Center for the Environment
Center for the Environment
Datta P.,Center for the Environment |
Pandey L.M.,Center for the Environment
International Journal of Biological Macromolecules | Year: 2017
Various metal ions are recently implicated in protein aggregates and are associated with numerous neurodegenerative diseases. In the present work, we have scrutinized the effect of stoichiometric variation of Cu(II) on BSA fibrillation at physiological pH 7.4 through Thioflavin-T dye binding study, residual protein concentration, Fourier Transform Infrared spectroscopy (FTIR), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) and Isothermal Titration Calorimetry (ITC). Fibrillation kinetics was studied through ThT fluorescence, which illustrated dependency on stoichiometric ratio of Cu(II). The ThT intensity data were fitted to a single exponential expression to determine the aggregation rate, k, which revealed a slight lower k value for 1:1 ratio of BSA-Cu(II) reaction as compared to BSA alone whereas k value for 1:2 ratio of BSA-Cu(II) reaction was higher. Higher equilibrium residual concentration in case of 1:1 ratio of BSA-Cu(II) agreed to the lower aggregation rate. IR spectroscopy revealed the presence of increased β-sheet proportion to the detriment of α-helix conformation with increasing concentration of Cu(II) and illustrated maximum β-sheet proportion in 1:2 ratio of BSA-Cu(II). These results were combined with scattering results that showed the higher average hydrodynamic radius (Z-average value) of aggregates in 1:2 ratio of BSA-Cu(II) with respect to BSA and 1:1 ratio of BSA-Cu(II). AFM analysis confirmed the fibril formation. ITC analysis has shown the presence of two binding sites with many fold difference in binding affinity at prescribed in vitro conditions. An N-terminal binding site with many fold higher binding affinity was found as the first Cu(II) binding site. The free thiol group of the cysteine residue positioned at 34 (cys-34) in BSA was covalently capped and this modified BSA also showed the presence of two binding sites, which declined the cys-34 site as the second Cu(II) bind site. Therefore Zn(II) binding site was predicted as the second Cu(II) binding site. The binding of Cu(II) at N-terminal binding site marks a square planner geometry; while that at zinc binding site marks a rigid coordination geometry. Conclusively, analyzed data has concluded that the variation in Cu(II) efficacy in the different stoichiometric ratio results because of two different coordination types in different stoichiometric ratios. © 2017 Elsevier B.V.
Mapp J.,University of East Anglia |
Hunter E.,University of East Anglia |
Hunter E.,Center for the Environment |
Van Der Kooij J.,Center for the Environment |
And 2 more authors.
Fisheries Research | Year: 2017
Stock-separation of highly mobile Clupeids (sprat – Sprattus sprattus and herring – Clupea harengus) using otolith morphometrics was explored. Analysis focused on three stock discrimination problems with the aim of reassigning individual otoliths to source populations using experiments undertaken using a machine learning environment known as WEKA (Waikato Environment for Knowledge Analysis). Six feature sets encoding combinations of size and shape together with nine learning algorithms were explored. To assess saliency of size/shape features half of the feature sets included size indices, the remainder encoded only shape. Otolith sample sets were partitioned by age so that the impact of age on classification accuracy could be assessed for each method. In total we performed 540 experiments, representing a comprehensive evaluation of otolith morphometrics and learning algorithms. Results show that for juveniles, methods encoding only shape performed well, but those that included size indices held more classification potential. However as fish age, shape encoding methods were more robust than those including size information. This study suggests that methods of stock discrimination based on early incremental growth are likely to be effective, and that automated classification techniques will show little benefit in supplementing early growth information with shape indices derived from mature outlines. © 2017
News Article | October 23, 2015
