scholarly journals Female Weddell seals show flexible strategies of colony attendance related to varying environmental conditions

Ecology ◽  
2015 ◽  
Vol 96 (2) ◽  
pp. 479-488 ◽  
Author(s):  
Thierry Chambert ◽  
Jay J. Rotella ◽  
Robert A. Garrott
Keyword(s):  
Environmental Conditions ◽  
Weddell Seals ◽  
Colony Attendance

scholarly journals Thermoregulatory costs in molting Antarctic Weddell seals: impacts of physiological and environmental conditions

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Skyla M Walcott ◽  
Amy L Kirkham ◽  
Jennifer M Burns
Keyword(s):  
Ambient Temperature ◽  
Environmental Conditions ◽  
Infrared Imaging ◽  
Conservation Strategies ◽  
Energetic Cost ◽  
Ambient Conditions ◽  
Mixed Effect ◽  
Small Surface ◽  
Weddell Seals ◽  
Imaging Results

Abstract For polar marine mammals, the energetic cost of thermoregulation depends on ambient conditions in the highly variable surrounding environment. Heat conservation strategies used by pinnipeds to reduce total heat loss include small surface area to volume ratios, the ability to limit perfusion and thick subcutaneous blubber layers. There are limits to how cool the skin surface may remain without compromising function, especially during the annual pelage molt, when hair and skin are replaced. To determine if actively molting seals incur higher thermoregulatory costs, surface temperature (ST) and heat flux (HF) were measured in 93 adult female Weddell seals (Leptonychotes weddellii) both prior to and during the active molting period using direct sensors and infrared imaging. Linear mixed-effect models revealed that ST increased significantly with increased ambient temperature and decreased wind speed (contributing 44.6 and 41.7% of the attributed variance, respectively). Seal STs were not impacted by molt status, but were maintained at 11.2 ± 0.3°C warmer than the ambient temperature. Infrared imaging results averaged 15.1 ± 1.4°C warmer than direct ST measurements. In contrast, HF was significantly higher in seals in early molting stages compared to the pre-molt season ( P < 0.001) and molt status accounted for 66.5% of the variance in HF. Thermoregulatory costs calculated from estimated basal metabolic rate and measured HF were more than double for molting seals as compared to those in pre-molt. This suggests that perfusion is increased during molt to support follicle development, despite the increased energetic costs associated with higher HF rates. Because ST, HF and thermoregulatory costs are strongly influenced by ambient conditions, molt timing is likely under selective pressure to occur during the warmest period of the year. Shifts in environmental conditions that delay molt phenology or increase HF rates could negatively impact seal populations by further increasing thermoregulatory costs.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

The influence of external conditions on sound pressure in the pistonphone at the infrasound frequency range

2020 ◽  
pp. 67-72
Author(s):  
A. V. Konkov ◽  
D. V. Golovin
Keyword(s):  
Environmental Conditions ◽  
Sound Pressure ◽  
Primary Method ◽  
Frequency Range ◽  
External Conditions ◽  
Numerical Estimations

The influence of environmental conditions on a sound pressure reproduced by the primary method in the measuring chambers of the Pistonphone in the frequency range from 1 mHz to 250 Hz is estimated. Numerical estimations of influence of environmental conditions on sound pressure in pistonphone measuring chambers are given and special requirements to system of maintenance of required external conditions are specified.

Disentangling the role of shared ancestry and the environment on leaf stable isotopes

2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1
Keyword(s):  
Stable Isotopes ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Environmental Control ◽  
Phylogenetic Signal ◽  
Individual Species ◽  
Habitat Types ◽  
Δ13c And Δ15n ◽  
Environmental Controls ◽  
Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

Freshwater Mussel (Batissa violacea) Fishery and its Value in Fiji

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Jimaima Lako ◽  
Nanise Kuridrani ◽  
Milika Sobey
Keyword(s):  
Value Chain ◽  
Environmental Conditions ◽  
Rural Women ◽  
Freshwater Mussel ◽  
Face To Face

This paper examines the local freshwater mussel, or kai (Batissa violacea), fishery value chain, its values and contribution to the livelihood of people in Viti Levu, Fiji. The assessment was performed through face-to-face interviews, with the use of semi-structured questionnaires administered to 125 actors. A walk through the value-chain was also conducted that confirmed the sites’ environmental conditions. Results revealed that even though the kai fishery is dominated by rural women, men were also employed as kai processors, transporting agents and exporters. This fishery generated at least 58 other employments through the 500 kai harvesters within the five major provinces understudy. These were drivers, boat builders, retailers, processors, exporters, and harvesters. Three sales pathways were identified that determined the revenues and profits: (i) harvesters sell own harvests directly to the consumer at the municipal markets, (ii) harvesters sell through intermediary traders to consumers, and (iii) harvesters sell through processors to supermarkets, hotels or exporters. When revenues and profits were calculated, harvesters earned much less, compared to intermediary traders, processors, and exporters. Major constraints include continuous reduction in catch size of kai, lack of transport, and marketing at the local municipal markets that require improvements.

Relationships between temperature and Pacific hake distribution vary across latitude and life-history stage

2020 ◽  
Vol 639 ◽  
pp. 185-197 ◽  
Author(s):  
MJ Malick ◽  
ME Hunsicker ◽  
MA Haltuch ◽  
SL Parker-Stetter ◽  
AM Berger ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Vancouver Island ◽  
Additive Models ◽  
Life History Stage ◽  
Fish Stocks ◽  
Merluccius Productus ◽  
Multiple Dimensions ◽  
Effects Of Temperature

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

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