Spiders in mountain habitats of the Giant Mountains

Ground-living spiders were studied using modified pitfall traps during several years in four characteristic habitats in Giant Mountains (Krkono?e Mts.), the High Sudetes, Czech Republic: alpine tundra, subalpine mire, tall-herb stand at the bottom of a glacial corrie, and decaying mountain spruce forest. Ecological and zoogeographical aspects of spider communities were analysed. The spider communities of alpine tundra, subalpine mire, and glacial corrie exhibited long-term stability, whereas the community of decaying mountain forest changed during observations. Small linyphiid spiders, dominating in mature forest, were gradually replaced by larger Iycosid and gnaphosid species. Zoogeographic characterization of mountain habitats was made based on species exhibiting disjunctive area. In contrast to plants, for spiders of boreal origin alpine tundra is the most important habitat for survival, followed by screes, mires, spruce forests, and corries.     

Depth-related shift in life history strategies of a brooding and broadcasting deep-sea asteroid

Combining field and laboratory work, this study investigated the reproductive cycle, aggregative behavior, spawning periodicity, development and early growth of the sea star Henricia lisa living at bathyal depths off eastern Canada. Marked differences were found between individuals from ~1,300 and ~600 m deep. The former had a male biased sex ratio and an aperiodic reproductive cycle, whereas the latter displayed an equal sex ratio and a biannual breeding pattern. Furthermore, the maximum size was larger and female fecundity roughly five times higher in shallower compared to deeper populations. In the tanks, aggregative behavior was recorded twice a year during the summer and winter breeding periods. The onset of aggregations and spawning coincided with a temperature of 3–4°C. Males spawned first and females typically responded inside 30–60 min. Between 12 and 20 eggs were retained to be brooded under the arched arms of the female, whereas the remainder were broadcasted and developed without parental care. The fertilized eggs underwent a first cleavage after 12 h, reached the brachiolaria stage in 1 month, became juveniles within 3–4 months and reached ~ 4 mm in diameter after 14–17 months of growth. The embryos and juveniles developed at the same rate whether brooded or not, and development of winter cohorts was typically slower due to lower prevailing temperatures. This study of H. lisa provides the first evidence of lecithotrophy in a seasonally breeding deep-sea echinoderm and of brooding in a deep-sea asteroid.     

Bioluminescence in the high Arctic during the polar night

This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord, Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night. The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle, to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination.     

The semiochemically mediated interactions between bacteria and insects

In natural environment, semiochemicals are involved in many interactions between the different trophic levels involving insects, plants and hosts for parasitoids or prey for predators. These volatile compounds act as messengers within or between insect species, inducing particular behaviours, such as the localisation of a source of food, the orientation to an adequate oviposition site, the selection of a suitable breeding site and the localisation of hosts or prey. In this sense, bacteria have been shown to play an important role in the production of volatile compounds which ones act as semiochemicals. This review, focusing on the semiochemically mediated interactions between bacteria and insects, highlights that bacterial semiochemicals act as important messengers for insects. Indeed, in most of the studies reported here, insects respond to specific volatiles emitted by specific bacteria hosted by the insect itself (gut, mouthparts, etc.) or present in the natural environment where the insect evolves. Particularly, bacteria from the families Enterobacteriaceae, Pseudomonaceae and Bacillaceae are involved in many interactions with insects. Because semiochemicals naturally produced by bacteria could be a very interesting option for pest management, advances in this field are discussed in the context of biological control against insect pests.     

Natural and anthropogenic influences on heavy metals in airborne particles over the Korean Peninsula

Six monitoring stations were selected to characterize the variations in airborne concentrations of heavy metals in South Korea between 1999 and 2012. Three stations represented higher concentrations, and three represented lower concentrations. The heavy metals monitored at these stations include cadmium, chromium, copper, iron (Fe), lead, manganese (Mn), and nickel. During the study period, concentrations of heavy metals at many stations, including those around the Seoul metropolitan area, showed a decreasing trend. However, concentrations of Mn and Fe that are primarily of crustal origin increased at four of the six stations. Some stations were significantly affected by emissions from the local industrial complex (IC), and heavy metal concentrations at those stations were relatively high even in summer. Many heavy metal concentrations were higher in spring than in winter, but wintertime concentrations of Cr and Pb were higher at the stations representing lower concentrations due to the dominant influence of combustion emissions. At stations less affected by emissions from the IC, concentrations of Fe and Mn that are predominantly crustal in origin were higher in spring, when Asian dust (AD) events are most frequent. Although Mn concentrations were also high at stations within the steelmaking IC during AD periods, they were much higher during non-AD periods due to local emissions. Variations in heavy metal concentrations, which are heavily influenced by emissions from the IC, warrant individual analysis because their emission characteristics differ from those of typical cases.     

