Biogeomorphology at the micro-scale: biogeochemical weathering of rock surfaces in the cold and warm deserts

Author(s):  
Andrea Zerboni

<p><span>Biogeochemical weathering of stable rock surfaces in warm and cold deserts is a notable biogeomorphological process, which contribute to mineralogical transformation of rock constituents and rock disaggregation. Endolithic microorganisms (mostly bacteria, fungi and lichens) play a major role in controlling the destabilization and rejunevation of rock surfaces; but occasionally, biofilms can stabilize rock surfaces. In most of the casis, endolithic communities precipitates byproducts (e.g. oxalates) contributing to enhance discotnituity and promoting exfoliation and disaggregation. On the contrary, rock varnish can develop as an external crust protecting the underliyng rock from erosion and dissolution. In this contribution, a number of case-studies of fossil and active examples of biogeochemical weathering from warm deserts of Africa and Arabian peninsula and from Antarctica are considered. The comaprison of evidence suggests a highly differentiate –  and occasioanlly surprisingly – array of effects of endolithic communities on rock surfaces.</span></p>

2016 ◽  
Vol 11 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Kyungsun Lee ◽  
Catherine Park

1. INTRODUCTION In New York City a decline in manufacturing has propelled social and economic changes that have transformed certain districts [1,2]. Unused building stock there has been the basis for adaptive reuse yielding new housing for families of varying compositions. The constant pressure of the need for affordable housing has resulted in the conversion of existing abandoned industrial structures, providing a green, environmentally friendly alternative to new construction [3,4,5]. Adaptive reuse provides an opportunity to bring a building up to current codes, to make the layout and building systems more appropriate and efficient, and to help revitalize neighborhoods. The nineteenth through the middle of the twentieth centuries were characterized by urban environments which provided manufacturing jobs and the municipal services and education that supported them [6]. American cities such as Detroit, Cleveland, and Pittsburgh became boom-towns as people followed employment opportunities and moved to these locations throughout this period [7,8,9]. In the decades after World War II, the creation of highways and freeways–including the interstate highway system that stretched east to west and north to south–led to suburbanization, exemplified by Long Island's mushrooming Levit-town and many more like it [5,10]. These were the Baby Boom years. The suburban sprawl ultimately resulted in the creation of mega cities like New York City. Families typically consisted of a father, mother, and at least two children [16]. This trend was supported by strong manufacturing industries and plentiful space that allowed much of the population to fulfill the American dream of home ownership [2,11]. As labor cost increased due to stricter labor laws, unions, increasing land cost, and higher taxes, many manufacturers began a search for less costly environments, moving first to locations in the less expensive suburbs and then to the South [4,8]. Eventually, American factories moved overseas to places such as China, other Asian countries, and South America. This became known as out sourcing manufacturing [6,7,12]. With the subsequent boom town collapse that began in the 1980s and continued through the new millennium, old U.S. industrial cities faced declining populations, and Detroit, Cleveland, Pittsburgh, and their like were soon deserted by those who could no longer find employment there [14,40]. City populations decreased by as much as 50% and in some places even more steeply [13]. According to the U.S. Census (figure 1) [13,14], among American cities only New York City's and Los Angeles's populations have grown since the 1980s. Migration for employment opportunities became common and members per household, and households of one or two became not uncommon [15,16]. Typical housing no longer required a big space for shelter and a lawn or garden, and many people looked for smaller units [11,16]. Smaller working spaces made micro-scale businesses possible. New York City is an example of this change. Left with abandoned super block manufacturing buildings such as the Brooklyn Navy Yard and Brooklyn Army Terminal and retired infrastructure, New York City has looked for ways to repurpose these structures [10,17]. Super block, old manufacturing buildings and factories still stand, but in New York and elsewhere some have become mixed-use spaces. The goal of this paper is to examine how New York City served the public by providing working and living space through the conversion of existing super block buildings and creating new public spaces out of under-used or abandoned infrastructure. Comparative case studies are conducted focusing on the micro-scale movement and renewed use of old infrastructure. It considers a future model for sub-divided building spaces and repurposed structures providing shared, public venues as it analyzes this movement structurally and the changes it has wrought on local communities.


