Constantine Alexander's blog

New study shows predators affect the carbon cycle

Credit: Constantine Alexander

A new study shows that the predator-prey relationship can affect the flow of carbon through an ecosystem. This previously unmeasured influence on the environment may offer a new way of looking at biodiversity management and carbon storage for climate change.

The study, conducted by researchers at the Yale School of Forestry & Environmental Studies, comes out this week in the Proceedings of the National Academy of Sciences. It looks at the relationship between grasshoppers and spiders—herbivores and predators in the study's food chain—and how it affects the movement of carbon through a grassland ecosystem. Carbon, the basic building block of all organic tissue, moves through the food chain at varying speeds depending on whether it's being consumed or being stored in the bodies of plants. However, this pathway is seldom looked at in terms of specific animal responses like fear from predation.

"We're discovering that predators are having important effects on shaping the make-up of ecosystems," says Dr. Oswald Schmitz, professor of ecology and one of the co-authors of the study. "But we've not really spent a lot of time measuring how that translates into other functions like nutrient cycling and recycling."

The researchers manipulated the food chains of grassland ecosystem to see how the levels of carbon would change over time. Dr. Schmitz and his team created several controlled ecosystems: some that contained only native grasses and herbs, others that had plants and an herbivore grasshopper, and some others that had plants and herbivores along with a carnivore spider species—all three tiers of the food chain. In addition, a form of traceable carbon dioxide was injected into sample cages covered with Plexiglas, which allowed the team to track the carbon levels by periodically taking leaf, root, and dead animal samples.

The study found that the presence of spiders drove up the rate of carbon uptake by the plants by about 1.4 times more than when just grasshoppers were present and by 1.2 more times than when no animals were present. It was also revealed that the pattern of carbon storage in the plants changed when both herbivores and carnivores were present. The grasshoppers apparently were afraid of being eaten by the spiders and consumed less plant matter when the predators were around. The grasshoppers also shifted towards eating more herbs instead of grass under fearful scenarios.

At the same time, the grasses stored more carbon in their roots in a response to being disturbed at low levels when both herbivores and carnivores were present. In cases where only herbivores were present, the plants stored less carbon overall, likely due to the more intense eating habits of the herbivores that put pressure on plants to reduce their storage and breathe out carbon more. These stress impacts, then, caused both the plants and the herbivores to change their behaviors and change the composition of their local environment.

This has significance for biodiversity conservation and ecosystem management. Although the study was carried out on a small scale, it could inform practices done in much larger areas. Places such as the Alaskan wilderness, for example, are home to animals that have the same predator-and-prey dynamics that drive the carbon cycle, and so protecting lands and storing carbon could be linked at the same time. Appreciating the role of predators is also important currently, given that top predators are declining at rates faster than that of many other species in global trends of biodiversity loss.

"It's going to force some thinking about the vital roles of animals in regulating carbon," concludes Dr. Schmitz, pointing to the fact that the UN's body of scientific experts who study climate change don't consider these multiplier effects in their models. "People are arguing for a paradigm change."

Contact: Oswald Schmitz
203-432-5110
Yale School of Forestry & Environmental Studies

Pesticides significantly reduce biodiversity in aquatic environments

Current pesticide risk assessment falls short of protecting biodiversity

Common Bluetail (Ischnura senegalensis). Photo: André Künzelmann/UFZ (Place: Banaue/Phillippines)

The pesticides, many of which are currently used in Europe and Australia, are responsible for reducing the regional diversity of invertebrates in streams and rivers by up to 42 percent, researchers report in the Proceedings of the US Academy of Sciences (PNAS). Mikhail A. Beketov and Matthias Liess from the Helmholtz Centre for Environmental Research (UFZ) in Leipzig, together with Ben Kefford from the University of Technology, Sydney and Ralf B. Schäfer from the Institute for Environmental Sciences Landau, analysed the impact of pesticides, such as insecticides and fungicides, on the regional biodiversity of invertebrates in flowing waters using data from Germany, France and Victoria in Australia. The authors of the now-published study state that this is the first ever study which has investigated the effects of pesticides on regional biodiversity.

Pesticides, for example those used in agriculture, are among the most-investigated and regulated groups of pollutants. However, until now it was not known whether, or to which extent, and at what concentrations their use causes a reduction in biodiversity in aquatic environments. The researchers investigated these questions and compared the numbers of species in different regions: in the Hildesheimer Boerde near Braunschweig, in southern Victoria in Australia and in Brittany in France.

