scholarly journals Distribution of overwintering <i>Calanus</i> in the North Norwegian Sea

2006 ◽  
Vol 3 (2) ◽  
pp. 25-53 ◽  
Author(s):  
A. Edvardsen ◽  
J. M. Pedersen ◽  
D. Slagstad ◽  
T. Semenova ◽  
A. Timonin
Keyword(s):  
Seawater Temperature ◽  
Calanus Finmarchicus ◽  
High Abundance ◽  
Survey Area ◽  
Norwegian Sea ◽  
The North ◽  
Copepod Abundance ◽  
Shelf Slope ◽  
Annual Changes ◽  
The Difference

Abstract. During winter 2003 and 2004, zooplankton and hydrographic data were collected in the northern parts of the Norwegian Sea (68–72° N, 8–17° E) west of the Norwegian shelf break at depths down to 1800 m. The results cover both inter and intra annual changes of hydrography and distribution of Calanus spp. For the whole survey area, average seawater temperature down to 1000 m was higher in 2004 than in the same period in 2003. For the upper 500 m the difference was ca. 1°C. Calanus finmarchicus dominated at ca. 75% of the total copepod abundance. Typical abundance of C. finmarchicus in the survey area was 30 000–40 000 m−2. C. hyperboreus was found deeper than C. finmarchicus while other copepods were found at the depth of C. finmarchicus or shallower. From January to February 2004, the peak of abundance of C. finmarchicus and C. hyperboreus shifted ca. 300 m upwards indicating that ascent from overwintering depth took place at a speed of 10 m d−1 during this period. In general, high abundance of copepods was found adjacent to the shelf slope while oceanic areas had low and intermediate abundance. In the southern part of the survey area, location of high and low copepod abundance shifted both between and within years. In the northern part of the survey area where the shelf slope is less steep, copepods was present at intermediate and high abundance during all surveys.

scholarly journals Distribution of overwintering <i>Calanus</i> in the North Norwegian Sea

Ocean Science ◽  
2006 ◽  
Vol 2 (2) ◽  
pp. 87-96 ◽  
Author(s):  
A. Edvardsen ◽  
J. M. Pedersen ◽  
D. Slagstad ◽  
T. Semenova ◽  
A. Timonin
Keyword(s):  
Seawater Temperature ◽  
Calanus Finmarchicus ◽  
High Abundance ◽  
Survey Area ◽  
Norwegian Sea ◽  
The North ◽  
Copepod Abundance ◽  
Shelf Slope ◽  
Annual Changes ◽  
The Difference

Abstract. During winter 2003 and 2004, zooplankton and hydrographic data were collected in the northern parts of the Norwegian Sea (68–72° N, 8–17° E) west of the Norwegian shelf break at depths down to 1800 m. The results cover both inter and intra annual changes of hydrography and distribution of Calanus spp. For the whole survey area, average seawater temperature down to 1000 m was higher in 2004 than in the same period in 2003. For the upper 500 m the difference was ca. 1°C. Calanus finmarchicus dominated at ca. 75% of the total copepod abundance. Typical abundance of C. finmarchicus in the survey area was 30 000–40 000 m−2. C. hyperboreus was found deeper than C. finmarchicus while other copepods were found at the depth of C. finmarchicus or shallower. From January to February 2004, the peak of abundance of C. finmarchicus and C. hyperboreus shifted approximately 300 m upwards indicating that ascent from overwintering depth took place at a speed of 10 m d−1 during this period. In general, high abundance of copepods was found adjacent to the shelf slope while oceanic areas had low and intermediate abundance. In the southern part of the survey area, location of high and low copepod abundance shifted both between and within years. In the northern part of the survey area where the shelf slope is less steep, copepods was present at intermediate and high abundance during all surveys.

scholarly journals POTENSI ARUS LAUT DAN KONVERSI DAYA LISTRIK SEBAGAI ENERGI BARU TERBARUKAN DI PERAIRAN PALALAWAN DAN INDRAGIRI HILIR, PROVINSI RIAU

