Pond Inlet Research Articles

Only the Greenhouse Gas, Water Vapor, Measurably Warms the Earth

Data is available for the 61 greenhouse gases (GHGs) in Table 2.14 of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) to calculate their contribution to global warming in degrees Celsius. The procedure is described in the recently published study Reliable Physics Demand Revision of the IPCC Global Warming Potentials. In the current study, the contribution was calculated for each 61 GHG. The sum of the contributions of the 61 GHGs was 0.00833oC out of 26oC, which, for this example, is the difference in temperature between Pond Inlet and Amsterdam. This amount of temperature is too small to measure. Thus, with all other GHGs except water vapor eliminated as warming gases, water vapor is the only GHG that causes measurable warming of the Earth’s atmosphere. This is the exact result of the mathematical model of the Earth’s atmosphere developed in 1904 by Willis Carrier, i.e., the psychrometric chart, which is now a computer program, i.e., Humidair. Thus, the two methods used 120 years apart are robust and give the same result, confirming the unique role of water vapor in the temperature of Earth’s atmosphere and the virtually non-temperature role of the 61 GHGs.

A typology of Inuit youth engagement in environmental research

The roles of Indigenous youth in environmental research remain largely unexplored with little practical guidance for achieving meaningful engagement in environmental research. This paper aims to characterize the varying types of Inuit youth engagement in environmental research conducted in Inuit Nunangat. Findings were derived from a community-engaged participatory research approach in Mittimatalik (Pond Inlet, Nunavut). Our typology of Inuit youth engagement in environmental research suggests three types of engagements: “participate”, “conduct”, and “control”. Results highlight that Inuit youth who are interested in undertaking their own environmental research projects expect to enhance their knowledge of natural and life sciences more than those who may seek short-term supportive research roles. Strategies employed by researchers seeking to enhance youth research capacity may also vary based on youth wants and expectations. Our findings suggest that there is no one-size-fits all solution. None of the engagement types identified were necessarily and inherently considered better than the others by project contributors, unlike what has been proposed in other, hierarchical, typologies. Our proposed typology contributes to a better understanding of the varying roles that Inuit youth can play in environmental research, as well as inform potential frameworks for enhancing Inuit youth engagement and leadership in research.

Surveillance for Zoonotic Pathogens and Inuit Qaujimajatuqangit of Ringed Seals (nattiit) (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada

Ringed seals (Pusa hispida) (nattiq (s.), nattiit (pl.) [Inuktut]) provide an important food staple for Nunavummiut (Indigenous residents of Nunavut). We studied the health of nattiit harvested by hunters from Baffin Island, Nunavut, via Inuit Qaujimajatuqangit and veterinary science. We conducted serological surveys and polymerase chain reaction (PCR) for select zoonotic pathogens, including Brucella spp., Erysipelothrix rhusiopathiae, Leptospira interrogans, and Toxoplasma gondii, in 55 nattiit from Frobisher Bay (FB) and 58 nattiit from Eclipse Sound (ES). We used a digestion assay to determine the presence of Trichinella spp. larvae in muscle samples from these seals. We conducted interviews with nine Local Knowledge Holders (LKHs) from Iqaluit (FB) and nine from Pond Inlet (ES) to gather their observations about nattiq health. The hunters evaluated nattiq health through a combination of behavior, nutritional condition, and appearance of skin and organs. They rarely observed severely ill nattiit. Hunters from ES but not from FB observed declining nattiit population numbers. In both regions, they observed increased numbers of harp seals (Phoca groenlandica). Frequencies of natural exposure among nattiit from FB and ES, based on seroprevalence, were 20.5% and 37% for Brucella spp., 25% and 11% for E. rhusiopathiae, 93% and 100% for L. interrogans, and 10% and 27% for T. gondii, respectively; PCR was negative for these pathogens in organs and tissues of seropositive animals. We did not detect larvae of Trichinella spp. Knowledge and experience from the LKHs in assessing nattiq health, complemented by negative findings from direct detection methods, provide reassurance about the safety of nattiit as country food, despite their exposure to some zoonotic pathogens in their natural environment.

