scholarly journals Cryogenian glaciostatic and eustatic fluctuations and massive Marinoan-related deposition of Fe and Mn in the Urucum District, Brazil

Geology ◽  
2021 ◽  
Author(s):  
B.T. Freitas ◽  
I.D. Rudnitzki ◽  
L. Morais ◽  
M.D.R. Campos ◽  
R.P. Almeida ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Global Scale ◽  
Iron Formation ◽  
Santa Cruz ◽  
Fe And Mn ◽  
Glacial Outwash ◽  
Continental Glaciation ◽  
Age Constraints ◽  
Eustatic Fluctuations ◽  
Glacial Advance

Global Neoproterozoic glaciations are related to extreme environmental changes and the reprise of iron formation in the rock record. However, the lack of narrow age constraints on Cryogenian successions bearing iron-formation deposits prevents correlation and understanding of these deposits on a global scale. Our new multiproxy data reveal a long Cryogenian record for the Jacadigo Group (Urucum District, Brazil) spanning the Sturtian and Marinoan ice ages. Deposition of the basal sequence of the Urucum Formation was influenced by Sturtian continental glaciation and was followed by a transgressive interglacial record of >600 m of carbonates that terminates in a glacioeustatic unconformity. Overlying this, there are up to 500 m of shale and sandstone interpreted as coeval to global Marinoan glacial advance. Glacial outwash delta deposits at the top of the formation correlate with diamictite-filled paleovalleys and are covered by massive Fe and Mn deposits of the Santa Cruz Formation and local carbonate. This second transgression is related to Marinoan deglaciation. Detrital zircon provenance supports glaciostatic control on Cryogenian sedimentary yield at the margins of the Amazon craton. These findings reveal the sedimentary response to two marked events of glacioeustatic incision and transgression, culminating in massive banded iron deposition during the Marinoan cryochron.

Ubiquitous Computing for Microbial Forensics and Bioterrorism

2011 ◽  
pp. 86-101
Author(s):  
Gaya Prasad
Keyword(s):  
Ubiquitous Computing ◽  
Environmental Changes ◽  
Database Systems ◽  
Global Scale ◽  
Genetically Engineered ◽  
Microbial Diseases ◽  
High Resolution Data ◽  
Microbial Forensics ◽  
Genetically Engineered Bacteria ◽  
Diverse Data

Microorganisms are ubiquitous in their presence. They are present in air, soil, water, and all kinds of living creatures. Varieties of microbes have been linked to diseases of humans, animals, and plants. Advances in molecular biology, electronics, nanotechnology, computer sciences, and information technology have made it possible to hybridize these to create ubiquitous devices and biosensors that would indicate presence of microbial agents in water, foods, air, hospitals, animal farms, and other environments. Analyses of microbial genomes and phylogenies have become increasingly important in the tracking and investigation of events leading to spread of microbial diseases and biocrimes. The capability of microorganisms to communicate with similar as well as different microorganisms, the ability to react to the environmental changes, and most of all, the intelligence to manage themselves without the need for supervision during deployment and operation; makes them attractive agents for use in Biosensors. Biosensors such as genetically engineered bacteria have been proven useful. It appears possible to develop biosensors that could detect the presence of biocrime/bioterror agents in diverse environments. Ubiquitous computing technology has the potential to develop integrated small devices which could detect bioterrorism agents. Similarly, pervasive computing could be a tool to monitor the microbial pollution in water, milk, and other edible commodities. Microbial forensics has become an important field for research and development due to increased threats of biocrimes. Microbial forensics requires utilization of diverse data that are acquired through standard processes in distributed locations. Technologies for data production are evolving rapidly, especially with respect to instrumentation and techniques that produce high-resolution data about the molecular constituents of living cells (DNA, mRNA, proteins, and metabolites) that are used as microbial signatures/fingerprints. Both bioinformatics and computational biology have grown over the last 20 years, and diverse database systems and analytical tools have been developed and deployed. Some public domain resources, such as GenBank, have become very important resources of research on a global scale. Effective responses to natural, accidental, or intentional outbreaks of infectious diseases in humans, livestock, and agricultural crops, will require that the information be easily accessed in realtime or near real-time. Flexible, decentralized, modular information system architectures, able to adapt to evolving requirements and available on the Internet, are needed.

scholarly journals β-Glucosidase genes differentially expressed during composting

