Constantine Alexander's Journal

Reasons for cautious optimism about (micro) plastic pollution.

Although I am always heartbroken when I learn of the devastating consequences of the global (micro)plastic pollution problem, I am cautiously optimistic about what can be done about it. There is growing evidence that private industry, civic organisations and consumers are beginning to make a difference (albeit very slowly), with the added bonus of employment creation. Here are a few examples.

One common, but infrequently discussed, source of plastic debris is the microplastic fibers from synthetic clothes that are cleaned in domestic washing machines and as a result mix with the waste water that is discharged from the machines. The types of microplastic fibers (less than 1mm in size) include polyester, acrylic, polypropylene, polyethylene and polyamide that are used in everyday items such as synthetic blankets, fleeces, shirts, trousers and blouses. More than 100 fibers per litre of water can be found in washing machine wastewater following a wash. Ultrafiltration is one method that can be used to remove microplastic fibers from sewage waste water and, although this has not yet become a widespread practice, its utilisation appears to be gaining attention.

More of us are focused on plastic debris mitigation measures such as reducing or eliminating plastic shopping bag use, recycling plastic materials and encouraging manufacturers as well as food suppliers to minimise plastic wrapping of consumer products and food items. Just as one example, by 2006, Japan had achieved an “effective plastic utilisation” rate of 72% leaving only 28% of plastic waste destined for land-fills. “Effective utilization” embraces plastic waste recycling and, to some extent, efforts aimed at controlled plastic incineration through the process of thermal depolymerization which mitigates the release of toxins and large amounts of carbon dioxide for energy recovery purposes to generate heat or electric power.

There are an increasing number of international initiatives designed to mitigate the general problem of plastic and other ocean debris, such as the U.K. “Fishing for Litter” aimed at removing 100 tonnes of rubbish from the country’s marine environment. The program operated by KIMO (Local Authorities International Environmental Organisation) provided fishing boats with plastic bags for the collection of litter that accompanied their catch. These bags are then left for collection on the quayside when the fishermen land.

Project Kaisei - involving the Ocean Voyages Institute (a California non-profit marine conservation NGO), the University of California at San Diego and the Scripps Institution of Oceanography - includes the participation of former fishermen whose boats were decommissioned due to declining fish stocks. As part of the mission, these former fishing vessels were transformed into specialised plastic-consuming machines to collect the waste and convert it into fuel using patented technology that is just beginning to be utilised in a number of countries. A system using low heat and no oxygen allows for a wide variety of plastic waste to be processed into diesel fuel.

The concept of transforming plastic as well as other marine debris into usable products is taking hold in many parts of the world. One of the world’s largest home appliance manufacturers – The Electrolux Group – has been working in association with environmental organisations, stakeholders and public sector institutions to collect plastic debris from the Pacific Ocean, Atlantic Ocean, Indian Ocean, Mediterranean Sea, Baltic Sea and North Sea for the production of vacuum cleaners. Some Electrolux models are made with up to 70% recycled plastic, and the company aims to achieve 100% recycled plastic that is incorporated into the appliances. The plastic debris has been collected in partnership with private and public sector organisations such as B.E.A.C.H. in Hawaii (Pacific Ocean); Blue View Divers in Thailand (Indian Ocean); Sotenas Municipality in Sweden (North Sea); Surfrider Foundation in France (Mediterranean Sea); Sandhamn Islanders in Sweden, The Hel Marine Station in Poland, and the NGO Pedas in Latvia (Baltic Sea); and KIMO International/Fishing for Litter (Atlantic Ocean).

As responsible waste management and recycling are increasingly recognized for their creation of jobs, consumer products as well as energy sources, positive economic indicators including potential profits motivate business to contribute to plastic pollution mitigation and clean-up. According to the EU, in 2009, waste management and recycling industries in the European Union (EU) had an estimated turnover of €95 billion and provided 1.5 million jobs.

