Environmental conditions of a salt-marsh biodiversity experiment on the island of Spiekeroog (Germany)

Field experiments investigating biodiversity and ecosystem functioning require the observation of abiotic parameters, especially when carried out in the intertidal zone. An experiment for biodiversity–ecosystem functioning was set up in the intertidal zone of the back-barrier salt marsh of Spiekeroog Island in the German Bight. Here, we report the accompanying instrumentation, maintenance, data acquisition, data handling and data quality control as well as monitoring results observed over a continuous period from September 2014 to April 2017. Time series of abiotic conditions were measured at several sites in the vicinity of newly built experimental salt-marsh islands on the tidal flat. Meteorological measurements were conducted from a weather station (WS, https://doi.org/10.1594/PANGAEA.870988), oceanographic conditions were sampled through a bottom-mounted recording current meter (RCM, https://doi.org/10.1594/PANGAEA.877265) and a bottom-mounted tide and wave recorder (TWR, https://doi.org/10.1594/PANGAEA.877258). Tide data are essential in calculating flooding duration and flooding frequency with respect to different salt-marsh elevation zones. Data loggers (DL) for measuring the water level (DL-W, https://doi.org/10.1594/PANGAEA.877267), temperature (DL-T, https://doi.org/10.1594/PANGAEA.877257), light intensity (DL-L, https://doi.org/10.1594/PANGAEA.877256) and conductivity (DL-C, https://doi.org/10.1594/PANGAEA.877266) were deployed at different elevational zones on the experimental islands and the investigated salt-marsh plots. A data availability of 80% for 17 out of 23 sensors was achieved. Results showed the influence of seasonal and tidal dynamics on the experimental islands. Nearby salt-marsh plots exhibited some differences, e.g., in temperature dynamics. Thus, a consistent, multi-parameter, long-term dataset is available as a basis for further biodiversity and ecosystem functioning studies

Newspaper commentaries on terrorism in China and Australia: A contrastive genre study

This thesis is a contrastive genre study which explores newspaper commentaries on terrorism in Chinese and Australian newspapers. The study examines the textual patterning of the Australian and Chinese commentaries, interpersonal and intertextual features of the texts as well as considers possible contextual factors which might contribute to the formation of the newspaper commentaries in the two different languages and cultures. For the framework of its analysis, the study draws on systemic functional linguistics, English for Specific Purposes and new rhetoric genre studies, critical discourse analysis, and discussions of the role of the mass media in the two different cultures. The study reveals that Chinese writers often use explanatory rather than argumentative expositions in their newspaper commentaries. They seem to distance themselves from outside sources and seldom indicate endorsement of these sources. Australian writers, on the other hand, predominantly use argumentative expositions to argue their points of view. They integrate and manipulate outside sources in various ways to establish and provide support for the views they express. It is argued that these textual and intertextual practices are closely related to contextual factors, especially the roles of the media and opinion discourse in contemporary China and Australia. The study, by providing both a textual and contextual view of the genre under investigation in the two languages and cultures, aims to establish a framework for contrastive rhetoric research which moves beyond the text into the context of production and interpretation of the texts as a way of exploring reasons for the linguistic and rhetorical choices made in the two sets of texts

Cell size as driver and sentinel of phytoplankton community structure and functioning

