Ocean acidification will severely impair coral reef growth before the end of the century if carbon dioxide emissions continue unchecked, according to new research on Australia's Great Barrier Reef led by Carnegie's Ken Caldeira and the California Academy of Sciences' Rebecca Albright.

Experimental set-up and research team at a coral reef flat study site at One Tree Island in Australia's Great Barrier Reef. The studies conducted here represent the first ocean acidification  experiment of a natural coral reef community, providing evidence that near-future ocean acidification projections severely depressed coral reef growth [Credit: Aaron Takeo Ninokawa of UC Davis]

Their work, published in Nature, represents the first ocean acidification experiment in which seawater was made artificially acidic by the addition of carbon dioxide and then allowed to flow across a natural coral reef community. The acidity of the seawater was increased to reflect end-of-century projections if carbon dioxide from greenhouse gas emissions are not abated.

Two years ago, Caldeira and Albright, then at Carnegie, published a landmark study providing evidence that ocean acidification is already slowing coral reef growth.

In that work, they made a coral reef community's seawater chemistry more alkaline -- essentially giving the reef an antacid -- and demonstrated that the coral's ability to construct its architecture was improved under these conditions. It was the first time that seawater chemistry was experimentally manipulated in a natural coral reef environment.

They once again altered seawater chemistry of reef flats surrounding One Tree Island off the coast of Australia. But this time they gave the reef heartburn, increasing acidity by adding carbon dioxide to seawater flowing over a coral reef community.

"Last time, we made the seawater less acidic, like it was 100 years ago, and this time, we added carbon dioxide to the water to make it more acidic, like it could be 100 years from now," Caldeira explained.

Experimental plume of carbon dioxide-enriched seawater and a dye tracer flowing across a coral reef flat in Australia's Great Barrier Reef. This study represents the first ocean acidification experiment on a natural coral reef community and provides evidence that near-future ocean acidification projections severely depressed coral reef growth [Credit: Aaron Takeo Ninokawa of UC Davis]

When coal, oil, or gas is burned, the resulting carbon dioxide is released into the atmosphere. It is well established that these emissions are the culprit of global climate change, the warming from which has a negative impact on coral reefs. But this atmospheric carbon is also absorbed into the ocean, where it remains for millennia.

A chemical reaction between the seawater and these soaked-up carbon emissions produces carbonic acid, which is corrosive to coral reefs, shellfish, and other marine life. Reefs are especially vulnerable to this ocean acidification, because their skeletons are constructed by accreting calcium carbonate, a process called calcification. As the surrounding water becomes more acidic, calcification becomes more difficult.

"Our findings provide strong evidence that ocean acidification caused by carbon dioxide emissions will severely slow coral reef growth in the future unless we make steep and rapid reductions in greenhouse gas emissions," said first author Albright.

Furthermore, by working in controlled areas of a natural reef community, Caldeira, Albright, and their team were able to demonstrate how acidification affects coral reefs on the ecosystem scale, not just in terms of individual organisms or species, as other studies have done.

They say this approach is crucial to understanding the full scope and complexity of ocean acidification's impact, as well as to predicting how acidification will affect the coastal communities that depend on these ecosystems.

"Coral reefs offer economic opportunities to their surrounding communities from fishing and tourism," Caldeira said. "But for me the reef is a beautiful and diverse outpouring of life that we are harming with our carbon dioxide emissions. For the denizens of the reef, there's not a moment to lose in building an energy system that doesn't dump its waste into the sky or sea."

Source: Carnegie Institution for Science [March 14, 2018]

A growing network of lakes on the Greenland ice sheet has been found to drain in a chain reaction that speeds up the flow of the ice sheet, threatening its stability.

Melting of Greenland ice sheet forms lakes that drain in summer [Credit: Timo Lieber]

Researchers from the UK, Norway, US and Sweden have used a combination of 3D computer modelling and real-world observations to show the previously unknown, yet profound dynamic consequences tied to a growing number of lakes forming on the Greenland ice sheet.

Lakes form on the surface of the Greenland ice sheet each summer as the weather warms. Many exist for weeks or months, but drain in just a few hours through more than a kilometre of ice, transferring huge quantities of water and heat to the base of the ice sheet. The affected areas include sensitive regions of the ice sheet interior where the impact on ice flow is potentially large.

Previously, it had been thought that these 'drainage events' were isolated incidents, but the new research, led by the University of Cambridge, shows that the lakes form a massive network and become increasingly interconnected as the weather warms. When one lake drains, the water quickly spreads under the ice sheet, which responds by flowing faster. The faster flow opens new fractures on the surface and these fractures act as conduits for the drainage of other lakes. This starts a chain reaction that can drain many other lakes, some as far as 80 kilometres away.

These cascading events -- including one case where 124 lakes drained in just five days -- can temporarily accelerate ice flow by as much as 400%, which makes the ice sheet less stable, and increases the rate of associated sea level rise. The results are reported in the journal Nature Communications.

The study demonstrates how forces within the ice sheet can change abruptly from one day to the next, causing solid ice to fracture suddenly. The model developed by the international team shows that lakes forming in stable areas of the ice sheet drain when fractures open in response to a high tensile shock force acting along drainage paths of water flowing beneath the ice sheet when other lakes drain far away.

Scientists abseil into large fracture produced by a drained lake on Greenland ice sheet [Credit: Samuel Doyle]

"This growing network of melt lakes, which currently extends more than 100 kilometres inland and reaches elevations as high a 2,000 metres above sea level, poses a threat for the long-term stability of the Greenland ice sheet," said lead author Dr Poul Christoffersen, from Cambridge's Scott Polar Research Institute. "This ice sheet, which covers 1.7 million square kilometres, was relatively stable 25 years ago, but now loses one billion tonnes of ice every day. This causes one millimetre of global sea level rise per year, a rate which is much faster than what was predicted only a few years ago."

The study departs from the current consensus that lakes forming at high elevations on the Greenland ice sheet have only a limited potential to influence the flow of ice sheet as climate warms. Whereas the latest report by Intergovernmental Panel on Climate Change concluded that surface meltwater, although abundant, does not impact the flow of the ice sheet, the study suggests that meltwater delivered to the base of the ice sheet through draining lakes in fact drives episodes of sustained acceleration extending much farther onto the interior of the ice sheet than previously thought.

"Transfer of water and heat from surface to the bed can escalate extremely rapidly due to a chain reaction," said Christoffersen. "In one case we found all but one of 59 observed lakes drained in a single cascading event. Most of the melt lakes drain in this dynamic way."

Although the delivery of small amounts of meltwater to the base of the ice sheet only increases the ice sheet's flow locally, the study shows that the response of the ice sheet can intensify through knock-on effects.

When a single lake drains, the ice flow temporarily accelerates along the path taken by water flowing along the bottom of the ice sheet. Lakes situated in stable basins along this path drain when the loss of friction along the bed temporarily transfers forces to the surface of the ice sheet, causing fractures to open up beneath other lakes, which then also drain.

