scholarly journals Ampelisca eschrichtii Krøyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter

2018 ◽  
Author(s):  
Valentina B. Durkina ◽  
John W. Chapman ◽  
Natalia L. Demchenko
Keyword(s):  
Gonad Development ◽  
Biomass Concentration ◽  
Okhotsk Sea ◽  
Gray Whales ◽  
Reproductive Synchrony ◽  
Important Prey ◽  
Sakhalin Shelf ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
Growth And Reproduction

Background. Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent in summer. However, they are not accessible for sampling in winter to test a previous default conclusion that they grow and reproduce in winter. Methods. We tested the default winter growth and reproduction hypothesis by detailed comparisons of the brood and gonad development among 40 females and 14 males and brood sizes among females observed since 2002. Our test included six predictions of reproductive synchrony that would be apparent from gonad and brood morphology if active reproduction occurs in summer. Results. We found high prevalences of undersized and damaged oocytes, undersized broods, a lack of females brooding fully formed juveniles, atrophied ovaries, and males with mature sperm but lacking fully developed secondary sex morphologies required for pelagic mating. All of these conditions are consistent with trophic stress and starvation. Discussion. These A. eschrichtii populations therefore appear to starve in summer and to grow and reproduce in winter. The Offshore A. eschrichtii populations occur in summer below water strata bearing high phytoplankton biomasses. These populations are more likely to feed successfully in winter when storms mix phytoplankton to their depths.

scholarly journals Ampelisca eschrichtii Krøyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4841 ◽  
Author(s):  
Valentina B. Durkina ◽  
John W. Chapman ◽  
Natalia L. Demchenko
Keyword(s):  
Gonad Development ◽  
Biomass Concentration ◽  
Okhotsk Sea ◽  
Gray Whales ◽  
Reproductive Synchrony ◽  
Important Prey ◽  
Sakhalin Shelf ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
Growth And Reproduction

Background Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent in summer. However, they are not accessible for sampling in winter to test a previous default conclusion that they grow and reproduce in winter. Methods We tested the default winter growth and reproduction hypothesis by detailed comparisons of the brood and gonad development among 40 females and 14 males and brood sizes among females observed since 2002. Our test included six predictions of reproductive synchrony that would be apparent from gonad and brood morphology if active reproduction occurs in summer. Results We found high prevalences of undersized and damaged oocytes, undersized broods, a lack of females brooding fully formed juveniles, atrophied ovaries, and males with mature sperm but lacking fully developed secondary sex morphologies required for pelagic mating. All of these conditions are consistent with trophic stress and starvation. Discussion These A. eschrichtii populations therefore appear to starve in summer and to grow and reproduce in winter. The Offshore A. eschrichtii populations occur in summer below water strata bearing high phytoplankton biomasses. These populations are more likely to feed successfully in winter when storms mix phytoplankton to their depths.

scholarly journals Ampelisca eschrichtii Krøyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter

2018 ◽  
Author(s):  
Valentina B. Durkina ◽  
John W. Chapman ◽  
Natalia L. Demchenko
Keyword(s):  
Gonad Development ◽  
Biomass Concentration ◽  
Okhotsk Sea ◽  
Gray Whales ◽  
Reproductive Synchrony ◽  
Important Prey ◽  
Sakhalin Shelf ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
Growth And Reproduction

Background. Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. Growth and reproduction in this population has not been apparent in summer. However, they are not accessible for sampling in winter to test a previous default conclusion that they grow and reproduce in winter. Methods. We tested the default winter growth and reproduction hypothesis by detailed comparisons of the brood and gonad development among 40 females and 14 males and brood sizes among females observed since 2002. Our test included six predictions of reproductive synchrony that would be apparent from gonad and brood morphology if active reproduction occurs in summer. Results. We found high prevalences of undersized and damaged oocytes, undersized broods, a lack of females brooding fully formed juveniles, atrophied ovaries, and males with mature sperm but lacking fully developed secondary sex morphologies required for pelagic mating. All of these conditions are consistent with trophic stress and starvation. Discussion. These A. eschrichtii populations therefore appear to starve in summer and to grow and reproduce in winter. The Offshore A. eschrichtii populations occur in summer below water strata bearing high phytoplankton biomasses. These populations are more likely to feed successfully in winter when storms mix phytoplankton to their depths.

