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Terrestrial productivity

Xiangbin Ran, Bochao Xu, Jun Liu, Chenying Zhao, Sen Liu, Jiaye Zang
The study was carried out to address a method for separation of terrestrial and marine biogenic silica (BSi) in estuaries based on BSi compositions and δ(13)C values in BSi associated organic matter (δ(13)CBSi). We used two world-class major rivers - the Changjiang (Yangtze) and Huanghe (Yellow) Rivers as examples to illustrate our approach. Our results for these rivers indicate that riverine BSi is comprised mainly of phytoliths and diatoms. River BSi concentrations vary with terrestrial inputs and in-stream primary production...
November 29, 2016: Science of the Total Environment
Yolanda García-Huante, Maribel Cayetano-Cruz, Alejandro Santiago-Hernández, Claudia Cano-Ramírez, Rodolfo Marsch-Moreno, Jorge E Campos, Guillermo Aguilar-Osorio, Claudia G Benitez-Cardoza, Sergio Trejo-Estrada, María Eugenia Hidalgo-Lara
A hyperthermophilic and thermostable xylanase of 82 kDa (TtXynA) was purified from the culture supernatant of T. terrestris Co3Bag1, grown on carboxymethyl cellulose (CMC), and characterized biochemically. TtXynA showed optimal xylanolytic activity at pH 5.5 and at 85 °C, and retained more than 90% of its activity at a broad pH range (4.5-10). The enzyme is highly thermostable with a half-life of 23.1 days at 65 °C, and active in the presence of several metal ions. Circular dichroism spectra strongly suggest the enzyme gains secondary structures when temperature increases...
November 29, 2016: Extremophiles: Life Under Extreme Conditions
Sven Schenk, Christian Krauditsch, Peter Frühauf, Christopher Gerner, Florian Raible
Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy-costly step of reproductive maturation...
November 29, 2016: ELife
Marjorie T Jones, William R Milligan, Lee B Kats, Thomas L Vandergon, Rodney L Honeycutt, Robert N Fisher, Courtney L Davis, Timothy A Lucas
We introduce a mathematical model for studying the population dynamics under drought of the California newt (Taricha torosa), a species of special concern in the state of California. Since 2012, California has experienced a record-setting drought, and multiple studies predict drought conditions currently underway will persist and even increase in severity. Recent declines and local extinctions of California newt populations in Santa Monica Mountain streams motivate our study of the impact of drought on newt population sizes...
November 22, 2016: Journal of Theoretical Biology
Timothy M Lenton, Stuart J Daines
I. II. III. IV. V. VI. Acknowledgements References SUMMARY: There is growing evidence that life has been on land for billions of years. Microbial mats fuelled by oxygenic photosynthesis were probably present in terrestrial habitats from c. 3.0 billion yr ago (Ga) onwards, creating localized 'oxygen oases' under a reducing atmosphere, which left a characteristic oxidative weathering signal. After the Great Oxidation c. 2.4 Ga, the now oxidizing atmosphere masked that redox signal, but ancient soils record the mobilization of phosphorus and other elements by organic acids in weathering profiles...
November 24, 2016: New Phytologist
Nicholas Colvard, Brian Helmuth
Urbanization of coastlines is leading to increased introduction of nutrients from the terrestrial environment to nearshore habitats. While such nutrient influxes can be detrimental to coastal marine organisms due to increased eutrophication and subsequent reduced oxygen, they could also have positive effects (i.e., increased food availability) on species that are nitrogen-limited such as macroalgae. Nutrient enrichment in this environment thus has the potential to counteract some of the negative impacts of increasing temperatures, at least for some species...
November 22, 2016: Ecological Applications: a Publication of the Ecological Society of America
Hudson Carlos Maia Santos, Henrique Leonardo Maranduba, José Adolfo de Almeida Neto, Luciano Brito Rodrigues
Current research identifies, analyzes, and suggests improvements for minimizing environmental impacts in the manufacture of cheese using the life cycle assessment. Data collection and development of the inventory were performed in a small-sized dairy industry in Brazil. A cradle-to-gate approach was conducted based on the primary data from cheese production and secondary data from databases. The ReCiPe method was used for the impact assessment, considering the categories climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, photochemical oxidant formation, particulate matter formation, water depletion, and fossil depletion...