Inlet retrofitting improves the hydraulic performance of a waste stabilization pond

Wastewater is transitioning from being viewed as a waste to being utilized as a resource in the production of reclaimed water. Reclaimed water, obtained through waste stabilization pond treatment technologies, has the potential to offset potable water needs for irrigation purposes as well as fertilizers for crop growth. In developing countries, where waste stabilization ponds are widely used, a major issue is the lack of maintenance which can lead to considerable amounts of sludge piled at the bottom of the pond. This sludge accumulation reduces the treatment capacity of the waste stabilization pond and possibly, the treatment efficiency which is vital for reuse purposes. In cases for which desludging of the pond is a challenge, retrofitting the pond inlet can offer an alternative to improve pond hydraulic performance. In this study, two inlet retrofit geometries are investigated in a waste stabilization pond with significant sludge accumulation using computational fluid dynamics. It is seen that retrofitting the pond with a three-way pipe inlet increases the mean residence time of the pond from 21.9 days to 25 days over a single pipe inlet while significantly reducing the strength of short-circuiting.

Phytoplankton Population as Phytoremediation Agents in Jatibarang Landfill Leachate Pond of Central Java, Indonesia

Remediation of microalgae from leachate is less explored because of its very high level of pollutants such as ammonia-nitrogen, heavy metals, inorganic salts, and organic chlorinated. Moreover, leachate poisons many organisms. This study aimed to determine the phytoplankton species in the leachate pond Jatibarang landfill, Central Java, Indonesia, and as an effort in phycoremediation. Sample was obtained from 4 stations; Inlet pond (J1), aerobic pool (aeration pool) (J2), sedimentation pond (J3), and pond outlet (J4). The results showed two phytoplankton species, Chlorella sp. and Chlamydomonas sp. Based on the abundance of Chlorella sp., the highest number was found at sedimentation pond with an average of 54,904 cells L-1, followed by pond outlet with an average of 17,449 cells L-1, aerobic pool with an average of 8,869 cells L-1, and pond Inlet with an average of 3,424 cells L-1. Chlamydomonas sp. was only found at pond Inlet with an average of 12,375 cells L-1. Further, the BOD decreased from station 2, 3, and 4 with percentages 12%, 29%, and 32%, respectively; COD gained 28%, 33%, 33%, respectively; and TSS, respectively, gained 22%, 35%, and 30%. To sum up, the pond’s water quality as producing leachate in Jatibarang landfill concerning pH, DO, and Cd are still below the leachate quality standard. Whereas the BOD, COD, and TSS exceed leachate quality standards.

Computational fluid dynamics modeling of floating treatment wetland retrofitted stormwater pond: Investigation on design configurations

Floating Treatment Wetland (FTW) is a cost-effective and easy-to-retrofit device for stormwater treatment. Its treatment efficiency largely depends on the fraction of inflow entering FTW and the residence time within it. Thus hydrodynamics play a crucial role, which is affected by the design configurations of FTW and stormwater pond. Despite a spike in research on FTWs, very little is known about how various design configurations affect treatment efficiency by an FTW. Our study hypothesizes that relative positions of FTW geometry, FTW position and pond inlet–outlet have impact on the hydrodynamics and as a consequence, treatment efficiency. To explore these design features, we employed computational fluid dynamics (CFD) modeling conducted in ANSYS Fluent, validated by experimental data to examine the impact of the aforementioned design features. The results revealed that circular FTW geometry positioned near inlet coupled with center inlet–side outlet configuration achieved the highest removal (94.8%) for a non-dimensional removal rate of krtHRT = 20 (kr is the first order removal rate in per day, tHRT is the nominal hydraulic residence time of the pond in days). Far side inlet–side outlet configuration performed the worst due to profound promotion of short-circuiting. FTW positioned near inlet performed better (61.8% mass removal on an average) than center (42.7%) and near outlet positions (54.1%) for krtHRT = 20. Sensitivity analysis revealed that the treatment efficiency is most sensitive to inlet–outlet configurations. The design implications of this study will help practitioners achieving better water quality and ecological improvement goals.