2016 ◽  
Vol 10 (2) ◽  
pp. 69
Author(s):  
Beben Rachmat ◽  
Ediar Usman ◽  
Dida Kusnida
Keyword(s):  
Neap Tide ◽  
Electrical Potential ◽  
Current Speed ◽  
Survey Area ◽  
Effective Time ◽  
The North ◽  
Submarine Channel ◽  
Marine Current Turbine ◽  
Marine Current ◽  
The Difference

Kecepatan arus pada saat kondisi air surut di bagian utara daerah penelitian berkisar antara 1 – 1,5 m/s dan di selatan berkisar antara 0,1 – 0,5 m/s dengan arah menuju tenggara - selatan. Pada saat kondisi air pasang pada kedua daerah tersebut (bagian utara dan selatan) kecepatan arus berkisar antara 0,5 – 1,2 m/s dengan arah menuju barat daya - utara. Secara umum kecepatan arus dari utara ke selatan semakin berkurang kecepatannya, hal ini bisa dilihat dari perbedaan kecepatan arus di bagian utara dan selatan daerah penelitian pada kondisi air laut surut. Kondisi tersebut disebabkan oleh perbedaan morfologi bawah laut pada ke dua daerah tersebut. Di bagian utara, lebar lembah relatif lebih sempit (daerah selat) dengan morfologi membentuk alur bawah laut. Di bagian selatan merupakan daerah perairan terbuka, menyebabkan aliran air laut dan arus terdistribusi pada daerah yang lebih luas dan kecepatan arusnya makin berkurang. Potensi daya listrik untuk Turbin Kobold saat surut mencapai 60 – 65 kW, dan 20 kW saat pasang selama 13 jam, sedangkan saat neap tide maksimum mencapai 8 kW saat surut dan 4 kW saat pasang dengan waktu efektif selama 11 jam. Potensi daya listrik untuk Turbin Marine Current saat surut mencapai 3 – 3,2 kW dan 1 kW saat pasang dengan masa kerja selama 13 jam dalam sehari semalam, sedangkan saat neap tide maksimum mencapai 0,4 kW saat surut dan 0.2 kW saat pasang dengan waktu efektif selama 10 jam. Jenis turbin ini cukup optimal dan dapat bekerja dengan baik untuk menghasilkan listrik dengan potensi arus yang ada di perairan Pelalawan – Indragiri Hilir. Kata kunci: kecepatan arus, energi, potensi daya listrik, turbin Current speed during the low waters level in the northern part of survey area range between 1 to 1.5 m/s with southeast and south direction. During the high waters level (HWL) in the both areas range from 0.1 – 0.5 m/s with southwest and north direction. Generally, the current speed from the north to the south in the survey area is decrease, it can be seen from difference value of current speed at the northern and the southern of the survey area during the low waters level (LWS) condition. These condition caused by the difference of under sea morphology at bothside of areas. At the northern part of survey area, the wide of valley morphology is smaller (straits region) forming the submarine channel. At the southern part in an opening waters region, causing the sea current distributed in regions and the speed more decreasing. Electrical potency for Kobold Turbine during ebb tide reach 60 - 65 kW, and 20 kW during the flood as long as 13 hours, while during maximum neap tide reach 8 kW during the ebb and 4 kW during the flood with effective time as long as 11 hours. Electrical Potential for Marine Current Turbine during ebb reach 3 – 3.2 kW, and 1 kW during the flood as long as 13 hours, while during maximum neap tide reach 0.4 kW during the ebb and 0.2 kW during the flood with effective time as long as 10 hours. This kind of the turbine is optimum enough and can work well to produce the electricity with existing current potential in waters of Pelalawan – Indragiri Hilir. Keywords: current speed, energy, electrical potency, turbine

scholarly journals Comparative ecology of over-wintering Calanus finmarchicus in the northern North Atlantic, and implications for life-cycle patterns