November 21, 2016: Environmental Science and Pollution Research International
E W Slessarev, Y Lin, N L Bingham, J E Johnson, Y Dai, J P Schimel, O A Chadwick
Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems. However, soil pH is not an independent regulator of soil fertility-rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients. Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy...
November 21, 2016: Nature
Hortênsia S Gripp, Juliane S Freitas, Eduardo A Almeida, Márcia C Bisinoti, Altair B Moreira
Amphibians are very sensitive to environmental change and pollution because they have both aquatic and terrestrial life cycle stages and high skin permeability. Particularly during the larval stages, when these animals are restricted to small, transient ponds, exposure to high concentrations of pesticides is inevitable in agricultural areas. Given that pesticide application increases during the summer, which coincides with the reproductive season and the occurrence of most neotropical tadpoles in their natural environment, strong indications exist that tadpoles are developing in contaminated ponds...
November 18, 2016: Ecotoxicology and Environmental Safety
T Gjesteland, N Østgaard, S Laviola, M M Miglietta, E Arnone, M Marisaldi, F Fuschino, A B Collier, F Fabró, J Montanya
 We present three terrestrial gamma ray flashes (TGFs) observed over the Mediterranean basin by the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) satellite. Since the occurrence of these events in the Mediterranean region is quite rare, the characterization of the events was optimized by combining different approaches in order to better define the cloud of origin. The TGFs on 7 November 2004 and 16 October 2006 came from clouds with cloud top higher than 10-12 km where often a strong penetration into the stratosphere is found...
December 16, 2015: Journal of Geophysical Research. Atmospheres: JGR
Kai Yue, Dario A Fornara, Wanqin Yang, Yan Peng, Zhijie Li, Fuzhong Wu, Changhui Peng
Over the last few decades there has been an increasing number of controlled-manipulative experiments to investigate how plants and soils might respond to global change. These experiments typically examined the effects of each of three global change drivers (i.e. nitrogen (N) deposition, warming, and elevated CO2 ) on primary productivity and on the biogeochemistry of carbon (C), N and phosphorus (P) across different terrestrial ecosystems. Here we capitalize on this large amount of information by performing a comprehensive meta-analysis (>2000 case studies worldwide) to address how C:N:P stoichiometry of plants, soils and soil microbial biomass might respond to individual vs...
November 17, 2016: Global Change Biology
Vinicius F Farjalla, Angélica L González, Régis Céréghino, Olivier Dézerald, Nicholas A C Marino, Gustavo C O Piccoli, Barbara A Richardson, Michael J Richardson, Gustavo Q Romero, Diane S Srivastava
Food webs of freshwater ecosystems can be subsidized by allochthonous resources. However, it is still unknown which environmental factors regulate the relative consumption of allochthonous resources in relation to autochthonous resources. Here, we evaluated the importance of allochthonous resources (litterfall) for the aquatic food webs in Neotropical tank bromeliads, a naturally replicated aquatic microcosm. Aquatic invertebrates were sampled in more than 100 bromeliads within either open or shaded habitats and within five geographically distinct sites located in four different countries...
August 2016: Ecology
William J Ripple, Katharine Abernethy, Matthew G Betts, Guillaume Chapron, Rodolfo Dirzo, Mauro Galetti, Taal Levi, Peter A Lindsey, David W Macdonald, Brian Machovina, Thomas M Newsome, Carlos A Peres, Arian D Wallach, Christopher Wolf, Hillary Young
Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 301 terrestrial mammal species are threatened with extinction. Nearly all of these threatened species occur in developing countries where major coexisting threats include deforestation, agricultural expansion, human encroachment and competition with livestock...
October 2016: Royal Society Open Science
Dan Wang, Scott A Heckathorn, Kumar Mainali, Rajan Tripathee
Heat-waves with higher intensity and frequency and longer durations are expected in the future due to global warming, which could have dramatic impacts in agriculture, economy and ecology. This field study examined how plant responded to heat-stress (HS) treatment at different timing in naturally occurring vegetation. HS treatment (5 days at 40.5°C) were applied to 12 1 m(2) plots in restored prairie vegetation dominated by a warm-season C4 grass, Andropogon gerardii, and a warm-season C3 forb, Solidago canadensis, at different growing stages...