As travel constitutes a significant global industry, holidaymakers can make a difference by raising the plastic debris and pollution issue with hoteliers, restaurateurs, car rental agencies and other service providers at holiday destinations. I discovered that this can influence community behaviour and provide some economic pressure when I was director of an NGO that I founded on a Greek island that enabled me to meet most of the island visitors. Tourist comments to these service providers were then discussed among the island residents who rely heavily on tourism, and the potential economic consequences (i.e. revenue loss) of tourists who were appalled at plastic and other debris actually made a difference.

By (i) spreading the word that we as consumers wield an enormous amount of economic power and social influence by sourcing and selecting products/services and by changing our own household habits, and (ii) demonstrating to business that there are profits to be made by collecting and converting existing waste, I believe there is reason for cautious optimism that we can eventually clean up and reduce plastic pollution.

Relevant Publications:

• Economic Impacts of Marine Litter (2010 Report)
• Fishing for Litter Scotland (Final Report 2005 - 2008)
• Microscopic Plastic Particles in Swedish Coastal Waters 
• Save the North Sea Final Report
• Impacts of Marine Debris and Oil - Economic and Social Costs to Coastal Communities

Related Articles:

• Sea Education Association finds widespread floating plastic debris in the western North Atlantic Ocean
• Scripps study finds plastic in 9 percent of 'garbage patch' fishes
• Dining out in an ocean of plastic: How foraging albatrosses put plastic on the menu
• Seabirds study shows plastic pollution reaching surprising levels off coast of Pacific Northwest
• Biologists record increasing amounts of plastic litter in the Arctic deep sea
• Plastic trash altering ocean habitats, Scripps study shows
• Seabird ingestion of plastic litter still exceeding policy targets
• Rising levels of plastic waste on Arctic seafloor a cause for concern
• Plastic litter found in fish guts

Contact: Constantine Alexander

Sharks worth more in the ocean than on the menu

Credit: Shawn Heinrichs

Sharks are worth more in the ocean than in a bowl of soup, according to researchers from the University of British Columbia.

A new study, published today in Oryx – The International Journal of Conservation, shows that shark ecotourism currently generates more than US$314 million annually worldwide and is expected to more than double to US$780 million in the next 20 years.

In comparison, the landed value of global shark fisheries is currently US$630 million and has been in decline for the past decade. An estimated 38 million sharks are killed per year to feed the global fin trade alone.

"The emerging shark tourism industry attracts nearly 600,000 shark watchers annually, directly supporting 10,000 jobs," says Andrés Cisneros-Montemayor, a PhD candidate with UBC's Fisheries Economics Research Unit and lead author of the study. "It is abundantly clear that leaving sharks in the ocean is worth much more than putting them on the menu."

 

"Sharks are slow to mature and produce few offspring," says Rashid Sumaila, senior author and director of UBC's Fisheries Centre. "The protection of live sharks, especially through dedicated protected areas, can benefit a much wider economic spectrum while helping the species recover."

The research team from UBC, the University of Hawaii and Universidad Autónoma de Baja California Sur in Mexico examined shark fisheries and shark ecotourism data from 70 sites in 45 countries. Almost $124 million in tourism dollars were generated annually in the Caribbean from shark tourism, supporting more than 5,000 jobs. In Australia and New Zealand, 29,000 shark watchers help generate almost $40 million in tourism expenditure a year.

Contact: Andras Cisneros-Montemayor
[email protected]
778-891-3836
University of British Columbia

Climate change threatens extinction for 82 percent of California native fish

Top 20 native California fish at risk of extinction from climate change

Kern River rainbow trout

Salmon and other native freshwater fish in California will likely become extinct within the next century due to climate change if current trends continue, ceding their habitats to non-native fish, predicts a study by scientists from the Center for Watershed Sciences at the University of California, Davis.

The study, published online in May in the journal PLOS ONE, assessed how vulnerable each freshwater species in California is to climate change and estimated the likelihood that those species would become extinct in 100 years.

