How seabirds are affected by climate change

Collaboration between ecologists and climate researchers has generated fascinating new insight into how seabirds are affected by climate change. 

Until recently, ecologists used a specific set of methods to study the relationship between animals and climate change, one of which is the NAO index (North Atlantic Oscillation), which measures differences in air pressure between Portugal and Iceland.
If no correlation was found here, some ecologists refuted that climate change is causing the observed changes.
Dark figures
"This is a gross oversimplification. You could even say that until now we have not been able to see the trees for the forest. Now we are trying to see each individual tree as well. Many changes caused by climate change will never be detected using only the NAO Index. We are revolutionising the research on the connection between animals and climate change," says researcher Michel d. S. Mesquita at Uni Research Climate and the Bjerknes Centre.
Mesquita has started collaborating with ecologists at the High North Research Centre for Climate and the Environment (the Fram Centre), the Norwegian Institute for Nature Research (NINA), the Norwegian University of Science and Technology (NTNU) and climatologists at the University of Reading in the UK and the Max Planck Institute for Meteorology in Hamburg. Together they have used traditional methods from climate research to study how animals are affected by changes in the climate. This has not been done before.
Virtually extinct
Researchers have studied the distribution of the common guillemot, a seabird similar to penguins. The common guillemot is an endangered species in Norway and is on the Norwegian Red List. In the 1960s there were around 160,000 pairs in Norway; today there are only 15,000 breeding pairs left.
Senior Researcher Kjell Einar Erikstad has studied the common guillemot population closely. There are therefore good coherent data on this population. In winter 1986-87 something strange happened to the common guillemot population. An unusually large number of birds were found starving and dead in the sea. Researchers looked into this incident to try to determine if it could be linked to climate change.
"We found out that that winter there was an unusually high number of high pressure systems over the Barents Sea combined with polar lows. We found this out using traditional methods from climate research, such as point maps," says Mesquita.
Point maps are maps where the same climatic data are measured at a number of different geographical points for comparison with changes in animal populations. This is the method used by Jacob Bjerknes in 1969 to explain El Niño. El Niño is a global phenomenon that arises in the ocean and in the atmosphere, leading to large temperature fluctuations in the surface water of the Pacific Ocean.
Less upwelling
One of the consequences of the high pressure was that there was less upwelling of the water in the ocean. This meant that food and nutrients remained on the seabed and were therefore not available for fish. Fish stocks declined, which in turn affected the seabirds.
The extreme high pressure over the Barents Sea also led to a decrease in the air temperature. Guillemots are sensitive to temperature and cannot survive if it is too cold for any length of time.
"The findings we have made here may be relevant to climate change in the future, resulting in more or fewer birds. This is part of the research we are working on going forwards. We observe that climate change can lead to a decline in animal populations," says Mesquita.
The common guillemot spends the whole winter out in the Barents Sea and is therefore particularly vulnerable to the conditions there during the winter months. The birds dive to find food, and can dive down to depths of up to 150 metres. Using dive logs that record the pressure the birds are exposed to, we now know that the birds dive down to 150 metres in the winter and some 7-8 metres in the summer. The common guillemot only goes ashore to nest.
"Using these traditional methods and not only the NAO Index gives us a better understanding of what is happening to the seabirds. We can also use these methods to find out how other species are affected by climate change," says Mesquita.
Looking ahead
"A challenge for the coming years is to use these kinds of climate models to be able to make predictions about populations and ecosystems in the future. This collaboration has already given us several new projects at the Fram Centre in Tromsø, and we are currently preparing projects for the Research Council of Norway," says Kjell Einar Erikstad, Senior Researcher at NINA.

This story is taken from Science Daily

Unmanned aerial vehicle used to study gray whales from above

Scientists are using an unmanned aerial vehicle to take very precise overhead images of migrating gray whale mothers and calves. This research will help scientists understand how environmental conditions control the reproductive success of individual whales and ultimately of the population. 

NOAA Fisheries scientists have stood at this point of land each year for the past 22 years, binoculars in hand, to estimate the number of gray whale calves born each year. That's an important step in monitoring the ups and downs of the population. But scientists would like to understand more completely what causes those ups and downs, and this year, with the addition of the hexacopter, they hope to find out.
As the hubcap-sized hexacopter hovered high above the whales it shot straight-down photos from a digital camera mounted in its belly. In addition to a camera, the hexacopter also carried a very precise pressure altimeter, allowing scientists to know the exact altitude at which each image was taken. Later in the lab, they would analyze the images, measuring the length and girth of the whales to within a few centimeters.
"We can't put a gray whale on a scale, but we can use aerial images to analyze their body condition--basically, how fat or skinny they are," Durban said.
Durban and co-pilot Holly Fearnbach, also a NOAA Fisheries scientist, would ultimately capture images of more than 60 cow/calf pairs.
A Long and Difficult Journey
The amount of fat on a gray whale cow is critical to the survival of her calf. Gray whales don't feed during most of their months-long migration, and while the mothers are fasting, they're also nursing their fast-growing calves. Therefore they need a lot of blubber to fuel the journey to their Arctic feeding grounds.
How much blubber they're carrying depends in part on conditions in the Arctic the summer before. If the whales had access to plentiful prey, the cows will have sufficient fat on them, and most calves will likely survive the journey. But if conditions weren't favorable, fewer calves will be born, and fewer still will make it.
"By studying the body condition of females, we hope to connect the dots between conditions in the Arctic one year and calf production the next," Durban said. "Ultimately, we're trying to understand how environmental conditions affect the reproductive success of the population."
Throughout the study, scientists kept the hexacopter at least 120 feet above the whales. When used at this altitude by trained scientists, unmanned aerial vehicles offer a safe and non-invasive way to collect important data on marine mammals and other protected species.
A Recovery Success Story
Gray whales were hunted nearly to extinction during the whaling days. Thanks to legal protections, the U.S. population of gray whales recovered and was taken off the endangered species list in 1994 (though a second population of gray whales on the Russian side of the Pacific remains endangered).
This success presents scientists with a unique opportunity to study the ecology of large whales, including how environmental conditions put an upper limit on population growth. Because most other large whales are still threatened or endangered, scientists have had few opportunities to observe these dynamics in action.
"With gray whales, we're just beginning to understand what a recovered population of large whales looks like," Durban said.
This understanding will help scientists set recovery goals for other species. And once a species is recovered, it will help scientists distinguish between normal ups and downs in a population and signs of--should it happen--a more serious decline.
"We'll have to get used to seeing recovered populations have good years and bad years," Durban said. "That's what happens when you've recovered and you're hovering around a food ceiling."
As the sun descended toward the horizon, Durban brought the hexacopter in for the day's final landing. He still had a lot of work in front of him, minutely analyzing images on a computer screen. Though all the images from this study would be of gray whales, other species of large whale are also showing promising signs of recovery.
"Hopefully in the not-too-distant future," Durban said, "there will be many healthy populations of large whales to study."

This story is taken from Science Daily

First artificial insemination of Yangtze giant softshell turtle

A female Yangtze giant softshell turtle (Rafetus swinhoei) -- potentially the last female of her species -- has been artificially inseminated. The procedure, which brought together top scientists from China, Australia and the United States, provides a ray of hope in a continuing effort to save the world's most endangered turtle. 