In both Europe and Australia, the researchers were able to demonstrate considerable losses in the regional biodiversity of aquatic insects and other freshwater invertebrates. A difference in biodiversity of 42 percent was found between non-contaminated and strongly-contaminated areas in Europe; in Australia, a decrease of 27 percent was demonstrated.

The researchers also discovered that the overall decrease in biodiversity is primarily due to the disappearance of several groups of species that are especially susceptible to pesticides. These mainly include representatives of the stoneflies, mayflies, caddisflies, and dragonflies and are important members of the food chain right up to fish and birds. Biological diversity in such aquatic environments can only be sustained by them because they ensure a regular exchange between surface and ground water, thus functioning as an indicator of water quality.

Protection concepts fall short of requirements

One worrying result from the study is that the impact of pesticides on these tiny creatures is already catastrophic at concentrations which are considered protective by current European regulation. The authors point out that the use of pesticides is an important driver for biodiversity loss and that legally-permitted maximum concentrations do not adequately protect the biodiversity of invertebrates in flowing waters. New concepts linking ecology with ecotoxicology are therefore urgently needed. "The current practice of risk assessment is like driving blind on the motorway", cautions the ecotoxicologist Matthias Liess. To date, the approval of pesticides has primarily been based on experimental work carried out in laboratories and artificial ecosystems. To be able to assess the ecological impact of such chemical substances properly, existing concepts need to be validated by investigations in real environments as soon as possible. "The latest results show that the aim of the UN Convention on Biological Diversity to slow down the decline in the number of species by 2020 is jeopardized. Pesticides will always have an impact on ecosystems, no matter how rigid protection concepts are, but realistic considerations regarding the level of protection required for the various ecosystems can only be made if validated assessment concepts are implemented." The threat to biodiversity from pesticides has obviously been underestimated in the past.

Citation: M.A. Beketov, B.J. Kefford, R.B. Schäfer, and M. Liess (2013): "Pesticides reduce regional biodiversity of stream invertebrates". PNAS, Early Edition. 17 June 2013, DOI: 10.1073/pnas.1305618110

Contact: Tilo Arnhold
49-341-235-1635
Helmholtz Association of German Research Centres

Submarine springs reveal how coral reefs respond to ocean acidification

Calcifying corals can grow under low pH conditions, although their carbonate skeletons are not dense and are more vulnerable to physical erosion. (Photo courtesy of A. Paytan)

Ocean acidification due to rising carbon dioxide levels will reduce the density of coral skeletons, making coral reefs more vulnerable to disruption and erosion, according to a new study of corals growing where submarine springs naturally lower the pH of seawater.

The study, led by researchers at the University of California, Santa Cruz, and published in the Proceedings of the National Academy of Sciences (PNAS), is the first to show that corals are not able to fully acclimate to low pH conditions in nature.

"People have seen similar effects in laboratory experiments," said coauthor Adina Paytan, a research scientist in the Institute of Marine Sciences at UC Santa Cruz. "We looked in places where the corals are exposed to low pH for their entire life span. The good news is that they don't just die. They are able to grow and calcify, but they are not producing robust structures."

With atmospheric carbon dioxide rising steadily, the oceans are absorbing more carbon dioxide, which lowers the pH of the surface waters. Ocean acidification refers to changes in seawater chemistry that move it closer to the acidic range of the pH scale, although seawater is not expected to become literally acidic. Paytan's team studied coral reefs along the Caribbean coastline of Mexico's Yucatan Peninsula where submarine springs lower the pH of the surrounding seawater in a localized, natural setting. The effect is similar to the widespread ocean acidification that is occurring as the oceans absorb increasing amounts of carbon dioxide from the atmosphere.

Led by first author Elizabeth Crook, a graduate student in Paytan's lab, the researchers deployed instruments to monitor seawater chemistry around the springs and removed skeletal cores from colonies of Porites astreoides, an important Caribbean reef-building coral. They performed CT scans of the core samples to measure their densities and determine annual calcification rates in the laboratory of coauthor Anne Cohen at Woods Hole Oceanographic Institution.

The results showed that coral calcification rates decrease significantly along a natural gradient in seawater pH. Ocean acidification lowers the concentration of carbonate ions in seawater, making it more difficult for corals to build their calcium carbonate skeletons.