The researchers found that, of 121 native fish species, 82 percent are likely to be driven to extinction or very low numbers as climate change speeds the decline of already depleted populations. In contrast, only 19 percent of the 50 non-native fish species in the state face a similar risk of extinction.

"If present trends continue, much of the unique California fish fauna will disappear and be replaced by alien fishes, such as carp, largemouth bass, fathead minnows and green sunfish," said Peter Moyle, a professor of fish biology at UC Davis who has been documenting the biology and status of California fish for the past 40 years.

"Disappearing fish will include not only obscure species of minnows, suckers and pupfishes, but also coho salmon, most runs of steelhead trout and Chinook salmon, and Sacramento perch," Moyle said.

Fish requiring cold water, such as salmon and trout, are particularly likely to go extinct, the study said. However, non-native fish species are expected to thrive, although some will lose their aquatic habitats during severe droughts and low-flow summer months.

The top 20 native California fish most likely to become extinct in California within 100 years as the result of climate change include (asterisks denote a species already listed as threatened or endangered):

1. Klamath Mountains Province summer steelhead
2. McCloud River redband trout
3. Unarmored threespine stickleback*
4. Shay Creek stickleback
5. Delta smelt*
6. Long Valley speckled dace
7. Central Valley late fall Chinook salmon
8. Kern River rainbow trout
9. Shoshone pupfish
10. Razorback sucker*
11. Upper Klamath-Trinity spring Chinook salmon
12. Southern steelhead*
13. Clear Lake hitch
14. Owens speckled dace
15. Northern California coast summer steelhead
16. Amargosa Canyon speckled dace
17. Central coast coho salmon*
18. Southern Oregon Northern California coast coho salmon*
19. Modoc sucker*
20. Pink salmon

The species are listed in order of vulnerability to extinction, with No. 1 being the most vulnerable.

Climate change and human-caused degradation of aquatic habitats is causing worldwide declines in freshwater fishes, especially in regions with arid or Mediterranean climates, the study said. These declines pose a major conservation challenge. However, there has been little research in the scientific literature related to the status of most fish species, particularly native ones of little economic value.

Moyle saw the need for a rapid and repeatable method to determine the climate change vulnerability of different species. He expects the method presented in the study to be useful for conservation planning.

"These fish are part of the endemic flora and fauna that makes California such a special place," said Moyle. "As we lose these fishes, we lose their environments and are much poorer for it."

Co-authors on the study were postdoctoral students Joseph Kiernan, Patrick Crain and Rebecca Quiñones of the Center for Watershed Sciences at UC Davis. Funding for the study was provided by the California Energy Resources Conservation and Development Commission Instream Flow Assessment Program.

Citation: Moyle PB, Kiernan JD, Crain PK, Quiñones RM (2013) Climate Change Vulnerability of Native and Alien Freshwater Fishes of California: A Systematic Assessment Approach. PLoS ONE 8(5): e63883. doi:10.1371/journal.pone.0063883

Contact: Peter Moyle
[email protected]
530-752-6355
University of California - Davis

Global warming caused by CFCs, not carbon dioxide, study says

Qing-Bin Lu, a professor of physics and astronomy, biology and chemistry in Waterloo's Faculty of Science.

Chlorofluorocarbons (CFCs) are to blame for global warming since the 1970s and not carbon dioxide, according to new research from the University of Waterloo published in the International Journal of Modern Physics B this week.

CFCs are already known to deplete ozone, but in-depth statistical analysis now shows that CFCs are also the key driver in global climate change, rather than carbon dioxide (CO2) emissions.

"Conventional thinking says that the emission of human-made non-CFC gases such as carbon dioxide has mainly contributed to global warming. But we have observed data going back to the Industrial Revolution that convincingly shows that conventional understanding is wrong," said Qing-Bin Lu, a professor of physics and astronomy, biology and chemistry in Waterloo's Faculty of Science. "In fact, the data shows that CFCs conspiring with cosmic rays caused both the polar ozone hole and global warming."

