Calcification in changing oceans

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What do mollusks, starfish, and corals have in common? Aside from their shared marine habitat, they are all calcifiers — organisms that use calcium from their environment to create hard carbonate skeletons and shells for stability and protection.The June issue of the Biological Bulletin, published by the Marine Biological Laboratory, addresses the challenges faced by these species as ocean composition changes worldwide.As atmospheric carbon dioxide rises, the world’s oceans are becoming warmer and more acidic. This impact of global climate change threatens the survival of calcifying species because of the reduced saturation of the carbonate minerals required for calcification.The ability to calcify arose independently in many species during the Cambrian era, when calcium levels in seawater increased. This use of calcium carbonate promoted biodiversity, including the vast array of calcifiers seen today.”Today, modern calcifiers face a new and rapidly escalating crisis caused by warming and acidification of the oceans with a reduction in availability of carbonate minerals, a change driven by the increase in atmospheric CO2 due to anthropogenic emissions and industrialization. The CO2 itself can also directly cause metabolic stress,” write the issue’s co-editors, Maria Byrne of the University of Sydney; and Gretchen Hofmann of the University of California-Santa Barbara.Contributors to the journal address this timely issue across many taxa and from a variety of perspectives, from genomic to ecosystem-wide.Janice Lough and Neal Cantin of the Australian Institute of Marine Science review historical data on coral reefs to look at potential environmental stressors, while Philippe Dubois (Universit Libre de Bruxelles) discusses sea urchin skeletons.Other researchers address lesser-known organisms that are nevertheless critical to marine ecosystems. Abigail Smith of the University of Otago examines how bryozoans, a group of aquatic invertebrate filter-feeders, increase biodiversity by creating niche habitats, and what features make them particularly sensitive to calcium fluctuations.Evans and Watson-Wynn (California State University-East Bay) take a molecular approach in a meta-analysis showing that ocean acidification is effecting genetic changes in sea urchin larvae. Several papers take a broader population-based view by studying the effect of ocean acidification on predator-prey interactions in mollusks (Kroeker and colleagues of the University of California-Davis) and oysters (Wright and colleagues of the University of Western Sydney).”The contributors have identified key knowledge gaps in the fast evolving field of marine global change biology and have provided many important insights,” the co-editors write.By sharing research on this topic from researchers around the world, the Biological Bulletin is raising awareness of some of the greatest threats to the oceans today and emphasizing the global nature of the problem.Story Source:The above story is based on materials provided by The Marine Biological Laboratory. The original article was written by Gina Hebert. Note: Materials may be edited for content and length.


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What Leads To Vitamin D Deficiency?

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Those who are busy from day to day might not think much about nutrition that they uphold. Yes, they are certainly going to try to get the standard three meals a day in so that they can feel comfortable knowing they did exactly that. With that said, though, it’s very easy to overlook certain n...

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Robotic construction crew needs no foreman

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On the plains of Namibia, millions of tiny termites are building a mound of soil — an 8-foot-tall “lung” for their underground nest. During a year of construction, many termites will live and die, wind and rain will erode the structure, and yet the colony’s life-sustaining project will continue.Inspired by the termites’ resilience and collective intelligence, a team of computer scientists and engineers at the Harvard School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University has created an autonomous robotic construction crew. The system needs no supervisor, no eye in the sky, and no communication: just simple robots — any number of robots — that cooperate by modifying their environment.Harvard’s TERMES system demonstrates that collective systems of robots can build complex, three-dimensional structures without the need for any central command or prescribed roles. The results of the four-year project were presented this week at the AAAS 2014 Annual Meeting and published in the February 14 issue of Science.The TERMES robots can build towers, castles, and pyramids out of foam bricks, autonomously building themselves staircases to reach the higher levels and adding bricks wherever they are needed. In the future, similar robots could lay sandbags in advance of a flood, or perform simple construction tasks on Mars.”The key inspiration we took from termites is the idea that you can do something really complicated as a group, without a supervisor, and secondly that you can do it without everybody discussing explicitly what’s going on, but just by modifying the environment,” says principal investigator Radhika Nagpal, Fred Kavli Professor of Computer Science at Harvard SEAS. She is also a core faculty member at the Wyss Institute, where she co-leads the Bioinspired Robotics platform.Most human construction projects today are performed by trained workers in a hierarchical organization, explains lead author Justin Werfel, a staff scientist in bioinspired robotics at the Wyss Institute and a former SEAS postdoctoral fellow.”Normally, at the beginning, you have a blueprint and a detailed plan of how to execute it, and the foreman goes out and directs his crew, supervising them as they do it,” he says. “In insect colonies, it’s not as if the queen is giving them all individual instructions. Each termite doesn’t know what the others are doing or what the current overall state of the mound is.”Instead, termites rely on a concept known as stigmergy, a kind of implicit communication: they observe each others’ changes to the environment and act accordingly. That is what Nagpal’s team has designed the robots to do, with impressive results. Supplementary videos published with the Science paper show the robots cooperating to build several kinds of structures and even recovering from unexpected changes to the structures during construction.Each robot executes its building process in parallel with others, but without knowing who else is working at the same time. …


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Drifting herbicides produce uncertain effects

