scholarly journals Does Growth Rate Determine the Rate of Metabolism in Shorebird Chicks Living in the Arctic?

2007 ◽  
Vol 80 (5) ◽  
pp. 500-513 ◽  
Author(s):  
Joseph B. Williams ◽  
B. Irene Tieleman ◽  
G. Henk Visser ◽  
Robert E. Ricklefs
Keyword(s):  
Growth Rate ◽  
The Arctic ◽  
Rate Determine

scholarly journals The Granular Sea Ice Model in Spherical Coordinates and Its Application to a Global Climate Model

2007 ◽  
Vol 20 (24) ◽  
pp. 5946-5961 ◽  
Author(s):  
Jan Sedlacek ◽  
Jean-François Lemieux ◽  
Lawrence A. Mysak ◽  
L. Bruno Tremblay ◽  
David M. Holland
Keyword(s):  
Growth Rate ◽  
Sea Ice ◽  
Climate Model ◽  
Heat Budget ◽  
Global Climate ◽  
Global Climate Model ◽  
Internal Heat ◽  
The Arctic ◽  
Spherical Coordinates ◽  
Ice Model

Abstract The granular sea ice model (GRAN) from Tremblay and Mysak is converted from Cartesian to spherical coordinates. In this conversion, the metric terms in the divergence of the deviatoric stress and in the strain rates are included. As an application, the GRAN is coupled to the global Earth System Climate Model from the University of Victoria. The sea ice model is validated against standard datasets. The sea ice volume and area exported through Fram Strait agree well with values obtained from in situ and satellite-derived estimates. The sea ice velocity in the interior Arctic agrees well with buoy drift data. The thermodynamic behavior of the sea ice model over a seasonal cycle at one location in the Beaufort Sea is validated against the Surface Heat Budget of the Arctic Ocean (SHEBA) datasets. The thermodynamic growth rate in the model is almost twice as large as the observed growth rate, and the melt rate is 25% lower than observed. The larger growth rate is due to thinner ice at the beginning of the SHEBA period and the absence of internal heat storage in the ice layer in the model. The simulated lower summer melt is due to the smaller-than-observed surface melt.

Pan-Svalbard growth rate variability and environmental regulation in the Arctic bivalve Serripes groenlandicus

2011 ◽  
Vol 88 (2) ◽  
pp. 239-251 ◽  
Author(s):  
Michael L. Carroll ◽  
William G. Ambrose ◽  
Benjamin S. Levin ◽  
William L. Locke V ◽  
Gregory A. Henkes ◽  
...  
Keyword(s):  
Growth Rate ◽  
Environmental Regulation ◽  
The Arctic ◽  
Serripes Groenlandicus

scholarly journals A dynamic model for determining the optimum cutting schedule of Italian ryegrass

1975 ◽  
Vol 47 (2) ◽  
pp. 71-137
Author(s):  
Veli Pohjonen
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Maximum Yield ◽  
Crop Growth ◽  
Italian Ryegrass ◽  
Growth Potential ◽  
The Arctic ◽  
Daily Growth ◽  
Crop Growth Rate ◽  
Optimum Cutting

A quantitative approach to the determination of the optimum cutting schedule of Italian ryegrass (Lolium multiflorum Lam.) was presented. Optimization was based on a dynamic growth model which included the concepts crop growth rate, development rate and proper growth rate. The proper growth rate measured the growth potential associated with the stages of development in the sward. The crop growth rate of Italian ryegrass was studied at the Arctic Circle Experiment Station during 1973 and 1974. The proper growth rate was determined from primary observations as the derivative of an ordinary logistic curve which passes through origin. The maximum theoretical daily growth of Italian ryegrass was calculated as approx. 300 kg • ha-1• day-1. The optimum cutting schedules using gradient method were sought for Italian ryegrass sward. First, the maximum total dry-matter yield was looked for. Then the maximization was extended to the case, when the yield was weighted with the digestibility of the dry-matter. The maximum yield was obtained when the sward was cut three times, and when the cuttings were concentrated into the latter half of the growing season. The yield of the optimum cutting schedule was not sensitive to small changes in the cutting dates. In the conditions of Finnish Lapland the optimum cutting schedule of Italian ryegrass was: first cut at the end of July, second cut at the end of August and the third cut at the end of September.

