Determining the agricultural ammonia immission using bark bio-monitoring: comparison with passive sampler measurements

Bark samples of spruce, pine and oak trees were collected at two sites in southern Bavaria which are characterized by high agricultural ammonia emissions. The samples were taken using a recently developed bark sampling device which removes a defined layer of the bark. The bark was then analysed for ammonium concentration in order to reflect the environmental ammonia immission. The measured bark concentrations decreased with rising distance between the sample trees and the ammonia source. This applied (i) to measurements inside a closed forest stand ranging from forest edge with high immission to forest interior with much lower immission, and (ii) to the open field where single-standing trees were sampled. Comparing the ammonium concentrations among the three different tree species revealed significant correlations. Thus, it could be shown that old spruce trees are as usable for bark bio-monitoring as the traditionally used pine and oak trees. The ammonium concentrations of the bark were significantly correlated to measurements taken by ammonia passive samplers at the same locations. These results indicate that bark samples may be used for a standardised monitoring of airborne ammonia load. A major advantage of the technique is the determination of the long-term accumulative ammonia load using a single measurement.     

GVO-Pollenmonitoring zum Bt-Maisanbau im Bereich des NSG/FFH-Schutzgebietes Ruhlsdorfer Bruch

Aim and Background Precautionary regulations for the production of genetically modified crops (Gentechnik-Pflanzenerzeugungsverordnung, GenTPflEV 2008) provide isolation distances for the cultivation of genetically modified maize – Bt-maize – in the vicinity of conventional maize cultivation (150?m) as well as of organic maize cultivation (300?m). Nature reserves are not included. The aim of this study was to investigate whether maize pollen of surrounding fields were dispersed in the Flora-Fauna-Habitat (FFH) Ruhlsdorfer Bruch. In the vicinity of the nature reserve Bt-maize species MON 810 as well as conventional maize was grown. The survey should provide appropriate isolation distances for the cultivation of Bt-maize with regard to sustainable protection of non-target-organisms (NTO) in the Ruhlsdorfer Bruch. Materials and Methods The collection of maize pollen in the Ruhlsdorfer Bruch was carried out at three sampling sites in the FFH or rather in the immediate vicinity in July and August 2007 by means of twelve technical and three biological pollen samplers. The technical samplers Sigma-2/PMF enable point sampling. They are primarily influenced by wind and topography and provide information about the effective entry, the maize pollen flow and the maize pollen deposition at the location of the sampler. Honey bees roam over longer distances and are hence planar collectors. Thus, they also provide information about the plants blooming in a distinct area. Furthermore, the biological preferences during the collection are captured, whereas a technical sampler does not perform a species dependent selection. Hence, both the technical and the biological samplers complement one another in their scope of application. The pollen samples were identified microscopically, enumerated quantitatively, and the pollen-DNA was analysed by means of the PCR-method. Results All monitoring sites at the Ruhlsdorfer Bruch revealed maize pollen entries. The pollen deposition reached values of 1.75 million maize pollen/m² in the close-up range. The monitoring sites located 120?m within the protected area still featured 99,000 maize pollen/m². As shown by the statistical analysis, at a distance of 1,000?m still 28,000 maize pollen/m² must be expected. The results of the microscopic pollen analysis of the pollen pellets proved that the bees collect maize pollen at all three sites. Although maize pollen is not the main food source the high collection efficiency of the bees resulted in large amounts of introduced pollen. The biomolecular proof of pollen-DNA in the field samples was corroborated by analogue results for both the technical and biological pollen sampling by two independent laboratories. The results of these quality controlled analyses gave unambiguous evidence that under the cultivation conditions in 2007 an entry of Bt-maize pollen into the FFH Ruhlsdorfer Bruch was existent. Discussion The maize pollen deposition at the Ruhlsdorfer Bruch corresponds with additional supra-regional investigations which were conducted over several years with the same method. However, the pollen entries into the Ruhlsdorfer Bruch are above-average. Possible reasons are the size of the maize fields (>?10?ha), the geographical collocation between maize fields and protected area (lee location, through-shaped, thermal currents) as well as weather conditions and maize bloom during the sampling period July and August 2007. A distance of 1,000?m or more is necessary to avoid maize pollen deposition of more than 100,000/m² with a probability of 90?%. Conclusions The results of this investigation prove an entry of Bt-maize pollen into the FFH under the cultivation and weather conditions in summer 2007. According to the results of this and related studies and considering precautionary principle and the effect terms defined in the Federal Immission Protection Law, it becomes clear that reasonable isolation distances between Bt-maize fields and protected areas have to be introduced in order to minimise the entry of GM-maize pollen and to prevent adverse effects on protected NTOs. Recommendations Due to the fact that no toxicological investigations are available for the butterflies occurring in the FFH, highest protection standards should be implemented to avoid Bt-maize pollen entries into the Ruhlsdorfer Bruch. That implies that highest possible isolation distances for Bt-maize cultivation have to be considered, but at least a distance of 1,000?m is recommended. Following this a maize pollen deposition of more than 100,000 maize pollen/m² should be pevented with a certainty of 90?% as well as an exceeding exposure of foraging insects. Outlook By means of the pollen monitoring it becomes possible to survey empirically defined limits of pollen exposure. This should be performed in the nature reserve area at sites of expected maximum exposure, e.?g. at the boundaries of the FFH towards the maize fields and at exposed sites.     