Body size is a decisive functional trait in many organisms, especially for phytoplankton, which span several orders of magnitude in cell volume. Therefore, the analysis of size as a functional trait driving species’ performance has received wide attention in aquatic ecology, amended in recent decades by studies documenting changes in phytoplankton size in response to abiotic or biotic factors in the environment. We performed a systematic literature review to provide an overarching, partially quantitative synthesis of cell size as a driver and sentinel of phytoplankton ecology. We found consistent and significant allometric relationships between cell sizes and the functional performance of phytoplankton species (cellular rates of carbon fixation, respiration and exudation as well as resource affinities, uptake and content). Size scaling became weaker, absent or even negative when addressing C- or volume-specific rates or growth. C-specific photosynthesis and population growth rate peaked at intermediate cell sizes around 100 µm3. Additionally, we found a rich literature on sizes changing in response to warming, nutrients and pollutants. Whereas small cells tended to dominate under oligotrophic and warm conditions, there are a few notable exceptions, which indicates that other environmental or biotic constraints alter this general trend. Grazing seems a likely explanation, which we reviewed to understand both how size affects edibility and how size structure changes in response to grazing. Cell size also predisposes the strength and outcome of competitive interactions between algal species. Finally, we address size in a community context, where size-abundance scaling describes community composition and thereby the biodiversity in phytoplankton assemblages. We conclude that (a) size is a highly predictive trait for phytoplankton metabolism at the cellular scale, with less strong and nonlinear implications for growth and specific metabolism and (b) size structure is a highly suitable sentinel of phytoplankton responses to changing environments. A free Plain Language Summary can be found within the Supporting Information of this article

Effect of continuous nutrient enrichment on microalgae colonizing hard substrates

In order to understand the effect of changing nutrient conditions on benthic microalgae on hard substrates, in-situ experiments with artificial substrates were conducted in Kiel Fjord, Western Baltic Sea. As an extension of previous investigations, we used artificial substrates without silicate and thus were able to supply nutrient media with different Si:N ratios to porous substrates, from where they trickled out continuously. The biofilm developing on these substrates showed a significant increase in biovolume due to N + P enrichment, while Si alone had only minor effects. The stoichiometric composition of the biomass indicated nitrogen limitation during most of the year. The C:N ratios were lowered by the N + P addition. The algae were dominated by diatoms in most cases, but rhodophytes and chlorophytes also became important. The nutrient treatment affected the taxonomic composition mostly at the species level. The significance of the results with regard to coastal eutrophication is discussed

The impact of hyperactivity and leptin on recovery from anorexia nervosa

In anorexia nervosa (AN), hyperactivity is observed in about 80% of patients and has been associated with low leptin levels in the acute stage of AN and in anorexia animal models. To further understand the importance of this correlation in AN, we investigated the relationship between hypoleptinaemia and hyperactivity in AN patients longitudinally and assessed their predictive value for recovery

Grazer diversity effects in an eelgrass–epiphyte–microphytobenthos system

The dramatic loss of biodiversity and its consequences for ecosystem processes have been of considerable interest in recent ecological studies. However, the complex and interacting processes influencing diversity effects in multitrophic systems are still poorly understood. We used an experimental eelgrass system to study the effects of changing richness of three consumer species on the biomass, diversity and taxonomic composition of both epiphytic and benthic microalgal assemblages. After 1 week, consumer richness enhanced the grazing impact on epiphyte biomass relative to single consumer treatments and a positive effect of consumer richness on prey diversity was found. Moreover, strong effects of consumer species identity on taxonomic composition were found in both microalgal assemblages. However, the effects of consumer richness were not consistent over time. The consequences of high nutrient availability seemed to have masked consumer richness effects

Iron, silicate, and light co-limitation of three Southern Ocean diatom species

The effect of combined iron, silicate, and light co-limitation was investigated in the three diatom species Actinocyclus sp. Ehrenberg, Chaetoceros dichaeta Ehrenberg, and Chaetoceros debilis Cleve, isolated from the Southern Ocean (SO). Growth of all species was co-limited by iron and silicate, reflected in a significant increase in the number of cell divisions compared to the control. Lowest relative Si uptake and drastic frustule malformation was found under iron and silicate co-limitation in C. dichaeta, while Si limitation in general caused cell elongation in both Chaetoceros species. Higher light intensities similar to SO surface conditions showed a negative impact on growth of C. dichaeta and Actinocyclus sp. and no effect on C. debilis. This is in contrast to the assumed light limitation of SO diatoms due to deep wind driven mixing. Our results suggest that growth and species composition of Southern Ocean diatoms is influenced by a sensitive interaction of the abiotic factors, iron, silicate, and light