"The transformation of forces within the ice sheet when lakes drain is sudden and dramatic," said co-author Dr Marion Bougamont, also from the Scott Polar Research Institute. "Lakes that drain in one area produce fractures that cause more lakes to drain somewhere elsewhere. It all adds up when you look at the pathways of water underneath the ice."

The study used high-resolution satellite images to confirm that fractures on the surface of the ice sheet open up when cascading lake drainage occurs. "This aspect of our work is quite worrying," said Christoffersen. "We found clear evidence of these crevasses at 1,800 metres above sea level and as far 135 kilometres inland from the ice margin. This is much farther inland than previously considered possible."

While complete loss of all ice in Greenland remains extremely unlikely this century, the highly dynamic manner in which the ice sheet responds to Earth's changing climate clearly underscores the urgent need for a global agreement that will reduce the emission of greenhouse gases.

Source: University of Cambridge [March 14, 2018]

A team led by scientists from Scripps Institution of Oceanography at the University of California San Diego and the J. Craig Venter Institute (JCVI) has demonstrated that the excess carbon dioxide added to the atmosphere through the combustion of fossil fuels interferes with the health of phytoplankton which form the base of marine food webs.

Photosynthetic plankton like these Ross Sea diatoms are key players in the global carbon cycle and form the base of marine food webs, but a new study reveals their ability to acquire iron is highly sensitive to ocean acidification [Credit: Jeff McQuaid]

Phytoplankton are microscopic plants whose growth in ocean surface waters supports ocean food webs and global marine fisheries. They are also key agents in the long-term removal of carbon dioxide (CO2)

As reported in the journal Nature, the team shows that a mechanism widely used by phytoplankton to acquire iron has a requirement for carbonate ions. Rising concentrations of atmospheric CO2 are acidifying the ocean and decreasing carbonate, and the team shows how this loss of carbonate affects the ability of phytoplankton to obtain enough of the nutrient iron for growth. Ocean acidification is poised to decrease the concentration of sea surface carbonate ions 50 percent by the end of this century.

The study, "Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms," was funded by the National Science Foundation, the Gordon and Betty Moore Foundation, and the U.S. Department of Energy. It reveals an unexpected twist to the theory of how iron controls the growth of phytoplankton. By showing how the loss of seawater carbonate hampers the ability of phytoplankton to grab onto iron, the authors show a direct connection between the effects of ocean acidification and the health of phytoplankton at the base of the marine food chain.

"Ultimately our study reveals the possibility of a 'feedback mechanism' operating in parts of the ocean where iron already constrains the growth of phytoplankton," said Jeff McQuaid, lead author of the study who made the discoveries as a PhD student at Scripps Oceanography. "In these regions, high concentrations of atmospheric CO2 could decrease phytoplankton growth, restricting the ability of the ocean to absorb CO2 and thus leading to ever higher concentrations of CO2 accumulating in the atmosphere."

"Studies investigating the effects of high CO2 on phytoplankton growth have shown mixed results to date. In some cases, certain phytoplankton seem to benefit from high CO2," added Andrew E. Allen, a biologist with a joint appointment at Scripps and JCVI who is senior author and initiator of the study. "Most of these studies, however, have been conducted under high-iron conditions. Our study uncovers a widespread cellular mechanism that suggests high CO2 might be particularly problematic for phytoplankton growth in low-iron regions of the ocean."

Lead author Jeff McQuaid watches an array of pumps designed to test the effects of high CO2 on Ross Sea phytoplankton in Antarctica. Several recent studies have noted that high CO2 has a negative effect on phytoplankton growing in low iron environments like the Southern Ocean [Credit: A.E. Allen]

One consequence of acidification is a nearly one-for-one reduction in the concentration of carbonate ions for every molecule of CO2 that dissolves in the ocean. The concentration of atmospheric CO2 is predicted to double by the end of this century; thus, the concentration of carbonate ions at the surface of the ocean will nearly halve by the year 2100. While the negative influence of acidification on corals and shellfish is known, this is the first study to reveal a mechanism that affects life which forms the base of most marine food webs.

This study revises a key concept in oceanography that the growth of phytoplankton in vast areas of the ocean is regulated by the concentration of iron. In ocean regions that are high in dissolved nutrients like nitrogen and phosphorous, iron limitation results in low numbers of phytoplankton relative to amounts of available nutrients. Addition of iron to these areas causes phytoplankton, particularly diatoms, to grow. In the largest of these regions, the Southern Ocean, concentrations of available iron are below one trillionth of a gram per liter, approaching the limit supporting life.

Marine scientists have spent decades investigating how phytoplankton are able to grab such low concentrations of iron from seawater and internalize it.

"Understanding the mechanism of iron uptake is critical to develop meaningful predictions on how phytoplankton may respond to future ocean conditions, but this understanding has been elusive," said Adam Kustka, a trace metal physiologist and project collaborator from Rutgers University.

Clues began to emerge in 2008, when Allen discovered several iron-responsive genes in diatoms that had no known function. That same year, McQuaid was traveling around East Antarctica assisting in a survey of plankton in the Southern Ocean. DNA analysis of those samples revealed that one of Allen's iron genes was not only present in every sample of seawater, but every major phytoplankton group in the Southern Ocean seemed to have a copy.

"This gene, called ISIP2A, was one of the most abundantly transcribed genes in low-iron Southern Ocean, suggesting it had a really important role in the environment," said Allen.

Andrew Allen prepares a sample of phytoplankton filtered from the Ross Sea. In several of the Antarctic marine samples,  phytotransferrin was among the most abundant proteins detected [Credit: E. Bertrand]

Earlier studies suggested a transferrin-like protein, called phytotransferrin, was at work in the marine environment, but ISIP2A looked nothing like transferrin. It took the development of an entirely new discipline, synthetic biology, to help prove the team's hypothesis that ISIP2A was a type of transferrin. Synthetic biology is the fusion of biology and engineering, and in collaboration with scientists with the Venter Institute, the team developed methods to insert synthetic DNA into a marine diatom. The scientists deleted ISIP2A and replaced it with a synthetic gene for human transferrin, demonstrating that ISIP2A was a type of transferrin.

The team then initiated a study to investigate the evolutionary relationships of transferrin and phytotransferrin. To their surprise, the proteins were functional analogs whose ancient origins extend to the pre-Cambrian period of Earth history, predating the appearance of modern plants and animals.

"The appearance of phytotransferrin some 700 million years ago is consistent with a time in Earth's history marked by massive changes in ocean chemistry, and this ancient evolutionary history helps explain why no one has connected ISIP2A and transferrin," said Miroslav Oborník, a molecular evolutionary biologist from the University of South Bohemia and co-author on the paper.

In transferrin, iron and carbonate bind simultaneously, and neither can bind in the absence of the other. Such synergistic binding is unique among biological interactions. The research team hypothesized that diatom phytotransferrin uses a similar mechanism and that, as a result, reductions in carbonate ion could lead to reduced phytoplankton growth rates.

