How real-world marine food webs absorb change, recover and adapt (that is, ecological resilience) to climate change remains problematic. Here we apply a novel approach to show how the complex changes in resilience of food webs can be understood with a small core set of self-organizing configurations that represent different simultaneously nested and multiple-species interactions. We identified a recent emergent pattern of an improving but possibly short-lived resilience of a highly observed Arctic marine food web (2004–2016), considered a harbinger of future Arctic change. The changes can be explained by continuing subsidiary inputs of Atlantic species that repair (self-organize) interactions within some configurations. Despite significant environmental perturbation, we found that the core ecological processes are maintained. We conclude that Arctic marine food webs can absorb and begin to adapt to ongoing climate change.
The Arctic stratospheric polar vortex usually forms in autumn, reaches its peak intensity in mid-winter and decays in spring. The polar vortex strength and persistence in the winter–spring period play an important role in stratospheric ozone depletion with the return of solar radiation in late winter. The polar vortex breakdown in most cases occurs under the influence of vertically propagating planetary Rossby waves. The increased activity of planetary waves was observed in 1984/1985, 1998/1999 and 2012/2013 and led to the polar vortex breakdown in mid-winter, after which it was not observed for more than a month. In this study, Arctic sea ice loss is considered as the most likely cause of the increased activity of planetary waves resulting in the unusual weakening of the Arctic polar vortex. Arctic sea ice extent was a record low in autumn 1984, 1998 and 2012 in the Beaufort Sea, the Canadian Arctic Archipelago and the Central Arctic.
Coastal fishery systems in the Arctic are undergoing rapid change. This paper examines the ways in which Inuit fishers experience and respond to such change, using a case study from Pangnirtung, Canada. The work is based on over two years of fieldwork, during which semi-structured interviews (n = 62), focus group discussions (n = 6, 31 participants) and key informant interviews (n = 25) were conducted. The changes that most Inuit fishers experience are: changes in sea-ice conditions, Inuit people themselves, the landscape and the seascape, fish-related changes, and changes in weather conditions, markets and fish selling prices. Inuit fishers respond to change individually as well as collectively. Fishers’ responses were examined using the characteristics of a resilience-based conceptual framework focusing on place, human agency, collective action and collaboration, institutions, indigenous and local knowledge systems, and learning. Based on results, this paper identified three community-level adaptive strategies, which are diversification, technology use and fisheries governance that employs a co-management approach. Further, this work recognised four place-specific attributes that can shape community adaptations, which are Inuit worldviews, Inuit-owned institutions, a culture of sharing and collaborating, and indigenous and local knowledge systems. An examination of the ways in which Inuit fishers experience and respond to change is essential to better understand adaptations to climate change. This study delivers new insights to communities, scientists, and policymakers to work together to foster community adaptation.
Our goal is to study the role of demographic change in the development and spread of maritime adaptations in the North American Arctic over the last 6000 years. We compile and analyze a regional radiocarbon database (n = 935) for northern Alaska, using Oxcal to analyze demographic patterns in summed probability distributions. We find that northern Alaskan populations grew significantly over the last 4500 years, although growth was punctuated by three periods of decline from approximately 3700 to 3125 cal BP, 1000 cal BP, and 600 cal BP. We assess possible alternative explanations for the observed demographic patterns (e.g. calibration and taphonomic effects, investigator bias). Region-wide erosion and calibration effects likely contribute to the dearth of radiocarbon dates around 1000 cal BP, and sampling bias may contribute to the post-600 cal BP decline. However, we conclude that the overall pattern reflects regional population growth, decline, and recovery. Population growth predates intensification of marine resource procurement by at least 1200 years; we hypothesize that population growth was a possible driver for late Holocene marine intensification in the Arctic. These findings have further implications for understanding the process of intensification and the development of complexity in coastal hunter-gatherer societies.