There are four living Yangtze giant softshell turtles remaining in existence -- two in Vietnam (both thought to be males) and two in China at the Suzhou Zoo (a male and female). The male and female -- both believed to be greater than 100 years of age -- were brought together in 2008 as part of a captive breeding program initiated by TSA and the WCS (Wildlife Conservation Society) China program. The female was transported from the Changsha Zoo to the Suzhou Zoo through the efforts of four partners (Changsha Zoo, Suzhou Zoo, TSA, and WCS).
WCS China Reptile Program Director and coordinator of the Rafetus swinhoei breeding program, Dr. Lu Shunqing, mediated the program agreement among the partners and has coordinated the program during the past 8 years.
"It now appears that artificial insemination is the only possible option for the pair of Rafetus swinhoei in Suzhou Zoo to reproduce successfully," said Dr.Lu Shunqing. "The fate of the most endangered softshell turtle of the world is now in the balance."
Though the two turtles have before displayed courting behavior, eggs laid by the female have been infertile.
"We had to find out if the last known male in China no longer produces viable sperm due to old age or an inability to inseminate the female," said Dr. Gerald Kuchling, organizer of the artificial insemination effort and Rafetus breeding program leader for the TSA.
To determine the cause of the infertility, Suzhou Zoo, Changsha Zoo, and the China Zoo Association requested TSA assemble a team of scientists to conduct a reproductive evaluation of the male, collect semen, determine if he had viable sperm, and, if viable sperm could be demonstrated, artificially inseminate the female.
"At first we tried semen collection through manual stimulation and the use of a vibrator, but as previously found in another softshell turtle, the only way was through sedation of the male and electro-ejaculation -- risky procedures due to his old age," Dr.Kuchling said.
During the process, the male was determined to have damaged sex organs, perhaps due to a fight with another male decades ago. For this reason, the scientists believe the male incapable of inseminating the female, and therefore, fertilizing the eggs.
Dr. Barbara Durrant, Director of Reproductive Physiology at the San Diego Zoo Institute for Conservation Research said, "Normal semen parameters for Rafetus are unknown as this was the first attempt to collect and examine sperm from this species. The semen evaluation revealed that approximately half of the sperm were motile." Based on the results, it was determined the female could be artificially inseminated.
This attempt marks the first time artificial insemination has been tried with any softshell turtle species and based on results of insemination with other turtles, the odds are not good for success. With natural breeding unsuccessful however, the scientists felt it was time to explore this option. Both turtles recovered from the procedure in good condition.
"The attempts to breed this critically endangered species, and overcome obstacles to natural breeding by this global consortium of experts is a great example of international cooperation to save endangered species," said WCS Chief Veterinarian and Bronx-Zoo based Director of Zoological Health Dr. Paul P. Calle, who worked with Chinese veterinarians on the delicate sedation process. "We are grateful to our Chinese partners at the Suzhou Zoo, Changsha Zoo, and the China Zoo Association for inviting us to work with them in our collective attempt to save this species. "
"This was a great exploration to advance the conservation of Rafetus swinhoei, however, we cannot yet determine if the exploration was successful or not," said Director Chen Daqing of Suzhou Zoo. The female will lay the eggs in a few weeks and in a couple of weeks after that, the scientists will know if the eggs are fertile.
Listed on the International Union for the Conservation of Nature's Red List, the Yangtze giant softshell turtle is the most critically endangered turtle in the world. Its status in the wild has long been recognized as grim, but extinction risk now is believed higher than ever. Much of its demise has been attributed to over-harvesting and habitat degradation.
Fort Worth Zoo Biologist and TSA President Rick Hudson said, "The conservation world will once again be holding its collective breath until we know if this was successful. The optimism we felt back in 2008 when the pair was mating and laying eggs has slowly faded as reality sank in that this pair would not breed without intervention."
"This autumn, the female Rafetus swinhoei will be moved back to Changsha Zoo. We hope some children move together with her," said Vice Director Yan Xiahui of Changsha Zoo.

This story is taken from Science Daily

Changes in forest structure affect bees, other pollinators

Over the past century, many forests have shifted from open to closed canopies. The change in forest structure could be contributing to declines in pollinator species, especially native bees, according to a new study. 

The study shows how common present-day forest conditions affect pollinators, especially bees. "Bees prefer open forests," says Jim Hanula, a research entomologist at the Southern Research Station (SRS) Insects, Diseases, and Invasive Plants research unit. "We found that total tree basal area was the best predictor for how many bees would be present." Tree basal area describes the amount of space occupied by tree stems within a given piece of land.

Hanula and his colleagues found that in stands with high basal areas, bees were scarce. Bees were also less common in stands with dense shrub layers.

Hanula and his colleagues measured pollinator abundance and diversity across seven types of forest in the Oconee National Forest in Georgia, including dense young pines, thinned young pines, mature open pine with extensive shrub and sapling cover, mature open pine with extensive herbaceous plant cover, mature upland hardwood forest, and mature riparian hardwood forest.

Before becoming part of the National Forest System in 1959, the land now included in the Oconee National Forest was mostly deforested. Its land use history is shared by many other forests in the Southeast, where huge swathes of forests were clearcut during the late 19th and early 20th century. Because of the deforestation, as well as the repeated wildfires that swept through the region, reforestation and wildfire prevention were primary conservation goals throughout much of the 20th century. The new forests that have grown in their place tend to have closed canopies and denser shrub layers than before.

"We found that bees were most abundant in mature pine forests with open canopies with flowers and grasses in the understory which provide long-term, stable habitats for bees." Pollinators were also common in recently cleared patches of forests, but those quickly close and become dense stands of young pine trees that tend to support the fewest bees.

The results have already been incorporated into bee-friendly management principles recently drafted for federal lands. Hanula and co-author Scott Horn, an SRS entomologist, were part of a Forest Service team that wrote and edited the Forest Service best management practices to promote bee health. "We've been studying pollinators for more than 10 years," says Hanula, "and it was great to be a part of something like this that will help guide management and future research."

One of the principles discussed in the report is how open forests benefit bees. Before European settlement, forests in the Southeast were a mosaic of open pine and hardwood, prairies, and woodland savannas. Maintaining open canopy pine forests with diverse herbaceous communities typically requires prescribed fire, and although bee conservation is not a routine management objective, concern over the fate of pollinators is increasing.

Pollinator conservation is highly compatible with other goals, such as maintaining habitat for the endangered red-cockaded woodpecker. Without insect pollination, most plants would be unable to reproduce. "Pollinators are critically important to forest ecosystems and to people," says Hanula. "Managing for open forests has a number of benefits, and could also help sustain these species for the future."

This story is taken from Science Daily

Biodiversity: Eleven new species come to light in Madagascar

Madagascar is home to extraordinary biodiversity, but in the past few decades, the island's forests and associated biodiversity have been under greater attack than ever. Rapid deforestation is affecting the biotopes of hundreds of species, including the panther chameleon, a species with spectacular intra-specific colour variation. A new study reveals that this charismatic reptilian species, which is only found in Madagascar, is actually composed of eleven different species.

In collaboration with professor Achille Raselimanana of the University of Antananarivo, researchers from the Department of Genetics and Evolution in the UNIGE Faculty of Sciences, led by Michel Milinkovitch, sought to find the genetic keys behind panther chameleon's incredible colour palette. Their analyses, performed on site in Madagascar, reveal the presence of 11 rather than a single species.
A Talkative Drop of Blood
It took two expeditions led from East to West for the scientists to collect a drop of blood from each of 324 individuals and document them through colour photographs. The DNA (mitochondrial and nuclear) of each of the specimens were sequenced and analysed in the laboratory according to the hypothesis that a chameleon's dominant colour might be related to the geographic zone where it is found. Most importantly, the genetic material indicated strong genetic structure among geographically-restricted lineages, revealing very low interbreeding among populations.
A Key for Turning Genetics into Color
The mathematical analyses of the 324 colour photographs demonstrated that subtle colour patterns could efficiently predict assignment of chameleon individuals to their corresponding genetic lineage, confirming that many of the geographical populations might need to be considered separated species. The scientists then simplified their analyses of the colour diversity into a classification key, which allows to link most chameleons to their corresponding species using only the naked eye. This case of hidden speciation confirms a major characteristic of Madagascar: it is amongst the most diverse places for life on Earth; a biodiversity hotspot.
Madagascar, Unique but Precarious Conservatory
Each of the new chameleon species requires individual management, given that they each constitute a different part of the biodiversity of the whole. The visual classification key devised by the researchers could assist local biologists and trade managers to avoid local population over-harvesting. The task of biodiversity management is daunting because of the widespread destruction of the forest habitat for agricultural practices as well as for firewood and charcoal production by populations with very low living standards. These human activities threaten the survival of 400 species of reptile, 300 species of amphibians, 300 species of birds, 15,000 species of plants and countless species of invertebrates. In addition, approximately 80 to 90% of all living species found in Madagascar are endemic, meaning they exist nowhere else on earth.
Given the charismatic nature of chameleons, Milinkovitch hopes that, beside a better understanding of the genetic basis of colour variation in chameleons, his collaborative study with his Malagasy colleagues will help his colleague, Professor Raselimanana, to continue his difficult enterprise: raising awareness for the staggering but fragile biodiversity hosted by Madagascar.

