5 research outputs found
Interannual summer streamflow variability over Romania and its connection to large-scale atmospheric circulation
In this study, the spatial and temporal variability of summer (June–July–August, JJA) streamflow over Romania, as recorded at 46 hydrological stations over the period 1935–2010 is analysed. An empirical orthogonal function analysis and a canonical correlation analysis (CCA) were used to characterize the spatial and temporal variability of summer streamflow and its relationship with large-scale atmospheric factors. The dominant summer mode captures in-phase variability of river flow anomalies over the entire country, while the second mode of variability is characterized by a northwest–southeast dipole, emphasizing the influence of topography over the streamflow variability. Based on a CCA analysis, more than 50% of the summer streamflow variability is shown to be influenced by cloud cover and summer temperatures, via the modulation of precipitation and potential evapotranspiration. In general, positive (negative) streamflow anomalies, at country level, are associated with cyclonic (anticyclonic) circulation, the advection of moist (warm and dry) air, enhanced (reduced) precipitation and positive (negative) cloud cover anomalies
The Regulation of Carbon and Nutrient Assimilation in Diatoms is Significantly Different from Green Algae
Diatoms are important primary producers not only in the oceans but also in the freshwater
environment. The efficiency of biomass formation strongly depends on the metabolic
regulation of carbon and nutrient assimilation. Recent studies have given evidence that many
metabolic regulations are quite different from green algae and higher plants. The major
known differences concern the following processes: (1) pigment biosynthesis, (2) lightharvesting
organisation, (3) mechanism of photoprotection, (4) regulation of photosynthetic
electron flow, (5) regulation of the enzyme activity in the Calvin-Benson cycle, (6)
photorespiration, (7) carbon aquisition and CO2-concentrating mechanisms, (8) synthesis and
breakdown of storage products under starvation, (8) nutrient uptake (9) adaptation to extreme
environments. This review summarises these differences phenomenologically and presents the
actual knowledge of the underlying mechanisms. The availability of whole genome sequence
data is an important basis to learn in more detail how photosynthesis in these tremendously
successful primary producers is regulated