scholarly journals Curious case of the coastal tailed frog (ascaphus truei) near the northern extent of its range

2021 ◽  
Author(s):  
◽  
Cherie Marie Mosher
Keyword(s):  
British Columbia ◽  
Developmental Stages ◽  
Ice Age ◽  
Gut Contents ◽  
Ascaphus Truei ◽  
Forestry Practices ◽  
Dna Metabarcoding ◽  
Northern Portion ◽  
Last Ice Age ◽  
The Relationship

Ascaphus truei, an ancient species of frog, migrated into British Columbia, Canada, following the last ice age. A. truei is of conservation interest because forestry practices, and the associated infrastructure, may reduce habitat quality. There is also concern that a warmer and drier climate will change the distribution and abundance of this species. I used two genetic methods, microsatellites and next-generation sequencing, to compare the genetic diversity of A. truei from the northern extent of its range in British Columbia, CA to southern Washington, USA. Both methods suggested a dramatic reduction in diversity across the northern portion of the species’ range. The phylogeography suggests a northern range expansion from a single refugium. I used DNA metabarcoding to compare the gut contents of larvae across three stream reaches and two development classes near the northern extent of A. truei's range. Gut contents differed between stream reach but did not differ among development class. Wetted width and ultimately stream volume may influence differences in gut content among stream reaches. I also quantified the relationship between an index of larvae density and environmental factors hypothesized to influence population density near the northern extent of the range. I assessed the segregation of larvae at various developmental stages. Wetted width and wetted depth correlated with differences in the abundance of larvae. Older developmental stages were captured in stream reaches with greater slopes than younger stages. Management should minimize modifications of stream structure, such as in-stream siltation due to road building. We should maintain habitat connectivity and gene flow to ensure the continued migration and adaptive capacity of A. truei.

Electrophoretic Variation, Regional Differences, and Gene Flow in the Coho Salmon (Oncorhynchus kisutch) of Southern British Colombia

1987 ◽  
Vol 44 (4) ◽  
pp. 822-831 ◽  
Author(s):  
C F. Wehrhahn ◽  
R. Powell
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Ice Age ◽  
Enzyme Loci ◽  
Large Populations ◽  
Last Ice Age ◽  
The Mean ◽  
British Colombia ◽  
River Fish

Populations of coho salmon (Oncorhynchus kisutch) in southern British Columbia were assayed for genetic variation at 26 enzyme loci. The mean heterozygosity was only 0.25 ± 0.06%. Previously studied wild Oregon cohos had a mean heterozygosity of 1.36 ± 0.37% compared with 0.30 ± 0.09% in Lower Coastal Mainland and 0.13 ± 0.08% in Upper Fraser River fish for the same enzyme loci. A plausible explanation for the very low mean heterozygosity is that British Columbia coho salmon went through an extreme population bottleneck during or after the last ice age. Lower Coastal Mainland salmon are significantly different from the fish of Vancouver Island and can be easily distinguished from Oregon and Capilano Hatchery (Coastal Mainland, B.C.) fish, it should be feasible to determine the relative proportions of different stocks in large oceanic coho salmon samples. The maximum likelihood estimate of the migration rate between spawning populations is 5.8 ± 1.2 breeding adults per generation. This is enough to prevent adaptation to local habitats by small populations of fewer than 100 breeding adults, but it is not high enough to impede selection in large populations of 1000 or more breeding adults.

scholarly journals Brazilian sardine (Sardinella brasiliensis Steindachner, 1879) spawning and nursery habitats: spatial-scale partitioning and multiscale relationships with thermohaline descriptors

2012 ◽  
Vol 69 (6) ◽  
pp. 939-952 ◽  
Author(s):  
Luiz Eduardo de Souza Moraes ◽  
Douglas Francisco Marcolino Gherardi ◽  
Mario Katsuragawa ◽  
Eduardo Tavares Paes
Keyword(s):  
Spatial Scale ◽  
Developmental Stages ◽  
Spatial Scales ◽  
Medium Scale ◽  
Density Distributions ◽  
Brazil Current ◽  
Nursery Habitats ◽  
Northern Portion ◽  
The Relationship ◽  
Broad Scale