"Most conventional theories expect that global temperatures will continue to increase as CO2 levels continue to rise, as they have done since 1850. What's striking is that since 2002, global temperatures have actually declined – matching a decline in CFCs in the atmosphere," Professor Lu said. "My calculations of CFC greenhouse effect show that there was global warming by about 0.6 °C from 1950 to 2002, but the earth has actually cooled since 2002. The cooling trend is set to continue for the next 50-70 years as the amount of CFCs in the atmosphere continues to decline."

The findings are based on in-depth statistical analyses of observed data from 1850 up to the present time, Professor Lu's cosmic-ray-driven electron-reaction (CRE) theory of ozone depletion and his previous research into Antarctic ozone depletion and global surface temperatures.

Annual Global Temperature over Land and Ocean. Credit: Qing-Bin Lu, University of Waterloo

"It was generally accepted for more than two decades that the Earth's ozone layer was depleted by the sun's ultraviolet light-induced destruction of CFCs in the atmosphere," he said. "But in contrast, CRE theory says cosmic rays – energy particles originating in space – play the dominant role in breaking down ozone-depleting molecules and then ozone."

Lu's theory has been confirmed by ongoing observations of cosmic ray, CFC, ozone and stratospheric temperature data over several 11-year solar cycles. "CRE is the only theory that provides us with an excellent reproduction of 11-year cyclic variations of both polar ozone loss and stratospheric cooling," said Professor Lu. "After removing the natural cosmic-ray effect, my new paper shows a pronounced recovery by ~20% of the Antarctic ozone hole, consistent with the decline of CFCs in the polar stratosphere."

By proving the link between CFCs, ozone depletion and temperature changes in the Antarctic, Professor Lu was able to draw almost perfect correlation between rising global surface temperatures and CFCs in the atmosphere.

"The climate in the Antarctic stratosphere has been completely controlled by CFCs and cosmic rays, with no CO2 impact. The change in global surface temperature after the removal of the solar effect has shown zero correlation with CO2 but a nearly perfect linear correlation with CFCs - a correlation coefficient as high as 0.97."

Data recorded from 1850 to 1970, before any significant CFC emissions, show that CO2 levels increased significantly as a result of the Industrial Revolution, but the global temperature, excluding the solar effect, kept nearly constant. The conventional warming model of CO2, suggests the temperatures should have risen by 0.6°C over the same period, similar to the period of 1970-2002.

The analyses indicate the dominance of Lu's CRE theory and the success of the Montreal Protocol on Substances that Deplete the Ozone Layer.

11-Year Cyclic Antarctic Ozone Hole and Stratospheric Cooling. Credit: Qing-Bin Lu, University of Waterloo

"We've known for some time that CFCs have a really damaging effect on our atmosphere and we've taken measures to reduce their emissions," Professor Lu said. "We now know that international efforts such as the Montreal Protocol have also had a profound effect on global warming but they must be placed on firmer scientific ground."

"This study underlines the importance of understanding the basic science underlying ozone depletion and global climate change," said Terry McMahon, dean of the faculty of science. "This research is of particular importance not only to the research community, but to policy makers and the public alike as we look to the future of our climate."

Professor Lu's paper, Cosmic-Ray-Driven Reaction and Greenhouse Effect of Halogenated Molecules: Culprits for Atmospheric Ozone Depletion and Global Climate Change, also predicts that the global sea level will continue to rise for some years as the hole in the ozone recovers increasing ice melting in the polar regions.

"Only when the effect of the global temperature recovery dominates over that of the polar ozone hole recovery, will both temperature and polar ice melting drop concurrently," says Lu.

The peer-reviewed paper published this week not only provides new fundamental understanding of the ozone hole and global climate change but has superior predictive capabilities, compared with the conventional sunlight-driven ozone-depleting and CO2-warming models.