scholarly journals Atmospheric new particle formation characteristics in the Arctic as measured at Mount Zeppelin, Svalbard, from 2016 to 2018

2020 ◽  
Vol 20 (21) ◽  
pp. 13425-13441
Author(s):  
Haebum Lee ◽  
Kwangyul Lee ◽  
Chris Rene Lunder ◽  
Radovan Krejci ◽  
Wenche Aas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dimethyl Sulfide ◽  
Formation Rate ◽  
Production Capacity ◽  
Particle Formation ◽  
The Arctic ◽  
New Particle Formation ◽  
Low Loss ◽  
H2so4 Concentration ◽  
Average Formation

Abstract. We conducted continuous measurements of nanoparticles down to 3 nm size in the Arctic at Mount Zeppelin, Ny Ålesund, Svalbard, from October 2016 to December 2018, providing a size distribution of nanoparticles (3–60 nm). A significant number of nanoparticles as small as 3 nm were often observed during new particle formation (NPF), particularly in summer, suggesting that these were likely produced near the site rather than being transported from other regions after growth. The average NPF frequency per year was 23 %, having the highest percentage in August (63 %). The average formation rate (J) and growth rate (GR) for 3–7 nm particles were 0.04 cm−3 s−1 and 2.07 nm h−1, respectively. Although NPF frequency in the Arctic was comparable to that in continental areas, the J and GR were much lower. The number of nanoparticles increased more frequently when air mass originated over the south and southwest ocean regions; this pattern overlapped with regions having strong chlorophyll a concentration and dimethyl sulfide (DMS) production capacity (southwest ocean) and was also associated with increased NH3 and H2SO4 concentration, suggesting that marine biogenic sources were responsible for gaseous precursors to NPF. Our results show that previously developed NPF occurrence criteria (low loss rate and high cluster growth rate favor NPF) are also applicable to NPF in the Arctic.

Accumulation of Persistent Pollutants in Normal and Dwarfed Arctic Char (Salvelinus alpinus sp. complex)

1993 ◽  
Vol 50 (12) ◽  
pp. 2574-2580 ◽  
Author(s):  
Johan Hammar ◽  
Per Larsson ◽  
Maris Klavins
Keyword(s):  
Growth Rate ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Individual Growth ◽  
The Arctic ◽  
Growth Strategies ◽  
Sympatric Populations ◽  
Fast Growing ◽  
Persistent Pollutants ◽  
Slow Growing

Two extreme growth fractions of introgressed sympatric populations of the Arctic char (Salvelinus alpinus) species complex from Lake Blåsjön, northern Sweden, were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of SPCB (sum of PCB congeners found) and p,p-DDE (dominating DDT-compound) than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates (introduced Mysis relicta and Pallasea quadrispinosa) are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass "dilution" of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish.

scholarly journals Atmospheric new particle formation characteristics in the Arctic as measured at Mount Zeppelin, Svalbard, from 2016 to 2018

2020 ◽  
Author(s):  
Haebum Lee ◽  
KwangYul Lee ◽  
Chris Rene Lunder ◽  
Radovan Krejci ◽  
Wenche Aas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dimethyl Sulfide ◽  
Formation Rate ◽  
Production Capacity ◽  
Particle Formation ◽  
The Arctic ◽  
Average Particle ◽  
New Particle Formation ◽  
Low Loss ◽  
Average Growth

Abstract. We conducted continuous measurement of nanoparticles down to 3 nm size in the Arctic at Mount Zeppelin, Ny Ålesund, Svalbard, from 2016 to 2018, providing a size distribution of nanoparticles (3–60 nm) with a higher resolution than ever before. A significant number of nanoparticles as small as 3 nm were often observed during new particle formation (NPF), particularly in summer, suggesting that these were likely produced near the site rather than being transported from other regions after growth. The average NPF frequency per year was 24 % having the highest percentage in August (63 %). The average particle formation rate (J) for 3–7 nm particles was 0.1 cm−3 s−1 and the average growth rate (GR) was 2.62 nm h−1. Although NPF frequency in the Arctic was comparable to that in continental areas, the J and GR were much lower. The number of nanoparticles increased more frequently when air mass originated over the south and southwest ocean regions; this pattern overlapped with regions having strong chlorophyll-α concentration and dimethyl sulfide (DMS) production capacity (southwest ocean), and was also correlated with increased daily NH3 concentration, suggesting that marine biogenic and animal sources were responsible for gaseous precursors to NPF. Our results show that previously developed NPF occurrence criteria (low loss rate and high cluster growth rate favor NPF) are also applicable to NPF in the Arctic.