"Carbonate ions are the building blocks they need to grow their skeletons. When the pH is lower the corals have to use more energy to accumulate these carbonate building blocks internally. As a result, the calcification rate is lower and they lay down less dense skeletons," Paytan said.

The reduced density of the coral skeletons makes them more vulnerable to mechanical erosion during storms, organisms that bore into corals, and parrotfish, which sometimes feed on corals. This could lead to a weakening of the reef framework and subsequent degradation of the complex coral reef ecosystem.

"There are likely to be major shifts in reef species and some loss of coral cover, but if ocean acidification is the only impact there won't be total destruction," Paytan said. "We need to protect corals from other stressors, such as pollution and overfishing. If we can control those, the impact of ocean acidification might not be as bad."

In addition to Crook, Cohen, and Paytan, the coauthors of the paper include Mario Rebolledo-Vieyra and Laura Hernandez of the Centro de Investigacion Cientifica de Yucatan. This research was funded by the National Science Foundation and UC-MEXUS.

Contact: Tim Stephens
831-459-2495
University of California - Santa Cruz

Study identifies travel choices for a smaller carbon footprint

Planes, trains, or automobiles: what's the most climate-friendly way to travel? A new study by researchers from IIASA and CICERO brings better estimates of how much personal travel impacts the climate.

The study, published in the journal Environmental Science and Technology by researchers at IIASA and Center for International Climate and Environmental Research (CICERO) calculates the climate impact for passenger trips of 500-1000 km—typical distances for business or holiday trips. It shows that while air travel continues to have the biggest climate impact per distance travelled, the choices that people make about how they drive or take public transport make a big difference in how much they contribute to climate change.

"Traveling alone in a large car can be as bad for the climate as flying, but driving with three in a small car could have an equally low impact as a train ride," says IIASA's Jens Borken-Kleefeld. A 1000 km trip alone in a big car could emit as much as 250 kg of carbon dioxide (CO2), the researchers calculate, while a train trip or carpooling in a small car could emit as little as 50 kg of CO2 for each traveler.

Air travel has by far the biggest impact on climate per distance traveled, because it can lead to contrails and formation of cirrus clouds that have a strong climate impact, as well as ozone. These mechanisms have a strong effect on the climate, but cause warming over much shorter periods of time than CO2.

The study focused on the short-lived greenhouse gases and aerosols emitted by both ground transportation and airplanes. In addition, the researchers accounted for vehicle occupancy and efficiency, based on real-world emissions data from cars, buses, trains, and airplanes in Europe.

"These components have not been regulated in the Kyoto Protocol," says Terje Berntsen, climate researcher at CICERO. "This means they risk being overlooked when comparing the climate impact from different travel choices."

Previous work and publicly available carbon footprint calculators estimate only averages for the whole transport system, at best. That means that they can miss big differences in climate impact that come from other pollutants, personal choices, and local mitigation measures.

Technologies to control air pollutant emissions from cars, buses, power plants, and trains effectively minimizes their climate impact, the study also shows—benefiting not just air quality but also climate change mitigation efforts. The researchers say that mitigation efforts should concentrate on improving fuel efficiency and developing low-carbon fuels.

While this is also important for aircraft, they say, more needs to be done to avoid the contrail and cirrus clouds. For people wanting to minimize their climate impact, Borken-Kleefeld says, "Try to avoid flying, driving alone, and driving big cars. Instead, when you can, choose the train, bus, or carpool with 2 to 3 people."

Citation: Borken-Kleefeld, Jens, Jan Fuglestvedt, and Terje Berntsen, 2013. Mode, load, and specific climate impact from passenger trips. Environmental Science and Technology. doi: 10.1021/es4003713

Contact: Katherine Leitzell
43-223-680-7316
International Institute for Applied Systems Analysis

IIASA is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Its findings provide valuable options to policy makers to shape the future of our changing world. IIASA is independent and funded by scientific institutions in Africa, the Americas, Asia, and Europe. 

 

EU LIFE+ project produces new river restoration guide

The LIFE+ Information and Communication project RESTORE has published a new guide to river restoration called Rivers by Design. The guide is aimed at planners, developers, architects and landscape architects and seeks to show them how to maximise the benefits of river restoration in development projects.

The guide explains the context and need for river restoration, illustrating how well-planned river restoration can increase ecological quality, reduce flood risk and create social and economic benefits. It explains to the target audience the crucial role they can play in delivering such projects to meet the needs of people and the environment.