This story is taken from Science Daily

New model predicts fish population response to dams, other ecological factors

Researchers have developed a model to assess how dams affect the viability of sea-run fish species that need to pass dams as they use both fresh and marine waters during their lifetimes. The aim is to test how varying passage efficiency at dams related to survival rates for these species, using a model of endangered Atlantic salmon as a case study.

Using a model of endangered Atlantic salmon in Maine's Penobscot River as a case study, NOAA researchers found that abundance, distribution and number of fish increased upstream when dams in the primary downstream segments of the river, also called "mainstem dams," were removed or fish passage survival was increased. The findings were recently published online in the ICES Journal of Marine Science.

Models like this one, which analyze population viability based on a variety of biological, environmental, and functional factors, can be used to predict ecological responses of fish populations. They can also provide a way to evaluate and prioritize management and restoration actions for fish that migrate between fresh and salt water.

"The Dam Impact Analysis Model enables us to see what happens when you change one factor, like marine or freshwater survival," said Julie Nieland, a researcher at NEFSC's laboratory in Woods Hole, Mass. and lead author of the study. "For example, salmon abundance increased when marine or freshwater survival rates were increased. However, the increase was larger when marine survival increased than when freshwater survival increased. We are also able to change the survival rate and passage efficiency at individual or multiple dams to look at the effects on salmon abundance and distribution throughout the river system. Those changes tell us a lot about the factors influencing the population."

Dams and low marine survival rates are two of the biggest threats to many diadromous fishes, which spend part of their life in freshwater and part in the ocean. Dams can prevent or impede fish passage and degrade the habitats upstream by inundating formerly free-flowing rivers, reducing water quality, and altering fish communities. They can also kill and injure fish during migrations. Direct mortality occurs when fish pass through turbines, over fishways, or through fish bypasses. Indirect mortality comes from increased predation in altered habitats, health risks from injuries, and the added effects of stress and injury that come with passing one or more dams.

"The good news is that these effects can be reduced by installing or improving fish passage devices, modifying dam operations during peak migration periods, changing the structure of the dam to reduce injury and mortality, and by dam removal," Nieland said.

In the Penobscot River, the second largest river in New England, fish passage on the lower parts of the river has been helped by the removal of Great Works Dam in 2012 and Veazie Dam in 2013, and by building a natural river channel bypass around Howland Dam in 2015 as part of the Penobscot River Restoration Project. Access to habitat along the river and its tributaries has been improved for sea-run fish, including Atlantic salmon, American shad, river herring, striped bass, Atlantic sturgeon and shortnose sturgeon. In addition, increased survival standards for Atlantic salmon at many remaining dams have been implemented as part of the Federal Energy Regulatory Commission (FERC) licensing requirements.

In 2014, more than 800 American shad and 180,000 river herring were counted by scientists at the newly-installed fish lift at the Milford Dam, the first mainstem dam on the system. Prior to 2014, there were no known American shad above Milford and very few river herring. Diadromous fish that survive passage at the Milford fish lift will emerge into historic spawning, nursery and rearing grounds that have not been accessible since the early 1900s.

Passage at the remaining dams on the Penobscot River will be important to the recovery of diadromous fish populations. The model can be used to help estimate what passage rates are needed to avoid jeopardizing these populations.

NOAA Fisheries researchers used the model to look at the impacts of 15 FERC-licensed hydroelectric dams in the Penobscot River watershed. Their results showed the number and location of dams affected adult salmon abundance, distribution, and the proportion of wild fish using various parts of the watershed. Salmon numbers increased as the number of hydroelectric dams decreased. Mainstem river dams had more impact than dams on tributaries. Salmon abundance also decreased as indirect mortality from effects of having to navigate past dams and up fish ladders or other passages increased. FERC is required to consult with NOAA Fisheries Service to ensure that continued dam operation does not impede recovery of Atlantic salmon.

"The Dam Impact Analysis Model provides managers with a way to assess the levels of survival needed for Atlantic salmon at several large mainstem dams in the lower Penobscot River," said Jeff Murphy, an endangered species biologist at GARFO. "Going forward, it will be an extremely important tool for identifying survival standards for Atlantic salmon at other dams in the Penobscot River watershed as we work to recover the species in Maine."

"There is still a lot of work to do to improve access to more historic river habitat for diadromous fish," Nieland said. "Hundreds of dams and thousands of road-stream crossings, or culverts, remain as barriers to fish passage in the Penobscot watershed. The model can help us plan for restoration and management actions to increase survival and abundance of many of the sea-run fish species, including those that are endangered or threatened."

This story is taken from Science Daily

Surviving harsh environments becomes a death-trap for specialist corals

The success of corals that adapt to survive in the world's hottest sea could contribute to their demise through global warming, according to new research.

Researchers from the University of Southampton and the New York University Abu Dhabi found that local adaptation to high salinity levels in the southern Persian/Arabian Gulf (PAG) may prevent coral escaping their fate, as they lose their superior heat tolerance in waters with normal salinity levels.
The research is published this week in The ISME Journal.
Warm water corals depend on a vital partnership with unicellular algae of the genus Symbiodinium. Damage to the algal symbiont through heat stress can result in the breakdown of the association, leading to fatal coral bleaching. Most corals fall victim to bleaching at water temperatures above 32ºC. However, corals from the PAG region survive summer peak temperatures of up to 35ºC on a regular basis.
Senior author of the study, Professor Jörg Wiedenmann from Ocean and Earth Science at the University of Southampton, explains: "It was not clear whether this resilience is related to the presence of a new type of symbiotic alga (Symbiodinium thermophilum) that was recently discovered by our team in this region. Therefore, we used molecular markers to identify the algal partners of three coral species along the coast of the southern Gulf and the adjacent Gulf of Oman. We found that this special symbiont indeed seems to play an integral role for coral survival in the world's hottest sea."
The researchers studied corals along 1,000km of coastline in the southern PAG, a region where the world's warmest coral reef habitats are separated from the wider Indian Ocean by the narrow Strait of Hormuz. Notably, the PAG features not only record temperatures, but the water is also exceptionally salty.
Professor Wiedenmann, who runs the University's Coral Reef Laboratory based at the National Oceanography Centre Southampton, continues: "As soon as you leave the Gulf, corals start to host different symbionts. This 'partner exchange' starts when the salinity of the water approaches normal oceanic levels."
Lead-author Dr Cecilia D'Angelo, Senior Research Fellow at the University of Southampton, says: "We have simulated these conditions in our laboratory and found that corals from the Gulf lose their exceptional heat stress tolerance when they need to cope at the same time with salinity levels commonly found in coral reefs elsewhere. This may explain why the PAG-typical coral-alga associations are rarely found in the less salty water or the Gulf of Oman."
Dr D'Angelo adds: "Some corals may potentially escape their fate in waters heated by global warming by shifting their geographic distribution. However, our findings indicate that in addition to barriers such as landmasses, the lack of suitable substrate for settlement and adverse currents, the dependence on certain local environmental conditions may represent an invisible fence that could trap corals in their endangered habitat."
With rising ocean temperatures anticipated to cause a loss of most warm water reefs within the next 100 years, it has been discussed whether heat tolerant corals adapted to hot environments, such as PAG, could be used to replenish reefs damaged by global warming elsewhere.
Professor Wiedenmann comments: "Our results suggest that the transplantation of corals over large geographic distances is not a straight-forward solution to restore reefs since they may struggle to adjust to different environmental factors apart from the temperature in the new habitat. Efforts to protect coral reefs should rather focus on other measures including the reduction of nutrient enrichment, sedimentation, overfishing and destructive coastal development. At the same time all attempts should be made to reduce CO₂ emissions to prevent further global warming."