Nares Strait is the northern most outflow gateway of the Arctic Ocean, with a direct connection to the remaining multi-year ice covered central Arctic Ocean. Nares Strait itself flows into the historically highly productive North Water Polynya (Pikialasorsuaq). Satellite data show that Nares Strait ice is retreating earlier in the season. The early season surface chlorophyll signal, which was a characteristic of the North Water, has also moved north into Nares Strait. However, given the vast differences in the hydrography and physical oceanographic structure of the North Water and Nares Strait there is no a priori reason to assume that the species assemblages and overall productivity of this region between Greenland and Canada will be maintained in the face of ongoing sea ice decline. The North Water’s high marine mammal and bird populations are dependent on seasonally persistent diatom dominated phytoplankton productivity, and although there have been several studies on North Water phytoplankton, virtually nothing is known about the communities in Nares Strait. Here we investigated the microbial eukaryotes, including phytoplankton in Nares Strait using high-throughput amplicon sequencing. Samples were collected from Kennedy Channel below the northern ice edge of Nares Strait through the Kane Basin and into the northern limit of the North Water. The physical oceanographic structure and initial community rapidly changed between the faster flowing Kennedy Channel and the comparatively wider shallower Kane Basin. The community changes were evident in both the upper euphotic zone and the deeper aphotic zone. Heterotrophic taxa were found in the deeper waters along with ice algae that would have originated further to the north following release from the ice. Although there was a high proportion of pan-Arctic species throughout, the Nares Strait system showed little in common with the Northern North Water station, suggesting a lack of connectivity. We surmise that a direct displacement of the rich North Water ecosystem is not likely to occur. Overall our study supported the notion that the microbial eukaryotic community, which supports ecosystem function and secondary productivity is shaped by a balance of historic and current processes, which differed by seascape.
The Arctic is a complex geographical area to govern sustainably due to strong geopolitical and socio-economic interests, high ecological vulnerability and importance, and significant legal and institutional fragmentation. Intensifying human pressures in this area necessitate an ecosystem-based and adaptive governance approach, an approach that enables managing socio-ecological resilience in the Arctic. As the Arctic is a large geographic area crossing multiple national jurisdictions and maritime zones, including high seas areas, regionally coordinated and coherent governance approaches would be desirable. This paper assesses the status quo for ecosystem-based governance (EBG) in the Arctic, suggests a focus on three core components of EBG, and proposes three forms of legal coherence to foster these core components. The paper concludes with examining what role the Arctic Council plays and could play to strengthen EBG in the Arctic.
Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to organohalogen compounds (OHCs) in Arctic biota, there has been a considerable number of new Arctic effect studies. Here, we provide an update on the state of the knowledge of OHC, and also include mercury, exposure and/or associated effects in key Arctic marine and terrestrial mammal and bird species as well as in fish by reviewing the literature published since the last AMAP assessment in 2010. We aimed at updating the knowledge of how single but also combined health effects are or can be associated to the exposure to single compounds or mixtures of OHCs. We also focussed on assessing both potential individual as well as population health impacts using population-specific exposure data post 2000. We have identified quantifiable effects on vitamin metabolism, immune functioning, thyroid and steroid hormone balances, oxidative stress, tissue pathology, and reproduction. As with the previous assessment, a wealth of documentation is available for biological effects in marine mammals and seabirds, and sentinel species such as the sledge dog and Arctic fox, but information for terrestrial vertebrates and fish remain scarce. While hormones and vitamins are thoroughly studied, oxidative stress, immunotoxic and reproductive effects need further investigation. Depending on the species and population, some OHCs and mercury tissue contaminant burdens post 2000 were observed to be high enough to exceed putative risk threshold levels that have been previously estimated for non-target species or populations outside the Arctic. In this assessment, we made use of risk quotient calculations to summarize the cumulative effects of different OHC classes and mercury for which critical body burdens can be estimated for wildlife across the Arctic. As our ultimate goal is to better predict or estimate the effects of OHCs and mercury in Arctic wildlife at the individual, population and ecosystem level, there remain numerous knowledge gaps on the biological effects of exposure in Arctic biota. These knowledge gaps include the establishment of concentration thresholds for individual compounds as well as for realistic cocktail mixtures that in fact indicate biologically relevant, and not statistically determined, health effects for specific species and subpopulations. Finally, we provide future perspectives on understanding Arctic wildlife health using new in vivo, in vitro, and in silico techniques, and provide case studies on multiple stressors to show that future assessments would benefit from significant efforts to integrate human health, wildlife ecology and retrospective and forecasting aspects into assessing the biological effects of OHC and mercury exposure in Arctic wildlife and fish.