The new publication provides guidance and step-by-step practical advice on planning river restoration projects to make sure sustainable development is achieved, maximising ecological, social and economic benefits. A large section of the guide presents examples of successful river restoration projects from Munich to Milton Keynes to inspire practitioners in their own planning.

RESTORE is a networking project to support river restoration practices across Europe.

A step-by-step guide for planners, developers, architects and landscape architects on how to maximise the benefits of river restoration in development projects.

Download Rivers by Design

UCLA climate study predicts dramatic loss in Southern California snowfall

By midcentury, snowfall on Los Angeles–area mountains will be 30 to 40 percent less than it was at the end of the 20th century, according to a UCLA study released today and led by UCLA climate expert Alex Hall.

The projected snow loss, a result of climate change, could get even worse by the end of the 21st century, depending on how the world reacts. Sustained action to reduce global greenhouse gas emissions could keep annual average snowfall levels steady after mid-century, but if emissions continue unabated, the study predicts that snowfall in Southern California mountains will be two-thirds less by the year 2100 than it was in the years leading up to 2000.

"Climate change has become inevitable, and we're going to lose a substantial amount of snow by midcentury," said Hall, a professor in UCLA's Department of Atmospheric and Oceanic Sciences and UCLA's Institute of the Environment and Sustainability. "But our choices matter. By the end of the century, there will be stark differences in how much snowfall remains, depending on whether we begin to mitigate greenhouse gas emissions."

"This science is clear and compelling: Los Angeles must begin today to prepare for climate change," said Los Angeles Mayor Antonio Villaraigosa. "We invested in this study and created the AdaptLA framework to craft innovative solutions and preserve our quality of life for the next generation of Angelenos."

Less snowfall in general and a complete loss of snow at some lower elevations doesn't just have implications for snow enthusiasts who enjoy skiing and sledding in the local mountains; it also could mean sizeable economic losses for snow-dependent businesses and communities. Less snow could also mean changes in the seasonal timing of local water resources, greater difficulty controlling floods, and damage to mountain and river ecosystems.

The impact to actual snow on the ground may be even greater because the researchers quantified snowfall but not snow melt, said Hall, whose previous research found the region will warm 4 to 5 degrees by midcentury. By then, researchers estimate, the snowpack could melt an average of 16 days sooner than it did in 2000. "We won't reach the 32-degree threshold for snow as often, so a greater percentage of precipitation will fall as rain instead of snow, particularly at lower elevations," Hall said. "Increased flooding is possible from the more frequent rains, and springtime runoff from melting snowpack will happen sooner."

"As a California resident, I spend my winters snowboarding in mountains throughout our amazing state," said Jeremy Jones, founder of Protect Our Winters, an environmental nonprofit composed of winter sports enthusiasts. "It breaks my heart to see America's great natural resources harmed by climate change. We must, immediately, begin to reduce greenhouse gas emissions. There is no choice."

The UCLA study, "Mid- and End-of-Century Snowfall in the Los Angeles Region," is the most detailed research yet examining how climate change will affect snowfall in the Southern California mountains. The report was produced by UCLA with funding from the city of Los Angeles, and in partnership with the Los Angeles Regional Collaborative for Climate Action and Sustainability at UCLA's Institute of the Environment and Sustainability. The complete report, maps and graphics are available online at C-CHANGE.LA/snowfall, including a password-protected media site.

The study examined snowfall in the San Gabriel Mountains, San Bernardino Mountains, San Emigdio/Tehachapi Mountains and San Jacinto Mountains. The research team scaled down low-resolution global climate models to create high-resolution models with data specific to towns such as Lake Arrowhead, Big Bear, Wrightwood and Idyllwild. Hall's team included UCLA researchers Fengpeng Sun and Scott Capps, graduate student Daniel Walton and research associate Katharine Davis Reich.

The researchers used baseline snowfall amounts from 1981 to 2000 and predicted snow amounts for midcentury (2041 to 2060) and the end of the century (2081 to 2100) under a "business as usual" scenario, in which greenhouse gas emissions increase unchecked, and a "mitigation" scenario, in which the world significantly reduces emissions. By the end of the century, the contrast between the scenarios would be dramatic. In the mitigation scenario, midcentury snow levels would be 31 percent lower than baseline, but would remain relatively steady at only 33 percent below baseline by the end of the century.