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xinyue Zhang ◽  
Bo Ma ◽  
Jiawen Liu ◽  
Xiehui Chen ◽  
Shanshan Li ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Environmental Changes ◽  
Cellulose Degradation ◽  
Degradation Mechanism ◽  
Degradation Process ◽  
Global Scale ◽  
Expression Of Genes ◽  
Glucose Tolerant ◽  
Cooling Phase ◽  
And Function

Abstract Background Cellulose degradation by cellulase is brought about by complex communities of interacting microorganisms, which significantly contribute to the cycling of carbon on a global scale. β-Glucosidase (BGL) is the rate-limiting enzyme in the cellulose degradation process. Thus, analyzing the expression of genes involved in cellulose degradation and regulation of BGL gene expression during composting will improve the understanding of the cellulose degradation mechanism. Based on our previous research, we hypothesized that BGL-producing microbial communities differentially regulate the expression of glucose-tolerant BGL and non-glucose-tolerant BGL to adapt to the changes in cellulose degradation conditions. Results To confirm this hypothesis, the structure and function of functional microbial communities involved in cellulose degradation were investigated by metatranscriptomics and a DNA library search of the GH1 family of BGLs involved in natural and inoculated composting. Under normal conditions, the group of non-glucose-tolerant BGL genes exhibited higher sensitivity to regulation than the glucose-tolerant BGL genes, which was suppressed during the composting process. Compared with the expression of endoglucanase and exoglucanase, the functional microbial communities exhibited a different transcriptional regulation of BGL genes during the cooling phase of natural composting. BGL-producing microbial communities upregulated the expression of glucose-tolerant BGL under carbon catabolite repression due to the increased glucose concentration, whereas the expression of non-glucose-tolerant BGL was suppressed. Conclusion Our results support the hypothesis that the functional microbial communities use multiple strategies of varying effectiveness to regulate the expression of BGL genes to facilitate adaptation to environmental changes.

Occurrence and Significance of Iron, Manganese, and Titanium in Glacial Marine Sediments from the Estuary of the St. Lawrence River

1968 ◽  
Vol 25 (11) ◽  
pp. 2327-2347 ◽  
Author(s):  
D. H. Loring ◽  
D. J. G. Nota
Keyword(s):  
Marine Sediments ◽  
Environmental Changes ◽  
Lawrence Estuary ◽  
Elemental Ratios ◽  
Physicochemical Conditions ◽  
Sediment Size ◽  
Fe And Mn ◽  
St Lawrence Estuary ◽  
Iron Manganese ◽  
Significant Chemical

In glacial marine sediments from the St. Lawrence estuary, iron varies between 1.32 and 5.42%, manganese between 0.043 and 0.28%, and titanium between 0.31 and 0.64%. The regional distributions of these elements are related to sediment texture. Analyses of individual sediment size-fractions show that Fe, Mn, and Ti concentrations generally increase with decreasing grain size. Variations in elemental ratios between the different grades suggests that not all of the Fe and Mn is located in detrital silicate minerals. Dithionite extraction of selected sediments resulted in preferential dissolution of 3–16% of the total iron, presumably that derived from amorphous and crystalline iron oxides and from sorbed material.Hydroxylamine–hydrochloride removed 5–60% of the total manganese, presumably that derived from exchangeable Mn, easily reducible Mn oxides, and sorbed Mn material. The soluble fraction is highest in freshly deposited pelites from the center of the estuary. Soluble Fe and Mn occur as oxide films on the particles deposited from suspension, and the amount held depends on rate of deposition and on the physicochemical conditions in the waters and in the sediments. In contrast, Ti occurs in detrital minerals and accumulates at the same rate as detrital sedimentary material. It is unaffected by environmental changes. This investigation shows that, despite the derivation of the sedimentary material from the Canadian Shield predominantly by nonchemical erosional processes, small but significant chemical modification of iron- and manganese-bearing material is taking place in response to present physicochemical conditions.

scholarly journals Quaternary glaciation and hydrologic variation in the South American tropics as reconstructed from the Lake Titicaca drilling project

2007 ◽  
Vol 68 (3) ◽  
pp. 410-420 ◽  
Author(s):  
Sherilyn C. Fritz ◽  
Paul A. Baker ◽  
Geoffrey O. Seltzer ◽  
Ashley Ballantyne ◽  
Pedro Tapia ◽  
...  
Keyword(s):  
Water Balance ◽  
Global Scale ◽  
South American ◽  
Tropical Andes ◽  
The South ◽  
Lake Titicaca ◽  
Quaternary Glaciation ◽  
Scale Temperature ◽  
High Altitude Lake ◽  
Glacial Advance

