Life cycles and seasonal distributions of Calanus finmarchicus on the central Scotian Shelf

2001 ◽  
Vol 58 (4) ◽  
pp. 659-670 ◽  
Author(s):  
Ian A McLaren ◽  
Erica Head ◽  
D D Sameoto
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Shelf Break ◽  
Calanus Finmarchicus ◽  
Temperature Dependent ◽  
Scotian Shelf ◽  
Copepodid Stage

The life cycle of Calanus finmarchicus on and around Western Bank, 1991–1992, was essentially annual; the overwintered generation (G0) produced G1 that developed at temperature-dependent rates and then largely disappeared after June to winter as late copepodids at depth. However, a small fraction of G1 matured to spawn a less rapidly developing G2 that outnumbered G1 in the depths of Emerald Basin in autumn 1990. Estimated mortality on the central Scotian Shelf for G1 from egg to copepodid stage 5 in June was ~4%·day–1 but subsequently for G1 and G2 was nearly constant at ~1%·day–1. Populations on Western Bank mostly derived from reproduction by overwintered G2 on the Scotian Shelf. Larger populations in Emerald Basin in 1987–1988 were augmented from advected animals enabled to diapause there at depth and on Emerald Bank by inputs from beyond the shelf break, ultimately from farther north. Our observations and analyses match the physical circulation in the region.

Life cycles of four species of Pseudocalanus in Nova Scotia

1989 ◽  
Vol 67 (3) ◽  
pp. 552-558 ◽  
Author(s):  
I. A. McLaren ◽  
Estelle Laberge ◽  
C. J. Corkett ◽  
J.-M. Sévigny
Keyword(s):  
Life Cycle ◽  
Nova Scotia ◽  
First Generation ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Late Winter ◽  
Early Winter ◽  
Temperature Dependent ◽  
Scotian Shelf

The primarily arctic Pseudocalanus acuspes, relict in Bedford Basin, Nova Scotia, produces a first generation (G1) in late winter; most G1 individuals mature in late spring. The G1 then produces a G2, most of which "rest" in copepodite stages III and IV until early winter. These stages store large amounts of lipid in early summer, which slowly diminish subsequently. A small number of G2 individuals continue to develop at temperature-dependent rates, maturing in early autumn and producing G3 adults in November. Copepodites developing in winter and spring store less lipid. The primarily arctic Pseudocalanus minutus, rare in Bedford Basin and on the Scotia Shelf, is strictly annual, developing to a lipid-filled copepodite stage V after spawning in late winter. The arctic–temperate Pseudocalanus newmani is abundant on the Scotian Shelf, but may not be self-sustaining when advected into Bedford Basin. It stores little lipid and appears to have at least three mature generations at temperature-dependent intervals over Browns Bank between May and November. It may rest in winter, or its life-cycle synchrony by spring could result from food-limited development during winter. The temperate Pseudocalanus moultoni appears to have a life cycle similar to that of P. newmani, but was less common during summer on Browns Bank. These life cycles are appropriately adapted to the geographical ranges of the species, and show some parallels with species of Calanus.

Distribution of Calanus spp. on and around the Nova Scotia Shelf in April: evidence for an offshore source of Calanus finmarchicus to the central and western regions

1999 ◽  
Vol 56 (12) ◽  
pp. 2463-2476 ◽  
Author(s):  
Erica JH Head ◽  
Leslie R Harris ◽  
Brian Petrie
Keyword(s):  
Nova Scotia ◽  
Deep Water ◽  
Shelf Break ◽  
Calanus Finmarchicus ◽  
Surface Layers ◽  
Scotian Shelf ◽  
Near Surface ◽  
Calanus Hyperboreus

Observations of hydrography and Calanus spp. abundance were made at stations on lines across the central and eastern Scotian Shelf (SS) in April 1995 and 1997 and on additional lines on the western SS and across Cabot Strait (CS) and the Laurentian Channel (LC) in 1997. Calanus finmarchicus was more abundant on the central and western SS than in the east, and Calanus hyperboreus was concentrated in the east and in areas influenced by the Nova Scotia Current. Calanus spp. on the eastern SS probably originated mainly from populations overwintering in the Gulf of St. Lawrence. High abundances of C. finmarchicus occurred at or beyond the shelf break when warm slope water was present, suggesting that they derived from a population overwintering in the deep water south of the SS. In both years, slope water was present in the near-surface layers at shelf stations of the Halifax Line (HL), but in 1997 the degree of intrusion was greater. Calanus finmarchicus abundances were also substantially higher at shelf stations of the HL in 1997, implying contribution from the offshore population to the populations in central and western SS regions. Consistent with the suggested difference in their origins, C. finmarchicus on the western SS belonged primarily to the new year's generation, whereas those on the eastern SS belonged mainly to that of the previous year.