Journal reference: Cosmic-Ray-Driven Reaction and Greenhouse Effect of Halogenated Molecules: Culprits for Atmospheric Ozone Depletion and Global Climate Change. Qing-Bin Lu, University of Waterlo. Published on May 30 in International Journal of Modern Physics B Vol. 27 (2013) 1350073 (38 pages).

Contact: Nick Manning
[email protected]
519-888-4451
University of Waterloo

In just half a century, the University of Waterloo, located at the heart of Canada's technology hub, has become one of Canada's leading comprehensive universities with 35,000 full- and part-time students in undergraduate and graduate programs. Waterloo, as home to the world's largest post-secondary co-operative education program, embraces its connections to the world and encourages enterprising partnerships in learning, research and discovery. In the next decade, the university is committed to building a better future for Canada and the world by championing innovation and collaboration to create solutions relevant to the needs of today and tomorrow. 

Risk-averse behaviour may improve farmland biodiversity

Challacombe Farm, in the heart of Dartmoor National Park, is a working hill farm, set in a valley that has been farmed more or less continuously for around 4000 years.

‘Bet-hedging’ behaviour among farmers, who diversify land use to avoid investing in a single land use that might fail, can boost farmland biodiversity, a new study suggests. However, because historical data show this is not the most frequent strategy used by farmers, balancing environmental and economic concerns in agriculture may still require public policy instruments, such as subsidies or taxes.

Agricultural intensification has reduced farmland biodiversity, especially through degradation of habitats. More sustainable land use is needed to address this problem, which means considering biodiversity alongside economic concerns.

This study suggests that investigating and understanding the behaviour of individuals is useful to establish efficient management of agricultural landscapes. It uses the concept of risk aversion, which is the preference for a certain, but low, payoff, rather than a higher, but uncertain, payoff. In agriculture, a risk-averse farmer might develop a variety of agricultural activities in order to hedge his or her bets and reduce the risk of investing in a single activity that might fail.This study examined how risk aversion might affect the ecological and economic elements of agriculture.

Eight levels of risk aversion were used. Their impacts on biodiversity (in terms of the Farmland Bird Index), the economic value of the land (in terms of income per hectare) and the diversification of land use (in terms of the habitat heterogeneity index) were simulated from 2013 to 2050. Data on bird abundances, land use distributions and incomes at a local level were used for the analysis.

The results indicated that a strong risk aversion strategy, as expected, reduced the expected income, but decreased its variability. This strategy was also beneficial to biodiversity: to mitigate economic risk, a strong risk-averse strategy led to diverse land use. This creates a variety of habitats and available resources, allowing many bird species to co-exist. This diversification produces a more stable ecological community, providing a greater array of ecosystem services. However, strong risk aversion did not have a beneficial effect on income, which reduced over time.

However, the research showed that the estimated average risk aversion level is low. This is consistent with the land specialisation trends over past decades and the current decline of birds in agricultural landscapes. Moreover, the results exhibited strong local variations in the impacts of risk-averse behaviour on ecological performance: strong risk aversion does not systematically improve farmland bird biodiversity in all the regions, suggesting that other factors play a part in establishing local bird communities.

In the light of the results, the researchers suggest that public policies, such as taxes and subsidies, are necessary to manage biodiversity whilst also mitigating economic losses and reducing regional disparities. These policies should encourage risk aversion as a means to foster land use diversity and subsequent biodiversity, but within the context of other local drivers.

Source: Mouysset, L., Doyen, L. & Jiguet, F. (2013) How does economic risk aversion affect biodiversity? Ecological Applications 23(1): 96-109. DOI: 10.1890/11-1887.1

Contact: [email protected]

How do you measure something that’s not there? The case of waste prevention

The challenge of measuring the ‘absence of waste’ makes it particularly difficult to monitor and evaluate waste prevention policies. Researchers have examined the strengths and weaknesses of nine methods of assessing waste prevention, and recommend a hybrid approach, which combines the best of many methods, as particularly valuable.

