Vapor condensation, whether due to dew or fog, may add a stable and important source of water to deserts. This was also extensively assessed in the Negev, regarded as a dew desert. Dew deserts necessitate a large reservoir of vapor, and are therefore confined to near oceans or seas. Yet, examples of such deserts are scarce. Here we try to assess whether the Tabernas Desert in SE Spain can be regarded as a dew desert, and may therefore facilitate the growth of certain organisms that otherwise would not survive the dry season. We analyze some of the abiotic conditions of four relatively dry months (June, July, August, September) in the Tabernas and Negev deserts (with the Negev taken as an example of a dew desert) during 2003–2012. The analysis showed substantially lower values of relative humidity (by 10–13%) in the Tabernas in comparison to the Negev, with RH ≥95% being on average only 0.9–1.1 days a month in the Tabernas in comparison to 9.7–13.9 days in the Negev. Our findings imply that the Tabernas Desert cannot be regarded as a dew desert, suggesting that rain will be the main factor responsible for the food web chain in the Tabernas.
The paper summarises the results of the first year of the project GACR No. 205/99/1426 focused on the comparison of the pollutant concentration in the fog (low cloud ) water of two industrial regions of the Czech Republic with different atmospheric load. During the first project year the samples of the fog (cloud) water were collected and analysed. The number of samples, collected at the mountain observatories Milesovka (Mileschauer) and at Churanov, permitted the first preliminary comparison of the regions. The subject of comparison were the mean values of the pollutant concentration, the concentration of pollutants in dependence on the wind direction and in the dependence on the sector from which the air particles (and consequently also the pollutants) were transported to the considered stand. and Příspěvek shrnuje výsledky 1. roku řešení projektu GA CR 205/99/1426, který je věnován porovnání koncentrací polutantu v mlžné (oblačné) vode průmyslově odlišně zatížených oblastí ČR. V průběhu 1. roku řešení projektu byly odebrány a chemicky analyzovány vzorky mlžné (oblačné) vody. Počet odebraných a analyzovaných vzorků z horské observatoře ÚFA Milešovka a horského pracovište ÚH Churáňov umožnil první porovnání oblastí. Porovnávány byly průměrné hodnoty koncentrací polutantů, koncentrace polutantů v závislosti na směru větru a v závislosti na sektoru, ze kterého jsou vzduchové částice (tedy i polutanty) na dané
stanovište transportovány.
We investigated the physiological effect of night chilling (CN) on potted seedlings of two tropical tree species, Calophyllum polyanthum and Linociera insignis, in Xishuangbanna, southwest China. Seedlings grown under 8, 25, and 50 % daylight for five months were moved to a 4-6 °C cold storage house for three consecutive nights, and returned to the original shaded sites during the day. CN resulted in strong suppression of photosynthesis and stomatal conductance for L. insignis, and reduced photorespiration rates, carboxylation efficiency, and maximum photochemical efficiency of photosystem 2 (PS2) at dawn and midday for both species. CN increased dawn and midday rates of non-photochemical quenching, and the contents of malondialdehyde and H2O2 for both species. CN also induced inactivation or destruction of PS2 reaction centres. The impacts of CN on tropical seedlings increased with the number of CN. Shading could significantly mitigate the adverse effects of CN for both species. After 3-d-recovery, gas exchange and fluorescence parameters for both species returned to pre-treatment levels in most cases. Thus CN induced mainly stomatal limitation of photosynthesis for L. insignis, and non-stomatal limitation for C. polyanthum. C. polyanthum was more susceptible to CN than L. insignis. Fog, which often occurs in Xishuangbanna, could be beneficial to chilling sensitive tropical seedlings in this area through alleviating photoinhibition or photodamage by reducing sunlight. and Y.-L. Feng, K.-F. Cao.