Community Monitoring of Environmental Change: College-Based Limnological Studies at Crazy Lake (Tasirluk), Nunavut

In light of the difficult logistics and high cost of polar research into climate change, involvement of local people can contribute immensely to important data collection. One can use the knowledge and skills of human resources that are already present—teachers, students, and community members. An example is the long-term Arctic monitoring program established at Crazy Lake (63°51' N, 68°28' W) near Iqaluit, Nunavut, to monitor snow and ice thickness, biological components, and water chemistry. Nunavut Arctic College students collected basic limnological data at Crazy Lake during spring field camps held between 10 and 16 April in 2005 and 2006. Mean snow depth ± SD for Crazy Lake was 0.46 ± 0.13 m (n = 24). White ice averaged 0.13 ± 0.12 m and black ice 1.38 ± 0.28 m. Total ice thickness (white ice + black ice) ranged between 0.91 and 1.91 m (mean = 1.51 ± 0.22 m). The total lake cover (snow + ice) averaged 1.97 ± 0.20 m. Water depth ranged from 1.48 to 18.58 m (mean = 10.10 ± 4.99 m).À la lumière de la complexité de la logistique et du coût élevé de la recherche polaire en matière de changement climatique, la participation des gens de la collectivité de la région à la collecte des données peut jouer un rôle très important en ce sens qu’il est possible de recourir aux connaissances et aux compétences des ressources humaines déjà en place, comme les enseignants, les élèves et les membres de la collectivité. Le programme de surveillance de l’Arctique de longue date établi au lac Crazy (63°51' N, 68°28' O) près d’Iqaluit, au Nunavut, en constitue un exemple. Ce programme vise à surveiller l’épaisseur de la neige et de la glace, de même que leurs composantes biologiques et la composition chimique de l’eau. Les élèves du collège Nunavut Arctic ont recueilli des données limnologiques de base au lac Crazy à l’occasion d’études sur le terrain réalisées au printemps 2005 et 2006, du 10 au 16 avril. Au lac Crazy, l’épaisseur moyenne de neige ± DS était de 0,46 ± 0,13 m (n = 24). La glace blanche atteignait en moyenne 0,13 ± 0,12 m et la glace noire, 1,38 ± 0,28 m. L’épaisseur totale de glace (glace blanche + glace noire) variait entre 0,91 et 1,91 m (moyenne = 1,51 ± 0,22 m). La couche du lac (neige + glace) atteignait en moyenne 1,97 ± 0,20 m, tandis que l’épaisseur de l’eau variait entre 1,48 et 18,58 m (moyenne = 10,10 ± 4,99 m)

Urinary tract infections in children after renal transplantation

Urinary tract infections (UTI) after pediatric kidney transplantation (KTX) are an important clinical problem and occur in 15–33% of patients. Febrile UTI, whether occurring in the transplanted kidney or the native kidney, should be differentiated from afebrile UTI. The latter may cause significant morbidity and is usually associated with acute graft dysfunction. Risk factors for (febrile) UTI include anatomical, functional, and demographic factors as well as baseline immunosuppression and foreign material, such as catheters and stents. Meticulous surveillance, diagnosis, and treatment of UTI is important to minimize acute morbidity and compromise of long-term graft function. In febrile UTI, parenteral antibiotics are usually indicated, although controlled data are not available. As most data concerning UTI have been accumulated retrospectively, future prospective studies have to be performed to clarify pathogenetic mechanisms and risk factors, improve prophylaxis and treatment, and ultimately optimize long-term renal graft survival

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

High contributions of sea ice derived carbon in polar bear (Ursus maritimus) tissue.