2004 ◽  
Vol 61 (4) ◽  
pp. 698-708 ◽  
Author(s):  
Michael R Heath ◽  
Peter R Boyle ◽  
Astthor Gislason ◽  
William S.C Gurney ◽  
Stephen J Hay ◽  
...  
Keyword(s):  
North Atlantic ◽  
Lipid Content ◽  
Calanus Finmarchicus ◽  
Neutral Buoyancy ◽  
Norwegian Sea ◽  
The North ◽  
Iceland Basin ◽  
The North Sea ◽  
Life Cycle Patterns

Abstract Data from plankton net and Optical Plankton Counter sampling during 12 winter cruises between 1994 and 2002 have been used to derive a multi-annual composite 3-D distribution of the abundance of over-wintering Calanus finmarchicus in a swath across the North Atlantic from Labrador to Norway. Dense concentrations occurred in the Labrador Sea, northern Irminger Basin, northern Iceland Basin, eastern Norwegian Sea, Faroe–Shetland Channel, and in the Norwegian Trench of the North Sea. A model of buoyancy regulation in C. finmarchicus was used to derive the lipid content implied by the in situ temperature and salinity at over-wintering depths, assuming neutral buoyancy. The Faroe–Shetland Channel and eastern Norwegian Sea emerged as having the highest water column-integrated abundances of copepodites, the lowest over-wintering temperature, and the highest implied lipid content. The results are discussed in the context of spatial persistence of populations, seasonal patterns of abundance, and relationships between over-wintering and lipid accumulation in the surface waters.

scholarly journals Feeding strategy of mackerel in the Norwegian Sea relative to currents, temperature, and prey

2015 ◽  
Vol 73 (4) ◽  
pp. 1127-1137 ◽  
Author(s):  
Leif Nøttestad ◽  
Justine Diaz ◽  
Hector Penã ◽  
Henrik Søiland ◽  
Geir Huse ◽  
...  
Keyword(s):  
Swimming Speed ◽  
Swimming Performance ◽  
Feeding Strategy ◽  
Near Field ◽  
Norwegian Sea ◽  
Swimming Direction ◽  
Atlantic Mackerel ◽  
The North ◽  
Foraging Rate ◽  
Feeding Resources

Abstract High abundance of Northeast Atlantic mackerel (Scomber scombrus L.), combined with limited food resources, may now force mackerel to enter new and productive regions in the northern Norwegian Sea. However, it is not known how mackerel exploit the spatially varying feeding resources, and their vertical distribution and swimming behaviour are also largely unknown. During an ecosystem survey in the Norwegian Sea during the summer feeding season, swimming direction, and speed of mackerel schools were recorded with high-frequency omnidirectional sonar in four different regions relative to currents, ambient temperature, and zooplankton. A total of 251 schools were tracked, and fish and zooplankton were sampled with pelagic trawl and WP-2 plankton net. Except for the southwest region, swimming direction of the tracked schools coincided with the prevailing northerly Atlantic current direction in the Norwegian Sea. Swimming with the current saves energy, and the current also provides a directional cue towards the most productive areas in the northern Norwegian Sea. Average mean swimming speed in all regions combined was ∼3.8 body lengths s−1. However, fish did not swim in a straight course, but often changed direction, suggesting active feeding in the near field. Fish were largest and swimming speed lowest in the northwest region which had the highest plankton concentrations and lowest temperature. Mackerel swam close to the surface at a depth of 8–39 m, with all schools staying above the thermocline in waters of at least 6°C. In surface waters, mackerel encounter improved foraging rate and swimming performance. Going with the flow until temperature is too low, based on an expectation of increasing foraging rate towards the north while utilizing available prey under way, could be a simple and robust feeding strategy for mackerel in the Norwegian Sea.

scholarly journals Barotropic Regeneration of Upper-Level Synoptic Disturbances in Different Configurations of the Zonal Weather Regime