This story is taken from Science Daily

Changes in land use pose greater threat to aquatic diversity than climate change

For the first time, scientists have modeled the effects of land use changes on the species diversity in rivers and streams. Their results show that the loss of biodiversity is caused to a significantly higher degree by changes in land use practices than by climate change. In consequence, conservation concepts for this valuable ecosystem and the organisms that live in flowing water should be adapted accordingly. 

From their source to the mouth, rivers and streams are in constant motion and count among the world's most dynamic ecosystems. Although they only cover a small percentage of the land area, in their natural state these ecosystems are home to a multitude of living organisms: insects, fish, algae, bivalves and daphnias are but a few of the denizens of streams and rivers. "At the same time, however, rivers and streams are the most endangered ecosystems on a global scale," according Dr. Mathias Kuemmerlen from the Department of Freshwater Ecology and Nature Conservation Research at the Research Institute Senckenberg in Gelnhausen. He adds, "Rivers and streams are more sensitive to environmental changes than any other biotope."
Together with colleagues from China and Germany, the biologist from Gelnhausen studied the rivers and streams in a catchment area of approx. 1,700 square kilometers in Southern China, which is part of the drainage basin of the Yangtze River. "For the first time, we modeled a future projection of the species diversity in connection with land use changes," explains Dr. Sonja Jähnig, who conducts research at the Leibniz Institute for Freshwater Ecology and Inland Fisheries in Berlin and who initiated this study. She adds, "The loss of biodiversity is often studied in relation to climate change. Other important anthropogenic impacts on the environment -- such as changing land use practices -- are frequently neglected in this context."
Therefore, the team of scientists around Kuemmerlen modeled three scenarios for the development of freshwater-dwelling macroinvertebrates -- animals without a vertebral column easily recognized with the naked eye -- for the years from 2021 until 2050: the climate change, the change in land use, and a combined climate change and land use change scenario. "Our results will help us to better understand future changes in the invertebrate communities," according to Jähnig.
The 72 aquatic organisms that were studied display a wide range of different behaviors in the models. Thus, in the course of land use changes, the aquatic stonefly Togoperla sp. stands to lose 85 percent of its distribution area in the studied drainage basin and is locally threatened with extinction, while damselfly species of the family Protoneuridae gain an additional 9 percent of potential habitat. "In all of our models, there are 'losers' and 'winners,' both in the land use and climate change scenarios. However, across all species, it can be said that the changes in land use have the strongest negative effect on the species diversity in rivers and streams -- in this model, the local biodiversity decreased by 20 percent," explains Kuemmerlen.
In the scientists' models, the effect of climate change on the biodiversity in rivers and streams is only of secondary importance. According to Kuemmerlen, "There is a close interaction between flowing water and the landscapes in the drainage basin. Therefore, the species diversity is strongly affected by land use practices." In addition, the modeling results show that the combined effect of changes in land use and climate may lead to a general decrease in local species diversity. Moreover, a shift in the distributions of many aquatic invertebrates can be expected.
Although changing land use practices, e.g., the clear-cutting of forests for agricultural use, represent the most obvious change within an ecosystem, according to Kuemmerlen this factor is frequently neglected in the development of conservation concepts. "In order to preserve the species diversity, we must consider both changes in climate as well as in land use," he summarizes.

This story is taken from Science Daily

Which is most valuable: Gold, cocaine or rhino horn?

Elephants, rhinoceroses, hippopotamuses, gorillas and the majority of other very large animal species are threatened with extinction, an international team of scientists have reported. And if current trends continue, the loss of these animals would have drastic implications not only for the species themselves, but also for other animals and the environments and ecosystems in which they live. One of the critical factors behind the disturbing trend is the tremendous financial incentive for poachers to sell animal parts for consumer goods and food. For example, rhinoceros horn is more valuable by weight than gold, diamonds or cocaine, said the study's lead author. 

The study, which was co-authored by Blaire Van Valkenburgh, a UCLA professor of ecology and evolutionary biology, was recently published in the open-access online journal Science Advances.
One of the critical factors behind the disturbing trend is the tremendous financial incentive for poachers to sell animal parts for consumer goods and food. For example, rhinoceros horn is more valuable by weight than gold, diamonds or cocaine, said William Ripple, the study's lead author, a distinguished professor of ecology at Oregon State University's College of Forestry. (Bloomberg News reported in 2014 that the price of rhino horn in Asia has approached $60,000 per pound.)
Said Van Valkenburgh: "Decades of conservation efforts are being reversed by the entrance of organized crime into the ivory and rhino horn markets."
The study also found that:

• Between 2002 and 2011, the number of forest elephants declined by 62 percent.
• From 2007 to 2013, the number of rhinoceroses poached skyrocketed from 13 per year to 1,004 per year.
• More than 100,000 elephants -- one-fifth of the world's wild savannah elephant population -- were poached between 2010 and 2012.

"If this were to keep up, there would be very few or no savannah elephants in 10 years, and no African rhinos in 20 years," Van Valkenburgh said.
Van Valkenburgh said even the researchers were surprised to find that 60 percent of species in the study -- animals the size of reindeers and larger -- are now considered to be threatened. "I certainly was taken aback by the data," she said. "For some of the largest animals, such as elephants and rhinos, it is likely a matter of a few decades before they are extinct -- and no more than 80 to 100 years for the rest of the large herbivores. Even though an individual elephant or rhino might persist in the wild somewhere in Africa, they will be functionally extinct in terms of their impact on the ecosystem."
The scientists studied 74 species of wild herbivores that weigh an average of 220 pounds at adulthood. Their conclusion: "Without radical intervention, large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs."
The study notes that during the Pleistocene Epoch, which ended about 11,700 years ago, there were more than 40 species of herbivores in which adults weighed 2,200 pounds or more, but today there are only eight such species. The extinction of these "mega-herbivore" species has dramatically affected Earth's ecosystems, the researchers write. For example, large herbivores are the primary source of food for predators and scavengers, and their trampling and consumption of plants influence the ways that vegetation grows. And humans, especially in developing regions, rely on large herbivores for food: It is estimated that 1 billion people rely on wild meat for subsistence.
For the species analyzed in the study, today's two largest threats are hunting by humans and habitat change. Other key factors include growing human populations and increased competition with livestock. The authors write that the latter has been a particular threat in developing nations, where livestock production tripled between 1980 and 2002. As a result, one of their proposals for addressing the crisis is creating financial incentives for people who live near the animals' habitats to protect the animals, so it becomes more lucrative to safeguard the animals than to poach them.
The scientists also emphasized the need for social marketing and environmental education campaigns as tools to drive down demand for animal products as food and consumer goods. (They noted that a social media campaign featuring retired NBA player Yao Ming appeared to help save shark populations by reducing demand for shark fin soup in his native China.)
"Large herbivores, and their associated ecological functions and services, have already largely been lost from much of the developed world," the scientists write. "Now is the time to act boldly, because without radical changes in these trends, the extinctions that eliminated most of the world's largest herbivores 10,000 to 50,000 years ago will only have been postponed for these last few remaining giants."

This story is taken from Science Daily

Iconic Indian fish on the brink of extinction

The legendary humpback Mahseer, one of the world's most iconic freshwater fish, is on the brink of extinction according to scientists. Ever since the publication of HS Thomas's A Rod in India in 1873, this giant member of the carp family has been known to anglers around the globe as 'one of the largest and hardest fighting freshwater fish in the world'. With its distribution having always been limited to South India's River Cauvery basin, this fish is now believed to be so endangered it may be extinct in the wild within a generation. 

Ever since the publication of HS Thomas's A Rod in India in 1873, this giant member of the carp family has been known to anglers around the globe as 'one of the largest and hardest fighting freshwater fish in the world'. With its distribution having always been limited to South India's River Cauvery basin, this fish is now believed to be so endangered it may be extinct in the wild within a generation.