Polar bears (Ursus maritimus) rely upon Arctic sea ice as a physical habitat. Consequently, conservation assessments of polar bears identify the ongoing reduction in sea ice to represent a significant threat to their survival. However, the additional role of sea ice as a potential, indirect, source of energy to bears has been overlooked. Here we used the highly branched isoprenoid lipid biomarker-based index (H-Print) approach in combination with quantitative fatty acid signature analysis to show that sympagic (sea ice-associated), rather than pelagic, carbon contributions dominated the marine component of polar bear diet (72-100%; 99% CI, n = 55), irrespective of differences in diet composition. The lowest mean estimates of sympagic carbon were found in Baffin Bay bears, which were also exposed to the most rapidly increasing open water season. Therefore, our data illustrate that for future Arctic ecosystems that are likely to be characterised by reduced sea ice cover, polar bears will not only be impacted by a change in their physical habitat, but also potentially in the supply of energy to the ecosystems upon which they depend. This data represents the first quantifiable baseline that is critical for the assessment of likely ongoing changes in energy supply to Arctic predators as we move into an increasingly uncertain future for polar ecosystems

Data from: Dietary habits of polar bears in Foxe Basin, Canada: possible evidence of a trophic regime shift mediated by a new top predator

Polar bear (Ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. In the Foxe Basin region of Nunavut, Canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. We used fatty acid analysis to examine polar bear feeding habits in Foxe Basin and thus potentially identify ecological factors contributing to population stability. Adipose tissue samples were collected from 103 polar bears harvested during 2010–2012. Polar bear diet composition varied spatially within the region with ringed seal (Pusa hispida) comprising the primary prey in northern and southern Foxe Basin, whereas polar bears in Hudson Strait consumed equal proportions of ringed seal and harp seal (Pagophilus groenlandicus). Walrus (Odobenus rosmarus) consumption was highest in northern Foxe Basin, a trend driven by the ability of adult male bears to capture large-bodied prey. Importantly, bowhead whale (Balaena mysticetus) contributed to polar bear diets in all areas and all age and sex classes. Bowhead carcasses resulting from killer whale (Orcinus orca) predation and subsistence harvest potentially provide an important supplementary food source for polar bears during the ice-free period. Our results suggest that the increasing abundance of killer whales and bowhead whales in the region could be indirectly contributing to improved polar bear foraging success despite declining sea ice habitat. However, this indirect interaction between top predators may be temporary if continued sea ice declines eventually severely limit on-ice feeding opportunities for polar bears

Polar bear (<i>Ursus maritimus</i>) data.

<p>a) QFASA estimates of marine mammal prey (Bearded seal <i>(Erignathus barbatus</i>), beluga whale (<i>Delphinapterus leucas</i>), harbour seal (<i>Phoca vitulina</i>), harp seal (<i>Pagophilus groenlandicus</i>), ringed seal (<i>Pusa hispida</i>) and walrus (<i>Odobenus rosmarus</i>)) consumed by individual polar bears (stacked coloured bars) and overlaid with H-Prints (black circles) of individual bears. Individual polar bears are grouped according to the geographical location of collection and the corresponding subpopulation designation: Baffin Bay, western Hudson Bay and southern Hudson Bay (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0191631#pone.0191631.g002" target="_blank">Fig 2</a>). For each subpopulation, mean QFASA estimates of marine mammal prey and mean (black circles) and median (grey diamonds) H-Prints are summarised in the single plot adjacent to each subpopulation plot (for H-Print-derived estimates of sympagic carbon, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0191631#pone.0191631.t001" target="_blank">Table 1</a>). b) δ¹⁵N of individual bears (grey squares). For each subpopulation, mean δ¹⁵N are summarised in the single plot (box and whiskers) adjacent to each subpopulation plot.</p

Geographic setting.

<p>Map of polar bear subpopulations and locations of harvest (red dots) in Baffin Bay (BB), western Hudson Bay (WH) and southern Hudson Bay (SH). Coastlines were created using the Global Self-consistent, Hierarchical, High-resolution Geography database distributed under the GNU Lesser General Public license [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0191631#pone.0191631.ref028" target="_blank">28</a>].</p

Regional differences in polar bear prey.

<p>Regional differences in polar bear prey.</p