Development of a mobile energy system with offshore floating nuclear reactor and onshore solar energy system

In this study, a novel nuclear and solar hybridized energy system with onshore and offshore components is designed, analyzed and assessed by using thermodynamic-based energy and exergy approaches. A high-temperature gas-cooled pebble bed reactor is considered in the floating nuclear plant to integrate with a bifacial photovoltaic (PV) plant in order to supply heat and electricity to four different communities. The process/waste heat and excess electricity are exploited via the thermochemical copper-chlorine hydrogen production cycle to store the energy in a chemical form. The offshore floating nuclear plant is integrated with an onshore energy system in various locations to be able to cover the needs more communities. As a case study, The cities, namely Iqaluit, Rankin Inlet, Pond inlet, and Cambridge Bay, in Nunavut, Canada, are investigated with thermodynamic-based analyses. A time-dependent thermodynamic analysis is carried out by using hourly meteorological data and a shift schedule due to the demands of those communities. The integrated system potentially designed for the city of Iqaluit consists of a 25 MWp bifacial PV plant, a polymer electrolyte membrane (PEM) fuel cell stack at 15 MW capacity, a 150 MWth offshore-based floating nuclear power plant, which is coupled to a copper-chlorine-based thermochemical cycle for hydrogen production. This integrated system, which is extensively analyzed thermodynamically under dynamic conditions, is able to produce a total of 1648 tons of hydrogen, 47,239 MWh of electricity and 75,900 MWh of heat in a typical meteorological year. For the floating nuclear plant’s connected period, both energy and exergy efficiencies are found to be 24.5 % and 19.7 %, respectively. During the floating nuclear plant’s disconnected period, the energy and exergy efficiencies are calculated as 39.9 % and 46.0 %, respectively.

Multi-dietary tracer approach reveals little overlap in foraging ecology between seasonally sympatric ringed and harp seals in the high Arctic

The rapid rate of climate change in the Arctic is causing broad-scale changes to the physical environment and biological communities. Characterizing the foraging ecology and habitat use of Arctic marine top predators of high ecological and cultural significance is essential to our understanding of their vulnerability to ecosystem change, especially when there is potential for dietary resource competition in spatially co-occurring species. We therefore undertook this study to explore dietary resource competition between seasonally sympatric ringed seals (Pusa hispida) and harp seals (Pagophilus groenlandicus) in Mittimatalik (previously known as Pond Inlet), Nunavut, Canadian Arctic. We used bulk stable isotopes (δ13C and δ15N), fatty acid-specific carbon isotopes (δ13C), fatty acid profiles, and diatom lipid biomarkers in a multi-tracer framework to track carbon and trophic pathways in liver and muscle of both seal species. Altogether, the dietary tracers showed little overlap in the diet between ringed seals and harp seals when they co-occurred in the open-water season in northwest Baffin Bay. Though a high dependence on sea ice-derived carbon sources for both species was found, dietary tracers suggested that ringed seals relied to a far greater extent on sympagic carbon sources (~80% vs. 50% for harp seals) and a greater extent of benthic/coastal prey species compared to the more pelagic feeding harp seals. Ringed seal samples were available year-round, and analyses revealed a clear seasonal pattern of foraging on sympagic and benthic prey during ice-covered months of the year and shifting to greater reliance on pelagic prey during the summer open-water season. Overall, ringed seals may be more vulnerable to changes in sea-ice dynamics in the rapidly changing Arctic than harp seals, though it remains difficult to predict future dietary plasticity and competition between co-occurring top predators in an increasingly ice-free Arctic with a changing prey community.