scholarly journals Ampelisca eschrichtii Krøyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter

2018 ◽  
Author(s):  
Valentina B. Durkina ◽  
John W. Chapman ◽  
Natalia L. Demchenko
Keyword(s):  
Vertical Mixing ◽  
Biomass Concentration ◽  
Terminal Phase ◽  
Okhotsk Sea ◽  
Important Prey ◽  
Sakhalin Shelf ◽  
Far Eastern Russia ◽  
High Prevalence ◽  
Early Fall ◽  
Far Eastern

Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. The high prevalence of atrophied ovaries, undersized and damaged oocytes, undersized broods of embryos and the absence of terminal phase males or females brooding fully formed juveniles among these populations in late spring and early fall are consistent with trophic stress and starvation. A. eschrichtii therefore appear to starve in summer and grow and reproduce in late fall and winter. In summer, these populations, occur below water strata containing the bulk of phytoplankton biomass and appear more likely to receive their trophic sources with vertical mixing that occurs in winter.

scholarly journals Ampelisca eschrichtii Krøyer, 1842 (Ampeliscidae) of the Sakhalin Shelf in the Okhotsk Sea starve in summer and feast in winter

2017 ◽  
Author(s):  
Valentina B. Durkina ◽  
John W. Chapman ◽  
Natalia L. Demchenko
Keyword(s):  
Vertical Mixing ◽  
Biomass Concentration ◽  
Terminal Phase ◽  
Okhotsk Sea ◽  
Important Prey ◽  
Sakhalin Shelf ◽  
Far Eastern Russia ◽  
High Prevalence ◽  
Early Fall ◽  
Far Eastern

Ampelisca eschrichtii Krøyer, 1842 of the Sakhalin Shelf of the Okhotsk Sea, Far Eastern Russia, comprise the highest known biomass concentration of any amphipod population in the world and are a critically important prey source for western gray whales. The high prevalence of atrophied ovaries, undersized and damaged oocytes, undersized broods of embryos and the absence of terminal phase males or females brooding fully formed juveniles among these populations in late spring and early fall are consistent with trophic stress and starvation. A. eschrichtii therefore appear to starve in summer and grow and reproduce in late fall and winter. In summer, these populations, occur below water strata containing the bulk of phytoplankton biomass and appear more likely to receive their trophic sources with vertical mixing that occurs in winter.

scholarly journals Geographic Distribution and Phylogeny of Soricine Shrew-Borne Seewis Virus and Altai Virus in Russia

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1286
Author(s):  
Liudmila N. Yashina ◽  
Sergey A. Abramov ◽  
Alexander V. Zhigalin ◽  
Natalia A. Smetannikova ◽  
Tamara A. Dupal ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
Genomic Sequence ◽  
Common Shrew ◽  
The United States ◽  
Eastern Siberia ◽  
Geographic Ranges ◽  
Lena River ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
Eastern Russia

The discovery of genetically distinct hantaviruses (family Hantaviridae) in multiple species of shrews, moles and bats has revealed a complex evolutionary history involving cross-species transmission. Seewis virus (SWSV) is widely distributed throughout the geographic ranges of its soricid hosts, including the Eurasian common shrew (Sorex araneus), tundra shrew (Sorex tundrensis) and Siberian large-toothed shrew (Sorex daphaenodon), suggesting host sharing. In addition, genetic variants of SWSV, previously named Artybash virus (ARTV) and Amga virus, have been detected in the Laxmann’s shrew (Sorex caecutiens). Here, we describe the geographic distribution and phylogeny of SWSV and Altai virus (ALTV) in Asian Russia. The complete genomic sequence analysis showed that ALTV, also harbored by the Eurasian common shrew, is a new hantavirus species, distantly related to SWSV. Moreover, Lena River virus (LENV) appears to be a distinct hantavirus species, harbored by Laxmann’s shrews and flat-skulled shrews (Sorex roboratus) in Eastern Siberia and far-eastern Russia. Another ALTV-related virus, which is more closely related to Camp Ripley virus from the United States, has been identified in the Eurasian least shrew (Sorex minutissimus) from far-eastern Russia. Two highly divergent viruses, ALTV and SWSV co-circulate among common shrews in Western Siberia, while LENV and the ARTV variant of SWSV co-circulate among Laxmann’s shrews in Eastern Siberia and far-eastern Russia. ALTV and ALTV-related viruses appear to belong to the Mobatvirus genus, while SWSV is a member of the Orthohantavirus genus. These findings suggest that ALTV and ALTV-related hantaviruses might have emerged from ancient cross-species transmission with subsequent diversification within Sorex shrews in Eurasia.