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Farmers should take extra precautions so drifting herbicides do not create unintended consequences on neighboring fields and farms, according to agricultural researchers.The researchers found a range of effects — positive, neutral and negative — when they sprayed the herbicide dicamba on old fields — ones that are no longer used for cultivation — and on field edges, according to J. Franklin Egan, research ecologist, USDA-Agricultural Research Service. He said the effects should be similar for a related compound, 2,4-D.”The general consensus is that the effects of the increased use of these herbicides are going to be variable,” said Egan. “But, given that there is really so much uncertainty, we think that taking precautions to prevent herbicide drift is the right way to go.”Farmers are expected to use dicamba and 2,4-D on their fields more often in the near future because biotechnology companies are introducing crops genetically modified to resist those chemicals. From past experience, 2,4-D and dicamba are the herbicides most frequently involved in herbicide-drift accidents, according to the researchers.Because the herbicides typically target broadleaf plants, such as wildflowers, they are not as harmful to grasses, Egan said. In the study, the researchers found grasses eventually dominated the field edge test site that was once a mix of broadleaf plants and grass. The old field site showed little response to the herbicide treatments.Herbicide drift was also associated with the declines of three species of herbivores, including pea aphids, spotted alfalfa aphids and potato leaf hoppers, and an increase in a pest called clover root curculio, Egan said. The researchers found more crickets, which are considered beneficial because they eat weed seeds, in the field edge site.The researchers, who report their findings in the current issue of Agriculture, Ecosystems and Environment, did not see a drop in the number of pollinators, such as bees, in the fields. However, the relatively small size of the research fields limited the researchers’ ability to measure the effect on pollinators, according to Egan.”That may be because pollinators are very mobile and the spatial scale of our experiment may not be big enough to show any effects,” Egan said.Farmers can cut down on herbicide drift by taking a few precautions, according to Egan. They can spray low-volatility herbicide blends, which are less likely to turn to vapors, and use a nozzle design on the sprayer that produces larger droplets that do not easily drift in the wind.Egan also recommended that farmers follow application restrictions printed on herbicide labels and try to spray on less windy days when possible.The tests were conducted on two farms in Pennsylvania. …


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Help for a scarred heart: Scarring cells turned to beating muscle

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Poets and physicians know that a scarred heart cannot beat the way it used to, but the science of reprogramming cells offers hope–for the physical heart, at least.A team of University of Michigan biomedical engineers has turned cells common in scar tissue into colonies of beating heart cells. Their findings could advance the path toward regenerating tissue that’s been damaged in a heart attack.Previous work in direct reprogramming, jumping straight from a cell type involved in scarring to heart muscle cells, has a low success rate. But Andrew Putnam, an associate professor of biomedical engineering and head of the Cell Signaling in Engineered Tissues Lab, thinks he knows at least one of the missing factors for better reprogramming.”Many reprogramming studies don’t consider the environment that the cells are in — they don’t consider anything other than the genes,” he said. “The environment can dictate the expression of those genes.”To explore how the cells’ surroundings might improve the efficiency of reprogramming, Yen Peng Kong, a post-doctoral researcher in the lab, attempted to turn scarring cells, or fibroblasts, into heart muscle cells while growing them in gels of varying stiffness. He and his colleagues compared a soft commercial gel with medium-stiffness fibrin, made of the proteins that link with platelets to form blood clots, and with high-stiffness collagen, made of structural proteins.The fibroblasts came from mouse embryos. To begin the conversion to heart muscle cells, Kong infected the fibroblasts with a specially designed virus that carried mouse transgenes — genes expressed by stem cells.Fooled into stem cell behavior, the fibroblasts transformed themselves into stem-cell-like progenitor cells. This transition, which would be skipped in direct reprogramming, encouraged the cells to divide and grow into colonies rather than remaining as lone rangers. The tighter community might have helped to ease the next transition, since naturally developing heart muscle cells are also close with their neighbors.After seven days, Kong changed the mixture used to feed the cells, adding a protein that encourages the growth of heart tissue. This helped push the cells toward adopting the heart muscle identity. A few days later, some of the colonies were contracting spontaneously, marking themselves out as heart muscle colonies.The transition was particularly successful in the fibrin and fibrin-collagen mixes, which saw as many as half of the colonies converting to heart muscle.The team has yet to discover exactly what it is about fibrin that makes it better for supporting heart muscle cell. …


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Eat spinach or eggs for faster reflexes: Tyrosine helps you stop faster

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A child suddenly runs out into the road. Brake!! A driver who has recently eaten spinach or eggs will stop faster, thanks to the amino acid tyrosine found in these and other food products. Leiden cognitive psychologist Lorenza Colzato publishes her findings in the journal Neuropsychologia.The German philosopher Ludwig Feuerbach has already said it: Der Mensch ist was er iβt. You are what you eat. Substances that we ingest through our food can determine our behaviour and the way we experience our environment. Researchers at Leiden University and the University of Amsterdam have carried out the first-ever study to test whether the intake of tyrosine enhances our ability to stop an activity at lightning speed. The findings seem to indicate that this is the case.Stopping taskColzato and her colleagues created a situation in which test candidates had to interrupt a repetitive activity at a given instant. The researchers tested this using a stopping task: the participants were told to look carefully at a computer screen. Whenever a green arrow appeared, they had to press a button as quickly as possible. …


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