SOGC Guideline Retirement Notice No. 2

SOGC Guideline Retirement Notice No. 2

On the Moments of Probability Distribution Function of Amplitude Scintillation in the Polar Region

AbstractThe distortions seen in the Global Navigation Satellite Systems radio signal caused by ionospheric irregularities in the polar region are examined through the lens of probability distributions of fluctuations in the recorded scintillation signals. The first four moments of the probability distribution function (PDF) of the amplitude scintillation are computed and analyzed for 106 events collected at Pond Inlet station [Magnetic Coordinates = (80.0°N, 2.6°E)]. As a starting point, the background variation level is investigated using similar computations carried out with about 400 30‐s window segments. The resulting distribution for the skewness (third moment) and the kurtosis (fourth moment) strongly indicate that the background fluctuations are nearly Gaussian; given the computed variances, the Rayleigh distribution hypothesis is ruled out. In the case where scintillation is present, we found that the skewness distribution nearly overlaps with the background while the excess kurtosis strongly indicates a departure from normality. More precisely, the PDF appear mostly symmetric and leptokurtic (positive kurtosis K) and exhibit, in some cases, significant flatness (K ∼ 1). These results reveal that the analyzed scintillations are statistically consistent with stationarity and therefore vanishing skewness. Moreover, the empirical moments are compared with those derived from probability densities referred in the literature regarding scintillations. We have found that none of the log‐normal, Nakagami, Rician and α–μ distributions account for the analyzed data. The generalized Gaussian distribution with a shape parameter 1 < β < 2 seems the most probable and the most adequate to account for the results.

Inuit youth-engaged community-based environmental research as supporting local development in Nunavut, Canada

ABSTRACT Community leadership in Arctic environmental research is increasingly recognized to contribute to Indigenous self-determination and sustainable development in the Arctic. While experienced Inuit harvesters, hunters, trappers, and other recognized environmental knowledge experts are largely included in research, similar opportunities for Inuit youth remain limited. Our study explored pathways for community-based engagement in environmental research to serve as a form of experiential learning for Inuit youth and enhance capacity in Arctic communities. For that, we examined, through interviews and workshops, the perspectives of 41 northerners from Pond Inlet (Mittimatalik), Nunavut, including 19 Inuit youth aged between 18 and 35 years old. We found that mentor-mentee relationships between researchers and Inuit youth may enhance scientific literacy and complement traditional learning pathways and observational learning. On the other side, by engaging Inuit youth, researchers may benefit from the experiences and knowledge of this new generation of northern Indigenous peoples uniquely positioned to value multiple worldviews in designing studies that address local priorities.

Early seed dynamics and tidal marsh revegetation of a salt pond following tidal reconnection

AbstractQuestion(1) Following reconnection, does ground cover in the pond become similar to mature salt marsh sites over time? (2) Do seed densities and species composition of seed banks and seed rain differ between the pond and mature salt marsh, and between elevations? (3) Do seed densities vary over time? (4) Within the pond, can seed densities be explained by the abundance of reproductive plants, elevation, or distance from the pond inlet.LocationDry Creek salt field, South Australia.MethodsWe sampled seed rain (monthly) and seed banks (every three months) 6 to 18 months after tidal reconnection and surveyed ground cover (plant species, logs, seagrass wrack and bare ground) up to 34 months after reconnection. Samples were collected from the pond and from mature marsh vegetation at a reference site, and a site immediately adjacent to the pond inlet.ResultsVegetation cover in the pond increased more quickly at mid elevations compared with low elevations. Regarding the composition of ground cover, seed rain and seed banks, the site became more similar to the adjacent site than to the reference site. Seed densities increased from late autumn to early winter. The pattern of seed densities across sites and elevations differed between seed rain and seed banks. Seeds of Salicornia quinqueflora and Suaeda australis dominated in the pond, reflecting their high seed densities adjacent to the pond inlet. Variation in seed densities of both species in the pond was explained by the abundance of nearby, reproductive conspecifics but not by the distance from the inlet.ConclusionsEarly stages of salt marsh revegetation were driven by tidal import of seeds and by the rapid seed production of early colonising species; however, low seed densities may reduce rates of revegetation at low elevations. Seed dispersal and revegetation may be maximised by undertaking tidal reconnection when seed densities are highest.

