there is less resistance to drift. We conclude that the presence of ice-rafted sediment of Eurasian and North American origin at the North Pole does not imply a perennial sea-ice cover in the Arctic Ocean, reconciling the ACEX ocean core data with other land and marine records.

The activity was designed to provide guidance on future research questions in the Arctic over the next 10-20 years, identifying the key scientific questions that are emerging in different realms of Arctic science and exploring both disciplinary realms (e.g., marine, terrestrial, atmosphere, cryosphere, and social sciences) and cross cutting realms (e.g., integrated systems science and sustainability science). Based on the emerging research questions, the study also helps identify research infrastructure needs and collaboration opportunities. Attention was given to assessing needs where there may be a mismatch between rates of change and the pace of scientific research. Although it is understood that there is no one answer, the committee was asked to explore how agency decision makers might achieve balance in their research portfolios and associated investments. This report is meant to guide future directions in U.S. Arctic research so that research is targeted on critical scientific and societal questions and conducted as effectively as possible. This activity was sponsored by USARC, DOE, NASA, NOAA, NSF, and the Smithsonian Institution.

Earth Science instruction is challenged today by rapid information growth and a need to integrate information from a number of disciplines. Fortunately, most of this information is in digital form, so the computer's capacity to integrate, process and display data can help students learn from data. The Lamont Data Viewer, originally developed for research, has been modified to help students with this task. With it, students can view large data sets as maps, cross-sections or x–y plots of subdata sets or make calculations on the data set and view the resulting data as similar displays. All calculations and data transformations are made on a large Lamont server with the resulting figure or table being transmitted to the user via the Internet. Consequently, students can easily and rapidly access and process large data sets from disparate disciplines and view the resulting figures and tables in similar formats. Easy access to large Earth Science data sets adds a new dimension to the way students can learn about the Earth and requires certain data analysis skills. The educational value of acquiring and using such skills is beyond dispute, for they teach how science is done and are applicable to both scientific and nonscientific inquiry. Nevertheless, learning directly from data is a little explored activity, below the graduate level, and much needs to be learned to maximize the gain from this form of pedagogy.

During the past decades, a variety of transient tracers have been used to derive information on pathways and mean residence times of oceanic water masses. Here, we discuss how information obtained in such studies can be applied to studying the spreading of dissolved pollutants in the ocean. The discussion focuses on the transient tracers tritium/3He and the H218O/H216O ratio of water. These tracers are used in combination with CFCs and 14C in a case study of Arctic Ocean contaminant transport to: (1) separate the freshwater components contained in the near-surface waters; (2) infer mean pathways of freshwater and associated contaminants from the H218O/H216O distribution in the surface waters; and (3) determine mean residence times of the surface, intermediate, deep and bottom waters.

Export of sea ice from the Kara Sea may redistribute contaminants entrained from atmospheric, marine and riverine sources. Ice exiting the Kara Sea ice to the north, will influence the Fram Strait, Svalbard and Barents Sea regions. Kara Sea ice may also be exported to the Barents Sea through straits north and south of Novaya Zemlya. Some ice from the Kara Sea makes its way into the Laptev Sea to the north and south of Severnaya Zemlya. Data on ice exchange and contaminant levels are not adequate to assess contaminant flux.

Sea ice has been reported to contain contaminants from atmospheric and nearshore sediment resuspension processes. In this study successive passive microwave images from the 85.5 GHz channels on the Special Sensor Microwave Imager (SSM/I) were merged with drifting buoy trajectories from the International Arctic Buoy Program to compute Arctic sea ice motion in the Russian Arctic between 1988 and 1994. Smooth daily motion fields were averaged to prepare monthly maps making it possible to compute the 7-year mean and mean seasonal ice motions as well as principal components of directional variability of sea ice motion for the entire Arctic and surrounding basins. These mean motion vectors are used to simulate the advection of contaminants deposited on or contained within the sea ice and subsequently transported into the Arctic Ocean in order to predict both their mean trajectories and dispersal over time. The 3-year displacement of contaminants from a number of Russian sites and one American site display various behaviours from substantial displacement and dispersal to almost no movement. This computational procedure could be applied to realtime SSM/I and ice buoy data to provide detailed, all-weather, vector motion maps of ice circulation to predict the path and dispersal of any new substance introduced to the sea ice and transported into the Arctic or Antarctic ocean surface.