In the business-as-usual scenario, 42 percent of the snow is expected to disappear by mid-century before dwindling dramatically to a 67 percent loss of snow by the end of the century.

"The mountains won't receive nearly as much snow as they used to, and the snow they do get will not last as long," Hall said.

The snowfall study is the second part of UCLA's ongoing research project, "Climate Change in the Los Angeles Region." Through the Los Angeles Regional Collaborative for Climate Action and Sustainability, the city of Los Angeles obtained a grant from the U.S. Department of Energy to study and share climate research, with $484,166 for UCLA's climate-change studies. Additional funding came from the National Science Foundation. Future studies will cover other elements of climate change including precipitation, Santa Ana winds, soil moisture and streamflow.

The complete study, "Mid- and End-of-Century Snowfall in the Los Angeles Region," along with interactive maps and ways to get involved, is available online.

• The Los Angeles Regional Collaborative for Climate Action and Sustainability is a regional network developing the science and strategies to address climate change. Founded by the city of Los Angeles and Los Angeles County, LARC brings together leadership from government, the business community, academia, labor, and environmental and community groups to encourage greater coordination and cooperation at the local and regional levels. The goals are to share information, foster partnerships, develop system-wide strategies to address climate change, and promote a green economy. The collaborative is housed at the UCLA Institute of the Environment and Sustainability and governed by the LARC Steering Committee.
• C-CHANGE.LA serves as a clearinghouse for information about climate change and its impacts on Southern California. In 2012, C-CHANGE.LA will publish the groundbreaking studies included in the project "Climate Change in the Los Angeles Region" and provide the public with the tools to understand the scientific research and a variety of options to get involved in efforts to mitigate and adapt to climate change. C-CHANGE.LA is hosted by LARC and published by Climate Resolve, a project of Community Partners.
• UCLA is California's largest university, with an enrollment of more than 40,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer 337 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Six alumni and six faculty have been awarded the Nobel Prize.

Contact: Alison Hewitt
310-206-5461
University of California - Los Angeles

Study of oceans' past raises worries about their future

Data from end of the last ice age illuminate the precarious nature of global ocean chemistry

The ocean the Titanic sailed through just over 100 years ago was very different from the one we swim in today. Global warming is increasing ocean temperatures and harming marine food webs. Nitrogen run-off from fertilizers is causing coastal dead zones. A McGill-led international research team has now completed the first global study of changes that occurred in a crucial component of ocean chemistry, the nitrogen cycle, at the end of the last ice age. The results of their study confirm that oceans are good at balancing the nitrogen cycle on a global scale. But the data also shows that it is a slow process that may take many centuries, or even millennia, raising worries about the effects of the scale and speed of current changes in the ocean.

"For the first time we can quantify how oceans responded to slow, natural climate warming as the world emerged from the last ice age," says Prof. Eric Galbraith from McGill University's Department of Earth and Oceanic Sciences, who led the study. "And what is clear is that there is a strong climate sensitivity in the ocean nitrogen cycle."

The nitrogen cycle is a key component of the global ocean metabolism. Like the proteins that are essential to human health, nitrogen is crucial to the health of oceans. And just as proteins are carried by the blood and circulate through the body, the nitrogen in the ocean is kept in balance by marine bacteria through a complicated cycle that keeps the ocean healthy. The phytoplankton (microscopic organisms at the base of the food chain) 'fix' nitrogen in the shallow, sunlit waters of the ocean, and then as they die and sink, nitrogen is eliminated (a process known as 'denitrification') in dark, oxygen-poor pockets of the ocean depths.

Using sediment gathered from the ocean floor in different areas of the world, the researchers were able to confirm that as the ice sheets started melting and the climate warmed up at the end of the last ice age, 18,000 years ago, the marine nitrogen cycle started to accelerate. The ocean had stabilized itself in its new, warmer state, in which the overall nitrogen cycle was running faster, by about 8,000 years ago. Given the current dramatic rate of change in the ocean nitrogen cycle the researchers are not sure how long it will take for marine ecosystems to adapt.

"We are changing the planet in ways we are not even aware of," says Galbraith. "You wouldn't think that putting carbon dioxide into the atmosphere would change the amount of nitrogen available to fish in the ocean, but it clearly does. It is important to realize just how interconnected everything is."