AbstractA 136-m-long drill core of sediments was recovered from tropical high-altitude Lake Titicaca, Bolivia-Peru, enabling a reconstruction of past climate that spans four cycles of regional glacial advance and retreat and that is estimated to extend continuously over the last 370,000 yr. Within the errors of the age model, the periods of regional glacial advance and retreat are concordant respectively with global glacial and interglacial stages. Periods of ice advance in the southern tropical Andes generally were periods of positive water balance, as evidenced by deeper and fresher conditions in Lake Titicaca. Conversely, reduced glaciation occurred during periods of negative water balance and shallow closed-basin conditions in the lake. The apparent coincidence of positive water balance of Lake Titicaca and glacial growth in the adjacent Andes with Northern Hemisphere ice sheet expansion implies that regional water balance and glacial mass balance are strongly influenced by global-scale temperature changes, as well as by precessional forcing of the South American summer monsoon.

scholarly journals A Review of Earth Observation-Based Analyses for Major River Basins

2019 ◽  
Vol 11 (24) ◽  
pp. 2951 ◽  
Author(s):  
Soner Uereyen ◽  
Claudia Kuenzer
Keyword(s):  
Land Surface ◽  
Spatial Databases ◽  
Spatial Information ◽  
Environmental Changes ◽  
River Basins ◽  
Global Scale ◽  
Earth Observation ◽  
Basin Scale ◽  
The Status ◽  
Major River

Regardless of political boundaries, river basins are a functional unit of the Earth’s land surface and provide an abundance of resources for the environment and humans. They supply livelihoods supported by the typical characteristics of large river basins, such as the provision of freshwater, irrigation water, and transport opportunities. At the same time, they are impacted i.e., by human-induced environmental changes, boundary conflicts, and upstream–downstream inequalities. In the framework of water resource management, monitoring of river basins is therefore of high importance, in particular for researchers, stake-holders and decision-makers. However, land surface and surface water properties of many major river basins remain largely unmonitored at basin scale. Several inventories exist, yet consistent spatial databases describing the status of major river basins at global scale are lacking. Here, Earth observation (EO) is a potential source of spatial information providing large-scale data on the status of land surface properties. This review provides a comprehensive overview of existing research articles analyzing major river basins primarily using EO. Furthermore, this review proposes to exploit EO data together with relevant open global-scale geodata to establish a database and to enable consistent spatial analyses and evaluate past and current states of major river basins.

scholarly journals Threshold effects of hazard mitigation in coastal human–environmental systems

2014 ◽  
Vol 2 (1) ◽  
pp. 35-45 ◽  
Author(s):  
E. D. Lazarus
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Social Dynamics ◽  
Environmental Changes ◽  
Hazard Mitigation ◽  
Nonlinear Effects ◽  
Time Frame ◽  
Global Scale ◽  
Coupling Mechanism ◽  
Environmental Systems

Abstract. Despite improved scientific insight into physical and social dynamics related to natural disasters, the financial cost of extreme events continues to rise. This paradox is particularly evident along developed coastlines, where future hazards are projected to intensify with consequences of climate change, and where the presence of valuable infrastructure exacerbates risk. By design, coastal hazard mitigation buffers human activities against the variability of natural phenomena such as storms. But hazard mitigation also sets up feedbacks between human and natural dynamics. This paper explores developed coastlines as exemplary coupled human–environmental systems in which hazard mitigation is the key coupling mechanism. Results from a simplified numerical model of an agent-managed seawall illustrate the nonlinear effects that economic and physical thresholds can impart into coastal human–environmental system dynamics. The scale of mitigation action affects the time frame over which human activities and natural hazards interact. By accelerating environmental changes observable in some settings over human timescales of years to decades, climate change may temporarily strengthen the coupling between human and environmental dynamics. However, climate change could ultimately result in weaker coupling at those human timescales as mitigation actions increasingly engage global-scale systems.

