scholarly journals Trophodynamics of nekton communities in the epipelagic layer of the North-West Pacific in summer and winter seasons

2017 ◽  
Vol 188 (1) ◽  
pp. 181-203
Author(s):  
Svetlana V. Naydenko ◽  
Alexey A. Khoruzhiy
Keyword(s):  
Grazing Pressure ◽  
Trophic Levels ◽  
North West ◽  
The North ◽  
Energy Flows ◽  
Pacific Waters ◽  
Seasonal And Interannual Dynamics ◽  
The Pacific ◽  
Nekton Communities ◽  
June July

Trophic links between nekton and plankton are analyzed using the data collected in trawl surveys conducted by Pacific Fish. Res. Center (TINRO) in the Pacific waters at Kuril Islands and East Kamchatka in June-July of 2004-2016 and in the central and western parts of the Subarctic Front zone and adjacent subarctic waters in February-April of 2009-2011. Spatial, seasonal and interannual dynamics of nekton communities are detected, as well as changes in their composition and abundance. The most significant changes were caused by mass migrations of subtropical species, as in summer of 2014-2016. In these cases, new components were involved in the food web and energy flows between the low and upper trophic levels were changed, in the first place concerning to copepods, then to euphausiids, amphipods, and small-sized nekton prey. There were no such significant interannual changes in the energy flows in winter. The estimates of daily and seasonal energy flows between low and upper trophic levels, as well as the consumption rate of forage resources indicate no excess of allowable grazing pressure upon forage resources in the upper pelagic layer of the surveyed areas.

IX. Contributions to terrestrial magnetism.—No. IV

1843 ◽  
Vol 133 ◽  
pp. 113-143 ◽  
Keyword(s):  
Pacific Ocean ◽  
West Coast ◽  
China Seas ◽  
North West ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Times ◽  
The China Seas

In the present number of these Contributions, I resume the consideration of Captain Sir Edward Belcher’s magnetic observations, of which the first portion, viz. that of the stations on the north-west coast of America and adjacent islands, was discussed in No. II. The return to England of Her Majesty’s ship Sulphur by the route of the Pacific Ocean, and her detention for some months in the China Seas, have enabled Sir Edward Belcher to add magnetic determinations at thirty-two stations to those at the twenty-nine stations previously recorded. In the notice of the earlier observations, a provisional coefficient was employed in the formula for the temperature corrections of the results with the intensity needles, as no experiments had then been made for the determination of their individual co­efficients. As soon therefore as Sir Edward Belcher had completed the observation of the times of vibration of those needles at Woolwich, as the concluding station of the series made with them, Lieut. Riddell, R. A. undertook the determination of their several coefficients, which was performed in the manner and with the results described in the subjoined memorandum.

scholarly journals Global marine plankton functional type biomass distributions: coccolithophores

2012 ◽  
Vol 5 (2) ◽  
pp. 491-520 ◽  
Author(s):  
C. J. O'Brien ◽  
J. A. Peloquin ◽  
M. Vogt ◽  
M. Heinle ◽  
N. Gruber ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Seasonal Cycle ◽  
Marine Phytoplankton ◽  
The North ◽  
Carbon Biomass ◽  
Time Period ◽  
The Pacific ◽  
Individual Contributions ◽  
June July

Abstract. Coccolithophores are calcifying marine phytoplankton of the class Prymnesiophyceae. They are considered to play an import role in the global carbon cycle through the production and export of organic carbon and calcite. We have compiled observations of global coccolithophore abundance from several existing databases as well as individual contributions of published and unpublished datasets. We estimate carbon biomass using standardised conversion methods and provide estimates of uncertainty associated with these values. The database contains 58 384 individual observations at various taxonomic levels. This corresponds to 12 391 observations of total coccolithophore abundance and biomass. The data span a time period of 1929–2008, with observations from all ocean basins and all seasons, and at depths ranging from the surface to 500 m. Highest biomass values are reported in the North Atlantic, with a maximum of 501.7 μg C l−1. Lower values are reported for the Pacific (maximum of 79.4 μg C l−1) and Indian Ocean (up to 178.3 μg C l−1). Coccolithophores are reported across all latitudes in the Northern Hemisphere, from the Equator to 89° N, although biomass values fall below 3 μg C l−1 north of 70° N. In the Southern Hemisphere, biomass values fall rapidly south of 50° S, with only a single non-zero observation south of 60° S. Biomass values show a clear seasonal cycle in the Northern Hemisphere, reaching a maximum in the summer months (June–July). In the Southern Hemisphere the seasonal cycle is less evident, possibly due to a greater proportion of low-latitude data. The original and gridded datasets can be downloaded from Pangaea (http://doi.pangaea.de/10.1594/PANGAEA.785092).

