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This work is part of a series of aerobiological researches conducted in the city of Mar del Plata, Argentina. The annual, seasonal and daily features of the pollen cloud were analyzed over 2 years, together with the effects of the meteorological variables. Cupressaceae amounted to 75 and 54% of the annual total in each year, and it was analyzed separately due to its proven overrepresentation. Eighty-five pollen types were registered during the 2 years, bearing a similar annual pattern (more than 50% from August to November, December also being an important month). Arboreal pollen predominated between late winter and spring (61 and 49% of the annual total), while non-arboreal pollen did so from late spring to summer. The observed seasonality was significantly correlated with the monthly mean temperatures and associated with its effect on phenology. No significant differences along the day were detected between years and 50% of the daily total was recorded between 1000 and 1600 hours. The maximum concentration was registered at 1000 hours in spring and summer, but later in autumn and winter. Regarding the hourly scale, the significant correlation of total pollen with temperature and wind speed was positive, albeit negative with relative humidity. These effects are linked to airborne pollen release and transport.

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The atmosphere of Mar del Plata city (Argentina) was monitored using three different pollen traps-Burkard, Rotorod, and Tauber-during a flowering season (mid-winter to springtime) in order to compare the diversity and amounts of pollen grains collected in each trap. Sixty three percent of taxa diversity was simultaneously recorded by all three apparatuses. The five most abundant types of pollen in the three traps were Platanus, Ulmus, Quercus, Poaceae, and Fraxinus. The Tauber trap contained the most pollen from taxa with the largest grains, and exclusively trapped ten pollen types with entomophilous characteristics. The amount of pollen in each trap and local/extra-local plant abundance were compared to elucidate the effect of the method used on the pollen-vegetation relationship. The correlation coefficients for total pollen were positive and significant between all pairs of traps. The maximum peak was observed first in the Burkard trap, in agreement with an increase in temperature, but the general pattern in the three traps was similar, with a maximum in early spring. Opposite deviations from the mean value were observed for the Burkard and Tauber data; these deviations were associated negatively with wind speed and relative humidity, respectively. This paper discusses whether in some cases the pollen records could be used in an equivalent manner, although with some limitations.

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A first analysis of airborne phytoliths was carried out in Mar del Plata, Argentina. Its primary aims were to characterize the phytolith morphotypes present in the atmosphere, to quantify their abundance and to detect whether seasonal variations exist throughout the year. The standard method was used for monitoring airborne particulate matter applying a Hirst-type suction bioaerosol sampler. The mean daily phytoliths concentrations (p/m3) were calculated for eight selected days from the driest year, 1993, bearing in mind that its atmospheric conditions could favour the presence of biomineralizations in the air. The amount of phytoliths reached was of 1,543. It was composed of 61% isolated and 1% articulated types. The rest were unknown or unidentified phytoliths (38%). The most abundant morphotypes (72.1% of those identified) were elongates, followed by rondels (16.1%) already described for Poaceae subfamilies, such as Pooideae and Stipoideae. Finally, trapeziform and point shaped were identified with 3.8 and 3.4%, respectively. A lower abundance of silica particles was detected on high wind speed days from the south (sea coast) and under wetter conditions. Maximum phytoliths concentrations were recorded in winter when pasture burning is carried out alongside ploughing; this also coincides with the period in which soils were not covered by vegetation. These results shed light on the importance of considering the potential ways of phytoliths dispersion and the factors that could be affecting their aerial transport, especially when they are applied to the interpretation of paleovegetation from phytolith fossil records.