scholarly journals The Vertical Distribution of Marine Macroplankton. VII Observations on the Behaviour of Calanus finmarchicus

1928 ◽  
Vol 15 (2) ◽  
pp. 429-454 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Light Intensity ◽  
Vertical Distribution ◽  
Seasonal Change ◽  
Life Cycles ◽  
Calanus Finmarchicus ◽  
Low Light ◽  
Copepodid Stage ◽  
Males And Females ◽  
The Vertical Distribution ◽  
Trawl Catches

SUMMARYThe vertical distribution of Calanus finmarchicus adults in the daylight in the Plymouth region as shown by stramin ring-trawl catches in described for the period April to September in 1926. The general results confirmed the indications given in 1925 that there is a, gradual descent of the region of maximum abundance from about 10 metres in April to-metres in June, with a definite rise towards the surface ia July, August, and September.2. The rise towards the surface was evident on sunny days as well as dull, indicating that the suggestion that dull weather and low light intensity was its cause in 1925 may possibly have been incorrect.Measurements of the total lengths of Calanus were made which showed a seasonal change, a brood of small adults occurring in July, August, and September, as opposed to a brood of large adults whichdominated in the spring.It is suggested that possibly these two broods are physiologically different, and that the small type of adult prefers a higher light intensity and lives nearer the surface than the large type.The males and females differed in their behaviour, the males being always slightly deeper in the water than the females.Some indications are given of the course of the life-cycles of Calanus in the Plymouth area.While from April to the end of June the abundance of the last copepodid stage (Stage V) rarely exceeded more than 20% of the total Calanus in any one catch, they became very much more abundant in July, August, and September, reaching even 60% and 70%.

MERGERS AND ACQUISITIONS AND THEIR CORRELATION WITH THE LIFE CYCLES OF MEMBER COMPANIES ON THE EXAMPLE OF THE RUSSIAN MARKET 2017–2019

2020 ◽  
Vol 1 (10) ◽  
pp. 26-35
Author(s):  
E. A. SHUBINA ◽  
◽  
Yu. A. KOMAROVSKY ◽  
A. V. MERKUSHEV ◽  
◽  
...  
Keyword(s):  
Life Cycle ◽  
Mergers And Acquisitions ◽  
Life Cycles ◽  
Russian Market

The article is devoted to the study of the largest mergers and acquisitions (M&A, “Mergers & Acquisitions”) in Russia for 2017–2019. (the acquired block of shares is not less than 99%). The concept of life cycles of organizations and theoretical aspects of mergers and acquisitions are described. The stages of the life cycle of the merged and reorganized companies, the goals of mergers and acquisitions, depending on the stages of the life cycle are analyzed.

Life cycle of self-propelled machinery with waste generation at its disposal

2020 ◽  
pp. 28-35
Author(s):  
Valeriy S. Gerasimov ◽  
Vladimir I. Ignatov ◽  
Konstantin G. Sovin
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
The State ◽  
Research Purpose ◽  
Industrial Complex ◽  
Agricultural Machinery ◽  
Resource Saving ◽  
Secondary Resources ◽  
Branch System ◽  
Additional Funding