Characterization and Properties of Hydrophilic Cellulose Acetate Propionate Derivative

The chemical modification of Acrylamidomethyl Cellulose Acetate Propionate (AMCAP) was carried out by radical addition of acrylic acid. The structural modification was confirmed with the aid of FTIR, MS and NMR techniques. Thermal properties of hydrophilic cellulose derivative (AMCAP–H₂O₂) such as glass transition (T_g 153 °C) and thermal stability (372.7 °C) were determined by DSC and TGA techniques, respectively. These thermal properties confirmed the introduction of carboxylic groups into AMCAP structure, which causes an impact in their properties. The AMCAP–H₂O₂ shows minor contact angle compared to AMCAP, giving a more hydrophilic characteristic, due to acrylic acid addition into the side chains of AMCAP polymer.     

Noise disturbance caused by outdoor activities�� a simulated-environment study for Ali Sami Yen Stadium, ?stanbul

Negative effects of noise on individuals, the inevitable result of urbanization, have become a significant urban problem in our day. Introduction of an approach to the noise problem on an urban-planning scale lightens the burden of measures required to be taken against noise at the stages of regional and developmental planning. Stadiums, which should be also evaluated from the point of noise problem when planning decisions are made on the urban planning scale, may cause very serious problems differing depending on the region they are located in. In this article, various dimensions of the noise problem caused by stadiums have been exemplified by making an assessment on Ali Sami Yen football stadium located in Mecidiyeköy district which is among important residential and commercial centres of ?stanbul or Turkey. When the simulation results obtained for ordinary days and match days are evaluated, it has been found out that the people living in the area are exposed to noise levels substantially exceeding the acceptable values. Results of the survey conducted in the area have clearly revealed the existence of noise problem, too.     

Toxicity of atrazine and its bioaccumulation and biodegradation in a green microalga,Chlamydomonas mexicana

This study evaluated the toxicity of herbicide atrazine, along with its bioaccumulation and biodegradation in the green microalga Chlamydomonas mexicana. At low concentration (10 μg L^?1), atrazine had no profound effect on the microalga, while higher concentrations (25, 50, and 100 μg L^?1) imposed toxicity, leading to inhibition of cell growth and chlorophyll a accumulation by 22 %, 33 %, and 36 %, and 13 %, 24 %, and 27 %, respectively. Atrazine 96-h EC50 for C. mexicana was estimated to be 33 μg L^?1. Microalga showed a capability to accumulate atrazine in the cell and to biodegrade the cell-accumulated atrazine resulting in 14–36 % atrazine degradation at 10–100 μg L^?1. Increasing atrazine concentration decreased the total fatty acids (from 102 to 75 mg g^?1) and increased the unsaturated fatty acid content in the microalga. Carbohydrate content increased gradually with the increase in atrazine concentration up to 15 %. This study shows that C. mexicana has the capability to degrade atrazine and can be employed for the remediation of atrazine-contaminated streams.     

Mechanistic studies of N-nitrosodimethylamine (NDMA) formation in chlorinated drinking water

Studies were conducted to investigate the hypothesis that N-nitrosodimethylamine (NDMA) is a potential disinfection by-product specifically produced during chlorination or chloramination. Experiments were conducted using dimethylamine (DMA) as a model precursor. NDMA was formed by the reaction of DMA with free chlorine in the presence of ammonia and also with monochloramine. We proposed a mechanism for NDMA formation in chlorinated or chloraminated water, which does not require nitrite as in N-nitrosation. The critical NDMA formation reactions consist of (i) the formation of monochloramine by combination of free chlorine with ammonia, (ii) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (iii) the oxidation of UDMH by monochloramine to NDMA, and (iv) the reversible chlorine transfer reaction between free chlorine/monochloramine and DMA which is parallel with (i) and (ii). A kinetic model was also developed to validate the proposed mechanism.