Twelve new faculty members have been invited to join the ranks of the School of Engineering at MIT. Drawn from institutions and industry around the world, and ranging from distinguished senior researchers to promising young investigators, they will contribute to the research and educational activities of six academic departments in the school and a range of other labs and centers across the Institute. “This year we are welcoming another exceptionally strong group of new faculty to engineering,” says Ian A. Waitz, Dean of the School of Engineering. “They are remarkably accomplished, and their research spans some of the most important and pressing challenges in the world. I can’t wait to see what they do.” The new School of Engineering faculty members are: Mohammad Alizadeh will join the faculty as an assistant professor in the Department of Electrical Engineering and Computer Science in September 2015. He was a principal engineer at Cisco, which he joined through the acquisition of Insieme Networks in 2013. Alizadeh completed his undergraduate degree in electrical engineering at Sharif University of Technology and received his PhD in electrical engineering in 2013 from Stanford University, where he was advised by Balaji Prabhakar. His research interests are broadly in the areas of networked systems, data-center networking, and cloud computing. His dissertation focused on designing high-performance packet-transport mechanisms for data centers. His research has garnered significant industry interest: The Data Center TCP congestion control algorithm has been integrated into the Windows Server 2012 operating system; the QCN algorithm has been standardized as the IEEE 802.1Qau standard; and most recently, the CONGA adaptive load-balancing mechanism has been implemented in Cisco’s new flagship Application Centric Infrastructure products. Alizadeh is a recipient of a SIGCOMM best-paper award, a Stanford Electrical Engineering Departmental Fellowship, the Caroline and Fabian Pease Stanford Graduate Fellowship, and the Numerical Technologies Inc. Prize and Fellowship. Tamara Broderick will start as an assistant professor in electrical engineering and computer science in January 2015. She received a BA in mathematics from Princeton in 2007, a master of advanced study for completion of Part III of the Mathematical Tripos from the University of Cambridge in 2008, an MPhil in physics from the University of Cambridge in 2009, and an MS in computer science and a PhD in statistics from the University of California at Berkeley in 2013 and 2014, respectively. Her recent research has focused on developing and analyzing models for scalable, unsupervised learning using Bayesian nonparametrics. She has been awarded the Evelyn Fix Memorial Medal and Citation (for the PhD student on the Berkeley campus showing the greatest promise in statistical research), the Berkeley Fellowship, a National Science Foundation Graduate Research Fellowship, and a Marshall Scholarship. Michael Carbin will join the Department of Electrical Engineering and Computer Science as an assistant professor in January 2016. His research interests include the theory, design, and implementation of programming systems, including languages, program logics, static and dynamic program analyses, run-time systems, and mechanized verifiers. His recent research has focused on the design and implementation of programming systems that deliver improved performance and resilience by incorporating approximate computing and self-healing. Carbin’s research on verifying the reliability of programs that execute on unreliable hardware received a best-paper award at a leading programming languages conference (OOPSLA 2013). His undergraduate research at Stanford received the Wegbreit Prize for Best Computer Science Undergraduate Honors Thesis. As a graduate student at MIT, he received the MIT-Lemelson Presidential and Microsoft Research Graduate Fellowships. James Collins joined the faculty in the Department of Biological Engineering and as a core member of the Institute for Medical Engineering and Science. Collins received a PhD in mechanical engineering from the University of Oxford and was formerly the William F. Warren Distinguished Professor, university professor, professor of biomedical engineering, and director of the Center of Synthetic Biology at Boston University. He is a world leader in bringing together engineering principles and fundamental biology to make new discoveries and invent systems that can improve the human condition. Collins is among the founders of the field of synthetic biology. Otto X. Cordero will join the Department of Civil and Environmental Engineering as an assistant professor. He received a BS in computer and electrical engineering from the Polytechnic University of Ecuador, and an MS in artificial intelligence and PhD in theoretical biology from Utrecht University. For his dissertation, Cordero worked with Paulien Hogeweg on the scaling laws that govern the evolution of genome size in microbes. While a Netherlands Organization for Scientific Research Postdoctoral Fellow working with Martin Polz, he pursued a study of ecological and social interactions in wild populations of bacteria, and demonstrated the importance of these interactions in generating patterns of diversity and sustaining ecological function. In 2013 Cordero was awarded the European Research Council Starting Grant, the most