Greening boosts soil formation and soil organic matter accumulation in Maritime Antarctica

Global warming in the Antarctic Peninsula, Maritime Antarctica, within the past 45 years has accelerated rapid glacier retreatment, forming temporal gradients of soil development that concurs with the colonization of the ice-free soils by phototrophs. In the past decade the paradigm emerged that above- and belowground processes are interconnected, e.g. recently gained carbon fuels microbial activity and thus drives soil organic matter built-up and decomposition as well as mineral weathering. Studies of carbon allocation for Antarctic ecosystems, occurring in harsh conditions are lacking. Little is also known about the contribution of bacteria and fungi to decomposition of different soil carbon pools with different turnover rates in these soils, which is of utmost importance for the prediction of the future feedback of the Antarctic carbon balance to climate change. We followed soil horizon formation, soil organic carbon accumulation and carbon exchange with the atmosphere along a gradient of phototrophs of different trophic complexity level at King George Island by combining soil chemical analyses, field CO2 flux measurements, C-13 in situ labeling and molecular methods (PLFA and metabolomics). Our study revealed that colonization of the ice-free soils by vascular plant (Deschampsia antarctica) was leading to the formation of well-developed soil, with high contents of organic carbon and with a relatively high rates of photosynthesis and CO2 soil efflux. The soils sampled under D. antarctica showed the impact of this higher plant on the soil organic matter, containing significantly higher amounts of carbohydrates and amines, presumably as a result of root exudation. As determined by the C-13 labeling experiment more than 15% of the carbon recently assimilated by D. antarctica was transferred belowground, with a major flow into soil fungi. This suggests that not bacteria, but rather fungi preferentially and faster utilize the recently assimilated low molecular compounds allocated to the soil. Probably, successful performance of vascular plants in Maritime Antarctica may significantly foster biological weathering via enhanced microbial activity

How to study the city on instagram

We introduce Instagram as a data source for use by scholars in urban studies and neighboring disciplines and propose ways to operationalize key concepts in the study of cities. These data can help shed light on segregation, the formation of subcultures, strategies of distinction, and status hierarchies in the city. Drawing on two datasets of geotagged Instagram posts from Amsterdam and Copenhagen collected over a twelve-week period, we present a proof of concept for how to explore and visualize sociospatial patterns and divisions in these two cities. We take advantage of both the social and the geographic aspects of the data, using network analysis to identify distinct groups of users and metrics of unevenness and diversity to identify socio-spatial divisions. We also discuss some of the limitations of these data and methods and suggest ways in which they can complement established quantitative and qualitative approaches in urban scholarship

Filtering feminisms : Emergent feminist visibilities on Instagram

Based on interviews with feminist Instagram users, this article studies emergent feminist visibilities on Instagram through the concept of filtering. Filtering entails both enhancement and subtraction: some feminist sensibilities align with Instagram?s interaction order, while others become subdued and remain at the margins of visibility. Taken together, users? filtering practices contribute to the confident and happy image, individualistic streak, and accommodationist cast of popular feminism, while also amplifying feminist politics that affirm the pleasures of visibility and desire. Instagram proves a more challenging environment for feminists seeking to criticize competitive individualism and aesthetic norms. The notion of filtering enriches existing research on how online environments reconfigure feminist politics and problematizes the avowal of feminism in media culture.Non peer reviewe

Hot moments in the Antarctic due to climate warming?

Climate warming is severely affecting maritime Antarctica, causing accelerated glacier retreat and thus leading to an ongoing exposure of once ice- covered land. This initiates a succession of plant and soil development. Nevertheless, the temporal dynamics and controlling factors of these processes, like C and N status of soils and the effect of root exudation are widely unknown under these harsh climatic conditions. Topsoil samples from three different sites of a chronological soil sequence in the forefront of a retreating glacier of the Fildes Peninsula, King George Island, were collected and incubated at 2 °C for three weeks. To mimic the influence of C and N containing root exudates (primers) on the mineralization of soil C, we added 13C labeled glucose or alanine and compared CO2 evolution in comparison to samples without C and N addition. Soil microbes covered up to 90% of their C demand for anabolic functions with the added C-sources in the case of late soil successions while it was only 50% for the young soils. These findings were independent of the form of primer. Both primers increased the mineralization of soil carbon in the young soils as compared to the control. For the later stages of soil development, we found negative priming which was strongest for the latest stage. These results give evidence for a clear shift in the microbial community of the three investigated sites. While sites with initial soil formation seem to be dominated by k-strategists with low turnover rates that rather use complex C-sources, a significant number of r-strategists in the soils of the older sites uses simple C-substrates very efficiently. As this leads to a relative decrease in SOM mineralization for the late stages of soil development, it is questionable if higher plants can improve their nutrition by stimulating free living soil microbes with root exudates or if they rather have to rely on mycorrhiza

Blessed Disruption: Culture and Urban Space in a European Church Planting Network

New Protestant churches are being founded in cities around the world. They are the product of a conscious effort on the part of evangelicals to found, or ``plant,\u27\u27 new churches in urban areas. Behind this effort are a whole host of actors, including denominations, churches, seminaries, and parachurch organizations, who come together in church planting networks to establish theologically conservative churches that will speak to young urban professional audiences. The hope is that these efforts will scale up and turn into a movement bringing about religious revival among culturally influential groups. Among the focal areas for these efforts are European cities. The presence and vitality of newly planted churches in the European metropolis counters the trend of secularization observed in these places since the middle of the previous century. How do church planters go about and succeed in their quest to bring doctrine to hipsters and yuppies in the European metropolis? This dissertation studies the actors, sites and cultural processes behind a European church planting network to answer this question. The focus is on the anatomy of the network enabling church planting, the engagements with urban space and public culture by church planters, and their understanding of pastoral work. The dissertation engages both supply-side and neosecularization theories in the sociology of religion to make sense of the practices, successes and challenges of church planters in contemporary society. While the supply-side theory goes some way in explaining the form and dynamics of church planting efforts, understanding how the church planters engage with cities requires drawing on other bodies of work, such as David Martin\u27s revision of secularization theory. With Martin I argue that culture and the lived experience of urban space matter in the context of religious change, not just market dynamics in the religious economy. The project is based on multisited research employing focused ethnographic and interview methods. The main focus of the field research was on church plants in four German cities: Berlin, Hamburg, Frankfurt, and Cologne. In order to gain additional comparative insight, additional interviews and observations were conducted for shorter durations of time in Amsterdam, Paris, and Prague. In addition to field research, the dissertation draws on publications by church planting insiders, media reports, and digital resources. In addition to this research on what has been called contemporary evangelicalism\u27s cutting edge and default mode of evangelism, the dissertation also asks how and why Europe came to be seen as a mission field. It argues that the conception of Europe as a mission field dates to the interwar period, when mission societies began framing the European continent in these terms. Analysis of these framing processes shows that early instances of framing Europe as a mission field portrayed Europe as occupying an interstitial space between Christendom and heathendom. This history is a reminder not to exaggerate the novelty of contemporary trends, and it also helps to differentiate what is really distinctive about the contemporary mode of evangelistic engagement