scholarly journals Contributions to terrestrial magnetism

1843 ◽  
Vol 4 ◽  
pp. 465-465 ◽  
Keyword(s):  
Pacific Ocean ◽  
West Coast ◽  
Thin Layers ◽  
China Seas ◽  
Magnetic Intensity ◽  
North West ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The China Seas

In the present number of these contributions, the author resumes the consideration of Captain Sir Edward Belcher’s magnetic observations, of which the first portion, namely, that of the stations on the north-west coast of America and its adjacent islands, vas discussed in No. 2. The return to England of H. M. S. Sulphur by the route of the Pacific Ocean, and her detention for some months m the China Seas, have enabled Sir Edward Belcher to add magnetic determinations at thirty-two stations to those at the twenty-nine stations previously recorded. The author first describes the experiments which he instituted with the different needles employed by Captain Sir Edward Belcher for determining the coefficient to be employed in the formula for the temperature corrections; and takes this opportunity of noticing the singular fact that, in needles made of a particular species of Russian steel, this coefficient is negative; that is, in these needles, an increase of temperature increases the magnetic power. M. Adolphe Erman describes this particular kind of steel as consisting of alternate very thin layers of soft iron and of steel, so that when heated the soft iron layers increase their magnetic intensity and the steel layers diminish theirs.

scholarly journals «Wrong fish» or wrong hypotheses: what happens to nekton of the Pacific waters at Kuril Islands?

2021 ◽  
Vol 201 (1) ◽  
pp. 3-23
Author(s):  
V. P. Shuntov ◽  
O. A. Ivanov
Keyword(s):  
Structural Changes ◽  
Species Abundance ◽  
Kuril Islands ◽  
Chub Mackerel ◽  
Japanese Sardine ◽  
Cololabis Saira ◽  
Pacific Waters ◽  
The Pacific ◽  
Nekton Communities ◽  
The Kuroshio

A phenomenon of undulating fluctuations of nekton abundance in the Kuroshio system is discussed on example of japanese sardine Sardinops melanostictus, as the most abundant and the most fluctuating species. The so-called «sardine epochs» are distinguished according to this species abundance. The last such epoch ended in the early 1990s. Since 2014, structural changes occurred again in the nekton communities of the Pacific waters off Kuril Islands, caused by expansion of southern fish and squid species, primarily japanese sardine and chub mackerel Scomber japonicus, and decreasing in abundance of japanese anchovy Engraulis japonicus and saury Cololabis saira. The scope of these changes allowed Russian fishermen to resume the fishery on japanese sardine and chub mackerel in the Russian exclusive economic zone since 2016. Annual catch of Japanese sardine increased steadily from 6,700 t in 2016 to 315,500 t in 2020. Over these 5 years, Russian fishermen landed 531,700 t of sardine and 167,900 t of chub mackerel. However, many Russian fishery forecasters believe that these reconstructions is only a «rehearsal» of the upcoming «sardine epoch», being based on formal climatic indices, without delving into the mechanisms of abundance fluctuations. The authors note that new «sardine epochs» cannot be predicted as completely similar to the previous ones. Several hypotheses on causes of the beginning and end of japanese sardine blooms are considered critically, and the conclusion is made that mechanisms which determine its year-classes strength are still unclear, as well as the reasons of undulating fluctuations of this species and some other nekton species abundance, because of high complexity of this problem.

Chronological list of expeditions and historical events in northern Canada. IV. 1763–89

Polar Record ◽  
1971 ◽  
Vol 15 (98) ◽  
pp. 699-721
Author(s):  
Alan Cooke ◽  
Clive Holland
Keyword(s):  
The Arctic ◽  
Hudson Bay ◽  
Minor Importance ◽  
Hudson's Bay Company ◽  
Southern Boundary ◽  
Northern Canada ◽  
North West ◽  
The North ◽  
The Pacific ◽  
Hudson’S Bay Company

If the Treaty of Paris in 1763 secured the Hudson's Bay Company in its monopoly of Rupert's Land, it also, by the Cession of Canada, opened to British enterprise the river-and-lake routes, discovered by the French, from Montreal to the fur-rich country west of Hudson Bay. This instalment of our list covers the years of the Montreal traders' expansion into the North-west, their crossing of the Arctic watershed into the fur trader's Eldorado, the Athabasca district, their organization into the Hudson's Bay Company's formidable rival, the North West Company, and concludes with the climax of their north-westward surge, Alexander Mackenzie's arrival at the Arctic Ocean in 1789. This activity obliged the Hudson's Bay Company to change its policy of waiting for the Indians to bring their furs to posts on Hudson Bay and made them push inland to compete for furs with the pedlars from Montreal. In the meantime, the Moravians had established missions on the coast of Labrador, searches for a North-west Passage were directed away from Hudson Bay to the Pacific coast of North America, the first scientific expedition was sent to Hudson Bay, and the Indians were decimated by smallpox. Toward the end of this instalment, we begin to draw our southern boundary of “northern Canada” both westward and northward and to omit many expeditions and events of peripheral or minor importance, such as activities south of Saskatchewan River, or of regular occurrence, such as annual voyages northward from Churchill.