Mesopelagic sound scattering layers (SSL) are ubiquitous in all oceans. Pelagic organisms within the SSL play important roles as prey for higher trophic levels and in climate regulation through the biological carbon pump. Yet, the biomass and species composition of SSL in the Arctic Ocean remain poorly documented, particularly in winter. A multifrequency echosounder detected a SSL north of Svalbard, from 79.8 to 81.4°N, in January 2016, August 2016, and January 2017. Midwater trawl sampling confirmed that the SSL comprised zooplankton and pelagic fish of boreal and Arctic origins. Arctic cod dominated the fish assemblage in August and juvenile beaked redfish in January. The macrozooplankton community mainly comprised the medusa Cyanea capillata, the amphipod Themisto libellula, and the euphausiids Meganyctiphanes norvegica in August and Thysanoessa inermis in January. The SSL was located in the Atlantic Water mass, between 200–700 m in August and between 50–500 m in January. In January, the SSL was shallower and weaker above the deeper basin, where less Atlantic Water penetrated. The energy content available in the form of lipids within the SSL was significantly higher in summer than winter. The biomass within the SSL was >12-fold higher in summer, and the diversity of fish was slightly higher than in winter (12 vs. 9 species). We suggest that these differences are mainly related to life history and ontogenetic changes resulting in a descent toward the seafloor, outside the mesopelagic layer, in winter. In addition, some fish species of boreal origin, such as the spotted barracudina, did not seem to survive the polar night when advected from the Atlantic into the Arctic. Others, mainly juvenile beaked redfish, were abundant in both summer and winter, implying that the species can survive the polar night and possibly extend its range into the high Arctic. Fatty-acid trophic markers revealed that Arctic cod mainly fed on calanoid copepods while juvenile beaked redfish targeted krill (Thysanoessa spp.). The relatively high biomass of Arctic cod in August and of redfish in January thus suggests a shift within the SSL, from a Calanus-based food web in summer to a krill-based food web during winter.
The historic influence of interannual weather and climate variability on total mercury concentrations (THg) in the eggs of two species of Arctic seabird in the Canadian High Arctic was investigated. Time series of THg in the eggs of northern fulmars (Fulmarus glacialis) and thick-billed murres (Uria lomvia) from Prince Leopold Island span 40 years (1975–2014), making these among the longest time series available for contaminants in Arctic wildlife and uniquely suitable for evaluation of long-term climate and weather influence. We compiled a suite of weather and climate time series reflecting atmospheric (air temperature, wind speed, sea level pressure) and oceanic (sea surface temperature, sea ice cover) conditions, atmosphere-ocean transfer (snow and rain), as well as broad-scale teleconnection indices such as the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO). We staggered these to the optimal time lag, then in a tiered approach of successive General Linear Models (GLMs), strategically added them to GLMs to identify possible key predictors and assess any main effects on THg concentrations. We investigated time lags of 0 to 10 years between weather/climate shifts and egg collections. For both fulmars and murres, after time lags of two to seven years, the most parsimonious models included NAO and temperature, and for murres, snowfall, while the fulmar model also included sea ice. Truncated versions of the datasets (2005–2014), reflective of typical time series length for THg in Arctic wildlife, were separately assessed and generally identified similar weather predictors and effects as the full time series, but not for NAO, indicating that longer time series are more effective at elucidating relationships with broad scale climate indices. Overall, the results suggest a significant and larger than expected effect of weather and climate on THg concentrations in Arctic seabirds.
While hydrocarbon exploration and extraction in the Arctic ebb and flow, reduced sea ice has opened new travel routes across the Arctic. The opening of the Northwest Passage has allowed larger ships (including oil tankers) and higher traffic into remote regions. More ice loss is expected in the future. With this comes the potential for hydrocarbon spills. To quantify the ecosystem impacts of a spill in the Alaska North Slope region, an Ecospace model using the Ecopath with Ecosim software was developed. We highlight the impacts of four potential hydrocarbon contamination scenarios: a subsurface crude oil pipeline release, a surface platform oil spill, a surface cruise ship diesel spill, and a surface tanker oil spill. Hydrocarbon contamination was modeled using SIMAP (Spill Impact Model Analysis Package), which was developed from the oil fate sub-model in the Natural Resource Damage Assessment Model for the US Department of the Interior and under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA). Spatial-temporal SIMAP results were coupled to the Ecospace model. We show that in all four hydrocarbon contamination scenarios, there are spatial changes in harvested species resulting in long-term declines in harvest levels for the communities within the model area (Nuiqsut, Kaktovik, and Barrow Alaska), depending on the severity of the scenario. Responses to hydrocarbon events are likely to be slow in the Arctic, limited by the ice-free season. We highlight this area for scenario testing as ecological impacts are also an issue of food security to the local communities and human health issue.