Adrian Pinder of Bournemouth University and Dr Rajeev Raghavan of St. Albert's College have been studying the ecology, taxonomy and conservation status of 17 species of mahseer which populate rivers throughout south and southeast Asia since 2010. Four of these species are already listed as 'Endangered' on the IUCN [International Union for Conservation of Nature] Red List. Along with co-author Dr Robert Britton, the paper, published in the international research journal Endangered Species Research, clearly demonstrates that the endemic humpbacked Mahseer is now of the brink of extinction having been replaced by non-native relatives (blue-finned Mahseer) which have been artificially bred and introduced to the river in the name of species conservation.

The paper acknowledges that many pressures are placed upon the fish of India's rivers, including pollution; poaching (using dynamite and poisons); sand and gravel extraction; low river flows due to abstraction; and India's continuing thirst for electricity, which has resulted in dozens of hydro-electric which restrict the ability of fish to migrate to their spawning grounds.

Against this backdrop of threats, this research suggests that the introduction of non-native Mahseer has acted as the catalyst which has had a catastrophic effect on the numbers of endemic Mahseer remaining in the River Cauvery and its tributaries.

Adrian Pinder said, "This research all stems from my interest as an angler, when as a boy I had read about this great fish. In 2010 I made my first trip the River Cauvery, where I realised the fish I was catching did not match the appearance of the iconic specimens I'd seen in historic photos.

"On returning to the UK, I interrogated the scientific literature and made contact with Dr Rajeev Raghavan based at St Albert's College Kochi, to ask his opinion. Comparing photographs over the internet opened a can of worms and confirmed that very little was known about all of the Mahseer species found throughout south and south East Asia.

"As large monsoonal rivers are extremely difficult to survey, and angling was banned in all protected areas in India in 2012, I started to look for alternative data sources and discovered that the Galibore Fishing Camp [one of three former angling camps in the Karnataka jungle] had kept detailed angler catch records. This not only allowed us to analyse the temporal trends in population size over the previous 15 years but also form a detailed understanding of how the type and species of Mahseer had changed over time."

In 2012 Adrian Pinder and Dr Raghavan set up the Mahseer Trust, an NGO working to protect Mahseer and its habitats. The Trust is now working with national and international stakeholders to educate and promote better informed fisheries management practices and to save the humpback Mahseer from extinction.

Adrian Pinder concluded, "The blue-finned Mahseer, is not native to the River Cauvery, yet our studies over the last two years have shown that they are now one of the most abundant fish in the river. Without a doubt, their success has been at the expense of the humpbacked Mahseer that historically occurred throughout the entire river catchment. Despite the positive intention of conservationists, this is clearly a conservation programme which has backfired. The state of confusion surrounding Mahseer taxonomy means the humpback Mahseer currently lacks a valid scientific name and could potentially go extinct before being named!"

"My current priority is on sourcing specimens of the endemic humpbacked Mahseer. If we are not already too late, obtaining DNA from this animal will allow us to name the fish and, based on our data, get it classified as 'Critically endangered' on the IUCN Red List. When you consider that the iconic Giant panda and tiger are classified as 'endangered' this puts things in context and demonstrates the urgency to act in sourcing native fish for culturing in local hatcheries."

This story is taken from Science Daily

Hubble revisits tangled NGC 6240

NGC 6240 lies 400 million light-years away in the constellation of Ophiuchus (The Serpent Holder). This galaxy has an elongated shape with branching wisps, loops and tails. This mess of gas, dust and stars bears more than a passing resemblance to a butterfly and a lobster. New research is untangling the reasons for its odd shape. 

NGC 6240 lies 400 million light-years away in the constellation of Ophiuchus (The Serpent Holder). This galaxy has an elongated shape with branching wisps, loops and tails. This mess of gas, dust and stars bears more than a passing resemblance to a butterfly and a lobster.

This bizarrely-shaped galaxy did not begin its life looking like this; its distorted appearance is a result of a galactic merger that occurred when two galaxies drifted too close to one another. This merger sparked bursts of new star formation and triggered many hot young stars to explode as supernovae. A new supernova, not visible in this image was discovered in this galaxy in 2013, named SN 2013dc.

At the center of NGC 6240 an even more interesting phenomenon is taking place. When the two galaxies came together, their central black holes did so, too. There are two supermassive black holes within this jumble, spiraling closer and closer to one another. They are currently only some 3,000 light-years apart, incredibly close given that the galaxy itself spans 300,000 light-years. This proximity secures their fate as they are now too close to escape each other and will soon form a single immense black hole.

This story is taken from Science Daily

Auroras on Mars

One day, when humans go to Mars, they might find that, occasionally, the Red Planet has green skies. NASA's MAVEN spacecraft has detected evidence of widespread auroras in Mars's northern hemisphere. Unlike Earth, Mars does not have a global magnetic field that envelops the entire planet. Instead, Mars has umbrella-shaped magnetic fields that sprout out of the ground like mushrooms, here and there, but mainly in the southern hemisphere. These umbrellas are remnants of an ancient global field that decayed billions of years ago. 

In late Dec. 2014, NASA's MAVEN spacecraft detected evidence of widespread auroras in Mars's northern hemisphere. The "Christmas Lights," as researchers called them, circled the globe and descended so close to the Martian equator that, if the lights had occurred on Earth, they would have been over places like Florida and Texas.
"It really is amazing," says Nick Schneider who leads MAVEN's Imaging Ultraviolet Spectrograph (IUVS) instrument team at the University of Colorado. "Auroras on Mars appear to be more wide ranging than we ever imagined."
This isn't the first time a spacecraft has detected auroras on Mars. Ten years ago, the European Space Agency's Mars Express found an ultraviolet glow coming from "magnetic umbrellas" in the southern hemisphere.
Unlike Earth, Mars does not have a global magnetic field that envelops the entire planet. Instead, Mars has umbrella-shaped magnetic fields that sprout out of the ground like mushrooms, here and there, but mainly in the southern hemisphere. These umbrellas are remnants of an ancient global field that decayed billions of years ago.
"The canopies of the patchwork umbrellas are where we expect to find Martian auroras," says Schneider. "But MAVEN is seeing them outside these umbrellas, so this is something new."
Auroras occur, both on Earth and Mars, when energetic particles from space rain down on the upper atmosphere. On Earth, these particles are guided toward the poles by our planet's global magnetic field. That's why auroras are seen most often around the Arctic and Antarctic. On Mars, there is no organized planetary magnetic field to guide the particles north and south -- so they can go anywhere.
"The particles seem to precipitate into the atmosphere anywhere they want," says Schneider. "Magnetic fields in the solar wind drape across Mars, even into the atmosphere, and the charged particles just follow those field lines down into the atmosphere."
According to the MAVEN data, solar particles that caused the "Christmas lights" penetrated deeply into the Martian atmosphere -- sparking auroras less than 100 km from the surface. That's lower than auroras on Earth, which range from 100 km to 500 km high.
Like Mars Express 10 years ago, MAVEN has an ultraviolet camera, so it is not seeing the same thing as human eyes. What would a human see?
Schneider isn't certain. "We're still doing the physics," he says, "but we have some educated guesses."
Although the Martian atmosphere is primarily CO₂, it does contain some oxygen--and that is key to the color of the auroras. Excited oxygen atoms in the Martian atmosphere would likely produce green light.
"A diffuse green glow seems quite possible in the Mars sky, at least when the Sun is throwing off energetic particles," says Schneider.
MAVEN arrived at Mars in Sept. 2014 on a mission to investigate a planetary mystery: Billions of years ago, Mars was blanketed by layer of air massive enough to warm the planet and allow liquid water to flow on its surface. Life could have thrived in such an environment. Today, however, only a tiny fraction of that ancient air remains, leaving Mars a desiccated wasteland.
Where did the Martian atmosphere go? A favorite theory is solar wind erosion. Because Mars no longer has a global magnetic field to protect it, solar wind might strip away material from the upper layers of the atmosphere. Watching the auroras could help MAVEN mission scientists learn more about this process.
"Plus," says Schneider, who is looking forward to future data, "I just love auroras."

This story is taken from Science Daily

Supernovas help 'clean' galaxies

Astronomers have found that the black holes located at the cores of galaxies launch fountains of charged particles, which can stir up gas throughout the galaxy and temporarily interrupt star formation. But unless something intervenes, the gas will eventually cool and start forming stars again.

