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  • Author: Tomasz Grajewski x
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Short-term changes in thermal conditions and active layer thickness in the tundra of the Kaffiøyra region, NW Spitsbergen

Abstract

This article describes and discusses the results of observations concerning short-term changes in the thermal conditions and the thickness of the active layer in a test field located in the tundra of the Kaffiøyra (NW Spitsbergen) during the summer season of 2015. One of the objectives was to find a correlation between the dynamic of the changes and the local topography. In recent years, thawing of the active layer in the Kaffiøyra region has been considerably varied in individual summer seasons. The test field area was 100 square meters, comprised 36 measurement points and was situated at approximately 3 m a.s.l. in the tundra. The measurements of the thickness and temperature of the active layer were carried out in July, August and early September of 2015. The greatest thickness of the active layer in the tundra was found near the moraine, in the area with the sharpest slope (156 cm to 212 cm). Ground temperatures were observed to follow the prevailing weather conditions with a delay, which amounted to about 24 h at a depth of 25 cm, and as much as 48 h at a depth of 75 cm. A greater thickness of the active layer was found in the western part of the test field, in the vicinity of a tidal channel, and in the eastern part of the field, bordering on the foot of the Aavatsmarkbreen’s moraine. A considerable sloping of the land, combined with increased surface runoff and infiltration at the time of precipitation, makes the water penetrating into the active layer increase its temperature. This demonstrates that the local land forms (tidal channels and terminal moraines) have a substantial influence on the extent and rate of changes which occur in the active layer.

Open access
Genetic parameters of carcass traits in ducks from a crossbred population

Abstract

The aim of this study was to estimate coefficients of heritability as well as genetic and phenotypic correlations among body weight and carcass traits. The dataset contained records of 387 birds from the second crossbred generation. The following traits were recorded: body weight (BW) at 11 weeks, carcass weight (CW), breast muscle weight including superficial and deep muscle (BMW), leg muscle weight including thigh and shank (LMW), wings weight (WW), skin with subcutaneous fat weight (SW), abdominal fat weight (AFW), skeleton with the back muscle and inedible elements (SBM), and liver weight (LW). Estimates of variance components were obtained by the average information - REML algorithm in the ASReml package. Very high slaughter yield (74.90%) was obtained. Generally, the coefficients of heritability were high. The highest one of 0.75 was estimated for body weight at 11 weeks. High coefficients of h2 were estimated for breast muscle weight (0.69), wings weight (0.70), carcass weight (0.65), skin with subcutaneous fat weight (0.57) and skeleton with the back muscle (0.58), whereas h2 of liver weight was 0.29. Both phenotypic and genetic relationships between the recorded traits were usually positive. Generally, it seems that the crossbreeding scheme can be perceived as a suitable proposal for the breeding practice.

Open access