Response to selection for grazing tolerance in winter-active populations of phalaris (Phalaris aquatica L.). 1. Persistence under grazing in three environments

2009 ◽  
Vol 60 (11) ◽  
pp. 1097 ◽  
Author(s):  
R. A. Culvenor ◽  
S. P. Boschma ◽  
K. F. M. Reed
Keyword(s):  
Linear Response ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Response To Selection ◽  
North West ◽  
Phalaris Aquatica ◽  
Grazing Tolerance ◽  
The North ◽  
Breeding Populations ◽  
Selection For

Forage grass cultivars must have adequate grazing tolerance for use in the grazing systems for which they are intended. Response to 2 cycles of selection for persistence under heavy grazing pressure was examined in 3 winter-active breeding populations of the productive perennial grass, phalaris (Phalaris aquatica L.), from 2000 to 2003, at Bulart in western Victoria and Rye Park on the Southern Tablelands and Tamworth on the North-West Slopes of New South Wales. There was one continuously grazed and one rotationally grazed set of plots at Bulart to examine the effect of grazing management. All sites were affected by drought in later years but drought stress was most severe at Tamworth. A strongly positive linear response to selection was observed in an analysis of persistence measured as frequency of phalaris plant base across the 3 sites (excluding the rotational treatment at Bulart), but response interacted with site. By 2003, linear response averaged 14% frequency units or 34–40% proportional response per cycle at Rye Park and the continuously grazed plots at Bulart, sites that were environmentally suited to survival of phalaris. In contrast, response to selection was absent or slightly negative at Tamworth where conditions were drier and hotter. Populations responded similarly in analyses across all 3 sites but 1 population was less responsive when analyses were restricted to Bulart and Rye Park. Herbage mass measurements in 2001 at Bulart and 2002 at Rye Park indicated positive responses to selection, which were increasingly linked to frequency over time. Rotationally grazed plots at Bulart displayed higher frequency than continuously grazed plots after 3 years of grazing. The experiment showed that grazing tolerance was a heritable trait in the populations tested when environmental constraints were not limiting and that useful improvements in persistence had been obtained compared with existing cultivars.

Redescription and new records ofCeltodoryx ciocalyptoides(Demospongiae: Poecilosclerida)—a sponge invader in the north east Atlantic Ocean of Asian origin?

2011 ◽  
Vol 91 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Daniela Henkel ◽  
Dorte Janussen
Keyword(s):  
Abundant Species ◽  
East Atlantic ◽  
West Pacific ◽  
North West ◽  
North East ◽  
The North ◽  
First Case ◽  
The Pacific ◽  
Inshore Waters ◽  
Taxonomic Studies

In 1996 a sponge was found in a well studied area in the Ria of Etel, Brittany, France, that had never been recorded there before. This sponge was later described as a new species and genus,Celtodoryx girardaeby Perezet al.(2006), who concluded that it is probably an invasive species. Over several yearsC. girardaewas found to occur successively in the Gulf of Morbihan, France, and Oosterschelde estuary, Netherlands. This sponge is characterized by an extensive spatial broading and therewith it rates today among the dominant benthic megafauna in the shallow waters of the Gulf of Morbihan and Dutch inshore waters. During our recent survey of the Chinese Yellow Sea sponge fauna, we found an abundant species with close morphological similarities toC. girardae. Further taxonomic studies have revealed that both the Chinese and European sponges are in fact conspecific withCornulum ciocalyptoidesdescribed by Burton (1935) from Posiet Bay, Sea of Japan and later recorded from other localities of the North West Pacific (e.g. Koltun, 1971; Sim & Byeon, 1989). In this paper we transfer the species of Burton fromCornulumtoCeltodoryxand consequently it becomes the senior synonym ofC. girardae. Furthermore, we conclude thatCeltodoryx ciocalyptoideswas introduced to the North East Atlantic from the North West Pacific with aquaculture of the Pacific oysterCrassostrea gigasas the probable vector. This is probably the first case recorded so far of a sponge species being transferred from one ocean to another by human activity.

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