Waste prevention is a vital part of breaking the link between economic growth and environmental damage. In 2008, the total amount of waste produced in the EU was calculated to be 2.62 billion tonnes, or 5.2 tonnes per person, and this has since increased. Waste prevention, defined as reducing the amount and/or toxicity of waste, is therefore a pressing objective. The EU Waste Framework Directive, places waste prevention, rather than recycling, as a top priority, and requires Member States to develop waste prevention plans by the end of 2013.

The authors of the study suggest that effective monitoring and evaluation of waste prevention should be a key priority as part of these efforts, and examined five main approaches to assessing household waste prevention.

Self-monitoring schemes, where individual householders weigh their waste and record the data, were found to be a good motivational tool for increasing waste prevention. However, they can only be carried out with a limited number of individuals, data are often inconsistent and drop-out rates from these programmes can be high.

To monitor changing levels of waste prevention local authorities can also use data from waste collections from small groups of the population. This does return accurate data, which is extremely useful for policy development. However, the authors caution that groups must be representative of the whole population and that large numbers of households need to be included to allow meaningful statistical analysis.

An important step towards achieving waste reduction is to change attitudes which leads to changes in behaviour. For example, the authors identify the common confusion of recycling with waste reduction, as a particular problem. Attitude and behaviour surveys, which can include interviews and focus groups, as well as data on, for example, the number of compost bins sold, are valuable to policy development because they can provide an initial baseline, i.e. a picture of current behaviour, to compare against subsequent rates of change following policy implementation. Such data can also be used to design information campaigns. However, participants often fail to return surveys, which can hinder this kind of evaluation and monitoring.

‘Point of sale’ data, i.e. exactly which products are bought, is another useful source of information and can be used to identify how waste can be reduced even before reaching the consumer. For example, combining sales data with information on packaging creates potential for waste prevention through product redesign to be assessed.

Finally, the methodology identified by the researchers as having the greatest potential is a hybrid approach, which incorporates several of the methods already discussed. For example, after an initial survey to establish a baseline, using interviews or focus groups, changes can then be monitored using householder monitoring, which can help change attitudes, alongside waste collection monitoring, which can provide more accurate data.

Citation: Zorpas. A. A. & Lasaridi, K. (2013). Measuring waste prevention. Waste Management. DOI: 10.1016/j.wasman.2012.12.017.

Contact:[email protected]; [email protected]

New tool to assess the environmental impact of landfill sites

A fast and reliable method to measure the environmental impact of landfill sites has been developed by researchers. Analysis of the chemical composition of gas emissions and water leaching from sites provides a detailed picture of the extent of environmental pollution around landfill sites. Such monitoring is essential in order to manage risks to human health and natural resources. 

Despite the general decrease in landfilled waste and improved EU landfill standards, landfill sites still represent one of the most serious environmental threats in several European countries. However, there is currently no standard procedure for monitoring the environmental impact of landfill sites.

The emission of landfill gas, comprising the greenhouse gases CO₂ and methane, is a substantial source of pollution originating from landfill sites. Of equal concern are the toxic biological and radioactive substances which can dissolve into local water sources. It is important to monitor the levels of such pollution, so that steps can be taken to manage and control it, minimising damage to environmental and human health.

The authors of this paper set out to establish a standard procedure for rapid assessment of environmental impacts of landfill sites using two case study sites in Komotini, Greece. The researchers collected and analysed landfill gas emissions at ground level on both sites, one site of which is still active, while the other is closed. They also carried out chemical analysis of water draining through the sites (leachate), and of groundwater nearby, to monitor the impact on local water resources.

Analysis of leachate showed exceptionally high values of contamination. The findings also demonstrated that standard measurements currently taken to assess environmental impact of leachate on groundwater are unsatisfactory, as they do not take into account the background chemical composition of site location, so contamination levels can appear higher or lower than they actually are.