Abstract de Souza Moraes, L. E., Marcolino Gherardi, D. F., Katsuragawa, M., and Tavares Paes, E. 2012. Brazilian sardine (Sardinella brasiliensis Steindachner, 1879) spawning and nursery habitats: spatial-scale partitioning and multiscale relationships with thermohaline descriptors. – ICES Journal of Marine Science, 69: 939–952. We provide a detailed account of the spatial structure of the Brazilian sardine (Sardinella brasiliensis) spawning and nursery habitats, using ichthyoplankton data from nine surveys (1976–1993) covering the Southeastern Brazilian Bight (SBB). The spatial variability of sardine eggs and larvae was partitioned into predefined spatial-scale classes (broad scale, 200–500 km; medium scale, 50–100 km; and local scale, <50 km). The relationship between density distributions at both developmental stages and environmental descriptors (temperature and salinity) was also explored within these spatial scales. Spatial distributions of sardine eggs were mostly structured on medium and local scales, while larvae were characterized by broad- and medium-scale distributions. Broad- and medium-scale surface temperatures were positively correlated with sardine densities, for both developmental stages. Correlations with salinity were predominantly negative and concentrated on a medium scale. Broad-scale structuring might be explained by mesoscale processes, such as pulsing upwelling events and Brazil Current meandering at the northern portion of the SBB, while medium-scale relationships may be associated with local estuarine outflows. The results indicate that processes favouring vertical stability might regulate the spatial extensions of suitable spawning and nursery habitats for the Brazilian sardine.

scholarly journals Review article: Jesus’ resurrection in Joseph’s garden

2010 ◽  
Vol 66 (1) ◽  
Author(s):  
Estelle Dannhauser
Keyword(s):  
Developmental Stages ◽  
Faith Community ◽  
Review Article ◽  
Historical Jesus ◽  
Life And Death ◽  
The Relationship ◽  
Community Church

The article is a lengthy review of the book Jesus’ resurrection in Joseph’s garden by P.J.W. (Flip) Schutte. The book represents a quest to trace the relationship between Jesus’ resurrection, myth and canon. Schutte finds the origin of events underlying the biblical canon in proclamation. His focus in the book is the proclamation of the death and resurrection of Christ, which, in its developmental stages, hinged on the life and death of the historical Jesus. Proclamation developed into a mythical narrative that became the foundational myth for the Christ cult, validating its existence and rituals. With the growth and institutionalisation of the faith community (church), came an increased production of literature, causing the power-wielding orthodoxy to identify a body of literature containing the ‘truth’ and ‘correct teaching’, thus establishing the authoritative canon. In, through, behind and beyond Jesus of Nazareth, Schutte has perceived a canon behind the canon: a God of love. In Jesus, the man of myth with historical roots who has become to us the observable face of God, Schutte confesses the kerygma to open up before him. The proclamation therefore extends an invitation to join in a mythological experience and an encounter with God whose love is preached in the metaphor called Easter.

scholarly journals Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age

2021 ◽  
Author(s):  
Jesse R. Farmer ◽  
Daniel M. Sigman ◽  
Julie Granger ◽  
Ona M. Underwood ◽  
François Fripiat ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Surface Waters ◽  
Ice Age ◽  
The Arctic ◽  
Bering Strait ◽  
Central Arctic Ocean ◽  
Phytoplankton Productivity ◽  
Nitrate Consumption ◽  
Western Arctic ◽  
Last Ice Age

AbstractSalinity-driven density stratification of the upper Arctic Ocean isolates sea-ice cover and cold, nutrient-poor surface waters from underlying warmer, nutrient-rich waters. Recently, stratification has strengthened in the western Arctic but has weakened in the eastern Arctic; it is unknown if these trends will continue. Here we present foraminifera-bound nitrogen isotopes from Arctic Ocean sediments since 35,000 years ago to reconstruct past changes in nutrient sources and the degree of nutrient consumption in surface waters, the latter reflecting stratification. During the last ice age and early deglaciation, the Arctic was dominated by Atlantic-sourced nitrate and incomplete nitrate consumption, indicating weaker stratification. Starting at 11,000 years ago in the western Arctic, there is a clear isotopic signal of Pacific-sourced nitrate and complete nitrate consumption associated with the flooding of the Bering Strait. These changes reveal that the strong stratification of the western Arctic relies on low-salinity inflow through the Bering Strait. In the central Arctic, nitrate consumption was complete during the early Holocene, then declined after 5,000 years ago as summer insolation decreased. This sequence suggests that precipitation and riverine freshwater fluxes control the stratification of the central Arctic Ocean. Based on these findings, ongoing warming will cause strong stratification to expand into the central Arctic, slowing the nutrient supply to surface waters and thus limiting future phytoplankton productivity.

