scholarly journals The intriguing co-distribution of the copepods Calanus hyperboreus and Calanus glacialis in the subsurface chlorophyll maximum of Arctic seas

Elem Sci Anth ◽  
2019 ◽  
Vol 7 ◽  
Author(s):  
Moritz S. Schmid ◽  
Louis Fortier

Studying the distribution of zooplankton in relation to their prey and predators is challenging, especially in situ. Recent developments in underwater imaging enable such fine-scale research. We deployed the Lightframe On-sight Keyspecies Investigation (LOKI) image profiler to study the fine-scale (1 m) vertical distribution of the copepods Calanus hyperboreus and C. glacialis in relation to the subsurface chlorophyll maximum (SCM) at the end of the grazing season in August in the North Water and Nares Strait (Canadian Arctic). The vertical distribution of both species was generally consistent with the predictions of the Predator Avoidance Hypothesis. In the absence of a significant SCM, both copepods remained at depth during the night. In the presence of a significant SCM, copepods remained at depth in daytime and a fraction of the population migrated in the SCM at night. All three profiles where the numerically dominant copepodite stages C4 and C5 of the two species grazed in the SCM at night presented the same intriguing pattern: the abundance of C. hyperboreus peaked in the core of the SCM while that of C. glacialis peaked just above and below the core SCM. These distributions of the same-stage congeners in the SCMs were significantly different. Lipid fullness of copepod individuals was significantly higher in C. hyperboreus in the core SCM than in C. glacialis above and below the core SCM. Foraging interference resulting in the exclusion from the core SCM of the smaller C. glacialis by the larger C. hyperboreus could explain this vertical partitioning of the actively grazing copepodite stages of the two species. Alternatively, specific preferences for microalgal and/or microzooplankton food hypothetically occupying different layers in the SCM could explain the observed partitioning. Investigating the observed fine-scale co-distributions further will enable researchers to better predict potential climate change effects on these important Arctic congeners.

1988 ◽  
Vol 42 ◽  
pp. 289-301 ◽  
Author(s):  
RW Eppley ◽  
E Swift ◽  
DG Redalje ◽  
MR Landry ◽  
LW Haas

2019 ◽  
Vol 59 (5) ◽  
pp. 724-733
Author(s):  
I. N. Sukhanova ◽  
M. V. Flint ◽  
A. V. Fedorov ◽  
E. G. Sakharova ◽  
V. A. Artemyev ◽  
...  

The research was done at transect (11 stations) from inner part of the Khatanga Bay in the south to continental slope area in the north from 17 to 20 September 2017. Four biotops with different parameters of pelagic environment, composition, quantitative characteristics and vertical distribution of phytoplankton were allocated: inner part of the Khatanga Bay, estuarine frontal zone, western shelf of the Laptev Sea and continental slope area. Inner part of the Khatanga Bay and continental slope area were characterized by the highest values of phytoplankton numbers and biomass, which reached 1106 cell/l и 160 mg/m3, respectively. Formation of maximum at the depth of 45 meters was typical for phytoplankton vertical distribution in continental slope area. Algae biomass in the maximum reached 400 mg/m3 which was the highest value for the transect. Well pronounced latitudinal zoning in phytoplankton communities structure was revealed in the western part of the Laptev Sea which was similar to that in another areas the Arctic seas under strong impact of Siberian rivers discharge.


2021 ◽  
Vol 11 (6) ◽  
pp. 2616-2629
Author(s):  
Jake Goodall ◽  
Kristen Marie Westfall ◽  
Hildur Magnúsdóttir ◽  
Snæbjörn Pálsson ◽  
Erla Björk Örnólfsdóttir ◽  
...  

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Martin Edwards ◽  
Pierre Hélaouët ◽  
Eric Goberville ◽  
Alistair Lindley ◽  
Geraint A. Tarling ◽  
...  

AbstractIn the North Atlantic, euphausiids (krill) form a major link between primary production and predators including commercially exploited fish. This basin is warming very rapidly, with species expected to shift northwards following their thermal tolerances. Here we show, however, that there has been a 50% decline in surface krill abundance over the last 60 years that occurred in situ, with no associated range shift. While we relate these changes to the warming climate, our study is the first to document an in situ squeeze on living space within this system. The warmer isotherms are shifting measurably northwards but cooler isotherms have remained relatively static, stalled by the subpolar fronts in the NW Atlantic. Consequently the two temperatures defining the core of krill distribution (7–13 °C) were 8° of latitude apart 60 years ago but are presently only 4° apart. Over the 60 year period the core latitudinal distribution of euphausiids has remained relatively stable so a ‘habitat squeeze’, with loss of 4° of latitude in living space, could explain the decline in krill. This highlights that, as the temperature warms, not all species can track isotherms and shift northward at the same rate with both losers and winners emerging under the ‘Atlantification’ of the sub-Arctic.