According to forecasts for 2022, the number of self-propelled agricultural machinery that will fail will be about 100 thousand units. This will have a significant impact on the overall productivity in the field of agricultural production and will require additional financial costs for effective resource-saving environmental-oriented utilization of agricultural machinery with the maximum recovery of secondary resources in the processing of its components. (Research purpose) The research purpose is considering the main life cycles of machinery, including agricultural, and determining the possibility of obtaining secondary resources in the recycling of components of machinery and equipment. (Materials and methods) The authors found that the establishment of an industry-wide recycling system would allow the reuse of usable and recovered parts obtained from decommissioned equipment, as well as receive additional funding from the sale of secondary resources. The authors have found that for the functioning of the whole system, it is necessary to work with a large amount of data related to the ongoing recycling processes, as well as constantly monitor changes in the state and properties of materials. They also found that the maximum use of digital technology is the only way to combine all these requirements and make the system work. (Results and discussion) The article reviews the key points of the use of life cycle method for equipment, including agricultural, reviews the state of machine and tractor park of agro-industrial complex, shows the possibility of using resource-saving ecologically oriented branch system of recycling of agricultural machinery, as well as the movement of waste and material flows in the processing components of utilized machines. (Conclusion) The article presents recommendations on the possibility of efficient disposal of equipment, including agricultural, with the maximum recovery of secondary resources from recycled waste.

Life cycles of the rhizocephalan Boschmaella japonica Deichmann & Høeg, 1990 (Cirripedia: Chthamalophilidae) and its host barnacle Chthamalus challengeri Hoek, 1883 (Cirripedia: Chthamalidae)

2020 ◽  
Vol 40 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Miku Yabuta ◽  
Jens T Høeg ◽  
Shigeyuki Yamato ◽  
Yoichi Yusa
Keyword(s):  
Life Cycle ◽  
Brood Size ◽  
Life Cycles ◽  
The Body ◽  
Egg Volume ◽  
Size Number ◽  
Rhizocephalan Barnacles ◽  
Western Japan ◽  
Upper Intertidal ◽  
Chthamalus Challengeri

Abstract Although parasitic castration is widespread among rhizocephalan barnacles, Boschmaella japonica Deichmann & Høeg, 1990 does not completely sterilise the host barnacle Chthamalus challengeri Hoek, 1883. As little information is available on the relationships with the host in “barnacle-infesting parasitic barnacles” (family Chthamalophilidae), we studied the life cycles of both B. japonica and C. challengeri and the effects of the parasite on the host reproduction. Specimens of C. challengeri were collected from an upper intertidal shore at Shirahama, Wakayama, western Japan from April 2017 to September 2018 at 1–3 mo intervals. We recorded the body size, number of eggs, egg volume, and the presence of the parasite for each host. Moreover, settlement and growth of C. challengeri were followed in two fixed quadrats. Chthamalus challengeri brooded from February to June. The prevalence of B. japonica was high (often exceeded 10%) from April to July, and was rarely observed from September to next spring. The life cycle of the parasite matched well with that of the host. The parasite reduced the host’s brooding rate and brood size, to the extent that no hosts brooded in 2018.

scholarly journals Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich
Keyword(s):  
Life Cycle ◽  
Lithium Ion Batteries ◽  
Electric Vehicles ◽  
Energy Demand ◽  
Lithium Ion ◽  
Life Cycles ◽  
Future Research ◽  
Research Areas ◽  
Study Results ◽  
The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

scholarly journals Life Cycle Assessment of Households in Santiago, Chile: Environmental Hotspots and Policy Analysis

2021 ◽  
Vol 13 (5) ◽  
pp. 2525
Author(s):  
Camila López-Eccher ◽  
Elizabeth Garrido-Ramírez ◽  
Iván Franchi-Arzola ◽  
Edmundo Muñoz
Keyword(s):  
Global Warming ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impacts ◽  
Food Consumption ◽  
Household Income ◽  
Resource Scarcity ◽  
Life Cycles ◽  
The Impact ◽  
Freshwater Eutrophication

The aim of this study is to assess the environmental impacts of household life cycles in Santiago, Chile, by household income level. The assessment considered scenarios associated with environmental policies. The life cycle assessment was cradle-to-grave, and the functional unit considered all the materials and energy required to meet an inhabitant’s needs for one year (1 inh/year). Using SimaPro 9.1 software, the Recipe Midpoint (H) methodology was used. The impact categories selected were global warming, fine particulate matter formation, terrestrial acidification, freshwater eutrophication, freshwater ecotoxicity, mineral resource scarcity, and fossil resource scarcity. The inventory was carried out through the application of 300 household surveys and secondary information. The main environmental sources of households were determined to be food consumption, transport, and electricity. Food consumption is the main source, responsible for 33% of the environmental impacts on global warming, 69% on terrestrial acidification, and 29% on freshwater eutrophication. The second most crucial environmental hotspot is private transport, whose contribution to environmental impact increases as household income rises, while public transport impact increases in the opposite direction. In this sense, both positive and negative environmental effects can be generated by policies. Therefore, life-cycle environmental impacts, the synergy between policies, and households’ socio-economic characteristics must be considered in public policy planning and consumer decisions.

