Pteropods are a group of holoplanktonic gastropods for which global biomass distribution patterns remain poorly resolved. The aim of this study was to collect and synthesize existing pteropod (Gymnosomata, Thecosomata and Pseudothecosomata) abundance and biomass data, in order to evaluate the global distribution of pteropod carbon 5 biomass, with a particular emphasis on its seasonal, temporal and vertical patterns. We collected 25 902 data points from several online databases and a number of scientific articles. The biomass data has been gridded onto a 360 × 180• grid, with a vertical resolution of 33 WOA depth levels. Data has been converted to NetCDF format which can be downloaded from PANGAEA, http://doi.pangaea.de/10.1594/PANGAEA.777387. 10Data were collected between 1951-2010, with sampling depths ranging from 0-1000 m. Pteropod biomass data was either extracted directly or derived through converting abundance to biomass with pteropod specific length to weight conversions. In the Northern Hemisphere (NH) the data were distributed evenly throughout the year, whereas sampling in the Southern Hemisphere was biased towards the austral sum-15 mer months. 86 % of all biomass values were located in the NH, most (42 %) within the latitudinal band of 30-50 • N. The range of global biomass values spanned over three orders of magnitude, with a mean and median biomass concentration of 8.2 mg C l −1 (SD = 61.4) and 0.25 mg C l −1 , respectively for all data points, and with a mean of 9.1 mg C l −1 (SD = 64.8) and a median of 0.25 mg C l −1 for non-zero biomass values. 20 The highest mean and median biomass concentrations were located in the NH between 40-50 • S (mean biomass: 68.8 mg C l −1 (SD × 213.4) median biomass: 2.5 mg C l −1 ) while, in the SH, they were within the 70-80 • S latitudinal band (mean: 10.5 mg C l −1 (SD × 38.8) and median: 0.2 mg C l −1 ). Biomass values were lowest in the equatorial regions. A broad range of biomass concentrations was observed at all depths, with the 25 biomass peak located in the surface layer (0-25 m) and values generally decreasing with depth. However, biomass peaks were located at different depths in different ocean basins: 0-25 m depth in the N Atlantic, 50-100 m in the Pacific, 100-200 m in the Arctic,318 -500 m in the Brazilian region and >500 m in the Indo-Pacific region. Biomass in the NH was relatively invariant over the seasonal cycle, but more seasonally variable in the SH. The collected database provides a valuable tool for modellers for the study of ecosystem processes and global biogeochemical cycles. 25 sume up to 19 % of daily primary production (Hunt et al., 2008). Pteropods are also an 319
Thousand-seed weight and total germination from the first production year and two seed harvests were measured in tetraploid Italian ryegrass (cv. Tetraflorum) to study variations in seed quality. Four-year field experiments were carried out (2002-2006) in western Serbia and Italian ryegrass was established with three row spacings (20, 40 and 60 cm), four seeding rates (5, 10, 15 and 20 kg ha-1) and using four spring nitrogen rates (0, 50, 100 and 150 kg ha-1). High seed quality was obtained, except for the first experimental year (2003) and the second seed harvests which yielded the seed of unsatisfactory quality and validity. Applied factors and treatments did not change seed quality significantly unlike environmental conditions of production years which had considerable influence on seed quality
The study was performed in Mali Park, in the town of Obrenovac. Our findings are based on the data obtained after direct measurements of elements of growth and the derived indicators of tree vitality and ornamentalness. Cluster analysis was applied to determine the relatively homogeneous groups of tree species. The results show that the group with the best functional characteristics includes Platanus acerifolia, Tilia grandifolia and Fraxinus ornus, and the group of species with inferior characteristics includes Betula verrucosa, Juglans regia, Celtis australis, Acer platanoides, Cedrus atlantica and Acer negundo.
The effect of plantation density on the stem volume development phases of mean trees of Populus x euramericana (Dode) Guinier, cl. I-214 were studied in the test plantation aged 25 years with two different planting densities 4.25x4.25 m (treatment A) and 6.00x6.00 m (treatment B). The modeling of stem volume growth of mean trees enabled the identification of development phases based on biological laws. Different growth dynamics of mean trees of the clone I-214, depending on plantation density, had a clear effect on the beginning and the end of individual phases, i.e. subphases of development, as well as on the diameters, heights and volumes of mean trees at the end of each phase of volume development
Two experimental plantations of Euramerican poplar (Populus?euramericana (Dode) Guinier) - clone I-214 were researched on the river Sava alluvium in Srem. Three sample plots were established in each of the plantations, aged 31 years. The soil type was humofluvisol (alluvial semigley), planting space 6?6 m. The plantations were established with 278 rooted cuttings per hectare, and the number of trees at the age of 31 accounted for 46.5-60.6%. The constructed height curves, mean stand height (hg) and upper (hg20%) heights show that the study plantations were established on different site classes, which was significantly reflected on other plantation growth elements and productivity. However, there was no significant effect of site class on the variability (sd and cv) and shape of diameter structure (?3 and ?4). The constructed models of diameter structure for each site class (by Weibull function) differ by location parameter (a), and do not differ by parameter of scale (b) and shape (c). The tree and plantation growth elements show a high production potential of the clone I-214 which indicates that, on optimal soils and with the provided technological measures in the stage of nursery production and in the stage of plantation establishment, clone I-214 presents the good base for high production effects.
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