Diel and seasonal courses of ambient carbon dioxide concentration and their effect on productivity of the epilithic lichen Lecanora muralis in a temperate, suburban habitat

Ambient CO₂ concentration (together with CO₂ exchange and microclimate) was recorded every 30 min for 15 months for Lecanora muralis growing in the Botanical Garden Würzburg (Germany, northern Bavaria), a habitat on the outskirts of the city. Annual mean CO₂ was around 17 ppm higher than the global average reported for the time of measurement (361 ppm; 1995/96), and daily values ranged from 317 to 490 ppm. Diel courses of CO₂ could be classified into three different types. Type A, when CO₂ levels rose overnight and then fell strongly to below global levels during the day, which predominated in the summer (about 75 of days); Type B, irregular diel courses occurred during all seasons with often very rapid changes apparently due to advective CO₂ transport; Type C, CO₂ concentration was typically almost stable at generally between c. 330 and 430 ppm which predominated in the winter (63 of days). Under controlled conditions, CO₂ saturation of net photosynthesis (NP) of L. muralis at optimal hydration and light occurred at around 1000 ppm. NP was also affected by low CO₂ at limiting light and thallus water contents. Based upon these data, we estimated the improvement of NP of L. muralis due to transient increase of ambient CO₂ (as compared with the global average) for one selected combination of environmental factors (nocturnal dew or frost). This combination is an important source of water for the lichen, resulting in 40 of its annual production and, especially in these situations, photosynthesis was increased by high ambient CO₂ in the early morning under prevailing Type A conditions. After dew activation, light compensation point of NP occurred at an average concentration of 413 ppm and diel maxima of NP at 402 ppm. This allows a rough estimate that the transiently elevated CO₂ increased the photosynthetic gain of the lichen after dew of 7, or an improvement to its annual carbon balance of about 3. Conditions, especially interrelationships between lichen hydration, light and CO₂ are so complex that we are not yet able to extend our estimates to other environmental situations of photosynthetic activity of L. muralis

Ecophysiological adaptations of the lichen genera pseudocyphellaria and sticta to south temperate rainforests

Temperate rainforests are a poorly researched habitat with respect to lichen ecophysiology in comparison to desert and polar regions. The evergreen, broadleaf forests provide a dim, moist environment that is relatively stable throughout the year. Lichens are abundant in both quantity and species diversity with the large foliose genera Sticta and Pseudocyphellaria normally being dominant, visually and in terms of biomass. These lichens exhibit a great diversity of both form and habitat range. Physiological and morphological adaptation has also been demonstrated. Pseudocyphellaria dissimilis shows changes in thallus water storage capacity with evaporative demand and is also highly shade-adapted. The species has the lowest light saturation and compensation values for photosynthesis yet known for lichens (20 and 1-μmol m−2s−1, PAR, respectively). Unexpectedly it is also highly desiccation-sensitive with some thalli being killed after only 20 h exposure to 15% relative humidity. Photobiont versatility is also a feature of these genera. Photosymbiodemes occur, i.e. a single thallus containing both green algal and cyanobacterial sectors. Because the different sectors have the same fungal partner and grow in the same habitat, it is possible to investigate whether particular physiological traits are photobiont determined. The ability to recover photosynthetic activity in humid air is confined to thalli with green algal photobionts whilst the inability of thalli containing cyanobacterial photobionts to tolerate high light stress may be related to their lack of a protective xanthophyll cycle

An unusual growth form of Cladonia furcata: The trampling-resistant primary thallus colonizing a paved pathway

Lichens are well known to be susceptible to damage by trampling. Fruticose species, with their highly branched structure, are particularly sensitive and Bayfield et al. (1981) described substantial damage to Cladonia uncialis, C. arbuscula, C. rangiferina, and C. impexa on paths in lichen-rich heath communities in north-east Scotland. Less visible communities, biotic soil crusts in arid and semi-arid areas with their cover of crustose lichens, are also easily disturbed by walking, car driving, or grazing and recovery can take decades. We report here an interesting situation where a lichen (Cladonia furcata) is apparently being maintained and even spread in a habitat because trampling prevents it from completing its monocarpic life cycle

Versuche mit einem modifizierten Rollengeschirr für Garnelenbaumkurren

With a traditional roller gear, only the rollers in the centre are working correctly. The rollers on both sides are more or less gliding on the sea bottom because their axis are not in a position perpendicular to the towing direction. Sediment is stirred up by these gliding rollers coupled with a negative bottom impact of this gear. With a modified roller gear for shrimp beam trawls the axis of all rollers are orientated 90° to the towing direction enabling all rollers to roll correctly on the sea bottom

Rainfall as a cause of mechanical damage to Pseudocyphellaria rufovirescens in a New Zealand temperate rainforest

Lichens, like all poikilohydric plants, have a metabolism that is dependent on external moistening from their environment. In the case of green algal lichens high humidities may be sufficient for positive net photosynthesis to occur (Lange et al. 1993a). For these plants water stress is usually taken to mean a lack of water (Kappen 1988; Rundel 1988) but it can also mean an excess of water that leads to depressed CO2 exchange because of increased diffusion resistances at high thallus water contents (Lange & Tenhunen 1981; Kershaw 1985). Rather than this being an unusual occurrence, Lange et al. (19936) found reduced CO2 exchange at thallus supra-saturation to be present over long periods in the temperate rainforest of north-eastern New Zealand