Recent research, led by Michigan State University astronomers, finds that the black holes located at the cores of galaxies launch fountains of charged particles, which can stir up gas throughout the galaxy and temporarily interrupt star formation.
But unless something intervenes, the gas will eventually cool and start forming stars again.
One mega-outburst from the black hole, though, could heat the gas surrounding the galaxy enough to let supernovas take over and mop up the mess. A celestial cleaning partnership might help astronomers understand why some massive galaxies stopped forming stars billions of years ago.
"Our previous research had shown that black-hole outbursts can limit star formation in massive galaxies, but they can't completely shut it off," said team leader Mark Voit, MSU professor of physics and astronomy in the College of Natural Science. "Something else needs to keep sweeping out the gas that dying stars continually dump into a galaxy, and supernova sweeping appears to work perfectly for that."
Other members of the research team are Megan Donahue, MSU professor of physics and astronomy; Brian O'Shea, MSU associate professor of physics and astronomy; Greg Bryan, Columbia University professor of astronomy; Ming Sun, University of Alabama in Huntsville assistant professor of physics; and Norbert Werner, Stanford University research associate.

This story is taken from Science Daily

Most luminous galaxy in universe discovered

A remote galaxy shining brightly with infrared light equal to more than 300 trillion suns has been discovered using data from NASA's Wide-field Infrared Survey Explorer, or WISE. The galaxy, which belongs to a new class of objects recently discovered by WISE -- nicknamed extremely luminous infrared galaxies, or ELIRGs -- is the most luminous galaxy found to date.

"We are looking at a very intense phase of galaxy evolution," said Chao-Wei Tsai of NASA's Jet Propulsion Laboratory in Pasadena, California, lead author of a new report appearing in the 22 May issue of The Astrophysical Journal. "This dazzling light may be from the main growth spurt in the size of the galaxy's black hole"
Professor Andrew Blain, from the University of Leicester's Department of Physics and Astronomy, has been involved with WISE since its inception in 2001, and has been responsible for examining and validating the data from the WISE telescope. He is a co-author of the new report into this discovery.
The galaxy, known as WISE J224607.57-052635.0, may have a behemoth black hole at its belly, gorging itself on gas.
Supermassive black holes grow by drawing gas and matter into a disk around them. The disk heats up to beyond-sizzling temperatures of millions of degrees, blasting out high-energy, visible, ultraviolet, and X-ray light. The light is blocked by surrounding cocoons of dust. As the dust heats up, it radiates infrared light.
Immense black holes are common at the cores of galaxies, but finding one this big so far back in the cosmos is rare. Because light from the galaxy hosting the black hole has traveled 12.5 billion years to reach us, astronomers are seeing the object as it was in the past. The black hole was already billions of times the mass of our sun when our universe was only a tenth of its present age of 13.8 billion years.
"The massive black holes in ELIRGs could be gorging themselves on more matter for a longer period of time," said Professor Blain. "It's like winning a hot-dog-eating contest lasting hundreds of millions of years."
More research is needed to solve this puzzle of these dazzlingly luminous galaxies. The team has plans to better determine the masses of the central black holes. Knowing these objects' true hefts will help reveal their history, as well as that of other galaxies in this very crucial and frenzied chapter of our cosmos.
WISE has been finding hundreds of other, similar oddball galaxies from infrared images of the entire sky it took in 2010. By viewing the whole sky with more sensitivity than ever before, WISE has been able to catch rare cosmic specimens that might have been missed otherwise.
The new study reports a total of 20 new ELIRGs, including the most luminous galaxy found to date. These galaxies, which are even more luminous than the ultraluminous infrared galaxies (ULIRGs) reported before, were not found earlier because of their distance, and because dust converts their powerful visible light into an incredible outpouring of infrared light.
"We found in a related study with WISE that as many as half of the most luminous galaxies only show up well in infrared light," said Tsai.
NASA's Jet Propulsion Laboratory, Pasadena, California, manages, and operates, WISE for NASA's Science Mission Directorate. The spacecraft was put into hibernation mode in 2011 after it scanned the entire sky twice, completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects.

This story is taken from Science Daily

What our solar system looked like as a ‘toddler’

Astronomers have identified a young planetary system which may aid in understanding how our own solar system formed and developed billions of years ago.  

Using the Gemini Planet Imager (GPI) at the Gemini South telescope in Chile, the researchers identified a disc-shaped bright ring of dust around a star only slightly more massive than the sun, located 360 light years away in the Centaurus constellation. The disc is located between about 37 and 55 Astronomical Units (3.4 -- 5.1 billion miles) from its host star, which is almost the same distance as the solar system's Kuiper Belt is from the sun. The brightness of the disc, which is due to the starlight reflected by it, is also consistent with a wide range of dust compositions including the silicates and ice present in the Kuiper Belt.

The Kuiper Belt lies just beyond Neptune, and contains thousands of small icy bodies left over from the formation of the solar system more than four billion years ago. These objects range in size from specks of debris dust, all the way up to moon-sized objects like Pluto -- which used to be classified as a planet, but has now been reclassified as a dwarf planet.

The star observed in this new study is a member of the massive 10-20 million year-old Scorpius-Centaurus OB association, a region similar to that in which the sun was formed. The disc is not perfectly centred on the star, which is strong indication that it was likely sculpted by one or more unseen planets. By using models of how planets shape a debris disc, the team found that 'eccentric' versions of the giant planets in the outer solar system could explain the observed properties of the ring.

"It's almost like looking at the outer solar system when it was a toddler," said principal investigator Thayne Currie, an astronomer at the Subaru Observatory in Hawaii.

The current theory on the formation of the solar system holds that it originated within a giant molecular cloud of hydrogen, in which clumps of denser material formed. One of these clumps, rotating and collapsing under its own gravitation, formed a flattened spinning disc known as the solar nebula. The sun formed at the hot and dense centre of this disc, while the planets grew by accretion in the cooler outer regions. The Kuiper Belt is believed to be made up of the remnants of this process, so there is a possibility that once the new system develops, it may look remarkably similar to our solar system.

"To be able to directly image planetary birth environments around other stars at orbital distances comparable to the solar system is a major advancement," said Dr Nikku Madhusudhan of Cambridge's Institute of Astronomy, one of the paper's co-authors. "Our discovery of a near-twin of the Kuiper Belt provides direct evidence that the planetary birth environment of the solar system may not be uncommon."

This is the first discovery with the new cutting-edge Gemini instrument. "In just one of our many 50-second exposures we could see what previous instruments failed to see in more than 50 minutes," said Currie.

The star, going by the designation HD 115600, was the first object the research team looked at. "Over the next few years, I'm optimistic that GPI will reveal many more debris discs and young planets. Who knows what strange, new worlds we will find," Currie added

This story is taken from Science Daily

One-of-a-kind star discovered, nicknamed 'Nasty'

Astronomers have spent decades trying to determine the oddball behavior of an aging star nicknamed "Nasty 1" residing in our Milky Way galaxy. Looking at the star using NASA's Hubble Space Telescope, astronomers had expected to see a bipolar outflow of twin lobes of gas from the star. The astronomers were surprised, however, to find a pancake-shaped disk of gas encircling the star. The vast disk is nearly 1,000 times the diameter of our solar system.