Freedom to move: Arctic caterpillar (Lepidoptera) growth rate increases with access to new willows (Salicaceae)

2016 ◽  
Vol 148 (6) ◽  
pp. 673-682 ◽  
Author(s):  
Christopher J. Greyson-Gaito ◽  
Matthew A. Barbour ◽  
Mariano A. Rodriguez-Cabal ◽  
Gregory M. Crutsinger ◽  
Gregory H.R. Henry
Keyword(s):  
Growth Rate ◽  
Host Plant ◽  
Natural Enemies ◽  
Host Plants ◽  
Growing Season ◽  
The Arctic ◽  
Insect Herbivore ◽  
Insect Herbivores ◽  
Common Behaviour ◽  
Gynaephora Groenlandica

AbstractMovement between host plants during the growing season is a common behaviour among insect herbivores, although the mechanisms promoting these movements are poorly understood for many systems. Two possible reasons why insect herbivores relocate include compensating for host plant quantity and/or quality changes and the avoidance of natural enemies. The Arctic caterpillar (Gynaephora groenlandica (Wocke); Lepidoptera: Lymantriidae) moves several metres each day, feeds on its patchily distributed host plant, Arctic willow (Salix arctica Pallas; Salicaceae), and has two main natural enemies, the parasitoids Exorista thula Wood (Diptera: Tachinidae) and Hyposoter diechmanni (Nielsen) (Hymenoptera: Ichneumonidae). We physically moved caterpillars between Arctic willows and restricted other caterpillar individuals each to a single willow throughout the active period of Arctic caterpillars. We found that growth rate, herbivory rate, and the proportion of available leaf fascicles eaten were higher for experimentally moved caterpillars. Parasitoid abundances were low and did not differ between experimentally moved and stationary caterpillars. Taken together, our study addresses the bottom–up and top–down controls on insect herbivore movement during the short duration of the growing season in the Arctic. Our results suggest that caterpillars are likely moving to new willow shrubs to access high quality resources.

Decline of the Arctic 'ice factories' delayed by negative feedbacks

2021 ◽  
Author(s):  
Sam Cornish ◽  
Helen Johnson ◽  
Alice Richards ◽  
Yavor Kostov ◽  
Jakob Dörr
Keyword(s):  
Growth Rate ◽  
Sea Ice ◽  
Climate Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Growth ◽  
Air Temperatures ◽  
Arctic Sea ◽  
Negative Feedbacks ◽  
Ice Pack

<p>Over the past few decades, Arctic sea ice volume has been decreasing faster in summer than winter; winter sea ice growth has been increasing, helping to restore the ice pack, despite the fact that Arctic warming is most intense in the winter. This raises the questions: why? And for how long can we expect winter ice growth to keep increasing? We pose these questions with a regional focus on the Kara and Laptev seas. These seas are often termed the ice factories of the Arctic because of their outsized contributions to the Arctic sea ice budget, a consequence of their divergent settings. Using the CESM climate model ensemble, we separate out the influence of different levers on ice factory productivity (the ice growth rate), and show that 20th Century and RCP8.5 changes can be skilfully reconstructed by a linear model incorporating 2 m temperature, snow thickness, September sea ice area, total (gross) divergence and ice export. Ocean temperatures, meanwhile, help to explain the timing of the onset of freezing. Increasing air temperatures naturally decrease the growth rate, while positive contributions to growth rate are made by a decreasing September sea ice area, increasing divergence and increasing export. These positive influences are all associated with a thinning, more mobile ice pack: they are negative feedbacks on sea ice loss. In CESM, once the September sea ice area in the Kara-Laptev seas approaches zero, the year-on-year productivity of the ice factories starts to decline. We place these results in the context of observations and discuss the prospects for the productivity of the Arctic Ocean’s ice factories.</p>

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