scholarly journals Latin America in Global History: An Historiographic Overview

2017 ◽  
Vol 30 (60) ◽  
pp. 253-272 ◽  
Author(s):  
Diego Olstein
Keyword(s):  
Latin America ◽  
Sixteenth Century ◽  
New World ◽  
World History ◽  
The Other ◽  
Ice Age ◽  
Global History ◽  
The World ◽  
Last Ice Age ◽  
Great Divergence

Abstract World history can be arranged into three major regional divergences: the 'Greatest Divergence' starting at the end of the last Ice Age (ca. 15,000 years ago) and isolating the Old and the New Worlds from one another till 1500; the 'Great Divergence' bifurcating the paths of Europe and Afro-Asia since 1500; and the 'American Divergence' which divided the fortunes of New World societies from 1500 onwards. Accordingly, all world regions have confronted two divergences: one disassociating the fates of the Old and New Worlds, and the other within either the Old or the New World. Latin America is in the uneasy position that in both divergences it ended up on the 'losing side.' As a result, a contentious historiography of Latin America evolved from the very moment that it was incorporated into the wider world. Three basic attitudes toward the place of Latin America in global history have since emerged and developed: admiration for the major impact that the emergence on Latin America on the world scene imprinted on global history; hostility and disdain over Latin America since it entered the world scene; direct rejection of and head on confrontation in reaction the former. This paper examines each of these three attitudes in five periods: the 'long sixteenth century' (1492-1650); the 'age of crisis' (1650-1780); 'the long nineteenth century' (1780-1914); 'the short twentieth century' (1914-1991); and 'contemporary globalization' (1991 onwards).

Feeding ecology of Symbolophorus californiensis larvae (Teleostei: Myctophidae) in the southern transition region of the western North Pacific

2009 ◽  
Vol 90 (6) ◽  
pp. 1249-1256 ◽  
Author(s):  
Chiyuki Sassa
Keyword(s):  
Transition Region ◽  
North Pacific ◽  
Western North Pacific ◽  
Developmental Stages ◽  
Feeding Habits ◽  
Larval Growth ◽  
Trophic Niche ◽  
Size Class ◽  
Gut Contents ◽  
Wide Range

The feeding habits of myctophid larvae of Symbolophorus californiensis were examined in the southern transition region of the western North Pacific where the main spawning and nursery grounds of S. californiensis are formed. This species is a key component of the pelagic ecosystems of this region, and their larvae attain one of the largest sizes among myctophids. To analyse gut contents larvae, including most life history stages after yolk-sac absorption (3.7 to 22.2 mm body length (BL)), were collected in the upper 100 m layer in 1997 and 1998. Feeding incidence was higher during the day than at night (53.1–92.3% versus 0–5.6%), and daytime feeding incidence increased gradually with larval growth. Larvae fed mainly on copepods of various developmental stages. Larvae of S. californiensis showed an ontogenetic change in their diet: larvae ≤7.9 mm BL (i.e. preflexion stage) fed mainly on copepod eggs and nauplii, while the larvae ≥8 mm BL consumed mainly calanoid copepodites such as Pseudocalanus and Paracalanus spp. In the largest size-class (16–22.2 mm BL), the furcilia stage of euphausiids was also an important prey item. There was an increase in the average prey size with growth in larvae ≤11.9 mm BL, while the number of prey eaten positively correlated with growth in larvae ≥12 mm BL. The trophic niche breadth also increased with larval growth, which would ensure a wide range of available food resources for the larger size-class larvae.

scholarly journals Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Carbonate Content ◽  
Canadian Rocky Mountains ◽  
Density Profiles ◽  
Frost Action ◽  
Dominant Component ◽  
Freeze And Thaw ◽  
Calcite Cement ◽  
The Relationship

Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70°. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.Key words: landslide, cemented, glaciolacustrine sediments, British Columbia.

Evidence for a large surface ablation zone in central East Antarctica during the last Ice Age

2003 ◽  
Vol 59 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Martin J. Siegert ◽  
Richard C. A. Hindmarsh ◽  
Gordon S. Hamilton
Keyword(s):  
Ice Core ◽  
Remote Sensing Data ◽  
Ice Age ◽  
Internal Layers ◽  
Ice Flow ◽  
Glacial Ice ◽  
Ice Surface ◽  
Ice Flows ◽  
Last Ice Age ◽  
The Hill

AbstractInternal isochronous ice sheet layers, recorded by airborne ice-penetrating radar, were measured along an ice flowline across a large (>1 km high) subglacial hill in the foreground of the Transantarctic Mountains. The layers, dated through an existing stratigraphic link with the Vostok ice core, converge with the ice surface as ice flows over the hill without noticeable change to their separation with each other or the ice base. A two-dimensional ice flow model that calculates isochrons and particle flowpaths and accounts for ice flow over the hill under steady-state conditions requires net ablation (via sublimation) over the stoss face for the predicted isochrons to match the measured internal layers. Satellite remote sensing data show no sign of exposed ancient ice at this site, however. Given the lack of exposed glacial ice, surface balance conditions must have changed recently from the net ablation that is predicted at this site for the last 85,000 years to accumulation.

