Tag Archives: princeton university

How red crabs on Christmas Island speak for the tropics

By Guest PostOctober 12, 2013Environment, Natureallison shaw, australia national university, christmas island, climate pattern, cocos, crabs larvae, earth, ecosystem, el niño, erratic rainfall, fluctuations in rainfall, forest dynamics, indian ocean, kathryn kelly, keeling islands, migration data, migratory animals, next generation, North America, ocean, princeton university, red crabs, tropical zones, tropics, university of minnesota, university of washington

Each year, the land-dwelling Christmas Island red crab takes an arduous and shockingly precise journey from its earthen burrow to the shores of the Indian Ocean where weeks of mating and egg laying await.

Native to the Australian territories of Christmas Island and the Cocos (Keeling) Islands, millions of the crabs start rolling across the island roads and landscape in crimson waves when the November rains begin. After a two-week scuttle to the sea, the male crab sets up and defends a mating burrow for himself and a female of his kind, the place where she will incubate their clutch for another two weeks. Before the morning of the high tide that precedes the December new moon, the females must emerge to release their millions of eggs into the ocean. A month later, the next generation of crabs comes ashore. (more…)

Tropical forest carbon absorption may hinge on an odd couple

By Guest PostOctober 7, 2013Environmentabsorb, atmosphere, carbo loading bacteria, carbon absorption, carbon dioxide, carbon sink, component of biodiversity, david medvigy, dylan craven, Europe, excess nitrogen, human activities, infectious bacteria, jefferson hall, journal nature, lars hedin, legume family, michiel van breugel, models, nitrogen, nitrogen fixation, nitrogen fixing trees, non legume trees, North America, photosynthesis, princeton university, rhizobia, root nodules, sarah batterman, stri, tropical forest, united states

A unique housing arrangement between a specific group of tree species and a carbo-loading bacteria may determine how well tropical forests can absorb carbon dioxide from the atmosphere, according to a Princeton University-based study. The findings suggest that the role of tropical forests in offsetting the atmospheric buildup of carbon from fossil fuels depends on tree diversity, particularly in forests recovering from exploitation.

Tropical forests thrive on natural nitrogen fertilizer pumped into the soil by trees in the legume family, a diverse group that includes beans and peas, the researchers report in the journal Nature. The researchers studied second-growth forests in Panama that had been used for agriculture five to 300 years ago. The presence of legume trees ensured rapid forest growth in the first 12 years of recovery and thus a substantial carbon “sink,” or carbon-storage capacity. Tracts of land that were pasture only 12 years before had already accumulated as much as 40 percent of the carbon found in fully mature forests. Legumes contributed more than half of the nitrogen needed to make that happen, the researchers reported. (more…)

Movement of marine life follows speed and direction of climate change

By Guest PostSeptember 15, 2013Environmentbering sea, biological data, british columbia, changes in temperature, climate change, climate data, climate velocity, daniel pauly, direction, geological features, gulf of alaska, jorge sarmiento, malin pinsky, marine life, movement, ocean temperature move, predictions, princeton university, Rutgers University, simon levin, speed, survey data, temperature change, united states, university, warmer oceans

Scientists expect climate change and warmer oceans to push the fish that people rely on for food and income into new territory. Predictions of where and when species will relocate, however, are based on broad expectations about how animals will move and have often not played out in nature. New research based at Princeton University shows that the trick to more precise forecasts is to follow local temperature changes.

The researchers report in the journal Science the first evidence that sea creatures consistently keep pace with “climate velocity,” or the speed and direction in which changes such as ocean temperature move. They compiled 43 years of data related to the movement of 128 million animals from 360 species living around North America, including commercial staples such as lobster, shrimp and cod. They found that 70 percent of shifts in animals’ depth and 74 percent of changes in latitude correlated with regional-scale fluctuations in ocean temperature. (more…)

Cool heads likely won’t prevail in a hotter, wetter world

By Guest PostAugust 21, 2013Environmentarchaeology, australia, Berkeley, brazil, China, climate, cool heads, crime, criminology, critical factors, domestic violence, Economics, ethnic minority, ethnic violence, Europe, hotter, human conflict, human history, India, land invasions, marshall burke, middle ages europe, Netherlands, personal violence, point of violence, precipitation, princeton university, psychology, solomon hsiang, somalia, south asia, Tanzania, temperature, united states, university of california, wetter world

Should climate change trigger the upsurge in heat and rainfall that scientists predict, people may face a threat just as perilous and volatile as extreme weather — each other.