Using a number of biochemical methods, the researchers were able to independently manipulate pH along with the concentrations of iron and carbonate ion. As they pumped in increasing concentrations of CO2, the team showed that the ability of their diatom to grab onto iron decreased proportionally with the concentration of carbonate ions.

"Since carbonate and iron have to bind simultaneously, as carbonate concentrations drop, phytotransferrin is able to 'see' less iron," said McQuaid. "The total amount of iron isn't changing - rather the ability to grab onto it changes, and this ultimately influences the growth rate."

Source: University of California - San Diego [March 14, 2018]

Up to half of plant and animal species in the world's most naturally rich areas, such as the Amazon and the Galapagos, could face local extinction by the turn of the century due to climate change if carbon emissions continue to rise unchecked.

East Africa elephants [Credit: WWF]

Even if the Paris Climate Agreement 2°C target is met, these places could lose 25% of their species according to a landmark new study by the University of East Anglia (UK), the James Cook University (Australia), and WWF.

Published today in the journal Climatic Change and just ahead of Earth Hour, the world's largest environmental event, researchers examined the impact of climate change on nearly 80,000 plant and animal species in 35 of the world's most diverse and naturally wildlife-rich areas.

It explores a number of different climate change futures - from a no-emissions-cuts case in which global mean temperatures rise by 4.5°C , to a 2°C rise, the upper limit for temperature in the Paris Agreement . Each area was chosen for its uniqueness and the variety of plants and animals found there.

The report finds that the Miombo Woodlands, home to African wild dogs, south-west Australia and the Amazon-Guianas are projected to be some the most affected areas. If there was a 4.5°C global mean temperature rise, the climates in these areas are projected to become unsuitable for many the plants and animals that currently live there meaning:

• - Up to 90% of amphibians, 86% of birds and 80% of mammals could potentially become locally extinct in the Miombo Woodlands, Southern Africa
• - The Amazon could lose 69% of its plant species
• - In south-west Australia 89% of amphibians could become locally extinct
• - 60% of all species are at risk of localised extinction in Madagascar
• - The Fynbos in the Western Cape Region of South Africa, which is experiencing a drought that has led to water shortages in Cape Town, could face localised extinctions of a third of its species, many of which are unique to that region.
• 
  

Verreaux's sifaka in Madagascar [Credit: WWF]

As well as this, increased average temperatures and more erratic rainfall could become be the "new normal" according to the report - with significantly less rainfall in the Mediterranean, Madagascar and the Cerrado-Pantanal in Argentina. Potential effects include;

• - Pressure on the water supplies of African elephants - who need to drink 150-300 litres of water a day
• - 96% of the breeding grounds of Sundarbans tigers could become submerged by sea-level rise
• - Comparatively fewer male marine turtles due to temperature-induced sex assignment of eggs.

If species can move freely to new locations then the risk of local extinction decreases from around 25% to 20% with a 2°C global mean temperature rise. If species cannot they may not be able to survive. Most plants, amphibians and reptiles, such as orchids, frogs and lizards cannot move quickly enough keep up with these climatic changes.

Lead researcher Prof Rachel Warren from the Tyndall Centre for Climate Change Research at UEA said: "Our research quantifies the benefits of limiting global warming to 2°C for species in 35 of the world's most wildlife-rich areas. We studied 80,000 species of plants, mammals, birds, reptiles and amphibians and found that 50% of species could be lost from these areas without climate policy. However, if global warming is limited to 2°C above pre-industrial levels, this could be reduced to 25%. Limiting warming to within 1.5°C was not explored, but would be expected to protect even more wildlife."

Overall the research shows that the best way to protect against species loss is to keep global temperature rise as low as possible.

The Paris Agreement pledges to reduce the expected level of global warming from 4.5°C to around 3°C, which reduces the impacts, but we see even greater improvements at 2°C; and it is likely that limiting temperature rise to 1.5°C would protect more wildlife.

A giant panda from the Yangtze River area [Credit: WWF]

This is why on 24 March millions of people across the world will come together for Earth Hour, to show their commitment to reducing global emissions and protecting people and wildlife from the impacts of climate change. The event also sends a clear message to business and government that there is a global will to change this trajectory.

Tanya Steele, CEO of WWF commented: "Within our children's lifetime, places like the Amazon and Galapagos Islands could become unrecognisable, with half the species that live there wiped out by human-caused climate change. Around the world, beautiful iconic animals like Amur tigers or Javan rhinos are at risk of disappearing, as well as tens of thousands plants and smaller creatures that are the foundation of all life on earth. That is why this Earth Hour we are asking everyone to make a promise for the planet and make the everyday changes to protect our planet."

The models used in this research come from the Wallace Initiative, a near decade long partnership between the Tyndall Centre at UEA, eResearch at James Cook University, the Global Biodiversity Information Facility and WWF.

Dr Jeff Price, coordinator of the Wallace Initiative and also from UEA, said: "This research provides a view on the differing spatial impacts of climate change on biodiversity. It shows the benefits of combining citizen science with the research and resources of highly-ranked universities to assist an NGO with their conservation activities."

Source: University of East Anglia [March 13, 2018]

The temperature and salinity of seawater are key drivers for the global ocean circulation system. Warm and saline water transported poleward cools at the surface when it reaches high latitudes and becomes denser and subsequently sinks into the deep ocean. This process is called convection. At depth, the water is circulated back towards the equator drawing new water masses behind it. Deep convection occurs only in a few regions around the globe, including the Irminger Sea and the Labrador Sea near Greenland. But what happens if additional freshwater, for example from melting glaciers, enters this system? Model calculations predict a possible weakening of deep convection, but so far this could not be confirmed by direct observations.

The Irminger Sea seen from the research vessel MARIA S. MERIAN. It is one of the few regions in the world where deep convection occurs. The process is a key component global ocean circulation system [Credit: Arne Bendinger/GEOMAR]

By using long-term observations, scientists from the GEOMAR Helmholtz Centre for Ocean Research Kiel have now shown that freshwater has already impacted convection in the last decade. The results have been published in the international journal Nature Climate Change.

The study is based on the analysis of data obtained from moored observatories in the Labrador Sea and the Irminger See and from oceanographic floats. In addition, satellite observations of the ocean surface and atmospheric data were included. "For various periods over the last 60 years, we have been able to combine important processes: atmospheric variability, such as the North Atlantic Oscillation, water and air temperatures, the occurrence of fresh surface water, and the duration of convection," explains Dr. Marilena Oltmanns from GEOMAR, lead author of the study.

The evaluation of the data show a clear correlation between the sea surface temperatures in the Irminger Sea in summer, the amount of surface freshwater in this region and the atmospheric conditions and onset of convection in the following winter. "In case that warm summers with increased surface freshwater occur within extended warm periods, the ocean loses less heat in the following winter. As a result, the fresh surface layer that formed in summer remains stable for a longer time resulting in a delayed onset of convection", says Dr. Oltmanns.

Typically, freshwater is mixed down by convection each winter. If convection sets in later, a higher proportion of freshwater remains near the surface and combines with freshwater from the following spring. "This effect could add up in future warm periods and thus weaken the convection - especially with regard to the rising temperatures and increased melting", the oceanographer concludes.