prestigious career award in Europe, to reconstruct and model networks of ecological interactions that form between heterotrophic microbes in the ocean. Since November 2013, he has been an assistant professor at the Swiss Federal Institute of Technology in Zurich. The main goal of Cordero’s lab is to develop the study of natural microbial communities as dynamical systems, using a combination of experimental and computational approaches. Areg Danagoulian joined the faculty in the Department of Nuclear Science and Engineering (NSE) as an assistant professor in July 2014. He received a BS in physics from MIT and a PhD in experimental nuclear physics from the University of Illinois at Urbana-Champaign. He was a postdoctoral associate at the Los Alamos National Laboratory and subsequently worked as a senior scientist at Passport Systems Inc. Danagoulian’s research interests are focused in nuclear security. He works on problems in the areas of nuclear nonproliferation, technologies for arms-control treaty verification, nuclear safeguards, and nuclear-cargo security. Specific projects include the development of zero-knowledge detection concepts for weapon authentication, and research on monochromatic, tunable sources that can be applied to active interrogation of cargoes. Other areas of research include nuclear forensics and the development of new detection concepts. Danagoulian’s research and teaching will contribute to NSE’s growing program in nuclear security. Ruonan Han joined the electrical engineering and computer science faculty in September as an assistant professor. He is also a core member of the Microsystems Technology Laboratories. He earned his BS from Fudan University in 2007, an MS in electrical engineering from the University of Florida in 2009, and his PhD in electrical and computer engineering from Cornell University in 2014. Han’s research group aims to explore microelectronic-circuit and system technologies to bridge the terahertz gap between microwave and infrared domains. They focus on high-power generation, sensitive detection and energy-efficient systems. Han is the recipient of the Electrical Computing and Engineering Director’s Best Thesis Research Award and Innovation Award from Cornell, the Solid-State Circuits Society Pre-Doctoral Achievement Award and Microwave Theory Techniques Society Graduate Fellowship Award from IEEE, as well as the Best Student Paper Award from IEEE Radio-Frequency Integrated Circuits Symposium. Juejun (JJ) Hu joined the faculty in the Department of Materials Science and Engineering in January 2015 as an assistant professor and as the Merton C. Flemings Career Development Professor of Materials Science and Engineering. He comes to MIT from the University of Delaware, where he was a tenure-track assistant professor. Previously, he was a postdoc in MIT’s Microphotonics Center. As the Francis Alison Young Professor, Hu initiated and led research projects involving environmental monitoring, renewable energy, biological sensing, and optical communications. He received the 2013 Gerard J. Mangone Young Scholars Award, which recognizes promising and accomplished young faculty and is the University of Delaware’s highest faculty honor. His research is in three main areas: substrate-blind multifunctional photonic integration, mid-infrared integrated photonics, and 3-D photonic integrated circuits. Hu’s group has applied photonic technologies to address emerging application needs in environmental monitoring, renewable energy harvesting, communications, and biotechnology. He earned a BS in materials science and engineering from Tsinghua University, and a PhD from MIT. Rafael Jaramillo will join the materials science and engineering faculty as an assistant professor and the Toyota Career Development Professor in Materials Science and Engineering in the summer of 2015. He has a BS summa cum laude and an MEng, both in applied and engineering physics, from Cornell University. He also holds a PhD in physics from the University of Chicago. Jaramillo is currently a senior postdoctoral fellow at MIT in the Laboratory of Manufacturing and Productivity (LMP). His interests in renewable energy and accomplishments in developing materials systems and techniques for energy applications led to him receiving the Energy Efficiency and Renewable Energy Postdoctoral Research Fellowship from the U.S. Department of Energy. Prior to his appointment in LMP, Jaramillo was a postdoctoral fellow at the Harvard University Center for the Environment. His research interests lie at the intersection of solid-state physics, materials science, and renewable energy technologies. Stefanie Jegelka joined the faculty in the electrical engineering and computer science in January 2015. Formerly a postdoctoral researcher in the Department of Electrical Engineering and Computer