First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.
But Nasty 1 doesn't look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate. Instead, Hubble revealed a pancake-shaped disk of gas encircling the star. The vast disk is nearly 2 trillion miles wide, and may have formed from an unseen companion star that snacked on the outer envelope of the newly formed Wolf-Rayet. Based on current estimates, the nebula surrounding the stars is just a few thousand years old, and as close as 3,000 light-years from Earth.
"We were excited to see this disk-like structure because it may be evidence for a Wolf-Rayet star forming from a binary interaction," said study leader Jon Mauerhan of the University of California, Berkeley. "There are very few examples in the galaxy of this process in action because this phase is short-lived, perhaps lasting only a hundred thousand years, while the timescale over which a resulting disk is visible could be only ten thousand years or less."
According to the team's scenario, a massive star evolves very quickly, and as it begins to run out of hydrogen, it swells up. Its outer hydrogen envelope becomes more loosely bound and vulnerable to gravitational stripping, or a type of stellar cannibalism, by the nearby companion star. In that process, the more compact star winds up gaining mass, and the original massive star loses its hydrogen envelope, exposing its helium core to become a Wolf-Rayet star.
Another way Wolf-Rayet stars are said to form is when a massive star ejects its own hydrogen envelope in a strong stellar wind streaming with charged particles. The binary interaction model where a companion star is present is gaining traction because astronomers realize that at least 70 percent of massive stars are members of double-star systems. Direct mass loss alone also cannot account for the number of Wolf-Rayet stars relative to other less-evolved massive stars in the galaxy.
"We're finding that it is hard to form all the Wolf-Rayet stars we observe by the traditional wind mechanism, because mass loss isn't as strong as we used to think," said Nathan Smith of the University of Arizona in Tucson, who is a co-author on the new NaSt1 paper. "Mass exchange in binary systems seems to be vital to account for Wolf-Rayet stars and the supernovae they make, and catching binary stars in this short-lived phase will help us understand this process."
But the mass-transfer process in mammoth binary systems isn't always efficient. Some of the stripped matter can spill out during the dynamical gravitational tussle between the stars, creating a disk around the binary.
"That's what we think is happening in Nasty 1," Mauerhan said. "We think there is a Wolf-Rayet star buried inside the nebula, and we think the nebula is being created by this mass-transfer process. So this type of sloppy stellar cannibalism actually makes Nasty 1 a rather fitting nickname."
The star's catalog name, NaSt1, is derived from the first two letters of each of the two astronomers who discovered it in 1963, Jason Nassau and Charles Stephenson.
Viewing the Nasty 1 system hasn't been easy. The system is so heavily cloaked in gas and dust, it blocks even Hubble's view of the stars. So Mauerhan's team cannot measure the mass of each star, the distance between them, or the amount of material spilling onto the companion star.
Previous observations of Nasty 1 have provided some information on the gas in the disk. The material, for example, is travelling about 22,000 miles per hour in the outer nebula, slower than similar stars. The comparatively slow speed indicates that the star expelled its material through a less violent event than Eta Carinae's explosive outbursts, where the gas is travelling hundreds of thousands of miles per hour.
Nasty 1 may also be shedding the material sporadically. Past studies in infrared light have shown evidence for a compact pocket of hot dust very close to the central stars. Recent observations by Mauerhan and colleagues at the University of Arizona, using the Magellan telescope at Las Campanas Observatory in Chile, have resolved a larger pocket of cooler dust that may be indirectly scattering the light from the central stars. The presence of warm dust implies that it formed very recently, perhaps in spurts, as chemically enriched material from the two stellar winds collides at different points, mixes, flows away, and cools. Sporadic changes in the wind strength or the rate the companion star strips the main star's hydrogen envelope might also explain the clumpy structure and gaps seen farther out in the disk.
To measure the hypersonic winds from each star, the astronomers turned to NASA's Chandra X-ray Observatory. The observations revealed scorching hot plasma, indicating that the winds from both stars are indeed colliding, creating high-energy shocks that glow in X-rays. These results are consistent with what astronomers have observed from other Wolf-Rayet systems.
The chaotic mass-transfer activity will end when the Wolf-Rayet star runs out of material. Eventually, the gas in the disk will dissipate, providing a clear view of the binary system.
"What evolutionary path the star will take is uncertain, but it will definitely not be boring," said Mauerhan. "Nasty 1 could evolve into another Eta Carinae-type system. To make that transformation, the mass-gaining companion star could experience a giant eruption because of some instability related to the acquiring of matter from the newly formed Wolf-Rayet. Or, the Wolf-Rayet could explode as a supernova. A stellar merger is another potential outcome, depending on the orbital evolution of the system. The future could be full of all kinds of exotic possibilities depending on whether it blows up or how long the mass transfer occurs, and how long it lives after the mass transfer ceases."
The team's results will appear May 21 in the online edition of the Monthly Notices of the Royal Astronomical Society.

This story is taken from Science Daily

Is there life out there? Distant moons may provide the answer

Researchers who have modeled planetary systems far beyond our own solar system have found that massive moons larger than Mars might be the best bet in the search for life beyond Earth.

McMaster researchers who have modelled planetary systems far beyond our own solar system have found that massive moons larger than Mars might be the best bet.
Using data from our solar system and observations of huge planets far beyond the visual range of any telescope, astrophysicists René Heller and Ralph Pudritz have shown that some moons of those planets could be habitable.
Their findings, presented in two papers in the journals Astronomy and Astrophysics and The Astrophysical Journal, suggest that some moons of exoplanets -- planets beyond our solar system -- are the right size, in the right position and have sufficient water to support life.
"We could be just a few decades from proving if there is life elsewhere," says Heller, a post-doctoral fellow at McMaster's Origins Institute who worked with Pudritz, a professor of physics and astronomy and director of the Origins Institute. "For all this time, we have been looking on other planets, when the answer could be on a moon."
Exoplanets are being counted in the thousands since the development of new, non-visual methods that allow scientists to prove their existence by measuring light patterns from sun-like stars that dim slightly as the planets pass in front of them in orbit.
Many planets outside the solar system are even more massive than Jupiter, and they orbit their Sun-like stars at an Earth-like distance, but these faraway super-Jupiters are effectively giant gas balls that cannot support life because they lack solid surfaces. Their moons, though, might have the right conditions for liquid surface water and therefore for life to emerge and evolve.
While recent research has focused on exoplanets, the McMaster authors are eager to study the moons of those giant Jupiter-like planets, which they believe to have migrated into more temperate ranges of distant stars, towing watery moons in their orbits.
Closer to home, Heller and Pudritz modelled the early life of Jupiter, revealing a pattern of ice distribution on Jupiter's moons that led them to predict the formation of moons around the super-Jupiters of other solar systems. Those moons could be twice as massive as Mars.
No moon around an exoplanet, a so-called exomoon, has been discovered as of today, but they are certainly there, Heller says. With about 4,000 exoplanets known to exist so far, and with increasing technological capabilities, an exomoon discovery is now looming on the horizon.
If these giant moons around giant planets exist, they might already be present in the available data of NASA's Kepler space telescope, or they could be detectable with the European Space Agency's upcoming PLATO space mission and European Southern Observatory's ground-based European Extremely Large Telescope.

This story is taken from Science Daily

Galaxy’s snacking habits revealed

Astronomers have caught a greedy galaxy gobbling on its neighbors and leaving crumbs of evidence about its dietary past.