2013 ◽  
Vol 38 (4) ◽  
pp. 101-110
Author(s):  
Kheir Al-Kodmany ◽  
Mir M. Ali

Globalization has supported the exportation of exotic design and construction of many buildings including skyscrapers. In the past two decades skyscrapers have proliferated across cities all over the world, particularly those in the Arabian Peninsula. Because of their massive bulk and soaring height, these skyscrapers have dramatically altered the urban landscape and city identity. This paper examines the role of skyscrapers in supporting place identity in the Arabian Peninsula. Through case studies, the paper describes and evaluates skyscraper projects. While the “imported” iconic skyscrapers with their flamboyant forms have been transformative in re-imaging cities and their skylines, many of these have been transplanted to these cities with little consideration for local heritage and culture.


2017 ◽  
Vol 3 (3) ◽  
pp. 232-251 ◽  
Author(s):  
Geoff Harkness ◽  
Peggy Levitt

This article examines the working lives of creative-class professionals in the Global South using two case studies: university educators and museum professionals employed in Qatar. A small country on the Arabian Peninsula, Qatar is an ideal site for the study of professionals in a developing yet authoritarian nation. We argue that the cultural attributes of the professorial and curatorial communities, including creativity, autonomy, and intellectual freedom, are in conflict with the authoritarian political context, giving rise to professional dissonance. Professional dissonance occurs when the norms, values, and ideas embraced by a particular occupational group conflict with the norms, values, and ideas in the settings in which they work. To cope, university educators and museum professionals turn to five strategies—resistance, subversion, submission, conversion, and exit—although variations in the content and institutional structures of their work lead each group to deploy them in somewhat different ways. These strategies may be replicated in other contexts of high professional dissonance, caused by authoritarianism or otherwise.


2020 ◽  
Vol 44 (4) ◽  
pp. 119-157 ◽  
Author(s):  
Assaf Moghadam ◽  
Michel Wyss

Studies of conflicts involving the use of surrogates focus largely on states, viewing the relationship between sponsors and proxies primarily as one in which states utilize nonstate actors as proxies. They have devoted far less attention to sponsor-proxy arrangements in which nonstate actors play super-ordinate roles as sponsors in their own right. Why and how do nonstate actors sponsor proxies? Unlike state sponsors, which value proxies primarily for their military utility, nonstate sponsors select and utilize proxies mainly for their perceived political value. Simply put, states tend to sponsor military surrogates, whereas nonstate actors sponsor political ancillaries. Both endogenous actor-based traits and exogenous structural constraints account for these different approaches. An analysis of three case studies of nonstate sponsors that differ in terms of ideology and capacity—al-Qaida in the Arabian Peninsula, the People's Protection Units in Syria, and Hezbollah in Lebanon—confirms this argument, but also suggests that the ability and desire to control proxies varies with the sponsor's capacity. High-capacity nonstate sponsors such as Hezbollah behave similarly to state sponsors, but remain exceptional. Most nonstate sponsors are less dominant, rendering the relationships to their proxies more transactional and pragmatic, and ultimately less enduring than those of state sponsors and their clients.


2021 ◽  

The volume presents the proceedings of the second international workshop on the Archaeology of the Arabian Peninsula. Its subtitle, 'Connecting the evidence', portrayed our striving for investigating relationships and connections between different regions, materials and themes of research. The nine contributions straddle the entire expanse of the Peninsula and beyond, in order to counter the present divide in different academic disciplines. The chronological focus spans from the Pre Pottery Neolithic, the Bronze and Iron Ages down to the Islamic Middle Ages. The analyzed themes range from funerary to cultic landscapes, oasis formation and role of metallurgy for desert dwellers in state-of-the-art interdisciplinary perspectives and field case studies.


1990 ◽  
Vol 21 (1) ◽  
pp. 18-32 ◽  
Author(s):  
R. I. Dorn ◽  
D. Dragovich
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document