Science at the University of California at Berkeley, she received a PhD in computer science from the Swiss Federal Institute of Technology in Zurich (in collaboration with the Max Planck Institute for Intelligent Systems in Tuebingen, Germany), and a diploma in bioinformatics with distinction from the University of Tuebingen in Germany. During her studies, she was also a research assistant at the Max Planck Institute for Biological Cybernetics and spent a year at the University of Texas at Austin. She conducted research visits to Georgetown University, the University of Washington, the University of Tokyo, the French Institute for Research in Computer Science and Automation, and Microsoft Research. She has been a fellow of the German National Academic Foundation and its College for Life Sciences, and has received a Google Anita Borg Fellowship, a Fellowship of the Klee Foundation, and a Best Paper Award at the International Conference on Machine Learning. Jegelka organized several workshops on discrete optimization in machine learning, and has held three tutorials on submodularity in machine learning at international conferences. Her research interests lie in algorithmic machine learning. In particular, she is interested in modeling and efficiently solving machine-learning problems that involve discrete structure. She has also worked on distributed machine learning, kernel methods, clustering, and applications in computer vision. Aleksander Madry is a former assistant professor in the Swiss Federal Institute of Technology in Lausanne (EPFL) School of Computer and Communication Sciences and started as an assistant professor in electrical engineering and computer science in February 2015. His research centers on tackling fundamental algorithmic problems that are motivated by real-world optimization. Most of his work is concerned with developing new ideas and tools for algorithmic graph theory, with a particular focus on approaching central questions in that area with a mix of combinatorial and linear-algebraic techniques. He is also interested in understanding uncertainty in the context of optimization — how to model it and cope with its presence. Madry received his PhD in computer science from MIT in 2011 and, prior to joining EPFL, spent a year as a postdoctoral researcher at Microsoft Research New England. His work was recognized with a variety of awards, including the Association for Computing Machinery Doctoral Dissertation Award Honorable Mention, the George M. Sprowls Doctoral Dissertation Award, and a number of best paper awards at Foundations of Computer Science, Symposium on Discrete Algorithms, and Symposium on Theory of Computing meetings. Xuanhe Zhao joined the Department of Mechanical Engineering faculty in September 2014 as an assistant professor. Before joining MIT, he was an assistant professor in the Department of Mechanical Engineering and Materials Science at Duke University. He earned his PhD at Harvard University in 2009. Zhao conducts research on the interfaces between solid mechanics, soft materials, and bio-inspired design. His current research goal is to understand and design new soft materials with unprecedented properties for impactful applications. His current research projects are centered on three bio-inspired themes: artificial muscle (dielectric polymers and electromechanics), tough cartilage (tough and bioactive hydrogels and biomechanics), and transformative skin (functional surface instabilities and thin-film mechanics). Zhao’s discovery of new failure mechanisms of dielectric polymers in 2011 and 2012 can potentially enhance electric energy densities of dielectric elastomers and gels by a factor of 10. In 2012, he designed a new synthetic biocompatible hydrogel with hybrid crosslinking, which achieved fracture toughness multiple times higher than articular cartilage — unprecedented by previous synthetic gels. With fiber reinforcements, Zhao further controlled the modulus of the tough hydrogel over a wide range from a few kilopascals to over 10 megapascals in 2013 and 2014. By harnessing surface instabilities such as wrinkles and creases in 2014, he dynamically varied both surface textures and colors of an electro-mechano-chemically responsive elastomers to achieve the dynamic-camouflage function of cephalopods. This work was highlighted by Nature News, reported by the The Washington Post, and featured on the MIT homepage: “How to hide like an octopus.” Xuanhe is a recipient of the National Science Foundation CAREER Award, Office of Naval Research Young Investigator Program Award, and the Early Career Researchers Award from AVS Biomaterial Interfaces Division.
Dolphin T.J.,Center for the Environment |
Dolphin T.J.,University of East Anglia |
Vincent C.E.,University of East Anglia |
Wihsgott J.,University of East Anglia |
And 2 more authors.