2008 ◽  
Vol 65 (10) ◽  
pp. 3159-3178 ◽  
Author(s):  
Gwendal Rivière
Keyword(s):  
Large Scale ◽  
Deformation Field ◽  
Regeneration Process ◽  
Barotropic Model ◽  
Weather Regime ◽  
The North ◽  
The Difference ◽  
Upper Level ◽  
Composite Maps ◽  
Large Scale Flow

Barotropic dynamics of upper-tropospheric midlatitude disturbances evolving in different configurations of the zonal weather regime (i.e., in different zonal-like large-scale flows) were studied using observational analyses and barotropic model experiments. The contraction stage of upper-level disturbances that follows their elongation stage leads to an increase of eddy kinetic energy that is called the barotropic regeneration process in this text. This barotropic mechanism is studied through notions of barotropic critical regions (BtCRs) and effective deformation that have been introduced in a previous paper. The effective deformation field is equal to the difference between the square of the large-scale deformation magnitude and the square of the large-scale vorticity. Regions where the effective deformation is positive correspond to regions where the large-scale flow tends to strongly stretch synoptic disturbances. A BtCR is an area separating two large-scale regions of positive effective deformation, one located upstream and on the south side of the jet and the other downstream and on the north side. Such a region presents a discontinuity in the orientation of the dilatation axes and is a potential area where the barotropic regeneration process may occur. Winter days presenting a zonal weather regime in the 40-yr ECMWF Re-Analysis dataset are decomposed, via a partitioning algorithm, into different configurations of the effective deformation field at 300 hPa. A six-cluster partition is obtained. Composite maps of the barotropic generation rate for each cluster exhibit a succession of negative and positive values on both sides of the BtCRs. It confirms statistically that the barotropic regeneration mechanism occurs preferentially about BtCRs. Numerical experiments using a forced barotropic model on the sphere are performed. Each experiment consists of adding a synoptic-scale perturbation to one of the zonal-like jet configurations found in observations, which is kept fixed with time. The combined effects of the effective deformation and nonlinearities are shown to be crucial to reproduce the barotropic regeneration process about BtCRs.

United Front: Partisans of the Leningrad Region and their connections with the Central Asian Soviet Republics

2021 ◽  
Vol 2021 (02) ◽  
pp. 214-225
Author(s):  
Sergey Kulik ◽  
Аnatoliy Kashevarov ◽  
Zamira Ishankhodjaeva
Keyword(s):  
World War Ii ◽  
Weather Conditions ◽  
Leningrad Region ◽  
World War ◽  
North West ◽  
The North ◽  
Occupied Territory ◽  
Central Asian ◽  
The Difference ◽  
Almost All

During World War II, representatives of almost all the Soviet Republics fought in partisan detachments in the occupied territory of the Leningrad Region. Among them were many representatives of the Central Asian republics: Kazakhstan, Kyrgyzstan and Uzbekistan. Many Leningrad citizens, including relatives of partisans, had been evacuated to Central Asia by that time. However, representatives of Asian workers’ collectives came to meet with the partisans. The huge distance, the difference in cultures and even completely different weather conditions did not become an obstacle to those patriots-Turkestanis who joined the resistance forces in the North-West of Russia.

V.—Mr. Harkee and Mr. Debley on the Scandinavian Ice-Sheet

1894 ◽  
Vol 1 (11) ◽  
pp. 496-499
Author(s):  
Henry H. Howorth
Keyword(s):  
Ice Sheet ◽  
Good Effect ◽  
The North ◽  
The Matrix ◽  
Glacier Ice ◽  
Inductive Methods ◽  
The North Sea ◽  
Antarctic Continent ◽  
The Alps ◽  
The Difference