The study reveals the importance of long-term observations at key locations of the global ocean circulation. Dr. Johannes Karstensen, co-author of the study, emphasizes: "Only through long-term measurement programmes the connection between the complex oceanic and atmospheric processes can be identified. Thus, the continuous funding of personnel, ships and material is important--which in this case was provided through the support of individual projects of the German Science Foundation DFG, the German Federal Ministry of Education and Research."

Source: Helmholtz Centre for Ocean Research Kiel [March 13, 2018]

Poaching and habitat loss have reduced forest elephant populations in Central Africa by 63 percent since 2001. This widespread killing poses dire consequences not only for the species itself but also for the region's forests, a new Duke University study finds.

Populations of forests elephants, which play key roles in maintaining forest habitat, have declined 63 percent in Central Africa since 2001. Without intervention to prevent further losses, 96 percent of the region's forests could undergo major change [Credit: John Poulsen, Duke University]

"Without intervention to stop poaching, as much as 96 percent of Central Africa's forests will undergo major changes in tree-species composition and structure as local populations of elephants are extirpated and surviving populations are crowded into ever-smaller forest remnants," said John Poulsen, assistant professor of tropical ecology at Duke's Nicholas School of the Environment.

These changes will occur because elephants are ecological engineers that help create and maintain forest habitat by dispersing seeds, recycling and spreading nutrients, and clearing understories, Poulsen explained.

"Because they are very large animals, they can eat fruits and disperse seeds too big for other animals to digest. And because they are highly mobile, they help disperse these seeds far and wide through their dung," he said.

In the elephants' absence, scores of tree species may be left without a means of long-distance seed dispersal, which is essential for forest structure and colonization. Trees whose seeds are dispersed by smaller animals could fill the void, dramatically altering forest composition.

Fewer elephants will also mean a more limited distribution of the nutrients contained in their dung.

"Many of Central Africa's forests are nitrogen limited. Elephants help compensate by moving nutrients, especially nitrogen, across the landscape as they defecate. If populations continue to shrink, this nitrogen will be concentrated in smaller and smaller areas, limiting future tree growth elsewhere," Poulsen said.

Understory density will also be affected.

"Elephants have a large effect on forests by eating or trampling slow-growing plants and opening the understory, allowing more light in and reducing competition for water and nutrients," Poulsen said. "These changes alter the recruitment regimes of tree species -- favoring some and not others."

He and his colleagues published their peer-reviewed study in the journal Conservation Biology.

To conduct their analysis, they reviewed 158 previous studies on forest elephant behaviors and their cascading ecological impacts. By cross-referencing these impacts with data on local elephant populations, forest tree-species composition and structure, nutrient availability, and understory growth in existing Central African forests -- both protected and unprotected ones alike -- Poulsen and his team determined that up to 96 percent of all forests in the region were susceptible to dramatic changes if elephant populations shrank or disappeared.

"Stopping poaching is an urgently needed first step to mitigating these effects," he said, "but it will not be easy. Long-term conservation will require land-use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging."

Source: Duke University [March 12, 2018]

For decades, the world's leading scientists have observed the phenomena known as El Nino and La Nina. Both significantly impact the global climate and both pose a puzzle to scientists since they're not completely understood. Now, a new study helps clear up some of the obscurity surrounding El Nino and La Nina, which together are called the El Nino Southern Oscillation (ENSO). This new study examines ENSO frequency asymmetry during different phases of the Pacific Decadal Oscillation (PDO), a climate pattern in the North Pacific.

This is an artistic representation of the observed Pacific Decadal Oscillation spatial pattern in the North Pacific and its significant association with El Nino/La Nina occurrence, which is also evident in most CMIP5 models [Credit: Advances in Atmospheric Sciences]

Previous studies have investigated the relationship between ENSO and PDO but none have examined if the warm (positive) and cool (negative) phases of PDO in the North Pacific influence the frequency of ENSO events in the tropical Pacific. "For the first time," said Prof. ZHENG Fei from the Institute of Atmospheric Physics, Chinese Academy of Sciences, and coauthor on the study, "we quantitatively demonstrated that El Nino is 300 percent more (58 percent less) frequent than La Nina in positive (negative) PDO phases."

To arrive at their findings, the researchers used observational data and the output of 19 models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). "By adopting the observations and CMIP5 climate model simulations," said Zheng, "we had an opportunity to explore how PDO modulates the occurrence of ENSO." This type of exploration meets an increasing need today, which is for scientists to better understand the mechanisms that affect the occurrence of ENSO.

While all the answers surrounding these events aren't known, the effects of ENSO are well understood. When sea surface temperatures are warmer or cooler than normal in the equatorial Pacific Ocean, weather patterns around the world are impacted. Everything from pressure systems to wind and precipitation can be influenced by ENSO, including the supply of water in a region since it can cause moisture extremes.

ZHENG and his group at the Chinese Academy of Sciences have been focusing on ENSO for more than 10 years now. The results from their own recent studies showing that ENSO prediction highly relies on off-equatorial physical processes motivated this latest study exploring the effects of PDO, according to Zheng, who believes that this approach is necessary to understand ENSO better. "Our study suggests that more attention should be paid to the processes outside the equator when attempting ENSO predictions to provide reliable warning of climate extreme events and avoid potential economic loss," he said.

The findings were published in Advances of Atmospheric Sciences.

Source: Institute of Atmosperic Physics, Chinese Academy of Sciences [March 07, 2018]

High technology is being deployed to uncover long-forgotten irrigation systems and other features concealed in landscapes that farmers developed hundreds of years ago to nurture their land.

Geographically defined products such as Parma ham help to assess the social and cultural value of a landscape [Credit: Pxhere/1165797, licensed under CC0 Creative Commons]

By studying landscapes of the past and how they're used today, scientists can draw on Europe's cultural heritage to help tackle challenges such as climate change and rural exodus.

Professor José María Martín Civantos, of the department of medieval history at the University of Granada, Spain, sees lessons for today in the cultural history of mountainous Mediterranean landscapes in Spain, Italy and Albania, which he and his collaborators studied in a project called MEMOLA.

Centuries ago, farmers and rural communities in southern Europe adapted to become experts in water, soils, crops and animal management to keep their lands fertile and productive. These practices helped rural communities withstand periodic stresses such as drought and food scarcity.

‘In the race for modernisation, intensification of production and competitiveness, we have neglected, forgotten or even (discarded) all that knowledge, all that heritage, all that richness,’ said Prof. Martín Civantos.

The researchers conducted surveys using a laser scanning technique called LIDAR and created 3D maps of sophisticated irrigation systems dating back more than a thousand years. These were used for channelling water from areas of surplus to areas of demand.

The team combined the maps with a range of other techniques and disciplines, including ethnography, hydrology, archaeology, agronomy, botany, and soil science, to understand the co-evolution of the landscape with the people who live there.

They even worked with high school students who used the hugely popular video game Minecraft to create interactive 3D worlds demonstrating culturally important irrigation systems.