Journal of Coastal Research | Year: 2011
Beach rotation is the result of alternation between two prevailing wave directions in which sufficient time elapses to allow longshore sediment transport to drive sediment to one end or other of a headland enclosed bay. The key features of beach rotation are usually a bi-directional wave climate with sufficiently persistent episodes of each wave direction to alter the beach orientation, and headlands to trap the sediments transported along the shore. In this paper we examine shorelines derived from digital cameras that show a seasonal beach rotation due to changes in wave direction, but in the absence of any headlands. We speculate that the driving forces behind the beach rotation are the winter and spring wave regimes, and the presence of the adjacent sand bank. Beach rotation in the absence of headlands could conceivably result from longshore transport gradients. Coughlan et al. (2007) showed that there are steep gradients in longshore transport in the lee of the sand bank partly as a result of significant alongshore variability in wave height. The shoreline data also show longer-term responses that are likely to be connected to changes in bank position.
News Article | December 21, 2015
In a paper published by the National Bureau for Economic Research, two researchers say they have found a startling connection between exposure to outdoor pollution and an increase in violent crime. The study, released last week, presents “the first quasi-experimental evidence that air pollution affects violent criminal activity,” the researchers say. The authors are Evan Herrnstadt of Harvard’s Center for the Environment and Erich Muehlegger of the University of California, Davis. They drew on a vast crime dataset from the Chicago Police Department — more than 2 million major crimes committed between 2001 and 2012 in the city. The data included the crimes’ dates and locations, and researchers were able to figure out how close they were to major interstates that cross the city of Chicago, like I-290, which runs west and east. Finally, they had meteorological data, and thus could know when winds were blowing tailpipe pollution from vehicles into neighborhoods south of I-290, or into neighborhoods north of it (to give one example). The study design gets around a large problem that occurs if you simply try to correlate pollution with the occurrence of crime in a given location — namely, there are many counfounding factors such as income, Herrnstadt explains. By contrast, the study design of comparing neighborhoods with themselves, on days when they are and aren’t downwind, “allows us to drill down and really identify this causal effect of pollution on crime,” he says. Through this method, the authors report, they find an estimated 2.2 percent higher prevalence of violent crime when a neighborhood is on “the downwind side” of these major roads or interstates. However, there was no effect on property crimes. The researchers say they cannot distinguish which car-related pollutants – such as carbon monoxide or nitrogen oxides – are actually responsible for the effect. The authors also calculate that the economic cost of the crime caused by automotive pollution in this way could be $ 100 million to $ 200 million per year. It isn’t clear precisely how the pollution would be affecting people in a way that promotes criminal behavior — especially violent criminal behavior — but the authors list a number of possibilities, including cognitive impairment and just greater irritation. “We think the mechanism here is that you’re exposed to more pollution, either it’s an irritant, or it affects your impulse control in some other way, and basically results in you crossing lines that you wouldn’t otherwise cross,” says Herrnstadt. That’s why, he says, the data suggest more assault cases escalating into cases of battery in the presence of pollution. The research is part of the NBER’s working paper series and papers in this series “have not undergone the review accorded official NBER publications,” although as Paul Krugman notes, economic journals can be so slow to publish that working papers provide a very good forum for researchers to share their results (which others can then criticize). The result is actually not so surprising when considered in the context of prior research, suggests Josh Graff Zivin, an economist at the University of California-San Diego who commented on the paper at the Post’s request (but was not involved in the research). “There is a body of epidemiologic health literature that shows that pollution at high levels can impair judgement, can increase aggression, can impair cognition,” says Zivin. Indeed, a large body of prior research has tied another environmental factor — warmer temperatures — to crime and violence, and there has also been research suggesting that lead pollution drove a large amount of criminal activity that, once lead was phased out of gasoline, dropped off. There is also a small but growing body of research suggesting that poor indoor air quality can have significant cognitive effects. What’s more surprising about the study, says Zivin, is that “if you think the crime that they see in their paper, violent crimes, if you think that those are in part about impulse control, then this is really novel. As far as I know, we don’t really have evidence that pollution can lead to increased impulsivity.” Another economist familiar with the work, Reed Walker of the University of California-Berkeley, said the researchers did a good job of assuaging his skepticism. “There is an increasingly well developed literature studying the relationship between temperatures and crime, which made me initially somewhat skeptical of the findings in this paper (given the strong correlation between temperature and pollution),” said Walker by email. “However, the authors are careful to control very flexibly for temperature in their primary specifications.” Walker concludes that “this is interesting and important work and, at the very least, begs for more research on the subject.” The new study only looked at one type of air pollution — from vehicles — meaning that if the research is right, it could be the tip of the iceberg. “If we think this extends to all pollution, it could be a lot bigger than this,” Herrnstadt says. The world just adopted a tough new climate goal. Here’s how hard it will be to meet Obama just released the biggest energy efficiency rule in U.S. history Why the Paris agreement could be the beginning of the end for global warming denial For more, you can sign up for our weekly newsletter here, and follow us on Twitter here.