Neuartige flexible Selektionseinrichtungen für Schleppnetzsteerte

Die wissenschaftlich-technische Zusammenarbeit zwischen dem Institut für Fischereitechnik (IFH) und dem russischen Institut MariNPO in Kaliningrad war 1997/98 schwerpunktmäßig auf die Entwicklung flexibler Vorrichtungen zur Größenselektion von Fischen in Schleppnetzsteerten sowie deren gemeinsame Erprobung in der Ostsee-Dorschfischerei ausgerichtet. Die Vorteile solcher flexiblen Vorrichtungen aus textilem Material verglichen mit starren, meist aus Metall gefertigten bestehen darin, daß sie bei der Handhabung keine dauerhaften Verformungen bekommen, keine Erschwernisse oder Gefährdungen der Decksbesatzung, insbesondere bei schwerem Wetter, verursachen und problemlos mit dem Netz aufgetrommelt werden können. Außerdem sind sie wesentlich billiger in den Anschaffungskosten als Metallgitter aus nichtrostendem Stahl. Ihre Installation vor dem Hievteil ermöglicht zudem ein ungestörteres Selektieren als bei Fluchtfenstern im Bereich des Steertendes, wo die Fische stark verdichtet sind und mehr oder weniger gewaltsam an bzw. durch die Maschen gepreßt werden. Der Umlauftank in Kaliningrad sowie das geschleppte, steuerbare UW-Videosystem des IFH bieten gute Voraussetzungen für eine umfassende experimentelle Untersuchung der entwickelten Vorrichtungen, über die im folgenden berichtet wird

Automatic Identification of Synonym Relations in the Dutch Parliament’s Thesaurus

For indexing archived documents the Dutch Parliament uses a specialized thesaurus. For good results for full text retrieval and automatic classification it turns out to be important to add more synonyms to the existing thesaurus terms. In the present work we investigate the possibilities to find synonyms for terms of the parliaments thesaurus automatically. We propose to use distributional similarity (DS). In an experiment with pairs of synonyms and non-synonyms we train and test a classifier using distributional similarity and string similarity. Using ten-fold cross validation we were able to classify 75% of the pairs of a set of 6000 word pairs correctly

Growth Hormone (GH)-Releasing Peptide Stimulation of GH Release from Human Somatotroph Adenoma Cells: Interaction with GH-Releasing Hormone, Thyrotropin- Releasing Hormone, and Octreotide.

The synthetic hexapeptide GH-releasing peptide (GHRP; His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) specifically stimulates GH secretion in humans in vivo and in animals in vitro and in vivo via a still unknown receptor and mechanism. To determine the effect of GHRP on human somatotroph cells in vitro, we stimulated cell cultures derived from 12 different human somatotroph adenomas with GHRP alone and in combination with GH-releasing hormone (GHRH), TRH, and the somatostatin analog octreotide. GH secretion of all 12 adenoma cultures could be stimulated with GHRP, whereas GHRH was active only in 6 adenoma cultures. In GHRH-responsive cell cultures, simultaneous application of GHRH and GHRP had an additive effect on GH secretion. TRH stimulated GH release in 4 of 7 adenoma cultures; in TRH-responsive cell cultures there was also an additive effect of GHRP and TRH on GH secretion. In 5 of 9 adenoma cultures investigated, octreotide inhibited basal GH secretion. In these cell cultures, GHRP-induced GH release was suppressed by octreotide. In 5 of 5 cases, the protein kinase-C inhibitor phloretin partly inhibited GHRP-stimulated GH release, but not basal GH secretion. In summary, GH secretion was stimulated by GHRP in all somatotroph adenomas investigated, indicating that its unknown receptor and signaling pathway are expressed more consistently in somatotroph adenoma cells than those for GHRH, TRH, and somatostatin. Our data give further evidence that GHRP-stimulated GH secretion is mediated by a receptor different from that for GHRH or TRH, respectively, and that protein kinase-C is involved in the signal transduction pathway. Because human somatotroph adenoma cell cultures respond differently to various neuropeptides (GHRH, TRH, somatostatin, and others), they provide a model for further investigation of the mechanism of action of GHRP-induced GH secretion

The EPOS Research Infrastructure: a federated approach to integrate solid Earth science data and services

The European Plate Observing System (EPOS) is a Research Infrastructure (RI) committed to enabling excellent science through the integration, accessibility, use and re-use of solid Earth science data, research products and services, as well as by promoting physical access to research facilities. This article presents and describes the EPOS RI and introduces the contents of its Delivery Framework. In November 2018, EPOS ERIC (European Research Infrastructure Consortium) has been granted by the European Commission and was established to design and implement a long-term plan for the integration of research infrastructures for solid Earth science in Europe. Specifically, the EPOS mission is to create and operate a highly distributed and sustainable research infrastructure to provide coordinated access to harmonized, interoperable and quality-controlled data from diverse solid Earth science disciplines, together with tools for their use in analysis and modelling. EPOS relies on leading-edge e-science solutions and is committed to open access, thus enabling a step towards the change in multidisciplinary and cross-disciplinary scientific research in Earth science. The EPOS architecture and its Delivery Framework are discussed in this article to present the contributions to open science and FAIR (Findable, Accessible, Interoperable, and Reusable) data management, as well as to emphasize the community building process that supported the design, implementation and construction of the EPOS RI.publishedVersio