Researchers from Princeton University and the University of California-Berkeley report in the journal Science that even slight spikes in temperature and precipitation have greatly increased the risk of personal violence and social upheaval throughout human history. Projected onto an Earth that is expected to warm by 2 degrees Celsius by 2050, the authors suggest that more human conflict is a likely outcome of climate change. (more…)

Stunning images of Andromeda demonstrate the world’s most powerful astronomical camera

By Guest PostAugust 17, 2013Scienceandromeda galaxy, astronomical camera, baby galaxy, ceramic lens barrel, cosmic census, dark energy, dark matter, early universe, edge of galaxy, entire picture, hawaiian mountain, hsc, hyper suprime cam, images of andromeda, james bosch, kavli ipmu, light pollution, mauna kea, messier 31, michael strauss, milky way galaxy, naoj, paul price, princeton university, robert lupton, subaru telescope

Stunning images of the Andromeda Galaxy are among the first to emerge from a new wide-field camera installed on the enormous Subaru Telescope atop the Hawaiian mountain Mauna Kea. The camera, called the Hyper-Suprime Cam (HSC), is the result of an international collaboration between Princeton University astrophysicists and Japanese and Taiwanese scientists.

With this new camera, researchers will be able to conduct a “cosmic census” of hundreds of millions of galaxies in a wide swath of sky in sufficient depth to probe mysteries such as dark matter and dark energy, while searching for baby galaxies in the early universe. The images of the Andromeda Galaxy demonstrate the new camera’s ability to capture images for a large-scale survey that will help scientists understand the evolutionary history and fate of the expanding universe. The camera’s enormous field of view allowed the entire Andromeda Galaxy, which is some 60,000 light years across, to be captured in a single shot. (more…)

Evolution picks up hitchhikers

By Guest PostAugust 5, 2013Scienceandrew murray, bacteria, bioinformatics, daniel rice, data analysis, david botstein, Environment, evolution, fittest, functions, genetic hitchhikers, genome, gregory lang, harvard university, hitchhikers, michael desai, mutation, princeton university, resist chemotherapeutics, resistance to antibiotics, survival, tumors

In a twist on “survival of the fittest,” researchers have discovered that evolution is driven not by a single beneficial mutation but rather by a group of mutations, including ones called “genetic hitchhikers” that are simply along for the ride. These hitchhikers are mutations that do not appear to have a role in contributing to an organism’s fitness and therefore its evolution, yet may play an important role down the road.

Researchers from Princeton University found in a study of 1,000 generations of adaptation in 40 yeast populations that about five to seven specific mutations, rather than just a one, are needed for an organism to succeed. The knowledge of how mutations drive evolution can inform our understanding of how tumors resist chemotherapeutics and how bacteria evolve resistance to antibiotics. The study was published July 21 in the journal Nature. (more…)

Exercise reorganizes the brain to be more resilient to stress

By Guest PostJuly 10, 2013Healthbrain, brain cell, brain region, brian hsueh, elizabeth gould, exercise, fight, flight, gaba, gamma aminobutyric acid, human anxiety disorders, immediate early genes, mechanism, neurons, neurotransmitter, normal brain function, pedro pieruzzini, pedro rada, physical activity, princeton university, reaction, regulate anxiety, resilient to stress, sedentary mice, stanford university, timothy schoenfeld, university of los andes, Venezuela, ventral hippocampus

Physical activity reorganizes the brain so that its response to stress is reduced and anxiety is less likely to interfere with normal brain function, according to a research team based at Princeton University.

The researchers report in the Journal of Neuroscience that when mice allowed to exercise regularly experienced a stressor — exposure to cold water — their brains exhibited a spike in the activity of neurons that shut off excitement in the ventral hippocampus, a brain region shown to regulate anxiety. (more…)

Altitude sickness may hinder ethnic integration in the world’s highest places

By Guest PostJuly 4, 2013General, Scienceabu dhabi, access to sea, altitude sickness, andes dwellers, biological tolerance, Bolivia, China, chinese province, chinese security forces, christopher paik, clinica chimica acta, demographic patterns, effect of elevation, enze han, ethnic demographics, ethnic friction, ethnic integration, ethnic segregation, gansu, han chinese, highest places, himalayas, life on high, low oxygen conditions, migration patterns, modern times, new york university, population, princeton university, qinghai, qinghai tibet railway, role of factors, Sichuan, soil quality, tibetan autonomous region, tibetan name, tibetan plateau, tibetan settlements, traditional han settlements, university of london, wangyal shawa, world, yunnan

Ethnic segregation in nations straddling the world’s highest terrains may be reinforced by the biological tolerance different peoples have to altitude, according to one of the first studies to examine the effect of elevation on ethnic demographics.

Research from Princeton University published in the journal Applied Geography suggests that people native to low-lying areas can be naturally barred from regions such as the Tibetan Plateau, the Andes or the Himalayas by altitude sickness, which is caused by low oxygen concentration in the air and can be life-threatening. As a result, the homogeny of the local population can increase with elevation. In nations shared by people of high- and lowland extractions, this separation can potentially increase ethnic tension. (more…)