Sowing water

Among the principles MEMOLA researchers identified was channelling water from mountain peaks to areas where it can be used to recharge depleted aquifers. ‘Sowing’ water in good times and ‘harvesting’ it when it is most needed, is a sophisticated technique for dealing with environmental stress.


‘This is a most modern concept for the management of water in a river basin, but it is something that has been done in some communities for centuries,’ said Prof. Martín Civantos.

Ideas such as these can contribute materially to policies which improve sustainability and aid in mitigating the effects of climate change.

He sees room for further research to revive interest in the cultural history of the Sierra Nevada mountain range in Spain as well as in northern Italy and Sicily. Some features that fell into disuse fairly recently could benefit from restoration while other, older features not only provide lessons, but can also contribute to contemporary life through culture, education or tourism.

‘It is really worthwhile to preserve and promote (this cultural history), to ensure best practices in our relationship with the environment, but also in our social relationships, in the way that our natural resources and territories are managed,’ he said.

It's not only climate change that can threaten Europe's landscapes - rural exodus and urbanisation can also challenge their preservation. But scientists are finding new ways of gathering information about the significant aspects of a particular landscape.

Researchers on the HERCULES project tapped in to social media and other tools to populate incomplete data sets, piecing together a more complete picture of how people in specific communities value particular landscapes – not only for ecological value, but also cultural value.

Using photo sharing platforms such as Flickr and the now defunct Panoramio, they were able to assess the density of contributions of photographs of a particular landscape, providing an indicator of the social value being attached to it.

‘Among the new methods were online mapping tools, where local people were able to show us places and parts of the landscape that were important to them for particular reasons,’ said Dr Tobias Plieninger, now of the University of Göttingen and University of Kassel in Germany, but who coordinated the project while at the University of Copenhagen, Denmark.

The researchers were also able to use the number of traditional food products or geographically defined products as another indicator of the cultural and social value that people attach to particular regions.

‘Something such as Parma ham can be an indicator of the cultural importance that an agricultural landscape can have,’ Dr Plieninger said. ‘Combining these with farm-level and other indicators can be used to identify and characterise different types of cultural landscapes in Europe.’

Sustainable development

This is a crucial step in assessing how to preserve European landscapes of significant cultural, historical and archaeological value at local, national and pan-European scales. It can also contribute to policies in areas such as agriculture or biodiversity as part of an integrated landscape management approach, which can contribute to achieving the UN's sustainable development goals by taking into account the multiple uses of landscapes.

‘Landscapes do matter – they host multiple societal values,’ Dr Plieninger said. ‘And these cultural values have a broad set of meanings. Some of these are more tangible, such as a site being for recreational use. Others provide links to cultural heritage, or even nature conservation, agriculture or forestry.’

HERCULES put its findings into action through a knowledge hub for good landscape practice, capitalising on the crowdsourcing tools developed to provide a toolkit for landscape management. By combining the fruits of its multidisciplinary approach, this takes into account the natural environment, the human processes that co-produced it, and the human wellbeing that depends on it.

Author: Rex Merrifield | Source: Horizon Magazine, Horizon: The EU Research & Innovation Magazine [March 06, 2018]

A major study into an ancient climate change event that affected a significant percentage of Earth's oceans has brought into sharp focus a lesser-known villain in global warming: oxygen depletion.

Credit: wildestanimal/Getty Images

The study, just published in the prestigious Proceedings of the National Academy of Sciences, examined a past period of global warming around 94 million years ago, when oceans became de-oxygenated.

This famous period in Earth's geological history, known as an Oceanic Anoxic Event (OAE), was more severe and on much longer timescales than the current changes. But it has given the scientists studying this period an extreme case-study to help understand how the oceans are effected by high atmospheric CO2 emissions.

Research Fellow Dr. Matthew Clarkson and Professor Claudine Stirling, of the Chemistry Department at The University of Otago (New Zealand), applied a revolutionary new tool to examine how the oceans responded to climate change in the past.

Professor Tim Lenton, of the University of Exeter, developed a model to interpret the new data whilst visiting the University of Otago. The model enabled the team to quantify how much carbon was injected into the atmosphere to trigger each of the two phases of the oceanic anoxic event.

"What this tells us is how vulnerable the Earth system is to large emissions of carbon dioxide to the atmosphere – whether from volcanic processes or human activities," Professor Lenton said. "One long-term consequence of warming the climate is to deoxygenate the ocean – with severe consequences for marine life."

The scientists used a novel technique that measures naturally-occurring uranium isotopes from ancient sediments, which could be used to estimate ocean oxygen content, thus identifying an ancient geochemical record of how much of the ocean was deoxygenated these many millions of years ago. They applied this technique to geological sediments that were once deposited in the ocean and are today preserved on land at the white cliffs in the South of England, and also in Italy.

They found that the likely driving mechanism of this anoxic, or deoxygenation, event was nutrient run-off, itself driven by high CO2 emissions and warmer temperatures; and that when CO2 emissions reduced, along with nutrient levels, global oceans recovered for a period.

Professor Stirling says the ability to predict what could happen, thanks to the combination of uranium isotopes and modelling, is a significant breakthrough.

"It helps us understand the missing piece of the puzzle, what happens to oxygen levels in our oceans when they are effected by global warning. CO2 levels in the atmosphere were much higher than they are now, so we won't see this level of change for a long time, but we will see the same sequence of events" she says.

Areas of ocean deoxygenation, known as "dead zones", can be found currently in a number of oceans around the world such in the eastern parts of the tropical Pacific, Atlantic and Indian Oceans. The "dead zones" occur because it is harder to dissolve oxygen in water when the oceans are warm, and also more oxygen is used up during the breakdown of biological material. In these zones there are high amounts of nutrients, leading to high amounts of organic matter, and hence more oxygen is used up. Some of these nutrients come from run-off in rivers, and some from upwelling of deep ocean water.

Dr. Clarkson explains the importance of the study: "From studies like this scientists can describe the link between increased global temperatures and increased global weathering rates, which drive a high input of nutrients into the ocean.

"This leads to high primary productivity in the oceans and eventually the loss of oxygen as the organic matter degrades by aerobic respiration. This process is similar to eutrophication, which happens in many lakes and rivers due to the input of fertilisers, but in this case it occurred on a global oceanic scale," says Dr. Clarkson.

"Through comparison to other geochemical data, and simulating the event with a new biogeochemical model, we present strong evidence for the nutrient input hypothesis as a driving mechanism for anoxia (deoxygenation)."

The event was most likely caused by increased CO2 emissions from volcanic activity, over hundreds of thousands of years. Marine fauna suffered heavily during this event, although it is not considered one the major mass extinctions of Earth's history.

"Another significance of this study is that we are able to put a new estimate on the area of the seafloor that became anoxic, at around 8-15 percent, compared to only 0.3 percent in the modern ocean.

"Importantly, a number of completely independent studies, with very different methods, are finding consistent results for the Oceanic Anoxic Event. This helps gives scientists much greater confidence when trying to understand the legacy of modern human activity."