News Article | December 12, 2016
The planet is warming at an unprecedented rate and reducing emissions of greenhouse gasses alone is not enough to remove the risk. Last year's historic Paris climate agreement set the goal of keeping global temperatures no higher than 1.5 degrees Celsius above the preindustrial levels. Emission reductions will be central to achieving that goal, but supplemental efforts can further reduce risks One drastic idea is solar geoengineering -- injecting light-reflecting sulfate aerosols into the stratosphere to cool the planet. Researchers know that large amounts of aerosols can significantly cool the planet; the effect has been observed after large volcanic eruptions. But these sulfate aerosols also carry significant risks. The biggest known risk is that they produce sulfuric acid in the stratosphere, which damages ozone. Since the ozone layer absorbs ultraviolet light from the sun, ozone layer depletion can lead to increased rates skin cancer, eye damage and other adverse consequences. Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have identified an aerosol for solar geoengineering that may be able to cool the planet while simultaneously repairing ozone damage. The research is published in the Proceedings of the National Academy of Sciences. "In solar geoengineering research, introducing sulfuric acid into the atmosphere has been the only idea that had any serious traction until now," said David Keith, the Gordon McKay Professor of Applied Physics at SEAS and Professor of Public Policy at the Harvard Kennedy School and first author of the paper. "This research is a turning point and an important step in analyzing and reducing certain risks of solar geoengineering." This research fundamentally rethinks what kinds of particles should be used for solar geoengineering, said Frank Keutsch, the Stonington Professor of Engineering and Atmospheric Science at SEAS and Professor of Chemistry and Chemical Biology and coauthor of the paper. Previous research focused on ways to limit the ozone-damaging reactions produced by nonreactive aerosols. But Keutsch and Keith, along with coauthors Debra Weisenstein and John Dykema, took a completely different approach, targeting aerosols that are highly reactive. "Anytime you introduce even initially unreactive surfaces into the stratosphere, you get reactions that ultimately result in ozone destruction as they are coated with sulfuric acid," said Keutsch. "Instead of trying to minimize the reactivity of the aerosol, we wanted a material that is highly reactive but in a way that would avoid ozone destruction." In order to keep aerosols from harming the ozone, the particles would need to neutralize sulfuric, nitric, and hydrochloric acid on their surface. To find such a particle, Keutsch turned to his handy Periodic Table. After eliminating the toxic elements, the finicky and rare metals, the team was left with the Alkali and Alkaline Earth Metals, which included sodium and calcium carbonate. "Essentially, we ended up with an antacid for the stratosphere," said Keutsch. Through extensive modeling of stratospheric chemistry, the team found that calcite, a constituent of limestone, could counter ozone loss by neutralizing emissions-borne acids in the atmosphere, while also reflecting light and cooling the planet. "Calcite is one of the most common compounds found in the earth's crust," said Keith. "The amounts that would be used in a solar geoengineering application are small compared to what's found in surface dust," The researchers have already begun testing calcite in lab experiments that mimic stratospheric conditions. Keith and Keutsch caution that anything introduced into the atmosphere may have unanticipated consequences. "Stratospheric chemistry is complicated and we don't understand everything about it," Keith said. "There are ways that this approach could increase global ozone but at the same time, because of the climate dynamics in the polar regions, increase the ozone hole." The researchers emphasize that even if all the attendant risks could be reduced to acceptable levels, solar geoengineering is not a solution to climate change. "Geoengineering is like taking painkillers," said Keutsch. "When things are really bad, painkillers can help but they don't address the cause of a disease and they may cause more harm than good. We really don't know the effects of geoengineering but that is why we're doing this research." The research is supported by the Fund for Innovative Climate and Engineering Research and the Star Family Challenge for Promising Scientific Research. Keith and Keutsch are among several faculty who will be part of the Harvard's Solar Geoengineering Research Program, a new university-wide, interdisciplinary research effort that will be launched in the spring. Housed within the Harvard University Center for the Environment, it will be one of the largest and most visible solar geoengineering research initiatives.