Citation: Galbraith, Eric D.; Kienast, Markus; "The acceleration of oceanic denitrification during deglacial warming". Nature Geoscience; DOI: 10.1038/ngeo1832

Contact: Katherine Gombay
514-398-2189
McGill University

From Botswanan big cats to Surrey house cats

Scientists who designed GPS tracking collars to study hunting cheetahs in Botswana have miniaturised them to track 50 domestic cats in a Surrey village for a BBC programme. The BBC also deployed cat-cams which were turned on by the collar's activity sensor when the cat was moving. 'The Secret Life of The Cat' is broadcast on BBC Two Horizon on Thursday June 13th 2013 at 21:00.

In a first study of its kind the wanderings of our feline friends were recorded, revealing how far they roamed and what they got up to once they leave their owners behind. The team were concerned that cats were known to pop through the cat-flaps of neighbouring houses to steal food so they used the GPS to tell when the cats were indoors and switched off the cat-cams.

Professor Alan Wilson, from the Royal Veterinary College, University of London and his team are currently studying the cheetah in research funded by the Engineering and Physical Sciences Research Council (EPSRC), Biotechnology and Biological Sciences Research Council (BBSRC), and Defence Advanced Research Projects Agency (DARPA).

Their innovative tracking collars, which use GPS and motion sensors, have recorded hunting cheetahs at a top speed of 58mph as well as the first data on the animal's acceleration and manoeuvres. The results are published in the journal, 'Nature' on Thursday June 13th 2013.

Professor Wilson said: "If we understand an animal's speed and manoeuvrability we will be able to see how managing habitats will have an impact on predators and hunting."

Back in the UK the team used their expertise to design the technology for the study on domestic cats for BBC Two's Horizon programme. They designed the protocol, programmed the collars, and analysed the data of the domestic puss.

Professor Wilson said; "Our motivation for getting involved in the programme is to showcase scientific research methods to the public and demonstrate science is cool. It's an excellent large-scale deployment opportunity for our tracking collars and the analysis tools used for our studies on wild animals. Ironically we knew more about cheetahs than domestic cats, until this study."

Reference: Locomotion dynamics of hunting in wild cheetahs; A M Wilson, J. C. Lowe, K. Roskilly, P. E. Hudson, K. A. Golabek & J. W. McNutt is published in the journal Nature.

Contact: Alan Wilson, Professor of Locomotor Biomechanics Structure and Motion Laboratory
The Royal Veterinary College, University of London

Related BBC Story: Secret life of the cat: What do our feline companions get up to?

A bird’s eye view of fishery discard reforms

Reforms to reduce discards of over-quota fish catches are generally predicted to have positive effects on marine ecosystems and biodiversity. Although concerns have been raised over the impacts of the changes on scavenging seabirds who feed upon discarded fish, new research on gannets indicates that, while they often forage near fishing vessels, more than half their time is spent foraging ‘naturally’ in the open sea.

Vast amounts of fish are discarded by commercial fishing boats, roughly 7.3 million tonnes per year worldwide, either in the form of unwanted guts or catch that has exceeded quotas. The reforms to the EU’s Common Fisheries Policy to reduce discards are therefore essential to sustainable fisheries management. Little is known, however, about how seabirds will be affected by the reduction of such an abundant source of food.

The study, partly-funded by the EU, explored whether scavenging seabirds have become completely reliant on fisheries discards, or whether they will continue to hunt for naturally-occurring prey. The researchers focused on Northern gannets habiting an island off the west coast of Britain. This is a wide-ranging seabird that is known to feed on discards from fishing boats. To gather accurate data on feeding trips, the researchers attached miniature cameras and a GPS logger to 10 birds.

The camera, fitted to the tail of each bird, recorded pictures to allow researchers to identify the presence of fishing vessels, and the GPS logger recorded the exact location of the bird. Both devices recorded data every minute. Searching behaviour, indicated by the movements of the birds, was used to identify trips searching for food, or ‘foraging bouts’.

The results revealed that 42% of the birds’ active foraging bouts occurred when a fishing vessel was present. The results also suggested a difference between male and female birds, with males more likely to forage near fishing vessels (80% of foraging bouts) than females (30%). However, the researchers do point out that the number of birds they studied was very small, so it is difficult to draw firm conclusions about this.

Overall, the fact that 58% of foraging bouts were not associated with fishing vessels suggests that gannets may be able to switch to naturally-occurring prey under a discard ban. However, the study cautions that this switch will only be successful if there is enough natural prey available, and removing discards as a source of food could have an impact on gannets. Males could be particularly affected if the patterns observed among these 10 birds are true for the wider population.

