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Опубликована Июль 15, 2021
Noise and anthropogenic disturbances from vessel traffic are an important threat to the recovery of the endangered St. Lawrence Estuary (SLE) beluga population. The consequences of acoustic masking could be particularly adverse in the case of critical vocalizations that maintain contact between mothers and their dependent but mobile calves. This study models the communication range of adults, sub-adults and newborn beluga contact calls in the presence and absence of vessels in an important summering area for this population. Ambient noise measurements, a composite beluga audiogram and apparent source levels of adult/sub-adult and newborn calls, informed the model. Apparent source levels …
Опубликована Сен. 3, 2021
Until 2012, the St. Lawrence Estuary beluga population was considered stable with about 1100 individuals. An abnormally high number of calves reported dead that year triggered a population status reassessment. This review article summarizes the findings from this reassessment and various studies subsequent to it and provides an updated analysis of carcass recovery rates up to 2019. The 2013 review indicated a decreased incidence of cancer in adults, suggesting positive impacts from the regulation of toxic substances (e.g., PCBs and PAHs). However, the review also revealed that the population initiated a decline of ca. 1% per year in the early …
Опубликована Июль 15, 2021
Belugas (Delphinapterus leucas) in managed care have been reported to show seasonal variation in socio-sexual behaviour, hormone levels and respiration rates; however, little is known about the social interactions of wild belugas when they are not in summer, near-shore congregations. To better understand if belugas show seasonal variation in social interactions, this study recorded the behaviour of 10 belugas (five females, five males, ranging from birth to 10 years of age) housed in managed care. Social interactions typically peaked in the summer months but persisted at very low levels during the rest of the year. Seasonal variation was most dramatic …
Опубликована Ноя. 26, 2021
Aquaria that care for and maintain belugas (Delphinapterus leucas) under professional care have the opportunity to contribute to the conservation of wild belugas through research, expertise in animal care and husbandry, and engaging and educating the public about threats to the species’ health and population sustainability. In an aquarium setting, belugas can be studied under controlled conditions, with known variables that are often difficult to discern when studying wild belugas. Information on nutrition, health status and environmental parameters can be easily obtained in a controlled setting. Biological samples are collected from professionally trained whales that voluntarily participate in informative experimental …
Опубликована Янв. 1, 2022
The boreal wintertime atmospheric responses, especially cold events over central Asia, to low sea-ice concentration (SIC) with and without realistic daily variation over the Barents Sea are explored with the Community Atmosphere Model version 4.0 (CAM4.0). The results show that the general atmospheric responses to approximately equal winter-mean Arctic sea-ice loss with a similar pattern but with climatological versus realistic daily variation are different. With the forcing of low SIC with climatological daily variation, Asian cold events become a little longer and stronger than in the control experiment; this mainly results from the enhancement of a 500-hPa Ural anticyclonic anomaly. …
Опубликована Ноя. 9, 2022
Seabirds in cold biomes sometimes aggregate near glacier fronts and at sea-ice edges to forage. In this note, we report on large aggregations of black guillemots (Cepphus grylle) at the edge of sea ice in front of the tidewater glacier Kongsbreen (Kongsfjorden, Svalbard). During several days in the second half of June 2011, we observed 49–155 individuals of black guillemots at this ice edge. They foraged actively, and many of the dives were directed underneath the sea ice. The outflow of glacial meltwater and resulting upwelling generated opportunities for the black guillemots to feed, likely on zooplankton or fish. The …
Опубликована Июнь 20, 2022
To elucidate poorly known aspects of the microscopic metazoan distribution in ice-free parts of the Antarctic, we examined samples of the multicellular terrestrial alga Prasiola crispa, collected over the last decade in different parts of continental East Antarctica and Haswell Island. We found that the micrometazoans inhabiting the algae consist of remarkably abundant bdelloid rotifers (subclass Bdelloidea), followed by tardigrades. We did not find nematodes. The rotifer assemblages were characterized by low diversity (only six species). Nevertheless, rotifer densities were extremely high: mean densities ranged from 75 to 3030 individuals per 100 mg of the dry sample weight and the …
Опубликована Дек. 14, 2022
Alfred Edwin Eaton (1844–1929) was amongst numerous Victorian naturalists whose exotic collections disseminated to the natural history museums of Britain laid the groundwork for our understanding of biodiversity. What sets him apart from his contemporaries was his first-hand knowledge of organisms at the polar extremes. This paper describes Eaton’s contributions to polar biology, especially in the field of entomology, from two high-latitude expeditions: the 1873 Benjamin Leigh Smith Expedition to Svalbard in the European Arctic and the 1874 British Transit of Venus Expedition to Kerguelen Island in the southern Indian Ocean. His observations of flightless polar and subpolar insects, in …
Опубликована Июнь 20, 2022
For more than 20 years Antarctic Treaty Parties have been discussing how to appropriately manage cumulative impacts in the continent. Preventing cumulative impacts requires the fluent exchange of information to enable proper and timely assessment of, and response to, the impacts that result from multiple activities, undertaken by multiple stakeholders and supervised by different Parties. This is a particular challenge for the effective management of Antarctic Specially Protected Areas (ASPAs), as a lack of coordination may potentially put at risk the fulfillment of their conservation objectives. Here we suggest that incorporating lessons learnt from protected areas management elsewhere might improve …
Опубликована Янв. 1, 2023
In remote communities in the Canadian Arctic, petroleum hydrocarbons supply most household energy needs. Their transportation and use frequently incurs small volume spills in populated areas. The remediation method that is currently used when such spills affect the soil under northern villages’ stilted buildings is expensive and not well suited to local conditions. Here, we review local constraints and environmental considerations and select the best remediation technology for this context: in situ chemical oxidation, involving sodium persulfate (SPS) alkali activated with calcium peroxide (CP). Activated SPS presents a good reactivity and amenability to compounds found in diesel. Its high persistence …