News Article | November 10, 2016
For years, public health experts have warned against eating certain kinds of fish, including tuna, that tend to accumulate mercury. Still, tuna consumption provides more mercury to U.S. consumers than any other source. But recently, as industry cuts down on its mercury emissions, research has found mercury concentrations in some fish are dropping. The latest study, published in Environmental Science & Technology, reports that this is the case for prized Atlantic bluefin tuna. Although global mercury emissions continue to rise due largely to increases in coal burning in Asia, emissions in North America between 1990 and 2007 went down 2.8 percent per year, according to published studies in 2010 and 2013. Over a similar period, mercury in north Atlantic waters dropped 4.3 percent annually. And between 2001 and 2009, mercury in the air above the north Atlantic declined by 20 percent, or about 2.5 percent per year. To see whether the regional emissions reductions were having an effect on fish at the top of the ocean food chain, researchers from Stony Brook University, the University of Massachusetts and Harvard University collected and analyzed tissue samples from nearly 1,300 Atlantic bluefin tuna captured between 2004 and 2012. Tests for mercury content showed that over this eight-year period, the concentration in the fish dropped an average of 19 percent. The finding suggests that reductions in mercury emissions could rapidly lead to reduced mercury concentrations in some marine fish, the researchers say. The researchers acknowledge funding from the National Science Foundation, the National Institute of Environmental Health Sciences, the Gordon and Betty Moore Foundation, the Gelfond Fund for Mercury Research, the New York State Energy Research and Development Authority, the National Oceanic and Atmospheric Administration, the Nature Conservancy and the Harvard University Center for the Environment. The paper's abstract is available here: http://pubs. The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With nearly 157,000 members, ACS is the world's largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio. To automatically receive news releases from the American Chemical Society, contact email@example.com.
Barrio Frojan C.R.S.,Center for the Environment |
MacIsaac K.G.,Bedford Institute of Oceanography |
McMillan A.K.,Bedford Institute of Oceanography |
Del Mar Sacau Cuadrado M.,FARO |
And 4 more authors.
ICES Journal of Marine Science | Year: 2012
The benthic macrofaunal community structure is investigated within and around a closed area at Sackville Spur in the Northwest Atlantic to ascertain whether continued exclusion of bottom fishing can be justified. This and other similar closed areas have been introduced by the Northwest Atlantic Fisheries Organisation (NAFO) to protect areas of likely occurrence of taxa that are indicative of vulnerable marine ecosystems (VMEs) from the damaging effects of bottom-contact fishing gear. Results reveal subtle yet significant differences in macrofaunal assemblage composition and community structure between inside and outside the closed area, between above and below the 1200-m depth contour (i.e. the historical depth limit of fishing), and between areas where dense sponge spicule mats are either present or absent. Differences were observed in many assemblage metrics; however, the most revealing was the greater abundance, biomass, diversity, and number of VME indicative taxa inside the closed area than outside. Overall community composition is also significantly different between treatments. Depth, sediment temperature, and the proportion of clay within sediments are important in shaping the faunal assemblage. The importance of the effects of fishing is discussed, although it is not possible to ascertain if fishing is the direct cause behind observed differences in the macrofaunal assemblage. A continued closure of the area is recommended, as well as options for streamlining the evaluation process of other closed areas. © 2012 International Council for the Exploration of the Sea.