2020 ◽  
Vol 12 (24) ◽  
pp. 10420
Author(s):  
Ioannis Chatziioannou ◽  
Efthimios Bakogiannis ◽  
Charalampos Kyriakidis ◽  
Luis Alvarez-Icaza

One of the biggest challenges of our time is climate change. Every day, at different places of the world, the planet sends alarming messages about the enormous transformations it is experiencing due to human-based activities. The latter are responsible for changing weather patterns that threaten food production, energy production and energy consumption, the desertification of land, the displacement of people and animals because of food and water shortages due to the reductions in rainfall, natural disasters and rising sea levels. The effects of climate change affect us all, and if drastic measures are not considered in a timely manner, it will be more difficult and costly to adapt to the aforementioned effects in the future. Considering this context, the aim of this work is to implement a prospective study/structural analysis to the identified sectors of a regional plan of adaptation to climate change so as to promote the resilience of the region against the negative phenomena generated by the climate crisis. This was achieved in two steps: first, we identified the relationships between the strategic sectors of the plan and organized them in order of importance. Second, we assessed the effectiveness of several public policies oriented towards a city’s resilience according to their impact upon the strategic sectors of the plan and the co-benefits generated by their implementation for society. The results highlight that the most essential sectors for the mitigation of climate change are flood risk management, built environment, forest ecosystem management, human health, tourism and rise in sea level. As a consequence, the most important measures for the resilience of the North Aegean Region against climate change are the ones related to the preparation of strategic master plans for flood protection projects.


2021 ◽  
Vol 163 ◽  
pp. 105230
Author(s):  
Michael Weinert ◽  
Moritz Mathis ◽  
Ingrid Kröncke ◽  
Thomas Pohlmann ◽  
Henning Reiss

Author(s):  
Ю.Л. Бордученко ◽  
И.Г. Малыгин ◽  
В.Ю. Каминский ◽  
В.А. Аксенов

Арктическая зона в XXI веке становится важнейшим гарантом устойчивого развития Российской Федерации. Вклад Севера в экономику России во многом будет определяться масштабами и темпами развития Арктической транспортной системы. Необходимо расширение коммерческого и научно-исследовательского судоходства, развитие транспортных узлов и коридоров, полярной авиации, грузопассажирских морских полярных перевозок. В этих условиях Россия в целях обеспечения своих геополитических интересов должна постоянно поддерживать активное присутствие в этом регионе. Оно выражается в проведении научных исследований, разведке и добыче полезных ископаемых, обеспечении морских грузоперевозок с использованием ледоколов и специализированных ледокольно-транспортных судов. Этого невозможно достичь без развития уникального атомного ледокольного флота. В настоящее время Россия является мировым лидером в области применения атомного ледокольного флота для решения транспортных задач в морях Арктики и неарктических замерзающих морях. Для успешной конкуренции России необходимо не упускать этого лидерства и постоянно развивать и совершенствовать атомный ледокольный флот как ключевое звено инфраструктуры функционирования Северного морского пути. В статье представлен краткий обзор текущего состояния и перспектив развития атомного ледокольного флота России. Показана определяющая роль атомного ледокольного флота в обеспечении судоходства по трассам Северного морского пути для развития экономики Арктического региона России. The Arctic zone in the XXI century is becoming the most important guarantor of the sustainable development of the Russian Federation. The contribution of the North to the Russian economy will largely be determined by the scale and pace of development of the Arctic Transport System. It is necessary to expand commercial and research shipping, develop transport hubs and corridors, polar aviation, and cargo and passenger sea polar transportation. In these circumstances, Russia must constantly maintain an active presence in this region in order to ensure its geopolitical interests. It is expressed in conducting scientific research, exploration and extraction of minerals, providing sea cargo transportation using icebreakers and specialized icebreaker-transport vessels. This cannot be achieved without the development of a unique nuclear icebreaker fleet. Currently, Russia is a world leader in the use of nuclear-powered icebreaking fleet for solving transport problems in the Arctic seas and non-Arctic freezing seas. For successful competition, Russia must not lose this leadership, constantly develop and improve the nuclear icebreaker fleet as a key link in the infrastructure of the Northern Sea Route. The article provides a brief overview of the current state and prospects for the development of the Russian nuclear icebreaker fleet. The article shows the decisive role of the nuclear icebreaker fleet in ensuring navigation along the Northern Sea Route for the development of the economy of the Arctic region of Russia.


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