Quantitative micrograph, HPLC and FTIR profiles of Melissa officinalis and Nepeta cataria (Lamiaceae) from Argentina

Melissa officinalis L., so called "Melissa" or "Toronjil", is a perennial aromatic herb, whose leaves are used in traditional medicine as a carminative, digestive and sedative, both in simple as in mixtures. Meanwhile, Nepeta cataria L., commonly called "Cat mint" or "Toronjil", with some similar properties, often replacing M. officinalis in the market, although their chemical composition is not completely matched, and contains an iridoid potentially toxic (nepetalactone). It is therefore necessary to establish diacritic parameters to differentiate these species, both at crude drug level, mixtures and extracts. Samples from various sources in Argentina were studied and documental specimens are preserved in the Herbarium UNSL. Anatomical sections were analyzed, and quantitative micrographic parameters were obtained, together with HPLC and FTIR spectra from methanolic and aqueous lyophilized extracts. Significant differences were detected in the prevailing smell foliage, morphology of leaves and inflorescences, trichomata type, palisade ratio, veinlet termination number, rosmarinic acid concentration (with distinctive HPLC profiles), and the CO/CH relationships obtained by FTIR from the extracts, that together allow adequate differentiation of both drugs, even when they were ground or powdered.

Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Vertical distribution of phytoplankton pigments in the equatorial Pacific

Abundance distribution and cellular characteristics of picophytoplankton were studied in two distinct regions of the equatorial Pacific: the western warm pool (0°, 167°E), where oligotrophic conditions prevail, and the equatorial upwelling at 150°W characterized by high-nutrient low-chlorophyll (HNLC) conditions. The study was done in September-October 1994 during abnormally warm conditions. Populations of Prochlorococcus, orange fluorescing Synechococcus and picoeukaryotes were enumerated by flow cytometry. Pigment concentrations were studied by spectrofluorometry. In the warm pool, Prochlorococcus were clearly the dominant organisms in terms of cell abundance, estimated carbon biomass and measured pigment concentration. Integrated concentrations of Prochlorococcus, Synechococcus and picoeukaryotes were 1.5x10**13, 1.3x10**11 and 1.5x10**11 cells/m**2, respectively. Integrated estimated carbon biomass of picophytoplankton was 1 g/m**2, and the respective contributions of each group to the biomass were 69, 3 and 28%. In the HNLC waters, Prochlorococcus cells were slightly less numerous than in the warm pool, whereas the other groups were several times more abundant (from 3 to 5 times). Abundance of Prochlorococcus, Synechococcus and picoeukaryotes were 1.2x10**13, 6.2x10**11 and 5.1x10**11 cells/m**2, respectively. The integrated biomass was 1.9 g C/m**2. Prochlorococcus was again the dominant group in terms of abundance and biomass (chlorophyll, carbon); the respective contributions of each group to the carbon biomass were 58, 7 and 35%. In the warm pool the total chlorophyll biomass was 28 mg/m**2, 57% of which was divinyl chlorophyll a. In the HNLC waters, the total chlorophyll biomass was 38 mg/m**2, 44% of which was divinyl chlorophyll a. Estimates of Prochlorococcus, Synechococcus and picoeukaryotes cell size were made in both hydrological conditions.