Results of landfill gas analysis demonstrated that methane was the main component at both sites, with recorded concentrations of between 56.7 and 64.9%. The authors point out that reliable quantification of landfill gas emissions is essential, not only to monitor environmental impact, but also in order to design effective collection systems.

The results of this study suggest that the method followed provides a rapid and effective tool to inform on-site and off-site management plans to minimise the environmental impact of landfill sites. The authors argue that it should be considered a first and crucial step in understanding the extent of contamination from landfill sites.

Source: Raco, B., Dotsika, E., Battaglini, R., et al. (2013) A quick and reliable method to detect and quantify contamination from MSW landfills: a case study. Water Air and Soil Pollution. 224:1380. DOI:10.1007/s11270-012-1380-5

Contact: [email protected]

 

Going home

GEOMAR scientists found evidence why female loggerhead sea turtles always return to their place of birth

Worldwide, over 15,000 species are threatened by extinction, and the loggerhead sea turtle is no exception. Once the mysteries surrounding some of the species behavior are resolved, more effective conservation programs can be developed to facilitate their protection. The case of the loggerhead sea turtle is particularly interesting: Why do they migrate for several thousands of kilometers to eventually come back to their place of birth for reproduction after roughly 25 years?

To address this question, a group of evolutionary biologists from GEOMAR Helmholtz Centre for Ocean Research Kiel focused on the world's third largest nesting population of the loggerhead sea turtle which is found in the archipelago of Cape Verde. Despite the fact that the species is protected, the number of nesting turtles has been decreasing rapidly due to the slaughter of turtles for their meat, marine pollution, coastal development in nesting areas and fisheries by-catch. Hence, the loggerhead turtle has the "endangered" status on the Red List of Threatened Species (IUCN 2012).

The archipelago of Cape Verde is composed of numerous islands where turtles can be observed. In this study, GEOMAR scientists collected tiny skin samples from turtles on four different islands of the archipelago for analysis. Using multiple genetic tools, the scientists found that Cape Verdean female loggerheads not only return to Cape Verde to breed but also that they show a remarkably accurate philopatric (returning to reproduce at the place of birth) behavior of a couple tens of kilometers: "It was fascinating to demonstrate that most female turtles actually return to the exact island where they were born", said lead author Victor Stiebens.

This outstanding behavior has some advantages for the turtles. The study found that a certain region in the turtle's genome is responsible for fighting parasites and diseases, the so-called major histocompatibility complex. "Indeed, the study shows that turtles nesting at the most distant islands of the archipelago have different sets of these genes, providing the right genetic make-up to pass to the offspring to fight off the local parasite fauna present in that specific place", explains senior author Dr. Christophe Eizaguirre.

At the same time, always returning to the same island may have detrimental effects for species with small population sizes since it may lead to mating with relatives, i.e. inbreeding. However, it was rather interesting that in this study, the scientists were able to show that males counteract this inbreeding risk by being less selective in choosing their mating places. "Males seem to look for females over large regions of the archipelago, whereas females are more faithful to their place of birth to mate" reports Victor Stiebens. "These gender-specific behaviors assure genetic transfer between the nesting islands but also the existence of genes needed in these local environments" says Dr. Eizaguirre.

The conclusions of the study show that returning home to reproduce gives individuals an additional advantage to fight off parasites and diseases, and may thus add a piece to the puzzle of the intriguing journey of marine turtles. "From a conservation perspective, the results suggest that it is very important to not lose any of the nesting colonies as each singular location provides important genetic adaptation for the survival of the entire population in the case of major biotic/abiotic changes in a globally changing environment", says Dr. Eizaguirre.

Reference: Stiebens, V. A., Merino S. E. , Roder C., Chain F. J. J., Lee P. L. M., Eizaguirre C. (2013): Living on the edge: how philopatry maintains adaptive potential. Proceedings of the Royal Society B: Biological Sciences. 