Sea ice formed over shallow Arctic shelves often entrains sediments resuspended from the sea floor. Some of this sediment-laden ice advects offshore into the Transpolar Drift Stream and the Beaufort Gyre of the Arctic Basin. Through the processes of seasonal melting at the top surface, and the freezing of clean ice on the bottom surface, these sediments tend, over time, to concentrate at the top of the ice where they can affect the surface albedo, and thus the absorbed solar radiation, when the ice is snow free. Similarly, wind-blown dust can reduce the albedo of snow. The question that is posed by this study is what is the impact of these sediments on the seasonal variation of sea ice, and how does it then affect climate? Experiments were conducted with a coupled energy balance climate-thermodynamic sea ice model to examine the impact of including sediments in the sea ice alone and in the sea ice and overlying snow. The focus of these experiments was the impact of the radiative and not the thermal properties of the sediments. The results suggest that if sea ice contains a significant amount of sediments which are covered by clean snow, there is only a small impact on the climate system. However, if the snow also contains significant sediments the impact on sea ice thickness and surface air temperature is much more significant.

The main water masses in the northern Barents Sea are surface water, Arctic water, transformed Atlantic water, and cold bottom water. Using summer data from 1981 and 1982, the formation, distribution, modification and circulation of these water masses are discussed. Recent estimates show that about 2 Sv of Atlantic water enters the Barents Sea by the North Cape Current, balanced by a similar outflow through the strait between Novaya Zemlya and Frans Josef Land. Passing through the Barents Sea, Atlantic-derived water is modified by interaction with other water masses as well as with the atmosphere, and the end products are believed to be important contributors to the hydrographic structure of the Arctic Ocean.

The key features of the large-scale circulation of the Arctic Ocean are reviewed based on distributions of hydrographic parameters and natural and anthropogenic trace substances. Salinity and mass balances, as well as a combination of the tracers tritium and δ 18 O, suggest a mean residence time of the shelf waters in the Siberian seas of about 3 years. Potential pathways of pollutants released to the Siberian shelf seas from the dumpsites or from river runoff are inferred from the distributions of δ 18 O and salinity. Transit times needed for dissolved contaminants to cross the central Arctic basins (several years to one or two decades in near-surface waters) and mean residence times of contaminants in the intermediate (several decades) and deep waters (several centuries) are estimated from the distribution of transient tracers (tritium and its radioactive decay product, 3 He) and “steady-state” tracers ( 14 C and 39 Ar).

Nuclear activity on land and dumping of waste in the Siberian shelf seas mean that the Kara Sea is most likely to experience inputs of radioactivity. Industrial and other anthropogenic activities in the expansive Ob' and Yenisey watersheds also contribute organochlorines, heavy metals and oil to this region. Contaminant fate is influenced by the distribution of the river discharge and processes associated with ice formation and ocean currents. Although average conditions are important in the transport of pollutants, events such as storms and iceberg gouging may be critical in deciding the ultimate fate of dumped and released contaminants.

Drifting sea ice in the Arctic may transport contaminants from coastal areas across the pole and release them during melting far from the source areas. Arctic sea ice often contains sediments entrained on the Siberian shelves and receives atmospheric deposition from Arctic haze. Elevated levels of some heavy metals (e.g. lead, iron, copper and cadmium) and organochlorines (e.g. PCBs and DDTs) have been observed in ice sampled in the Siberian seas, north of Svalbard, and in Baffin Bay. In order to determine the relative importance of sea ice transport in comparison with air/sea and oceanic processes, more data is required on pollutant entrainment and distribution in the Arctic ice pack.

Satellite images from the Kara Sea show that, until July, fast-ice extends along the coast and Fills the estuaries of the Ob' and Yenisey rivers. It is separated from offshore drift-ice by a region of open water, comprising a flaw lead/polynya. By August, much of the fast and drift-ice has melted and retreated from the southwestern Kara Sea, leaving behind a persistent patch of sea-ice east of Novaya Zemlya. Because both the OF and Yenisey rivers discharge water throughout the winter, the fast-ice is likely to incorporate river-borne contaminants by bottom adfreezing. During peak river discharge in June, the fast-ice remains in place, and is potentially influenced by the river outflow throughout the length of the estuary. Breakup and melting of the fast-ice in July could release contaminants to the surface waters. By late July and August, when the fast-ice has disappeared, the river discharge is observed primarily along the shore in a zone that extends offshore more than 100 km. In fall, newly-forming ice may incorporate contaminants from the river plume, while in late winter, convection penetrating to the sea floor may allow resuspended sediments to be entrained in ice forming in the flaw lead/polynya. Drift-ice formed in this region could then advect contaminants offshore. The potential for exchange of water, ice and contaminants with the Barents Sea through Karskiye Vorota, south of Novaya Zemlya, is discussed in the context of the temperature and turbidity distribution observed in the satellite images.