Mr. Deeley tells your readers that he has recently been to the summit of Mont Blanc, and has been studying the difference between névé and glacier ice. This is interesting; but we thought that a great many people had done the same thing during the last hundred years, and we thought that one of them, Forbes, had studied the famous Mountain and the phenomenoninquestion to good effect, not in a casual visit to the Alps, but in the course of many years of patient labour. Among other things we also thought he had shown that in a viscous body like ice, the slope of the upper surface necessary to make it begin to move is the same as the slope which, would be required to induce motion in the ice if its bed were inclined at an angle. He further collected considerable evidence to show what the least angle is upon which ice will begin to move. This is the slope, the least slope, available. It is nothing less than astounding to me that anyone should venture to postulate a Scand in avian ice-sheet in the North Sea until he had considered this necessary factor, and how it would operate.The Scand in avian ice-sheet was, I believe, the invention of Croll, who, sittinginhis arm-chair and endowed with a brilliant imagination, imposed upon sober science this extraordinary postulate. He did not dream of testing it by an examination of the coasts of Norway, or even of Britain, but put it forward apparently as a magnificent deduction. All deductions untested by experiment are dangerous. Thus it came about that the great monster which is said to have come from Norway, goodness knows by what mechanical process, speedily dissolved away on the application of inductive methods. Of course it still maintained its hold upon that section, of geologists who dogmatiseinprint a great deal about the Glacial period before they have ever seen a glacier at work at all; but I am speaking of those who have studied the problem inductively. First Mr. James Geikie, a disciple of Croll, was obliged to confess that this ice-sheet, which is actually said to have advanced as far as the hundred-fathom line in the Atlantic, and there presented a cliff of ice like the Antarctic continent, never can have reached the Faroes, which had an ice-sheet of their own. Next Messrs. Peach and Home were constrained to admit that no traces of it of any kind occur in the Orkneys, or in Eastern Scotland. They still maintained its presence in the Shetlands; however, this was upon evidence which is somewhat extraordinary. I do not mean the evidence as to the direction of the striation, which was so roughly handled by Mr. Milne-Home, but I mean the evidence they adduce that the boulders found on the islands are apparently all local ones, and that, contrary to the deposits of glaciers, they diminish in number as we recede from the matrix whence they were derived.

New Faunal and Isotopic Evidence on the Late Weichselian—Holocene Oceanographic Changes in the Norwegian Sea

1984 ◽  
Vol 21 (1) ◽  
pp. 74-84 ◽  
Author(s):  
Hans Petter Sejrup ◽  
Eystein Jansen ◽  
Helmut Erlenkeuser ◽  
Hans Holtedahl
Keyword(s):  
Deep Water ◽  
Circulation Pattern ◽  
Oceanic Circulation ◽  
Surface Cooling ◽  
Norwegian Sea ◽  
Neogloboquadrina Pachyderma ◽  
The North ◽  
Lower Oxygen ◽  
Late Weichselian ◽  
Stage 1

Downcore studies of planktonic and benthonic foraminifera and δ18O and δ13C in the planktonic foraminifer Neogloboquadrina pachyderma (sin.) in two piston cores from the southern part of the Norwegian Sea suggest large changes in the oceanic circulation pattern at the end of oxygenisotope stage 2 and in the early part of stage 1. Prior to oxygen-isotope Termination IA (16,000–13,000 yr B.P.), an isolated watermass with lower oxygen content and temperature warmer than today existed below a low salinity ice-covered surface layer in the Norwegian Sea. Close to Termination IA, well-oxygenated deep water, probably with positive temperatures, was introduced. This deep water, which must have had physical and/or chemical parameters different from those of present deep water in the Norwegian Sea, could have been introduced from the North Atlantic or been formed within the basin by another mechanism than that which forms the present deep water of the Norwegian Sea. A seasonal ice cover in the southern part of the Norwegian Sea is proposed for the period between Termination IA and the beginning of IB (close to 10,000 yr B.P.). The present situation, with strong influx of warm Atlantic surface-water and deep-water formation by surface cooling, was established at Termination IB.

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