This particular Oceanic Anoxic Event was also thought to have lasted for around 1 million years, but the new data also shows for the first time that the global oceans briefly recovered in the middle of the event, before returning to widespread anoxia again.

"This recovery was the result of declining CO2 emissions from volcanic sources, and the removal of carbon from the atmosphere by weathering and the burial of organic matter. These two processes are known to help regulate the global climate, acting as negative feedback mechanisms similar to a thermostat, but they take a very long time."

Source: University of Exeter [March 06, 2018]

For nearly two decades, scientists have noted dramatic changes in arctic tundra habitat. Ankle-high grasses and sedges have given way to a sea of woody shrubs growing to waist- or neck-deep heights. This shrubification of the tundra challenges animals like caribou that are adapted to low-stature arctic vegetation.

Microscopic imaging reveals the pattern of annual rings in shrub stems, which the researchers used to determine that shrub growth is controlled by temperatures in June, the first month of the brief arctic growing season [Credit: Daniel Ackerman]

Pinpointing a cause has been difficult. However, new UMN research published in Environmental Research Letters found that regardless of soil fertility or rainfall amounts, the single variable that was by far the strongest determinant of how much a shrub grew in a given year was the temperature in June. A warmer June means faster shrub growth.

"It was a surprising result," said Daniel Ackerman, a Ph.D. candidate in the Department of Ecology, Evolution and Behavior in the College of Biological Sciences who led the UMN research team that traveled to the tundra in northern Alaska to investigate why the habitat was changing. "Other variables, including temperatures during the rest of the growing season in July and August, barely had an impact on shrub growth."

University of Minnesota researcher Daniel Ackerman wades through neck-deep shrubs in northern Alaska to collect samples [Credit: Meera Subramanian]

Like trees at lower latitudes, shrubs in the tundra form a concentric ring around their stem each growing season. Ackerman's team used these annual rings to their advantage, collecting hundreds of shrub stems across a range of soil conditions. They measured the size of each annual ring in their samples--no easy task given that these shrubs can contain more than 50 rings in a stem with the diameter of a pencil.

After painstakingly measuring 20,000 individual shrub rings through a microscope, the team created records of historic shrub growth from across northern Alaska. Next, before coming to their findings, the team compared these growth records to climate observations, examining factors like precipitation, temperature, and solar radiation.

"Our new understanding of the link between June temperature and shrub growth means that we can expect shrubification to continue throughout northern Alaska," said Ackerman. "With this study and others like it, we're beginning to understand the causes of shrubification. However, we still have a ways to go in predicting its effects. It seems like larger shrubs will benefit some animals, like moose and ptarmigan, while other animals, like caribou, could be harmed."

Source: University of Minnesota [March 06, 2018]

For the past 40 years, the total number of Adélie Penguins, one of the most common on the Antarctic Peninsula, has been steadily declining -- or so biologists have thought. A new study led by researchers from the Woods Hole Oceanographic Institution (WHOI), however, is providing new insights on of this species of penguin. In a paper published in the journal Scientific Reports, the scientists announced the discovery of a previously unknown "supercolony" of more than 1,500,000 Adélie Penguins in the Danger Islands, a chain of remote, rocky islands off of the Antarctic Peninsula's northern tip.

The researchers found that the Danger Islands have 751,527 pairs of Adélie penguins--more than the rest of the entire  Antarctic Peninsula region combined. They include the third and fourth largest Adélie penguin colonies in the world  [Credit: Michael Polito, Louisiana State University]

"Until recently, the Danger Islands weren't known to be an important penguin habitat," says co-PI Heather Lynch, Associate Professor of Ecology & Evolution at Stony Brook University. These supercolonies have gone undetected for decades, she notes, partly because of the remoteness of the islands themselves, and partly the treacherous waters that surround them. Even in the austral summer, the nearby ocean is filled with thick sea ice, making it extremely difficult to access.

Yet in 2014, Lynch and colleague Mathew Schwaller from NASA discovered telltale guano stains in existing NASA satellite imagery of the islands, hinting at a mysteriously large number of penguins. To find out for sure, Lynch teamed with Stephanie Jenouvrier, a seabird ecologist at WHOI, Mike Polito at LSU and Tom Hart at Oxford University to arrange an expedition to the islands with the goal of counting the birds firsthand.

When the group arrived in December 2015, they found hundreds of thousands of birds nesting in the rocky soil, and immediately started to tally up their numbers by hand. The team also used a modified commercial quadcopter drone to take images of the entire island from above.

Earlier reports based on satellite data suggested that the Danger Islands could be home to several penguin "supercolonies."  However, heavy pack ice is common around the Danger Islands, even in austral summer, making difficult to access this area  to conduct a comprehensive survey [Credit: Rachael Herman, Louisiana State University, © Stony Brook University]

"The drone lets you fly in a grid over the island, taking pictures once per second. You can then stitch them together into a huge collage that shows the entire landmass in 2D and 3D," says co-PI Hanumant Singh, Professor of Mechanical and Industrial Engineering at Northeastern University, who developed the drone's imaging and navigation system. Once those massive images are available, he says, his team can use neural network software to analyze them, pixel by pixel, searching for penguin nests autonomously.

The accuracy that the drone enabled was key, says Michael Polito, coauthor from Louisiana State University and a guest investigator at WHOI. The number of penguins in the Danger Islands could provide insight not just on penguin population dynamics, but also on the effects of changing temperature and sea ice on the region's ecology.

"Not only do the Danger Islands hold the largest population of Adélie penguins on the Antarctic Peninsula, they also appear to have not suffered the population declines found along the western side of Antarctic Peninsula that are associated with recent climate change," says Polito.


Being able to get an accurate count of the birds in this supercolony offers a valuable benchmark for future change, as well, notes Jenouvrier. "The population of Adélies on the east side of the Antarctic Peninsula is different from what we see on the west side, for example. We want to understand why. Is it linked to the extended sea ice condition over there? Food availability? That's something we don't know," she says.

It will also lend valuable evidence for supporting proposed Marine Protected Areas (MPAs) near the Antarctic Peninsula, adds Mercedes Santos, from the Instituto Antártico Argentino (who is not affiliated with this study but is one of the authors of the MPA proposal) with the Commission for the Conservation of the Antarctic Marine Living Resources, an international panel that decides on the placement of MPAs. "Given that MPA proposals are based in the best available science, this publication helps to highlight the importance of this area for protection," she says.

Source: Woods Hole Oceanographic Institution [March 02, 2018]

Spring is arriving earlier, but how much earlier? The answer depends on where on Earth you find yourself, according to a study led by the University of California, Davis.

Spring is springing earlier at northern latitudes, such as in Greenland, than it is at lower latitudes [Credit: Eric Post/UC Davis]

The study, published in Nature’s online journal Scientific Reports, found that for every 10 degrees north from the equator you move, spring arrives about four days earlier than it did a decade ago. This northward increase in the rate of springtime advance is roughly three times greater than what previous studies have indicated.