“When We’re on the Ice, All We Have is Our Inuit Qaujimajatuqangit”: Mobilizing Inuit Knowledge as a Sea Ice Safety Adaptation Strategy in Mittimatalik, Nunavut

Increased variability in weather and sea ice conditions due to climate change has led to high rates of injury, trauma, and death for Inuit travelling on the sea ice. Contributing to these high rates are the ongoing effects of colonial policies that diminish and disrupt the intergenerational transfer of sea ice Inuit Qaujimajatuqangit (IQ). Despite these challenges, place-based experiential IQ continues to be the most important information source for safe travel on the sea ice. This paper presents an Inuit-led, coproduced, cross-cultural research project in which Inuit youth documented and mobilized sea ice IQ in Mittimatalik (Pond Inlet), Nunavut for safe community sea ice travel. We outline the Inuit youth training to facilitate the terminology and participatory mapping workshops and to document this IQ. We also discuss the IQ that was most important to share, and the mapping and artistic methods used to mobilize this IQ into a booklet, maps, and posters. Inuktitut sea ice terms are the foundation to enable youth with the skills to learn about sea ice IQ with experienced hunters. IQ enables Inuit to interpret and synthesize information from weather forecasts, earth observations, and community-based monitoring to apply to local conditions. Seasonal IQ maps of safe and hazardous sea ice conditions provide travel planning information at spatial and temporal scales that supplemental information sources cannot address. The IQ products mobilize preparedness, situational awareness, navigation, and interpretation skills so Inuit youth can become more self-reliant, as access to technology is not always possible once out on the sea ice.

Inuit youth and environmental research: exploring engagement barriers, strategies, and impacts

Community leadership in Arctic environmental research is increasingly recognized as one of many pathways to Indigenous self-determination in Nunavut, Canada. While experienced Inuit hunters, trappers, and other recognized environmental knowledge experts are commonly included in research, similar opportunities for Inuit youth to meaningfully engage in environmental research remain limited. Finding ways to increase scientific literacy, particularly among Inuit youth, has been identified as an important step in the continuation of high-quality Arctic environmental research. This paper examines community perspectives on the roles and contributions of Inuit youth in environmental research in Nunavut, barriers that Inuit youth face in becoming meaningfully engaged in field-based environmental research, and strategies for enhancing Inuit youth engagement. Our study was conducted in Pond Inlet, Nunavut, and used interviews, workshops, and observation to gather stories and knowledge from community members about field- and land-based experiential learning pathways. This study found that a complex set of barriers, including a lack of credentials and support systems, among others, may inhibit meaningful Inuit youth engagement in environmental research. Key findings from the study support the view that collaborative land-based research activities can be an effective and meaningful method of enhancing scientific literacy among Inuit youth.

Beytepe Göleti’nin Zooplankton Faunası Üzerine Bir Ön Çalışma (Ankara/Turkey)

In this research, zooplankton and some water quality parameters were investigated in Beytepe Pond (Ankara / Turkey). The material of the study consists of zoplankton samples taken from 3 stations (3 zones on the pond) and water quality parameters taken from 5 stations (3 zones on the pond and pond inlet and outlet zones) in the field study on 24.09.2018. When evaluated according to general chemical and physicochemical parameters of inland water resources; In terms of nitrate nitrogen and orthophosphate values, the pond is of 2nd class quality; According to the same criteria, it was found as 3rd quality in terms of total nitrogen and total phosphorus. A total of 13 zooplankton species were identified. Rotifera groups (85%) and Cladocera (15%) were detected in the pond. The maximum number of species was found at the 1st station (11 species), and the minimum number of species was determined at the 2nd and 3rd (5 species) stations. The dominant species were determined as Polyarthra dolichoptera, Keratella cochlearis and Trichocerca pusilla.

Restoring a Degraded, Sentinel New England Salt Marsh to Mid-20th Century Conditions (Flax Pond, New York, U.S.A.)