The Holocene record of environmental changes in the ‘Stagno di Maccarese’ marsh (Tiber river delta, central Italy)

The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1461-1471 ◽  
Author(s):  
C Giraudi
Keyword(s):  
Environmental Changes ◽  
Central Italy ◽  
Global Scale ◽  
Beach Ridges ◽  
The Holocene ◽  
Tiber River ◽  
Environmental Variations ◽  
Holocene Record ◽  
The 19Th Century ◽  
Ird Events

The stratigraphic study of the Stagno di Maccarese, carried out on the sediments exposed in about 7 km of trenches excavated in an area of approximately 1.5 km2, has shown that in the course of the Holocene many environmental variations have taken place. The complex evolution of the marsh is demonstrated by the variations in water salinity and the presence of erosion surfaces and soils between the sediments. In the early Holocene, the area studied was an isolated marsh with water having variable salinity, and it was only about 6000 cal. yr BP that it was encompassed in the system of inner delta marshes. In the delta environment, the water of the marsh was oligohaline until about 9th–8th centuries bc, brackish from 9th–8th centuries bc to about 600 yr BP, and later oligohaline until the 19th century drainage. A number of environmental variations are connected with local phenomena, such as erosion of the beach ridges and Tiber floods, but the others can be correlated chronologically with climatic events recorded at regional and global scale. The millennial variations seem to be connected with changes in insolation, while abrupt variations can be correlated chronologically with the IRD events dated at 8200, 5900, 4200, 2800, 1400 and 500 cal. yr BP.

scholarly journals A New Framework for the Pleistocene Stratigraphy of the Central St. Lawrence Lowland, Southern Québec

2007 ◽  
Vol 43 (2) ◽  
pp. 119-129 ◽  
Author(s):  
Michel Lamothe
Keyword(s):  
Environmental Changes ◽  
Borehole Data ◽  
Depositional Sequence ◽  
Stratigraphic Framework ◽  
Stage 4 ◽  
Lithostratigraphic Units ◽  
New Framework ◽  
St Lawrence River ◽  
Glacial Advance ◽  
The Last Glacial

ABSTRACT For three decades, a stratigraphic framework involving one glaciation with two major ice advances (represented by the Bécancour Till and Gentilly Till), separated by one brief interstade (represented by the St. Pierre Sediments), has been invoked to explain the lithostratigraphic succession of Pleistocene sediments exposed in the St. Lawrence Lowland of southern Québec. New exposures found along the bluffs of the St. Lawrence River and recent borehole data provide evidence that the Pleistocene depositional sequence is the result of three glacial advances and two nonglacial events, each represented by organic-bearing units. Two lithostratigraphic units (Lotbinière Sand and Lévrard Till) and three climatostratigraphic units (St. Lawrence Stade, Grondines Interstade and Les Becquets Interstade) are introduced in the stratigraphie nomenclature. No definite age can be assigned to the lowermost till (Bécancour?) but it is now believed to be pre-Sangamonian. Field observations and geochronological data suggest the lower and upper interstadial sediments, and an intervening glacial unit represent brief but severe environmental changes that occurred at the beginning of the Wisconsin Glaciation, ca. 90-70 ka BP. This sequence may correlate with marine isotope stage 5a, stage 4, and the earliest part of stage 3. The age of the onset of the last glacial advance (Gentilly Till) is problematic, possibly ranging from 60 to 30 ka BP.

scholarly journals Threshold effects of hazard mitigation in coastal human–environmental systems

2013 ◽  
Vol 1 (1) ◽  
pp. 503-530
Author(s):  
E. D. Lazarus
Keyword(s):  
Climate Change ◽  
Time Scales ◽  
Human Activities ◽  
Environmental Changes ◽  
Hazard Mitigation ◽  
Coupled System ◽  
Time Frame ◽  
Global Scale ◽  
Coupling Mechanism ◽  
Environmental Systems

Abstract. Despite improved scientific insight into physical and social dynamics related to natural disasters, the financial cost of extreme events continues to rise. This paradox is particularly evident along developed coastlines, where future hazards are projected to intensify with consequences of climate change, and where the presence of valuable infrastructure exacerbates risk. By design, coastal hazard mitigation buffers human activities against the variability of natural phenomena such as storms. But hazard mitigation also sets up feedbacks between human and natural dynamics. This paper explores developed coastlines as exemplary coupled human–environmental systems in which hazard mitigation is the key coupling mechanism. Results from a simplified numerical model of an agent-managed seawall illustrate the nonlinear effects that economic and physical thresholds can impart into coupled-system dynamics. The scale of mitigation action affects the time frame over which human activities and natural hazards interact. By accelerating environmental changes observable in some settings over human time scales of years to decades, climate change may temporarily strengthen the coupling between human and environmental dynamics. However, climate change could ultimately result in weaker coupling at those human time scales as mitigation actions increasingly engage global-scale systems.

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