The study recommends an ecosystem-based approach to fisheries management, which takes account of all aspects of the ecosystem. This approach ensures that a range of impacts of different policies are fully understood. The researchers also highlight the value of their method to record illegal and unregulated fishing, which is extremely difficult to monitor.

Source: Votier, S. C., Bicknell, A., Cox, S. L. et al. (2013). A Bird’s Eye View of Discard Reforms: Bird-Borne Cameras Reveal Seabird/Fishery Interactions. PLoS ONE 8(3): e57376. DOI:10.1371/journal.pone.0057376.

Contact:stephen.votier@plymouth.ac.uk

Risk map shows European ‘hot spots’ for pharmaceuticals in the environment

Summed aquatic risk quotients (predicted surface water concentrations ÷ HC₅₀) due to exposure to (A) antibiotics and (B) antineoplastics. The grids with the highest summed risk quotients are accentuated with a solid black outline.

A new tool has been developed which highlights ‘hot spots’ of pharmaceutical pollution in Europe, where human health and aquatic environments could potentially be affected. The results suggest that the substances and locations posing the greatest risk are not the same for the aquatic environment as for human health.

Both the pharmaceuticals we consume, and those that we dispose of unused, are found in the environment and may potentially affect human health and ecosystems. For example, the pharmaceutical ethinyl estradiol has been found to have a feminising effect on fish in the environment. Such evidence, combined with the presence of very low levels of some pharmaceuticals in drinking water and certain foods, has also raised concerns about the potential effects of pharmaceutical pollution on humans.

The study quantified and compared the risks of pharmaceutical pollution to the aquatic environment and to human health on a regional basis in Europe. Conducted under the EU PHARMAS project, it focused on 11 common antibiotics and seven antineoplastics - a group of anti-cancer drugs.

The researchers took European pharmaceutical consumption data and estimated environmental emissions for individual countries, taking into account how many unused drugs were returned versus how many were flushed away, and how many would have been excreted into sewage systems. Sewage treatment can result in emissions via liquid effluent and from the application of sludge to agricultural land, offering another potential route of exposure as grazing animals ingest pharmaceuticals in soil and crops.

These data were used to generate a grid of emissions per 100 square kilometres, to be used as a screening tool for assessing the exposure of humans and aquatic ecosystems to pharmaceuticals on a location-by-location basis. These exposures were compared to threshold levels to produce indicative figures of risk.

Antibiotics posed a risk to aquatic environments far higher (around 1000 times) than antineoplastics, with levofloxacin, doxycycline and ciprofloxacin posing the greatest risks. Densely populated areas, such as Northern Italy, London, Krakow and the Ruhr, showed the highest levels of risk. The types of antibiotic most commonly prescribed significantly affected the environmental burden, as some are more easily broken down and toxicity varies. For example, even though the greatest number of antibiotics is prescribed in Greece, the area with the highest aquatic risk is Northern Italy, around Milan. This is because high levels of levofloxacin are used in Italy, the high population density of the Milan region, and the extreme persistence and toxicity of this antibiotic.

Risks for human health not only depend on the pharmaceutical and location, but also on behaviour, such as consumption patterns. For example, risk will be affected by whether an individual eats locally-grown food or food sourced more widely, or whether their water comes from a well, is conventionally-treated, or bottled. The main pathways for human contact with traces of pharmaceuticals from the environment are via drinking water, fruit, vegetables, meat, milk, fish, surface water and soil. Infants in eastern Spain consuming locally-produced food and conventionally-treated drinking water had the highest risk of exposure, mainly via contaminated soil, as a result of sewage sludge application to agricultural land. By contrast, infants in Paris were at relatively high risk of exposure to pharmaceuticals in water.

The researchers suggest that the study is significant because it indicates that the substances and locations posing the greatest risk are not the same for the aquatic environment as for human health, as health risks are also influenced by behaviour. This is the first tool that can be applied to prioritise pharmaceuticals, locations and exposure groups to identify hot spots for monitoring, and substances for which additional data should be gathered.

Source: Oldenkamp, R., Huijbregts, M.A.J., Hollander, A., et al. (2013) Spatially explicit prioritization of human antibiotics and antineoplastics in Europe. Environment International.
51:13-26. 

Contact:R.Oldenkamp@science.ru.nl