For example, at southern to mid latitudes such as Los Angeles, New Orleans or Dallas, the study suggests spring might be arriving a mere one day earlier than it did a decade ago. Farther north, in Seattle, Chicago or Washington D.C., it might be arriving four days earlier. And if you live in the Arctic, it might be arriving as much as 16 days earlier.

“This study verifies observations that have been circulating in the scientific community and popular reports for years,” said lead author Eric Post, a fellow of the John Muir Institute and polar ecologist in the UC Davis Department of Wildlife, Fish and Conservation Biology. “Yes, spring is arriving earlier, and the Arctic is experiencing greater advances of spring than lower latitudes. What our study adds is that we connect such differences to more rapid springtime warming at higher latitudes.”

Cottongrass blows in the Greenland wind [Credit: Eric Post/UC Davis]

Accelerated spring 
                                         
The study is the most comprehensive analysis to date of springtime advance, or phenology, as you move north with latitude. Such signs include birds migrating, flowers blooming, amphibians calling and the emergence of leaves.

The researchers analyzed 743 previously published estimates of the rate of springtime advance from studies spanning 86 years across the Northern Hemisphere, as well as rates of springtime warming over the same range of years and latitude. Even after accounting for differences in the length, time and location of those previous studies, the relationship between earlier springs and higher latitudes was strong.

A nest holding the eggs of northern wheatears rests on branches in Greenland. These birds are long-distance migrants, overwintering in sub-Saharan Africa and breeding in the Arctic. With earlier springs happening faster at higher but not lower latitudes, the birds may find themselves "late for dinner" if the insects they flew north to feast upon have already emerged [Credit: Eric Post/UC Davis]

Unknowns for birds, migratory species

Springtime provides important biological cues for many plant and animal species, and it is unclear how an accelerated spring could play out for these species across the planet.

The study notes that impacts to migratory birds are a potential concern. Many birds move from tropical zones to higher latitudes, such as the Arctic, to breed.

“Whatever cues they’re relying on to move northward for spring might not be reliable predictors of food availability once they get there if the onset of spring at these higher latitudes is amplified by future warming,” Post said. “The springtime emergence of the plants and insects they’ll eat when they arrive is happening faster than the changes at the lower latitudes those birds are departing from.”

Author: Kat Kerlin | Source: UC Davis [March 02, 2018]

In a study spanning twelve years, researchers from Kyoto University, and with Ryukoku University have developed a method to calculate the fluctuating stability of a natural ecological community in Maizuru Bay.

Kyoto researchers spend a decade tracking changes in fish communities [Credit: Kyoto University/Reiji Masuda]

Their findings, published in Nature, provide insight into and new methodologies for ecological and population research.

How biological communities are maintained is a big question in ecology. While current studies suggest community stability can be influenced by species diversity and interactions, these ideas have almost never been tested in natural ecosystems.

"Previous research focused on issues such as the birth-death process, like when a predator eats prey, and inside a somewhat controlled environment," explains lead author Masayuki Ushio. "Even then, it is challenging to measure the rapidly changing interactions of multiple species in nature."

A key reason for this is that natural ecosystems do not typically exhibit equilibrium dynamics, and so the most viable way to measure changes is to keep constant records of organisms in a particular location.

Fortunately, Reiji Masuda of the Field Science Education and Research Center has been doing just that in Maizuru Bay. For twelve years, he has been diving into the waters every two weeks, recording the populations of all the fish and jellyfish he encountered.

"I initially started these observations in 2002 to see what organisms lived in the area and how they change over time," Masuda describes. "When I showed my work to Masayuki Ushio and Michio Kondoh at Ryukoku University, they suggested we work together and build a model to chart the interactions between the organisms."

The model was constructed by applying a time series analysis tool -- empirical dynamic modeling, or EDM -- to the Maizuru Bay data set. EDM is designed to analyze the fluctuating dynamics of a natural ecosystem, without setting any defined equations. This was then further developed to analyze the ecosystem's dynamic stability.

What they found was a complex web of interactions, where organisms have positive or negative effects on each other, and more importantly, showed that short-term changes in the network influences overall community dynamics.

"We could even see that things such as diversity, species interactions, and stability itself fluctuate throughout time," says Ushio. "This suggests that these properties are key to understanding the mechanisms underlying the functioning of natural ecosystems."

The team's methods can be readily applied to other fields, from neuroscience, microbiology, to economics.

"This is by far one of the most comprehensive looks at how much an ecosystem can change in the natural world," concludes team leader Michio Kondoh. "I was surprised to see that community stability, which is often assumed to be constant, is in fact changing over time. The robustness of ecological communities depends on timing and seasons."

Source: Kyoto University [March 02, 2018]

A new study has confirmed that the world's last breeding population of leopards in Cambodia is at immediate risk of extinction, having declined an astonishing 72% during a five-year period. The population represents the last remaining leopards in all of eastern Indochina -- a region incorporating Cambodia, Laos and Vietnam.

One of Cambodia's last leopards [Credit: Susan Weller, Panthera]

The report was published this month in the Royal Society Open Science journal by Oxford University's Wildlife Conservation Research Unit (WildCRU), Panthera -- the global wild cat conservation organization, WWF-Cambodia, the American Museum of Natural History, and the Forestry Administration of the Ministry of Agriculture Forestry and Fisheries of Cambodia.

Carried out in Cambodia's Eastern Plains Landscape, the study revealed one of the lowest concentrations of leopards ever reported in Asia, with a density of one individual per 100 square kilometers. Increased poaching, especially indiscriminate snaring for the illegal wildlife trade and bushmeat, is to blame for the dramatic decline.

Panthera Southeast Asia Leopard Program Coordinator and study coauthor, Dr. Jan Kamler, stated, "This population represents the last glimmer of hope for leopards in all of Laos, Cambodia, and Vietnam -- a subspecies on the verge of blinking out. No longer can we, as an international community, overlook conservation of this unique wild cat."

Kamler continued, "As the world gathers to celebrate World Wildlife Day this Saturday, we must band together in action, not just in words, to curb the epidemic of poaching facing this gorgeous big cat and others around the globe."

Professor David Macdonald, Director of the WildCRU and also a co-author, added "Leopards are a monument to opportunism, adapting to habitats from desert to urban jungle, but their adaptability risks a deadly complacency: people think -- "oh, leopards will be fine." They won't! Almost everywhere they are doing worse than people thought, and our findings show that in SE Asia they are heading for catastrophe."

In addition to these somber results, scientists were shocked to discover that the primary prey of leopards was banteng -- a wild species of cattle weighing up to 800 kilograms (1,760 pounds). In particular, male leopards targeted this large ungulate, making this the only known leopard population in the world whose main prey weighed greater than 500 kg (1,100 pounds), more than five times the leopard's mass.

Scientists believe the Indochinese leopards' new choice of prey was triggered by the extirpation of tigers from the region in 2009, which created a predatory void for the opportunistic and highly adaptable species.

