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.     

Dispersal and social organization in the Neotropical Grey sac-winged bat Balantiopteryx plicata

Recent evidence suggests that tropical bats may frequently depart from the predominant mammalian male-biased dispersal pattern. So far, two emballonurid bat species that are closely related to our study species (Grey sac-winged bat, Balantiopteryx plicata) have been found to exhibit exceptional female-biased dispersal that is in accordance with father–daughter inbreeding avoidance. In contrast, using a combination of long-term behavioral observations of banded bats and DNA sequencing of the mitochondrial d-loop, our results suggest that B. plicata is the first Neotropical emballonurid with female philopatry and frequent male dispersal. However, just like in the other emballonurids, the age of females at first conception fell below the tenure of males. Thus, philopatric B. plicata females might face a father–daughter inbreeding risk if mating with males from their roosts. Such risk could be circumvented if mating occurs outside the nursing roost, e.g., in male mating aggregations. In contrast to other Neotropical emballonurid bats, the Grey sac-winged bat forms colonies with a greatly male-biased sex ratio (only 5 and 21 % females). Males of such colonies showed high roost fidelity and the sex ratio did not change throughout the year and for up to many years, suggesting an important role in mating. We conclude that studying the diverse mating and dispersal patterns of Neotropical emballonurids shows great potential to enlarge our understanding on how the proposed ultimate causes (i.e., avoidance of inbreeding and local competition between kin) affect the evolution of sex-biased dispersal.     

Influence of ionic strength and pH on the limitation of latex microsphere deposition sites on iron-oxide coated sand by humic acid

This study, for the first time, investigates and quantifies the influence of slight changes in solution pH and ionic strength (IS) on colloidal microsphere deposition site coverage by Suwannee River Humic Acid (SRHA) in a column matrix packed with saturated iron-oxide coated sand.Triple pulse experimental (TPE) results show adsorbed SRHA enhances microsphere mobility more at higher pH and lower IS and covers more sites than at higher IS and lower pH. Random sequential adsorption (RSA) modelling of experimental data suggests 1 μg of adsorbed SRHA occupied 9.28 ± 0.03 × 10⁹ sites at pH7.6 and IS of 1.6 mMol but covered 2.75 ± 0.2 × 10⁹ sites at pH6.3 and IS of 20 mMol. Experimental responses are suspected to arise from molecular conformation changes whereby SRHA extends more at higher pH and lower ionic strength but is more compact at lower pH and higher IS. Results suggest effects of pH and IS on regulating SRHA conformation were additive.     

Wissenschaftstheoretische Grundlagen der Beobachtung von GVO-Umweltwirkungen

Zusammenfassung Hintergrund und Ziel  Die Exposition gentechnisch ver?nderter Kulturpflanzen erfordert die Beobachtung ihrer Umweltwirkungen. Ziel der Beitragsserie über die Beobachtung ?kologischer Wirkungen von GVO ist es, den hierzu erreichten Stand der Wissenschaft vorzustellen. Da bei einem Bundesl?nder und ggf. europ?ische Staaten übergreifenden Monitoring besonders auf methodisch vergleichbare und r?umlich aussagekr?ftige Daten zu achten ist, werden in diesem einführenden Beitrag wissenschaftstheoretische und statistische Grundlagen des Monitoring sowie die Standardisierung der Beobachtungsverfahren behandelt. Schwerpunkte  Im Mittelpunkt stehen zun?chst ?kologische Anforderungen an das GVO-Monitoring. Um mit GVO ggf. zusammenh?ngende Umweltver?nderungen ermitteln zu k?nnen, ist eine Eingliederung in bestehende Umweltbeobachtungsprogramme erforderlich. GVO-Exposition und-Wirkung sind aufeinander bezogen über die Organisationsstufen ?kologischer Systeme hinweg zu erfassen. Ein effizientes und suffizientes Monitoring bedarf eines wissenschaftstheoretisch und statistisch soliden Designs. Deshalb werden einem weiteren Schwerpunkt dieses Beitrags wissenschaftstheoretische Grundlagen der Hypothesenbildung und-prüfung behandelt. Hierfür bedarf es Daten, die mehreren, im Einzelnen behandelten Qualit?tskriterien entsprechen müssen. Eines dieser Kriterien ist die r?umliche und zeitliche Verallgemeinerungsf?higkeit der Monitoring-Befunde, die in dem dritten Schwerpunkt des Beitrags dargestellt wird. Schlussfolgerungen  Für die Prüfung von Hypothesen über Umweltfolgen von GVO sind konsequent ?kosystemforschung und Monitoring eng miteinander zu vernetzen. Denn sie erfüllen komplement?re Funktionen, die für das Monitoring der Umweltwirkungen von GVO von gro?er praktischer und wissenschaftlicher Bedeutung sind. Empfehlungen  Das GVO-Monitoring sollte in bestehende Programme der ?kosystemforschung und der Umweltbeobachtung eingebettet werden und die ?kologischen Organisationsstufen sowie GVO-Exposition und-Wirkung einschlie?en. Die Lokalisierung der Messorte sollte die erwartete Exposition oder Wirkung berücksichtigen. Perspektiven  Weitere Beitr?ge dieser Serie werden die Messplanung, das Pollenmonitoring und die r?umliche Verallgemeinerung von Ergebnissen standortspezifischer Messungen oder Modellierungen behandeln.

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Environmental monitoring of ecological impacts of GMOs

Goal, Scope and Background  The release of genetically modified organisms (GMOs) may result in ecological impacts to be monitored. This series presents the state-of-art concerning the environmental monitoring of ecological impacts of GMOs. Since this monitoring is conducted by several authorities, the methodical comparability and spatial validity of the monitoring data is crucial. Thus, the respective fundamentals of philosophy of science and of statistics as well as the methodical standardisation form the focus of this article. Main Features  At first, the monitoring requirements will be described from the viewpoint of ecology. Consequently, the GMO monitoring needs to be integrated into existing programmes. Exposure and effects of GMOs have to be monitored across the hierarchy of ecological organisation. For monitoring to be efficient and sufficient, the design must be founded in terms of philosophy of science and statistics. Hence the fundamentals concerning the verification of hypotheses represent another feature of this article. The data used for the verification of hypotheses must comply with quality criteria. One of these criteria is the spatial and temporal extrapolation of the monitoring results, which is the third feature in this introductory article. Conclusions  The evaluation of hypotheses on GMO impacts requires the linkage to ecosystems research and environmental monitoring. These both are, in terms of methodology, complementary and of significant technical and scientific value for GMO monitoring. Recommendations  GMO-monitoring should closely be connected with ecosystems research and environmental monitoring. The levels of ecological organisation should be covered as well as the exposure and the effects of GMOs. The expected GMO exposure and effects should be considered by localising the monitoring sites. Perspectives  Further articles of this series will deal with network designing, GMO pollen monitoring and extrapolation of site-specific measurements and modelling results.

     

Occurrence of coal and coal-derived particle-bound polycyclic aromatic hydrocarbons (PAHs) in a river floodplain soil

A PAH contaminated river floodplain soil was separated according to grain size and density. Coal and coal-derived particles from coal mining, coal industry and coal transportation activities were identified by organic petrographic analysis in our samples. Distinct concentrations of PAHs were found in different grain size and density fractions, however, similar distribution patterns of PAHs indicated similar sources. In addition, although light fractions had the mass fraction by weight of less than 5%, they contributed almost 75% of the total PAHs in the soil. PAH concentrations of all sub fractions showed positive correlation with their TOC contents. Altogether, coal and coal-derived particles that were abundant in light fractions could be the dominant geosorbents for PAHs in our samples.     

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.