Swanson, R.L.; Giglio, K.W., and Chi, L., 2021. Restoring a degraded, sentinel New England salt marsh to mid-20th century conditions (Flax Pond, New York, U.S.A.). Journal of Coastal Research, 37(5), 993–1011. Coconut Creek (Florida), ISSN 0749-0208. Flax Pond, located between Crane Neck and Old Field Point on the north shore of Long Island, is designated as a Significant Coastal Fish and Wildlife Habitat by the U.S. Fish and Wildlife Service and as a Scenic Recreational Reserve by the New York State Department of Environmental Conservation. The pond's tidal prism has been reduced about 18% over the past half-century as its inlet has shoaled and its tidal range diminished 33%, 0.6 m, all in low water. Reduced flushing has led to loss of wetlands, reduced water quality, increased pond salinity, and nighttime summertime hypoxia with concomitant reduction in pH. Historic charts, topographic surveys, and vertical aerial photographs were used to study the evolution of the pond's inlet from Long Island Sound (LIS). Tide, tidal current, and water quality observations were made and/or historical measurements were acquired at these locations: the pond's inlet, a proposed seawater intake for the Flax Pond Marine Laboratory, and the U.S. Geological Survey (USGS) water quality station some 650 m into the pond. The flux of water through the inlet from LIS and the change in bed slope through the pond inlet were measured. USGS data within the pond were used to determine when hypoxic conditions are likely to occur: an increase in bottom-water salinity of 2.1 in 9 years and in the elevation of low water of 18 mm y–1 from 2008–14. The environmental benefits of reconfiguring the inlet to increase the tidal prism to that of the 1970s were explored. This would reduce the existing flushing time by more than 50%. The design of the cross-sectional shape for the inlet is based on this tidal prism and a compatible depth entering LIS; it should stabilize the inlet opening and improve much needed pond flushing.

Changes in Bacterial Communities During Treatment of Municipal Wastewater in Arctic Wastewater Stabilization Ponds

Wastewater stabilization ponds (WSPs) are commonly used to treat municipal wastewater in the Canadian Arctic. Bacterial community structure and functionality remain mostly uncharacterized for arctic WSPs, yet are presumed important for treatment outcomes during the 3-month summer treatment season with open water in the WSPs. The objective of this study was to investigate treatment performance and related temporal and spatial changes in the structure and putative function of bacterial communities during treatment of municipal wastewater in the WSPs of Pond Inlet and Clyde River, Nunavut over two consecutive summer treatment seasons. Influent raw wastewater contained a high organic load and large bacterial communities (~9 log 16S rRNA copies/mL) belonging mainly to Proteobacteria. Although designed to be facultative ponds, both WSPs remained anaerobic with neutral pH values (7.5–7.8) throughout the summer treatment season. Water quality data showed that nutrients [measured as carbonaceous biological oxygen demand (CBOD5)], total suspended solids, and total ammonia nitrogen were progressively reduced during treatment in the ponds as the summer progressed. The pond bacterial population size and species richness depended on the pond temperature (2–18°C), with 8.5 log 16S rRNA copies/mL and the largest alpha diversities (Shannon-Wiener index of 4-4.5) observed mid-season (late July). While the phylogenetic beta diversity in raw wastewater from the two locations remained similar, pond bacterial communities underwent significant (p < 0.05) changes to dominance of Comamonadaceae, Geobacteracea, and Porphyromonadaceae. Multivariate distance based redundancy analysis and predicted gene functionalities in the microbiota agreed with water quality results that microbial removal of nutrients (e.g., CBOD5) peaked in the middle of the summer coinciding with the treatment period with the highest pond temperatures. Information from this study will be useful for further development of models to predict biological treatment outcomes, which could be used to size and assess the feasibility of WSPs in extreme climates. Higher pond temperatures resulted in optimal biological processes and nutrient removal in the middle of the summer. While it is challenging to control environmental factors in a passive wastewater treatment system there are some design considerations that could be used to optimize temperature regimes, such as the depth of the pond.