Requirement of exogenous inducers for metamorphosis of axenic larvae and buds of Cassiopea andromeda (Cnidaria: Scyphozoa)

Planula larvae and asexually-produced buds of the rhizostome scyphozoan Cassiopea andromeda (collected throughout the year in Eilat, Israel) have the ability, under axenic conditions, to attach to a substrate and undergo morphogenetic development to form a polyp (=scyphistoma) in: (1) the presence of unidentified inducers found in the adult habitat and (2) the presence of cefined organic compounds. Axenic planulae and buds were unable to settle and complete metamorphosis in autoclaved artificial or natural seawater from the North Sea when maintained without food, but continued swimming while decreasing in size and protein content, eventually dying within three months. When maintained in autoclaved seawater from the Red Sea, between 25 and 46% of the planulae and 4 and 11% of the buds metamorphosed within 30 d. Axenic solutions of cholera toxin, thyroid stimulating hormone, and pancreatic casein hydrolysate peptides in artificial seawater induced morphogenic development of 20 to 100% of planulae and buds within 2 to 18 d. The natural inducer(s) in Red Sea seawater, though unidentified, may have characteristics similar to the large proteins and small peptide inducers used in this study. Planulae and buds older than 20 d metamorphosed sooner and responded to lower concentrations of pancreatic casein hydrolysate peptides than younger individuals. This may be a physiological mechanism for enhancing metamorphosis and survival in nature. The data show that settlement and metamorphosis can be induced by solutions of cholera toxin and thyroid stimulating hormone, suggesting that, as in mammalian systems, the mechanism of action of these chemicals may involve cyclic adenosine monophosphate (cAMP) as an intermediate messenger. However, dibutyric cAMP, which is capable of passing through membranes and functioning normally inside the cell, did not induce metamorphosis of buds, and the levels of intracellular cAMP in buds and larvae typically increased slowly during induction of metamorphosis, unlike the high and rapid increases associated with cAMP-mediated biochemical events in mammalian cells. These results suggest that the observed cAMP changes seen were associated with metamorphic development, but not with the triggering mechanism.     

Ecological half-life of 137Cs in lichens in an alpine region

About 17 years after the Chernobyl accident, lichen samples were collected in an alpine region in Austria (Bad Gastein), which was heavily contaminated by the Chernobyl fallout. Measured 137Cs activity concentrations in selected lichens (Cetraria islandica, Cetraria cucullata, and Cladonia arbuscula) ranged from 100 to 1100 Bq kg(-1) dry weight, depending on lichen species and sampling site. Ecological half-lives for 137Cs in different lichen samples, obtained by comparison with earlier measurements of the same lichen species at the same site, ranged from 2 to 6 years, with average values between 3 and 4 years. Comparison with earlier studies indicated that ecological half-lives hardly changed during the last 10 years, suggesting that ecological clearance mechanisms (e.g. washout or soil transfer) did not vary substantially at the selected sampling area.     

Physiological responses of the calcifying rhodophyte, <Emphasis Type="Italic">Corallina officinalis</Emphasis> (L.), to future CO<Subscript>2</Subscript> levels

Future atmospheric CO₂ levels will most likely have complex consequences for marine organisms, particulary photosynthetic calcifying organisms. Corallina officinalis L. is an erect calcifying macroalga found in the inter- and subtidal regions of temperate rocky coastlines and provides important substrate and refugia for marine meiofauna. The main goal of the current study was to determine the physiological responses of C. officinalis to increased CO₂ concentrations expected to occur within the next century and beyond. Our results show that growth and production of inorganic material decreased under high CO₂ levels, while carbonic anhydrase activity was stimulated and negatively correlated to algal inorganic content. Photosynthetic efficiency based on oxygen evolution was also negatively affected by increased CO₂. The results of this study indicate that C. officinalis may become less competitive under future CO₂ levels, which could result in structural changes in future temperate intertidal communities.     

