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of climate change on the composition and competitive capacity of southern European Pinus sylvestris L. forests in the Mediterranean basin were evaluated. The variation
over the period 1910-2008 through 30-year mobile averages of a Phytoclimatic
Suitability Index (PSI) of the main tree species of the forest cover are used
to indicate the competitive hierarchy of Pinus sylvestris and Fagus
sylvatica L. The methodology was applied at a specific location on
the Spanish south-facing slopes of the Pyrenees mountain range in the Iberian Peninsula, where the increase in the average temperature was 1.4?C in the
period of observation. The results indicated that the apparent equilibrium
between the two species studied changed from the 1934-1963 average. Due to the
loss of competitive capacity of Scots pine with respect to European beech,
particularly from the years 1970-1999, the model predicted an inversion of the
situation as it was up until now, so that beech had a higher PSI than pine. The
phytoclimatic approach proposed here offers new methodological horizons for the
study of the effects of climate change on the future of the forests.
The relationship between bacterial load and the microalga Chaetoceros muelleri was analyzed in a scale-up experiment. The microalga was grown during five days in a 0.4-L Erlenmeyer flask, 2-L Fernbach flask, 18-L Carboy and 400-L column, during which the cell density of C. muelleri, the abundance of heterotrophic bacteria, Vibrio spp., and total bacteria were determined. The highest specific growth rates (μ) of C. muelleri occurred during the first day of culture (0.88 to 2.29 d-1). Highest cell density was recorded on the fifth day at the 2-L (7.62 × 106 cells·mL-1) and 18-L (6.32 × 106 cells·mL-1), coinciding with the maximum counts of heterotrophic bacteria (16.55 × 105 and >30 × 105 CFU·mL-1, respectively). There was a high correlation (0.80, 0.75, 0.85; p <0.05) between microalgal cell density and total bacteria in the first three culture volumes and a low correlation (0.27; p = 0.34) at 400-L column. The highest mean concentration of total bacteria (884.13 × 105 cells·mL-1) during the five days occurred at 18-L Carboy. The concentration of total bacteria at all levels was always higher than that of heterotrophic bacteria. The average ratio of heterotrophic to total bacteria was higher in the 2-L (0.0108) and 18-L (0.0172) cultures. The high biomass of C. muelleri and the presence of Vibrio spp. at the 18-L and 400-L levels indicate that it is necessary to establish programs to prevent diseases and economic losses caused by pathogenic bacteria in penaeid shrimp farming.