Sila qanuippa? (how's the weather?): Integrating Inuit Qaujimajatuqangit and environmental forecasting products to support travel safety around Pond Inlet, Nunavut in a changing climate

AbstractAs Inuit hunters living in Pond Inlet, Nunavut, we (Natasha Simonee and Jayko Alooloo) travel extensively on land, water, and sea ice. Climate change, including changing sea ice and increasingly unpredictable weather patterns, has made it riskier and harder for us to travel and hunt safely. Inuit knowledge supporting safe travel is also changing and shared less between generations. We increasingly use online weather, marine, and ice products to develop locally relevant forecasts. This helps us to make decisions according to wind, waves, precipitation, visibility, sea ice conditions, and floe edge location. We apply our forecasts and share them with fellow community members to support safe travel. In this paper, we share the approach we developed from over a decade of systematically and critically assessing forecasting products such as: Windy.com; weather and marine forecasts; tide tables; C-CORE’s floe edge monitoring service; SmartICE; ZoomEarth; and time lapse cameras. We describe the strengths and challenges we face when accessing, interpreting, and applying each product throughout different seasons. Our analysis highlights a disconnect between available products and local needs. This disconnect can be overcome by service providers adjusting services to include: more seasonal and real-time information, non-technical language, familiar units of measurement, data size proportional to internet access cost and speed, and clear relationships between weather/marine/ice information and safe travel. Our findings have potential relevance in the Circumpolar Arctic and beyond, wherever people combine Indigenous weather forecasting methods and online information for decision-making. We encourage service providers to improve product relevance and accessibility.

Ontogenetic profiles of dentine isotopes (δ15N and δ13C) reveal variable narwhal Monodon monoceros nursing duration

Stable isotope analysis (SIA) of sequential dentine growth layer groups can be used to estimate the lifetime diet of individuals and infer major ontogenetic shifts such as the completion of nursing. We used SIA of dentine from narwhalMonodon monocerosembedded canine teeth to investigate ontogenetic dietary patterns, with a focus on nursing duration. We also determined whether nursing duration differed between sexes and between 2 periods during which narwhals may have undergone dietary shifts due to warming. Embedded teeth from both sexes were collected near Pond Inlet, Nunavut, Canada, in 1982 and 1983 (n = 17) and 2015 and 2017 (n = 14). Nursing duration ranged from ~2 to ~6 yr, with 60% of narwhals being nursed beyond the previously published estimate of <2 yr. The proportion of individuals nursed <2 yr versus >2 yr did not differ between sexes or periods. This study not only revealed that narwhals vary extensively in their nursing duration, but also indicated that extended nursing (>2 yr) with gradual introduction of solid food over this period was common. These findings provide insights into narwhal life-history strategies, as extended nursing may be another feature of a long-lived, slow-reproducing mammal adapted to unique polar conditions that are threatened by global warming.

Long-term consequences of goose exclusion on nutrient cycles and plant communities in the High-Arctic

Geese can profoundly affect arctic ecosystems directly (e.g., by grazing vegetation) and indirectly (e.g. by changing nutrient cycling resulting from faces inputs and by reducing plant litter). In the Arctic, behavior and abundance of geese have changed due to climate and land-use change. While the short-term effects of increased goose populations on tundra ecosystems are known, there is a knowledge gap for long-term consequences of goose population changes on nutrient cycling and plant communities, especially in the High-Arctic. Here, we compared wetland sites where geese have been almost absent for at least 50 years (Pond Inlet), and nearby sites where geese are abundant or sites where they have been excluded experimentally by cages and where the ground has been experimentally fertilized for over 16 years (Bylot Island). Long-term goose disappearance increased inorganic nutrients in wetlands through increased plant litter decomposition and changed community composition, likely by altering competitive relationships between three dominant vascular plant species that are different in terms of nutrient acquisition and use. In experimentally fertilized sites, inorganic nutrients were similarly increased, but fertilization had contrast effects on plant community composition compared with herbivory, released plant species from the nutrient limitation and converted wetland habitats to a dryer state. Overall, our results suggest that the direct effects of goose herbivory on vegetation are more profound than their indirect effects through an alternation of nutrient cycling even in nutrient-limited wetlands of the Arctic. These findings emphasize the need to assess long-term direct impacts of herbivores on vegetation.