Determining the Chernobyl impact on sediments of a pre-Alpine lake with a very comprehensive set of data

Man-made and natural radionuclides in Lake Wallersee were determined in the pre-Alpine environment at the northern slope of the Alps, which was heavily affected by the Chernobyl fallout in May 1986. The objective of this study was to get knowledge of location and quantity of man-made radionuclide input (especially (137)Cs) generated in the Chernobyl accident to lake sediments. Eleven sediment cores were sampled and activity depth profiles of (137)Cs and (210)Pb were determined with 5mm depth-resolution. The Chernobyl fallout produced an extreme (137)Cs peak in the sediment cores providing an excellent time marker. The chronological interpretation of deeper sediment layers was done by radiochemical analysis of (90)Sr and (239+240)Pu, which were released during atmospheric weapons' tests in the 1950s and 1960s. This allowed a complete chronological analysis of the sediment cores with a very compact set of data.     

Bud formation and metamorphosis inCassiopea andromeda (Cnidaria: Scyphozoa): A developmental and ultrastructural study

Asexual reproduction by formation of swimming buds which metamorphose directly into polyps plays a most important role in the propagation ofCassiopea andromeda (Cnidaria: Scyphozoa). (C. andromeda polyps, originally supplied by the Löbbecke Museum and Aquarium Düsseldorf, FRG, were cultured in our laboratories.) We have defined five budding stages and investigated epithelial recruitment and dynamics during bud formation using intracellular vital stains. The region of cell recruitment was found to encircle the budding site asymmetrically. The aboral side contributing considerably less to the developing bud than the oral and lateral sides. Furthermore, it was found that the epithelial flow involved in bud formation is part of a permanent apico-basal displacement of ectodermal cells. Light and electronmicroscopic investigations revealed that no drastic changes occur at the cellular level, neither in the ectoderm nor in the endoderm which both participate in bud formation. Scanning and transmissionelectron microscopic investigations of the swimming bud revealed that the ectoderm is composed of three, and the endoderm of two, cell types. Nerve elements have been detected near the mesoglea between both ecto- and endodermal cells. Amoebocytes are regularly found either at the basis of epidermal cells or within the mesoglea, whereas symbionts are located in the endoderm. Buds induced to metamorphose by a bacterial-inducing factor were used to investigate morphological and ultrastructural changes occurring during metamorphosis and scyphistoma morphogenesis. Metamorphosis starts with the settling of a bud, followed by the formation of the pedal disk in which desmocytes, as typical cnidarian adhesive structures, are differentiated. Metamorphosis is completed with the formation of the mouth and tentacles. Whereas metamorphosis of cnidarian planulae implies considerable changes at the cellular level, tissue remodeling processes prevail in bud metamorphosis ofC. andromeda.     

Strobilation,budding and initiation of scyphistoma morphogenesis in the rhizostome Cassiopea andromeda (Cnidaria: Scyphozoa)

Scyphistomae of Cassiopea andromeda Forskål, 1775 containing symbiontic zooxanthellae did not develop medusae at a constant temperature of 20°C, but monodisc strobilation was initiated after transfer of the polyps to 24°C. After release of the ephyrae and regeneration of the hypostome and tentacular region, the recovered polyps either produced vegetative buds or entered a new strobilation phase. Formation of motile, planula-like buds was not found to be indicative of unfavourable environmental conditions. Intensity of budding was positively correlated with available food and with increase of temperature. Budding was negatively correlated with the number of polyps maintained per dish and with the conditioning of the sea water. Under optimal feeding and temperature conditions, polyps could simultaneously produce chains of buds at 2 to 4 budding regions. Settlement and development of buds into scyphistomae was suppressed in pasteurized sea water and in pasteurized sea water containing antibiotics, but polyps developed from buds in the presence of algal material taken from the aquarium, debris or egg shells of Artemia salina, or on glass slides which had been incubated in used A. salina culture medium. Several species of marine bacteria were detected after staining these slides. One, a Gramnegative coccoid rod, which was identified as a nonpathogenic Vibrio species, was isolated, cultivated as a pure strain, and was proved to induce the development of C. andromeda buds into polyps. Millipore filter-plates coated with Vibrio sp. cells grown in suspension culture were ineffectual, but diluted filtrate initiated polyp morphogenesis. The inducing factor is obviously not a constituent of the bacterial cell surface, but is a product of growing Vibrio sp. cells released into the medium. This product was found to be relatively heat-stable and dialyzable. As to the basic mechanism involved in the induction of polyp formation, it is suggested that the inducing factor (s) acts bimodally by inducing pedal disc development and by eliminating a head inhibitor originating from the basal end of the bud. The life history, and various aspects of medusa-formation and of vegetative reproduction in scyphozoans are reviewed and discussed with particular reference to rhizostome species. Special attention has been paid to some reports of larval metamorphosis controlled by marine bacteria.