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The annual cycle of atmospheric nitrogen species and macroelements (Na+, K+, Ca2+, Mg2+ and Cl−) over the south-eastern Baltic region was investigated. A one-year record enabled the variability of nitrogen species and macroelements in the aerosol over the coastal station at Hel to be traced. The highest concentrations of sea salt components were recorded in summer, while anthropogenic nitrate concentrations were highest in winter. When the air masses were of mixed marine and continental origin, the nitric acid reacted with coarse sea salt particles to form stable, coarse sodium nitrate. This seems to be a permanent removal pathway for nitrate. Anthropogenic aerosol species like NH+4 or NO− 3 formed by gas-to-particle conversion were generally associated with fine particles (<1 μm). Coarse particles like sodium or chloride resulted from resuspension from seawater.
Grasshoppers and katydids (Orthoptera) were studied on sand dunes of the Hel Peninsula in northern Poland in 2013. Altogether, 11 species of grasshoppers and katydids were identified, three of them can be regarded as elements of the fauna characteristic for sand dunes. Species diversity and population density was higher in the seaside with sparse vegetation than in the neighboring pine forest. The reported low species richness is comparable to other peninsula covered by sand. Myrmeleotettix maculates was most abundant, particularly by the seaside with low shrubs and Tetrix bipuncata occurred frequently in each habitat, but especially on the forest gaps.
Coastal upwelling often reveals itself during the thermal stratification season as an abrupt sea surface temperature (SST) drop. Its intensity depends not only on the magnitude of an upwelling-favourable wind impulse but also on the temperature stratification of the water column during the initial stage of the event. When a ‘chain’ of upwelling events is taking place, one event may play a part in forming the initial stratification for the next one; consequently, SST may drop significantly even with a reduced wind impulse. Two upwelling events were simulated on the Polish coast in August 1996 using a three-dimensional, baroclinic prognostic model. The model results proved to be in good agreement with in situ observations and satellite data. Comparison of the simulated upwelling events show that the first one required a wind impulse of 28 000 kg m−1 s−1 to reach its mature, full form, whereas an impulse of only 7500 kg m−1 s−1 was sufficient to bring about a significant drop in SST at the end of the second event. In practical applications like operational modelling, the initial stratification conditions prior to an upwelling event should be described with care in order to be able to simulate the coming event with very good accuracy.
Ammonia concentrations in aerosols and ammonium concentrations in the air were measured in the coastal zone of the southern Baltic Sea. The main study area was the Hel Peninsula, where measurements were carried out from December 1997 to March 1998. There was a second such area in Gdynia, where the first measurement period extended from May to December 2000, and the second one lasted from February to May 2001. At the same time, chloride, sulphate and sodium concentrations in the aerosols were determined; meteorological parameters were also measured. Aerosol samples were collected with a filter pack, and the gaseous phase species were collected on denuders. At both stations, the ammonium concentration in aerosols was at least one order of magnitude higher than that of the ammonia in the air samples. It was found that the marine boundary layer always contained ammonium chloride and ammonium sulphate. The presence of ammonium nitrate was detected only when winds were slight and was attributed to local anthropogenic sources. The ammonia concentration related to nitrate increased with rising air humidity and a falling temperature. The contribution of marigenic ions in aerosols was noted at onshore wind of speeds > 3.5 m s−1. In winter as in summer, conditions occurred facilitating light backscattering by a ‘wet’ aerosol, which contained ammonium nitrate and ammonium sulphate in proportions of 2.5:1 and 1:1.
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