scholarly journals The life-cycle of the avian haemosporidian parasite Haemoproteus majoris, with emphasis on the exoerythrocytic and sporogonic development

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Mikas Ilgūnas ◽  
Carolina Romeiro Fernandes Chagas ◽  
Dovilė Bukauskaitė ◽  
Rasa Bernotienė ◽  
Tatjana Iezhova ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Life Cycle ◽  
Dna Sequences ◽  
Parus Major ◽  
Life Cycles ◽  
Internal Organs ◽  
Haemosporidian Parasite ◽  
Biting Midges ◽  
Vector Identity ◽  
Bayesian Phylogeny

Abstract Background Haemoproteus parasites (Haemosporida, Haemoproteidae) are cosmopolitan in birds and recent molecular studies indicate enormous genetic diversity of these pathogens, which cause diseases in non-adapted avian hosts. However, life-cycles remain unknown for the majority of Haemoproteus species. Information on their exoerythrocytic development is particularly fragmental and controversial. This study aimed to gain new knowledge on life-cycle of the widespread blood parasite Haemoproteus majoris. Methods Turdus pilaris and Parus major naturally infected with lineages hPHYBOR04 and hPARUS1 of H. majoris, respectively, were wild-caught and the parasites were identified using microscopic examination of gametocytes and PCR-based testing. Bayesian phylogeny was used to determine relationships between H. majoris lineages. Exoerythrocytic stages (megalomeronts) were reported using histological examination and laser microdissection was applied to isolate single megalomeronts for genetic analysis. Culicoides impunctatus biting midges were experimentally exposed in order to follow sporogonic development of the lineage hPHYBOR04. Results Gametocytes of the lineage hPHYBOR04 are indistinguishable from those of the widespread lineage hPARUS1 of H. majoris, indicating that both of these lineages belong to the H. majoris group. Phylogenetic analysis supported this conclusion. Sporogony of the lineage hPHYBOR04 was completed in C. impunctatus biting midges. Morphologically similar megalomeronts were reported in internal organs of both avian hosts. These were big roundish bodies (up to 360 μm in diameter) surrounded by a thick capsule-like wall and containing irregularly shaped cytomeres, in which numerous merozoites developed. DNA sequences obtained from single isolated megalomeronts confirmed the identification of H. majoris. Conclusions Phylogenetic analysis identified a group of closely related H. majoris lineages, two of which are characterized not only by morphologically identical blood stages, but also complete sporogonic development in C. impunctatus and development of morphologically similar megalomeronts. It is probable that other lineages belonging to the same group would bear the same characters and phylogenies based on partial cytb gene could be used to predict life-cycle features in avian haemoproteids including vector identity and patterns of exoerythrocytic merogony. This study reports morphologically unique megalomeronts in naturally infected birds and calls for research on exoerythrocytic development of haemoproteids to better understand pathologies caused in avian hosts.

The developmental stages of Neobrachiella robusta (Wilson, 1912), a parasitic copepod of Sebastes (Teleostei: Scorpaeniformes)

1987 ◽  
Vol 65 (6) ◽  
pp. 1331-1336
Author(s):  
Z. Kabata
Keyword(s):  
Life Cycle ◽  
Developmental Stages ◽  
Parasitic Copepod ◽  
Gill Arch ◽  
Gill Rakers ◽  
Copepodid Stage

The morphology of the developmental stages of Neobrachiella robusta (Wilson, 1912) (Copepoda: Siphonostomatoida) is described. The copepod is parasitic on the gill rakers of Sebastes alutus (Gilbert, 1890) (Teleostei: Scorpaeniformes). The life cycle of this copepod consists of a copepodid stage, followed by four chalimus stages and a relatively long preadult stage, which undergoes extensive metamorphosis. The copepods aggregate on the outer row of long gill rakers of the first gill arch, as many as 97% of them being attached to these rakers. Some of the rakers become distorted, but a connection between the presence of N. robusta and these abnormalities could not be established.

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