The sea floor of Fram Strait, the over 2500 m deep passage between the Arctic Ocean and the Norwegian-Greenland Sea, is part of a complex transform zone between the Knipovich mid-oceanic ridge of the Norwegian-Greenland Sea and the Nansen-Gakkel Ridge of the Arctic Ocean. Because linear magnetic anomalies formed by sea-floor spreading have not been found, the precise location of the boundary between the Eurasian and the North American plate is unknown in this region. Systematic surveying of Fram Strait with SEABEAM and high resolution seismic profiling began in 1984 and continued in 1985 and 1987, providing detailed morphology of the Fram Strait sea floor and permitting better definition of its morphotectonics. The 1984 survey presented in this paper provided a complete set of bathymetric data from the southernmost section of the Svalbard Transform, including the Molloy Fracture Zone, connecting the Knipovich Ridge to the Molloy Ridge; and the Molloy Deep, a nodal basin formed at the intersection of the Molloy Transform Fault and the Molloy Ridge. This nodal basin has a revised maximum depth of 5607 m water depth at 79°8.5′N and 2°47′E.

The deep eastern Arctic basin between the Lomonosov Ridge and the Eurasian continental margin differs from other ocean basins in the very slow spreading of its floor and unusual depositional environment under perennial sea-ice cover. The recent expedition ARK IV/3 of RV Polar stern for the first time made geoscientific investigations from the northern margin of the Barents Sea north to the Nansen-Gakkel Ridge. Much deeper than most other mid-ocean ridges, this ridge is poorly-surveyed, but has a central valley which in places is deeper than 5.5 km, 1–1.5 km below the basin floors on either side. Heat flow in the central part of the valley is very rapid; both basement rocks and overlying sediments showed unexpectedly the influence of intense and long-term hydrothermal activity. The sediments on the northern and southern flanks of the ridge are slightly calcareous pelagic mud layers alternating with carbonate-free horizons, where up to 40% of the sedimentary section is soft mud clasts. Similar mud aggregates were observed on the surface of the multi-year sea ice, appearing to represent a special type of sediment transport by sea ice in the Transpolar Drift. In contrast to the western Arctic, Fram Strait and the Norwegian-Greenland Sea, gravel is rarely found in sediment cores. Recovered cores indicate that icebergs and sea ice carrying coarse sediment seldom rafted detritus to the study area during the last approximately 300,000 years.

[1] Analysis of Arctic sea ice drift from 1979–1997 using a Lagrangian perspective shows the complexities of ice drift response to variations in atmospheric conditions. Changes in ice dynamics influence the redistribution of ice, and any transported material, from different source areas. Sources of ice exported to Fram Strait shifted in about 1986/87 from dominance of the Kara Sea and Severnaya Zemlya to the New Siberian Islands, East Siberian Sea, and Chukchi Sea. Average travel time of multiyear ice within the perennial pack of the central Arctic Basin, reached a maximum in 1987/88, and decreased by at least 1 year between 1984–1989 and 1990–1997. Consistent with the observations of other investigators, this decrease in ice travel time occurred following a major export or “surge” of old ice to Fram Strait from the Beaufort Gyre in 1988 through 1990, which decreased the fraction of thick, ridged ice within the central basin.

δ18O profiles in drifting Arctic sea ice are coupled with back trajectories of ice drift and an ice growth model to reconstruct the surface hydrography of the Arctic Ocean interior. The results compare well with δ18O values obtained by traditional oceanographic methods and known water mass distributions. Analysis of the stable isotopic composition of sea ice floes sampled at strategic and relatively accessible locations, e.g., Fram Strait, could aid in mapping spatial and temporal variations in Arctic Ocean surface waters.

Human activities increasingly lead to climate change, overuse of water, hazards and the destruction of biodiversity — to name just a few. Earth scientists need to take on the challenge of serving society on these issues, in close collaboration with engineering, social sciences and the humanities.