Prompted by the study's findings, Panthera and WildCRU are working with local and national collaborators to increase effective law enforcement and monitoring of this region, which will include the use of Panthera PoacherCams, and strengthen environmental laws to develop strictly protected conservation zones and increased fines for poachers.

Historically found throughout all of Southeast Asia, the Indochinese leopard has lost 95% of its range and is likely to be classified as Critically Endangered by IUCN later this year. A separate study recently authored by WildCRU, Panthera and partners estimates just over 1,000 breeding adult Indochinese leopards remain in all of Southeast Asia. However, just 20-30 reproductive individuals remain in eastern Cambodia, representing the last hope for the leopard's future in eastern Indochina.

Poaching for bushmeat and the illegal wildlife trade, habitat loss, prey decline due to bushmeat poaching, and conflict with people are to blame, creating a deadly cocktail of threats facing leopards in Asia, and around the globe.

WildCRU scientist and lead author, Susana Rostro-Garcia, stated, "Much of the snaring in Cambodia, and across Southeast Asia, is driven by the rising demand for bushmeat. Wild landscapes are covered with thousands of snares set to catch wild pig and deer to supply bushmeat markets. Unfortunately, these snares also negatively impact many other species, with leopards and other wildlife often caught as by catch, and their valuable parts removed and sold to illegal wildlife traders."

In particular, as tiger numbers plummet due to poaching pressure, leopard skins and other body parts are increasingly coveted for use as status symbols and in traditional Asian medicines sold through the illegal wildlife trade.

Source: Panthera [March 01, 2018]

Rainforest loss is fuelling a tsunami of tropical species extinctions. However, not all is doom and gloom. A new study, conducted in the Brazilian Amazon, suggests that ecological cataclysms prompted by the fragmentation of the forest can be reverted by the regeneration of secondary forests, offering a beacon of hope for tropical forest biodiversity across the world.

Credit: Mark Moffett/ Minden Pictures/National Geographic Stock

The international team of researchers found that species strongly associated with primary forest were heavily depleted after 15 years of man-made disruption including the burning and clearing of forest stands,

However, 30 years down the line, and with the regeneration of secondary regrowth, many of the species that had abandoned the area had made a comeback.

"If you compare the time periods, it is apparent that taking a long-term view is paramount to uncovering the complexity of biodiversity in human-modified landscapes," said senior researcher Dr. Christoph Meyer, lecturer in global ecology and conservation at the University of Salford.

The study, published in Nature: Scientific Reports, measured the impacts of forest break-up of 50 species of bat (approx. 6,000 animals).

Bats comprise roughly one fifth of all mammal species and display wide variation in foraging behaviour and habitat use, making them an excellent model group for the research.

"The responses exhibited by bats offer important insights into the responses of other taxonomic groups." says Ricardo Rocha, lead author of the study from the University of Lisbon.

"The recovery that we have documented mirrors the patterns observed for beetle and bird communities within the Amazon.

"These parallel trends reinforce the idea that the benefits of forest regeneration are widespread, and suggest that habitat restoration can ameliorate some of the harm inflicted by humans on tropical wildlife", he adds.

The results of the current study contrast with the catastrophic faunal declines observed during a similar time window in rodent communities in the 'forest islands' of the Chiew Larn reservoir in Thailand.

"The recovery observed at the Amazon was mostly due to the recolonization of previously deforested areas and forest fragments by old-growth specialist bats. This recolonization is likely attributable to an increased diversity and abundance of food resources in areas now occupied by secondary forest, fulfilling the energetic requirements of a larger set of species", explains Rocha.

However, the short-term nature of most studies has substantially impaired the capacity of researchers to properly capture the intricate time-related complexities associated with the effects of forest fragmentation on wildlife.

Source: University of Salford [February 28, 2018]

More than 70 percent of the global King penguin population, currently forming colonies in Crozet, Kerguelen and Marion sub-Antarctic islands, may be nothing more than a memory in a matter of decades, as global warming will soon force the birds to move south, or disappear. This is the conclusion of a study published in the journal Nature Climate Change and performed by an international team of researchers.

More than 70 percent of the global King penguin population may be nothing more than a memory in a matter of decades,  as global warming will soon force the birds to move south, or disappear [Credit: Robin Cristofari]

"The main issue is that there is only a handful of islands in the Southern Ocean and not all of them are suitable to sustain large breeding colonies" says Robin Cristofari, first author of the study, from the Institut Pluridisciplinaire Hubert Curien (IPHC/CNRS/University of Strasbourg) and the Centre Scientifique de Monaco (CSM).

King penguins are in fact picky animals: in order to form a colony where they can mate, lay eggs and rear chicks over a year, they need tolerable temperature all year round, no winter sea ice around the island, and smooth beach of sand or pebbles. But, above all, they need an abundant and reliable source of food close by to feed their chicks. For millennia, this seabird has relied on the Antarctic Polar Front, an upwelling front in the Southern Ocean concentrating enormous amounts of fish on a relatively small area.

Yet, due to climate change, this area is drifting south, away from the islands where most King penguins currently live. Parents are then forced to swim farther to find food, while their progeny is waiting, fasting longer and longer on the shore. This study predicts that, for most colonies, the length of the parents' trips to get food will soon exceed the resistance to starvation of their offspring, leading to massive King penguin crashes in population size, or, hopefully, relocation.

King penguins are picky animals [Credit: Celine LeBohec]

Using the information hidden away in the penguin's genome, the research team has reconstructed the changes in the worldwide King penguin population throughout the last 50,000 years, and discovered that past climatic changes, causing shifts in marine currents, sea-ice distribution and Antarctic Polar Front location, have always been linked to critical episodes for the King penguins. However, hope is not lost yet: King penguins have already survived such crises several times (the last time was 20 thousand years ago), and they may be particularly good at it.

"Extremely low values in indices of genetic differentiation told us that all colonies are connected by a continuous exchange of individuals," says Emiliano Trucchi formerly at the University of Vienna and now at the University of Ferrara, one of the coordinator of the study. "In other words, King penguins seem to be able to move around quite a lot to find the safest breeding locations when things turn grim."

But there is a major difference this time: for the first time in the history of penguins, human activities are leading to rapid and/or irreversible changes in the Earth system, and remote areas are no exception. In addition to the strongest impact of climate change in Polar Regions, Southern Ocean is now subject to industrial fishing, and penguins may soon have a very hard time fighting for their food.

Penguins form colonies in Crozet, Kerguelen and Marion sub-Antarctic islands [Credit: Celine LeBohec]

"There are still some islands further south where King penguins may retreat," notes Celine Le Bohec (IPHC/CNRS/University of Strasbourg and CSM), leader of the programme 137 of the French Polar Institut Paul-Emile Victor within which the study was initiated, "but the competition for breeding sites and for food will be harsh, especially with the other penguin species like the Chinstrap, Gentoo or Adelie penguins, even without the fisheries. It is difficult to predict the outcome, but there will surely be losses on the way. If we want to save anything, proactive and efficient conservation efforts but, above all, coordinated global action against global warming should start now."

Source: University of Vienna [February 26, 2018]