Metabolism-driven post-translational modifications of H3K9 in early bovine embryos

Reproduction ◽  
2021 ◽  
Vol 162 (3) ◽  
pp. 181-191
Author(s):  
Jessica Ispada ◽  
Aldcejam Martins da Fonseca Junior ◽  
Otávio Luiz Ramos Santos ◽  
Camila Bruna de Lima ◽  
Erika Cristina dos Santos ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Developmental Stages ◽  
De Novo ◽  
Blastocyst Stage ◽  
Developmental Model ◽  
Bovine Embryos ◽  
Acetyl Coa ◽  
Post Translational Modifications ◽  
The Relationship ◽  
Different Levels

Metabolic and molecular profiles were reported as different for bovine embryos with distinct kinetics during the first cleavages. In this study, we used this same developmental model (fast vs slow) to determine if the relationship between metabolism and developmental kinetics affects the levels of acetylation or tri-methylation at histone H3 lysine 9 (H3K9ac and H3K9me3, respectively). Fast and slow developing embryos presented different levels of H3K9ac and H3K9me3 from the earliest stages of development (40 and 96 hpi) and up to the blastocyst stage. For H3K9me3, both groups of embryos presented a wave of demethylation and de novo methylation, although it was more pronounced in fast than slow embryos, resulting in blastocysts with higher levels of this mark. The H3K9ac reprogramming profile was distinct between kinetics groups. While slow embryos presented a wave of deacetylation, followed by an increase in this mark at the blastocyst stage, fast embryos reduced this mark throughout all the developmental stages studied. H3K9me3 differences corresponded to writer and eraser transcript levels, while H3K9ac patterns were explained by metabolism-related gene expression. To verify if metabolic differences could alter levels of H3K9ac, embryos were cultured with sodium-iodoacetate (IA) or dichloroacetate (DCA) to disrupt the glycolytic pathway or increase acetyl-CoA production, respectively. IA reduced H3K9ac while DCA increased H3K9ac in blastocysts. Concluding, H3K9me3 and H3K9ac patterns differ between embryos with different kinetics, the second one explained by metabolic pathways involved in acetyl-CoA production. So far, this is the first study demonstrating a relationship between metabolic differences and histone post-translational modifications in bovine embryos.

Rhythmic changes in the serotonin content of the brain and eyestalk of crayfish during development

1999 ◽  
Vol 202 (20) ◽  
pp. 2823-2830 ◽  
Author(s):  
O. Castanon-Cervantes ◽  
B. Battelle ◽  
M.L. Fanjul-Moles
Keyword(s):  
Developmental Stages ◽  
Procambarus Clarkii ◽  
Cerebral Ganglion ◽  
Reversed Phase ◽  
Circadian Variations ◽  
Constant Illumination ◽  
Serotonin Content ◽  
Dim Light ◽  
The Relationship ◽  
The Brain

The present study investigated developmental circadian changes in the content of 5-hydroxytryptamine (5-HT) in two structures proposed to contain pacemakers in crayfish Procambarus clarkii: the cerebral ganglion and the eyestalks. Crayfish (N=260) from three developmental stages were divided into two groups: (1) animals subjected to 12 h:12 h light:dark cycles for 10 days and (2) animals treated as described above, then exposed to 72 h of continuous dim light. Crayfish from both groups were killed at different times of day, and the cerebral ganglion and the eyestalks of each were assayed for 5-HT by reversed-phase HPLC with electrochemical detection. In all stages of development, 5-HT content (expressed as (μ)g g(−)(1)wet mass tissue) showed circadian variations in both structures analyzed; rhythms continued to free-run under constant illumination, and total 5-HT content was higher in the brain (0.581+/−0.36 (μ)g g(−)(1); mean +/− s.e.m.) than in the eyestalks (0.299+/−0.15 (μ)g g(−)(1)). As development advances, the percentage of the rhythm that shows periods of 24 h diminishes, while the percentage of the rhythm that shows periods of 9 to 12 h increases. This seems to indicate that pulsatile variations in 5-HT content are superimposed in a circadian component. The relationship between the 5-HT rhythm and electroretinogram and motor activity rhythms during development is discussed.

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