Vertical angles and refraction in mountain areas

Summary The paper contains an analysis of the character and the quantity of variations of vertical angles, and an analysis of dependences of those variations upon meteorological elements, made on the basis of results of observations carried out at four points in the Polish Tatra Mountains (Figure 1). The analyses comprise four measurement periods: July 1963, June 1964, October 1964 and May 1965. The observations of the vertical angles and of the meteorological factors had been made simultaneously at three points. The meteorological findings have been complemented by data obtained from the mountain meteorological stations. The analysis of results reveals a fairly good consistency between the refraction variations and the changes in the mean temperature gradients for observations from the mountain peaks and for the sight lines with a quite great distance from the ground—provided a steady weather permits for observations of the zenith distance to be made during several days.     

Toxicity Assessment by Microtox® in Sediments,Pore Waters and Sediment Saline Elutriates in the Gulf of Gdansk (Baltic Sea)

The toxicity of sediments in the Gulf of Gdansk is analyzed in relation to the chemical composition of interstitial and near‐bottom waters, and sediment properties. The toxicity of sediments, pore waters and saline elutriates is determined by using the Microtox® test based on changes in light production of the luminescent bacteria Vibrio fischeri. The results indicate considerable toxicity in the majority of examined sediments. Since the sediment elutriates and pore waters are toxic in some cases, the total toxicity of the sediments is likely to be due to both sediment‐bound and water soluble substances. The sediment toxicity is related to the percentage contribution of the fine fraction of sediments. A significant correlation between the toxicity of the sediments and the black carbon content implies anthropogenic contamination. The toxicity of the sediments is seen to increase with the increase of hydrogen sulfide concentration in pore waters. The ammonia in pore waters was found not to be responsible for the toxicity of the sediments.