Whomersley P.,Center for the Environment |
Huxham M.,Napier University |
Bolam S.,Center for the Environment |
Schratzberger M.,Center for the Environment |
And 2 more authors.
Marine Environmental Research | Year: 2010
Two of the best-supported theories which describe the effects of disturbance within marine benthic habitats are the organic enrichment 'Successional Model' and the 'Intermediate Disturbance Hypothesis'. Underlying these models, biological mechanisms thought to drive community change include competition, facilitation, inhibition, tolerance and random colonisation. To further examine the effects of disturbance an experimental test of the effects of different types (burial, raking and organic enrichment) and intensities of disturbance on infaunal intertidal communities at two different sites with similar suites of species was carried out. The same type and frequency of disturbance, applied to the two different sites, produced different responses at the species, community and trophic group level. In models that assume a linear relationship between disturbance intensity and effect, knowledge of the intensity of any novel disturbance, combined with the original disturbance regime experienced by a community (i.e. its 'starting point'), should be sufficient to predict final community characteristics. The current results do not conform to such a linear interpretation, as at both sites the intensity of treatments did not always predict the degree of disturbance. Therefore the response to disturbance may depend on site-specific factors such as the history of prior disturbance and the inherent ecological plasticity exhibited by many benthic species. Whilst current models perform well in predicting benthic responses to gross disturbance, detecting subtler effects requires a recognition that community response may depend on the site, the species and the sources of disturbance. © 2009.
Saha B.,Center for the Environment |
Chakraborty S.,Center for the Environment |
Das G.,Center for the Environment
Journal of Physical Chemistry C | Year: 2010
In this article, we demonstrate the preparation of a new bionanocomposite by surface modification of malachite [Cu2(OH)2CO 3] nanoparticles with bovine serum albumin (BSA). The conformation of protein in BSA-malachite nanocomposite has been analyzed by employing fluorescence and Fourier transform infrared (FT-IR) spectroscopic methods. The BSA molecule loses its tertiary and secondary conformation partially in BSA-malachite nanocomposite. For the first time, bare malachite nanoparticles and BSA-malachite nanocomposite have been used for the adsorption of a series of toxic and precious metal ions from single-and multicomponent aqueous solution. We report a reversal in adsorption behavior of selected metal ions upon surface modification of malachite nanoparticle with BSA. Among different metal ions studied here, the "harder" ions (according to HSAB principle), likely, Cu2+, Ni2+, Cr3+, and Zn2+, were preferably adsorbed on bare malachite surface but show less adsorption on BSA-malachite nanocomposite. After surface modification with BSA, this situation reversed, where the "soft" metal ions Hg2+, Ag +, Au3+, and Pd2+ were highly adsorbed on BSA-malachite nanocomposite compared to the "harder" metal ions. However, Pb2+ was found to adsorb on both surfaces equally. The adsorption of metal ions has been investigated quantitatively with the help of adsorption kinetics, isotherm, and selectivity coefficient (k) analysis. The binding affinity of metal ions reduces Cr3+ > Pb2+ > Ni2+ > Zn2+, Cu2+ on malachite nanoparticles, while on BSA-malachite nanocomposite, binding affinity is found in the order Au3+ > Pd2+ > Hg2+ > Pb2+ > Ag+. We have also put our effort into studying the adsorption behavior of these metal ions from a synthetic wastewater solution containing a variable amount of metal ions. The results with synthetic wastewater solution also reflect the reversal adsorption phenomena of "harder" and "soft" metal ions on these two alternative surfaces, similar to the equimolar competitive study. © 2010 American Chemical Society.