Galaxies grow by churning loose gas from their surroundings into new stars, or by swallowing neighbouring galaxies whole. However, they normally leave very few traces of their cannibalistic habits.
A study published today in Monthly Notices of the Royal Astronomical Society not only reveals a spiral galaxy devouring a nearby compact dwarf galaxy, but shows evidence of its past galactic snacks in unprecedented detail.
Australian Astronomical Observatory (AAO) and Macquarie University astrophysicist, Ángel R. López-Sánchez, and his collaborators have been studying the galaxy NGC 1512 to see if its chemical story matches its physical appearance.
The team of researchers used the unique capabilities of the 3.9-metre Anglo-Australian Telescope (AAT), near Coonabarabran, New South Wales, to measure the level of chemical enrichment in the gas across the entire face of NGC 1512.
Chemical enrichment occurs when stars churn the hydrogen and helium from the Big Bang into heavier elements through nuclear reactions at their cores.
These new elements are released back into space when the stars die, enriching the surrounding gas with chemicals like oxygen, which the team measured.
"We were expecting to find fresh gas or gas enriched at the same level as that of the galaxy being consumed, but were surprised to find the gases were actually the remnants of galaxies swallowed earlier," Dr López-Sánchez said.
"The diffuse gas in the outer regions of NGC 1512 is not the pristine gas created in the Big Bang but is gas that has already been processed by previous generations of stars."
CSIRO's Australia Telescope Compact Array, a powerful 6-km diameter radio interferometer located in eastern Australia, was used to detect large amounts of cold hydrogen gas that extends way beyond the stellar disk of the spiral galaxy NGC 1512.
"The dense pockets of hydrogen gas in the outer disk of NGC 1512 accurately pin-point regions of active star formation," said CSIRO's Dr Baerbel Koribalski, a member of the research collaboration.
When this finding was examined in combination with radio and ultraviolet observations the scientists concluded that the rich gas being processed into new stars did not come from the inner regions of the galaxy either. Instead, the gas was likely absorbed by the galaxy over its lifetime as NGC 1512 accreted other, smaller galaxies around it.
Dr Tobias Westmeir, from the International Centre for Radio Astronomy Research in Perth, said that while galaxy cannibalism has been known for many years, this is the first time that it has been observed in such fine detail.
"By using observations from both ground and space based telescopes we were able to piece together a detailed history for this galaxy and better understand how interactions and mergers with other galaxies have affected its evolution and the rate at which it formed stars," he said.
The team's successful and novel approach to investigating how galaxies grow is being used in a new program to further refine the best models of galaxy evolution.
For this work the astronomers used spectroscopic data from the AAT at Siding Spring Observatory in Australia to measure the chemical distribution around the galaxies. They identified the diffuse gas around the dual galaxy system using Australian Telescope Compact Array (ATCA) radio observations. In addition, they identified regions of new star formation with data from the Galaxy Evolution Explorer (GALEX) orbiting space telescope.
"The unique combination of these data provide a very powerful tool to disentangle the nature and evolution of galaxies," said Dr López-Sánchez.
"We will observe several more galaxies using the same proven techniques to improve our understanding of the past behaviour of galaxies in the local Universe."

This story is taken from Science Daily

Dinosaurs were likely warm-blooded

Dinosaurs grew as fast as your average living mammal, according to a new research article. The article is a re-analysis of a widely publicized 2014 Science paper on dinosaur metabolism and growth that concluded dinosaurs were neither ectothermic nor endothermic -- terms popularly simplified as 'cold-blooded' and 'warm-blooded' -- but instead occupied an intermediate category. 

"The study that I re-analyzed was remarkable for its breadth -- the authors compiled an unprecedented dataset on growth and metabolism from studies of hundreds of living animals," said Dr. D'Emic, a Research Instructor in the Department of Anatomical Sciences as Stony Brook, when referring to "Evidence for mesothermy in dinosaurs."

"Upon re-analysis, it was apparent that dinosaurs weren't just somewhat like living mammals in their physiology -- they fit right within our understanding of what it means to be a 'warm-blooded' mammal," he said.

Dr. D'Emic specializes in bone microanatomy, or the study of the structure of bone on scales that are just a fraction of the width of a human hair. Based on his knowledge of how dinosaurs grew, Dr. D'Emic re-analyzed that study, which led him to the strikingly different conclusion that dinosaurs were more like mammals than reptiles in their growth and metabolism.

Dr. D'Emic re-analyzed the study from two aspects. First, the original study had scaled yearly growth rates to daily ones in order to standardize comparisons.

"This is problematic," Dr. D'Emic explains, "because many animals do not grow continuously throughout the year, generally slowing or pausing growth during colder, drier, or otherwise more stressful seasons.

"Therefore, the previous study underestimated dinosaur growth rates by failing to account for their uneven growth. Like most animals, dinosaurs slowed or paused their growth annually, as shown by rings in their bones analogous to tree rings," he explained.

He added that the growth rates were especially underestimated for larger animals and animals that live in very stressful or seasonal environments -- both of which characterize dinosaurs.

The second aspect of the re-analysis with the original study takes into account that dinosaurs should be statistically analyzed within the same group as living birds, which are also warm-blooded, because birds are descendants of Mesozoic dinosaurs.

"Separating what we commonly think of as 'dinosaurs' from birds in a statistical analysis is generally inappropriate, because birds are dinosaurs -- they're just the dinosaurs that haven't gone extinct."

He explained that re-analyzing the data with birds as dinosaurs lends more support that dinosaurs were 'warm-blooded,' not occupants of a special, intermediate metabolic category.

According to Holly Woodward, Assistant Professor in the Center for Health Sciences at Oklahoma State University, Dr. D'Emic's re-analysis is crucial to building research on the metabolism and development of dinosaurs.

"D'Emic's study reveals how important access to the data behind published results is for hypothesis testing and advancing our understanding of dinosaur growth dynamics," said Woodward.

Dr. D'Emic hopes that his study will also spur new research into when, why, and how pauses or slowdowns in growth are recorded in bones, which may have implications in the development of other species and in the study of bone diseases such as osteoporosis.

This story is taken from Science Daily

Shock Collision Inside Black Hole Jet

Astronomers have discovered for the first time a rear-end collision between two high-speed knots of ejected matter from a supermassive black hole. This discovery was made while piecing together a time-lapse movie of a plasma jet blasted from a supermassive black hole inside galaxy 3C 264, located 260 million light-years from Earth in the constellation Leo. 

The finding offers new insights into the behavior of "light-saber-like" jets that are so energized that they appear to zoom out of black holes at speeds several times the speed of light. This "superluminal" motion is an optical illusion due to the very fast real speed of the plasma, which is close to the universal maximum of the speed of light.
Such extragalactic jets are not well understood. They appear to transport energetic plasma in a confined beam from the active nucleus of the host galaxy. The new analysis suggests that shocks produced by collisions within the jet further accelerate particles and brighten the regions of colliding material.
The video of the jet was assembled with two decades' worth of NASA Hubble Space Telescope images of the elliptical galaxy NGC 3862, the sixth brightest galaxy and one of only a few active galaxies with jets seen in visible light. The jet was discovered in optical light by Hubble in 1992. NGC 3862 is in a rich cluster of galaxies known as Abell 1367, in the constellation Leo.
The jet from NGC 3862 has a string-of-pearls structure of glowing knots of material. Taking advantage of Hubble's sharp resolution and long-term optical stability, Eileen Meyer of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, matched archival Hubble images with a new, deep image taken in 2014, to better understand jet motions. Meyer was surprised to see a fast knot with an apparent speed of seven times the speed of light catch up with the end of a slower moving, but still superluminal, knot along the string.
The resulting "shock collision" caused the merging blobs to brighten significantly.
"Something like this has never been seen before in an extragalactic jet," said Meyer. As the knots continue merging they will brighten further in the coming decades. "This will allow us a very rare opportunity to see how the kinetic energy of the collision is dissipated into radiation."
It's not uncommon to see knots of material in jets ejected from gravitationally compact objects, but it is rare that motions have been observed with optical telescopes, and so far out from the black hole, thousands of light-years away. In addition to black holes, newly forming stars eject narrowly collimated streamers of gas that have a knotty structure. One theory is that material falling onto the central object is superheated and ejected along the object's spin axis. Powerful magnetic fields constrain the material into a narrow jet. If the flow of the infalling material is not smooth, blobs are ejected like a string of cannon balls rather than a steady hose-like flow.
Whatever the mechanism, the fast-moving knot will burrow its way out into intergalactic space. A knot launched later, behind the first one, may have less drag from the shoveled-out interstellar medium and catch up to the earlier knot, rear-ending it in a shock collision.
Beyond the collision, which will play out over the next few decades, this discovery marks only the second case of superluminal motion measured at hundreds to thousands of light-years from the black hole where the jet was launched. This indicates that the jets are still very, very close to the speed of light even on distances that start to rival the scale of the host galaxy. These measurements can give insights into how much energy jets carry out into their host galaxy and beyond, which is important for understanding how galaxies evolve as the universe ages.
Meyer is currently making a Hubble-image video of two more jets in the nearby universe, to look for similar fast motions. She notes that these kinds of studies are only possible because of the long operating lifetime of Hubble, which has now been looking at some of these jets for over 20 years.
Extragalactic jets have been detected at X-ray and radio wavelengths in many active galaxies powered by central black holes, but only a few have been seen in optical light. Astronomers do not yet understand why some jets are seen in visible light and others are not.
Meyer's results are being reported in the May 28 issue of the journal Nature.

This story is taken from Science Daily