The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, ...technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life--SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO(2) and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO(2) and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods.
Damming the rivers of the Amazon basin Latrubesse, Edgardo M; Arima, Eugenio Y; Dunne, Thomas ...
Nature (London),
06/2017, Letnik:
546, Številka:
7658
Journal Article
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More than a hundred hydropower dams have already been built in the Amazon basin and numerous proposals for further dam constructions are under consideration. The accumulated negative environmental ...effects of existing dams and proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin's floodplains, estuary and sediment plume. We introduce a Dam Environmental Vulnerability Index to quantify the current and potential impacts of dams in the basin. The scale of foreseeable environmental degradation indicates the need for collective action among nations and states to avoid cumulative, far-reaching impacts. We suggest institutional innovations to assess and avoid the likely impoverishment of Amazon rivers.
All known eukaryotes require copper for their development and survival. The essentiality of copper reflects its widespread use as a co-factor in conserved enzymes that catalyze biochemical reactions ...critical to energy production, free radical detoxification, collagen deposition, neurotransmitter biosynthesis and iron homeostasis. However, the prioritized use of copper poses an organism with a considerable challenge because, in its unbound form, copper can potentiate free radical production and displace iron-sulphur clusters to disrupt protein function. Protective mechanisms therefore evolved to mitigate this challenge and tightly regulate the acquisition, trafficking and storage of copper such that the metal ion is rarely found in its free form in the cell. Findings by a number of groups over the last ten years emphasize that this regulatory framework forms the foundation of a system that is capable of monitoring copper status and reprioritizing copper usage at both the cellular and systemic levels of organization. While the identification of relevant molecular mechanisms and signaling pathways has proven to be difficult and remains a barrier to our full understanding of the regulation of copper homeostasis, mounting evidence points to the mitochondrion as a pivotal hub in this regard in both healthy and diseased states. Here, we review our current understanding of copper handling pathways contained within the organelle and consider plausible mechanisms that may serve to functionally couple their activity to that of other cellular copper handling machinery to maintain copper homeostasis.
Practitioners can face significant challenges when managing the airways of infants and neonates because of their unique anatomical and physiological features. The requirement for emergency airway ...management in this age group is rare. Details of emergency airway techniques in paediatric practice guidelines are missing or lack consensus, and it is known that outcomes for affected children can be poor. Ideally, these children should be managed by experienced paediatric airway practitioners working in a team. However, situations can arise where practitioners, unfamiliar and inexperienced with infants, find themselves in charge. So, what happens when such a practitioner encounters this life-or-death scenario and feels ill-equipped to act? The ethical and legal issues surrounding the management of this emergency are clearly defined, but they can be unknown or misunderstood by doctors. Compounding the extreme stress of the scenario is the moral and ethical dilemma of whether to act or not. The following discussion explores these issues and examines the philosophical and psychological perspectives.
Superhard boron-rich boron carbide coatings were deposited on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) under controlled conditions, which led to either a disordered or ...crystalline structure, as measured by X-ray diffraction. The control of either disordered or crystalline structures was achieved solely by the choice of the sample being placed either directly on top of the sample holder or within an inset of the sample holder, respectively. The carbon content in the B-C bonded disordered and crystalline coatings was 6.1 at.% and 4.5 at.%, respectively, as measured by X-ray photoelectron spectroscopy. X-ray diffraction analysis of the crystalline coating provided a good match with a B50C2-type structure in which two carbon atoms replaced boron in the α-tetragonal B52 structure, or in which the carbon atoms occupied different interstitial sites. Density functional theory predictions were used to evaluate the dynamical stability of the potential B50C2 structural forms and were consistent with the measurements. The measured nanoindentation hardness of the coatings was as high as 64 GPa, well above the 40 GPa threshold for superhardness.
Describes the research that has enabled an advance in understanding of the nature and factors controlling the biogeography and biodiversity of the ecosystems in four geographic locations: the ...Atlantic Equatorial Belt (AEB), the New Zealand region, the Arctic and Antarctic, and the SE Pacific off Chile. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.
Global climate evolution during the last deglaciation Clark, Peter U; Shakun, Jeremy D; Baker, Paul A ...
Proceedings of the National Academy of Sciences - PNAS,
05/2012, Letnik:
109, Številka:
19
Journal Article
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Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the ...transient response of Earth’s climate system to external and internal forcings. During this interval of global warming, the decay of ice sheets caused global mean sea level to rise by approximately 80 m; terrestrial and marine ecosystems experienced large disturbances and range shifts; perturbations to the carbon cycle resulted in a net release of the greenhouse gases CO2 and CH4 to the atmosphere; and changes in atmosphere and ocean circulation affected the global distribution and fluxes of water and heat. Here we summarize a major effort by the paleoclimate research community to characterize these changes through the development of well-dated, high-resolution records of the deep and intermediate ocean as well as surface climate. Our synthesis indicates that the superposition of two modes explains much of the variability in regional and global climate during the last deglaciation, with a strong association between the first mode and variations in greenhouse gases, and between the second mode and variations in the Atlantic meridional overturning circulation.
As thin films become increasingly popular (for solar cells, LEDs, microelectronics, batteries), quantitative morphological and crystallographic information is needed to predict and optimize the ...film’s electrical, optical, and mechanical properties. This quantification can be obtained quickly and easily with X-ray diffraction using an area detector in two sample geometries. In this paper, we describe a methodology for constructing complete pole figures for thin films with fiber texture (isotropic in-plane orientation). We demonstrate this technique on semicrystalline polymer films, self-assembled nanoparticle semiconductor films, and randomly packed metallic nanoparticle films. This method can be immediately implemented to help understand the relationship between film processing and microstructure, enabling the development of better and less expensive electronic and optoelectronic devices.
Amazonia has a very high, although still incompletely known, species diversity distributed over a mosaic of heterogeneous habitats that are also poorly characterized. As a result of this ...multi‐faceted complexity, Amazonia poses a great challenge to geogenomic approaches that strive to find causal links between Earth's geological history and biotic diversification, including the use of genomic data to solve geologic problems. This challenge is even greater because of the need for interdisciplinary approaches despite the difficulties of working across disciplines, where misinterpretations of the literature in disparate research fields can produce unrealistic scenarios of biotic‐geologic linkages. The exchange of information and the joint work of geologists and biologists are essential for building stronger and more realistic hypotheses about how past climate may have affected the distribution and connectivity among populations, how the evolution of drainage networks influenced biotic diversification, and how ecological traits and species interactions currently define the spatial organization of biodiversity, and thus how this organization has changed in the past and may change in the future. The heterogeneity of Amazonia and the different effects of historical processes over its distinct regions and ecosystems have to be more completely recognized in biogeography, conservation; and policymaking. In this perspective, we provide examples of geological, climatological; and ecological information relevant to studies of biotic diversification in Amazonia, where recent advances (and their limitations) may not be apparent to researchers in other fields. The three examples, which include the limitations of climate model outputs, the complicated evolution of river drainages; and the complex link between species and their habitats modulated by ecological specialization, are a small subsample intended to illustrate the urgency for more integrated interdisciplinary approaches.
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