Continuous Improvement in Wellbore Position Accuracy: Ultra-Extended-Reach Drilling in Far Eastern Russia

2018 ◽  
Author(s):  
Benny Poedjono ◽  
Stefan Maus ◽  
Sheldon Rawlins ◽  
Nicholas Zachman ◽  
Adam Paul Row ◽  
...  
Keyword(s):  
Continuous Improvement ◽  
Position Accuracy ◽  
Far Eastern Russia ◽  
Extended Reach Drilling ◽  
Far Eastern ◽  
Eastern Russia

scholarly journals Major Patterns in the Neolithic Chronology of East Asia: Issues of the Origin of Pottery, Agriculture, and Civilization

Radiocarbon ◽  
2009 ◽  
Vol 51 (3) ◽  
pp. 891-903 ◽  
Author(s):  
Yaroslav V Kuzmin ◽  
J A Timothy Jull ◽  
G S Burr
Keyword(s):  
East Asia ◽  
Food Production ◽  
North China ◽  
State Level ◽  
Written Language ◽  
Far Eastern Russia ◽  
Neolithic Agriculture ◽  
Terminal Pleistocene ◽  
Far Eastern ◽  
Different Parts

General chronological frameworks created recently for the Neolithic complexes of China, Japan, Korea, and far eastern Russia allow us to reveal temporal patterns of Neolithization, origin of food production, and the emergence of civilizations. Pottery originated in East Asia, most probably independently in different parts of it, in the terminal Pleistocene, about 14,800–13,300 BP (uncalibrated), and this marks the beginning of the Neolithic. Agriculture in the eastern part of Asia emerged only in the Holocene. The earliest trace of millet cultivation in north China can now be placed at ∼9200 BP, and rice domestication in south China is dated to ∼8000 BP. Pottery in East Asia definitely preceded agriculture. The term “civilization,” which implies the presence of a state level of social organization and written language, has been misused by scholars who assert the existence of a very early “Yangtze River civilization” at about 6400–4200 cal BP. The earliest reliable evidence of writing in China is dated only to about 3900–3000 cal BP, and no “civilization” existed in East Asia prior to this time.

Are quasicrystals really so rare in the Universe?

2020 ◽  
Vol 105 (8) ◽  
pp. 1121-1125
Author(s):  
Luca Bindi ◽  
Vladimir E. Dmitrienko ◽  
Paul J. Steinhardt
Keyword(s):  
Milky Way ◽  
Solar Nebula ◽  
Carbonaceous Chondrite ◽  
Icosahedral Symmetry ◽  
Controlled Conditions ◽  
Far Eastern Russia ◽  
Far Eastern ◽  
The Universe ◽  
Eastern Russia

Abstract Until 2009, the only known quasicrystals were synthetic, formed in the laboratory under highly controlled conditions. Conceivably, the only quasicrystals in the Milky Way, perhaps even in the Universe, were the ones fabricated by humans, or so it seemed. Then came the report that a quasicrystal with icosahedral symmetry had been discovered inside a rock recovered from a remote stream in far eastern Russia, and later that the rock proved to be an extraterrestrial, a piece of a rare CV3 carbonaceous chondrite meteorite (known as Khatyrka) that formed 4.5 billion years ago in the pre-solar nebula. At present, the only known examples of natural quasicrystals are from the Khatyrka meteorite. Does that mean that quasicrystals must be extremely rare in the Universe? In this speculative essay, we present several reasons why the answer might be no. In fact, quasicrystals may prove to be among the most ubiquitous minerals found in the Universe.

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