2016: Frontiers in Plant Science
Jessica Dawson, Deena Pillay, Peter Jean Roberts, Renzo Perissinotto
Hippos transfer massive quantities of trophic resources from terrestrial to aquatic ecosystems through defecation. The ramifications of the latter for the functioning of benthic ecosystems are unknown, but are dependent ultimately on rates of utilisation relative to inputs. Low input and high utilisation can strengthen bottom-up pathways and enhance consumer biomass and abundance. However, if inputs exceed utilisation rates, dung can accumulate, leading to a decline in water quality, with important repercussions for resident assemblages...
November 17, 2016: Scientific Reports
Mike Peacock, Luke M Ridley, Chris D Evans, Vincent Gauci
Globally, large areas of peatland have been drained through the digging of ditches, generally to increase agricultural production. By lowering the water table it is often assumed that drainage reduces landscape-scale emissions of methane (CH4) into the atmosphere to negligible levels. However, drainage ditches themselves are known to be sources of CH4 and other greenhouse gases (GHGs), but emissions data are scarce, particularly for carbon dioxide (CO2) and nitrous oxide (N2O), and show high spatial and temporal variability...
November 12, 2016: Science of the Total Environment
Audrey Grech, Céline Brochot, Jean-Lou Dorne, Nadia Quignot, Frédéric Y Bois, Rémy Beaudouin
Environmental risk assessment of chemicals for the protection of ecosystems integrity is a key regulatory and scientific research field which is undergoing constant development in modelling approaches and harmonisation with human risk assessment. This review focuses on state-of-the-art toxicokinetic tools and models that have been applied to terrestrial and aquatic species relevant to environmental risk assessment of chemicals. Both empirical and mechanistic toxicokinetic models are discussed using the results of extensive literature searches together with tools and software for their calibration and an overview of applications in environmental risk assessment...
November 11, 2016: Science of the Total Environment
William Finnegan, Jamie Goggins, Eoghan Clifford, Xinmin Zhan
The abolition of the milk quota system that was in place in Europe was abolished in 2015, which instigated an immediate increase in milk production in many European countries. This increase will aid in addressing the world's ever growing demand for food, but will incur increased stresses on the environmental impact and sustainability of the dairy industry. In this study, an environmental life cycle assessment was performed in order to estimate the environmental impacts associated with the manufacture of milk powder and butter in the Republic of Ireland...
November 11, 2016: Science of the Total Environment
Tyson Sebastian, B Nagender Nath, Sangeeta Naik, D V Borole, Salou Pierre, Armoury Kazip Yazing
Environmental magnetic and geochemical analyses combined with (210)Pb dating were carried out on a sediment core off Goa from Arabian Sea to reconstruct the sedimentation history of last three and a half centuries and to investigate the impact of onshore iron ore mining on the offshore sedimentation. A drastic increase in sedimentation rate and mineral magnetic concentration parameters divides the core into two units (1 & 2) at a depth of 41cm (1982CE). The high magnetic susceptibility values in Unit 1 sediments are coeval with increased iron ore production on land and illustrate the role of terrestrial mining on the increased offshore sedimentation...
November 11, 2016: Marine Pollution Bulletin
Amira A Goda, Khayria M Naguib, Magdy M Mohamed, Hassan A Amra, Somaia A Nada, Abdel-Rahman B Abdel-Ghaffar, Chris R Gissendanner, Khalid A El Sayed
Penitrem A (PA) is a food mycotoxin produced by several terrestrial and few marine Penicillium species. PA is a potent tremorgen through selective antagonism of the calcium-dependent potassium BK (Maxi-K) channels. Discovery of natural products that can prevent the toxic effects of PA is important for food safety. Astaxanthin (AST) is a marine natural xanthophyll carotenoid with documented antioxidant activity. Unlike other common antioxidants, AST can cross blood brain barriers (BBBs), inducing neuroprotective effects...
November 9, 2016: Marine Drugs
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