Contact: Jan Steffen
[email protected]
Helmholtz Centre for Ocean Research Kiel (GEOMAR)

Forest and soil carbon is important but does not offset fossil fuel emissions

Why land-based carbon offsets are providing false hope

Leading world climate change experts have thrown cold water on the idea that planting trees can offset carbon dioxide emissions from fossil fuels.

Professor Brendan Mackey of Griffith University Climate Change Response Program is the lead author of an international study involving researchers from Australia and the U.K. Their findings are reported in "Untangling the confusion around land carbon science and climate change mitigation policy", published in the scientific journal Nature Climate Change.

"While protecting and restoring natural forests is part of the solution, the reality is that for all practical purposes fossil fuel CO2 emissions are irreversible," Professor Mackey said.

The findings highlight the urgent need for policy-makers worldwide to re-think the issue as many decision-makers, national and internationally, assume that fossil fuel emissions can be offset through sequestering carbon by planting trees and other land management practices.

"There is a danger in believing that land carbon sinks can solve the problem of atmospheric carbon emissions because this legitimises the ongoing use of fossil fuels", Professor Mackey said.

The study found that protecting natural forests avoids emissions that would otherwise result from logging and land clearing while also conserving biodiversity. Restoring degraded ecosystems or planting new forests helps store some of the carbon dioxide that was emitted from past land use activities.

"These land management actions should be rewarded as they are an important part of the solution," Professor Mackay said.

"However, no amount of reafforestation or growing of new trees will ultimately off-set continuing CO2 emissions due to environmental constraints on plant growth and the large amounts of remaining fossil fuel reserves.

"Unfortunately there is no option but to cut fossil fuel emissions deeply as about a third of the CO2 stays in the atmosphere for 2 to 20 millennia."

Citation: Nature Climate Change: "Untangling the confusion around land carbon science and climate change mitigation policy" by Brendan Mackey (Griffith Uni.), I. Colin Prentice (Macquarie Uni. & Imperial College), Will Steffen (ANU), Joanna I. House (Bristol Uni.), David Lindenmayer (ANU), Heather Keith (ANU) and Sandra Berry (ANU). (doi:10.1038/nclimate1804)

Contact: Heen Wright
[email protected]
61-047-840-6565
Griffith University

Small dams on Chinese river harm environment more than expected, study finds

A fresh look at the environmental impacts of dams on an ecologically diverse and partially protected river in China found that small dams can pose a greater threat to ecosystems and natural landscape than large dams. Although large dams are generally considered more harmful than their smaller counterparts, the research team's surveys of habitat loss and damage at several dam sites on the Nu River and its tributaries in Yunnan Province revealed that, watt-for-watt, the environmental harm from small dams was often greater—sometimes by several orders of magnitude—than from large dams.

Because of undesirable social, environmental, and political implications, the construction of large dams often stirs controversy. Current policies in China and many other nations encourage the growth of the small hydropower sector. But, "small dams have hidden detrimental effects, particularly when effects accumulate" though multiple dam sites, said Kelly Kibler, a water resources engineer who led this study as part of her PhD research while at Oregon State University in Corvallis. "That is one of the main outcomes of this paper, to demonstrate that the perceived absence of negative effects from small hydropower is not always correct."

She and Desiree D. Tullos, also a water resources engineer at Oregon State and Kibler's PhD advisor, report their findings in a paper accepted for publication in Water Resources Research, a journal of the American Geophysical Union. Kibler now works as a researcher at the International Centre for Water Hazard & Risk Management in Tsukuba, Japan, and as an Associate Professor at Japan's National Graduate Institute for Policy Studies in Tokyo.

To compare the impacts of small and large dams, Kibler investigated 31 small dams built on tributaries to China's Nu River and four large dams proposed for the main stem of the Nu River. She assessed the environmental effects of these dams in 14 categories—including the area and quality of habitat lost, the length of river channel affected, the amount of conservation land impacted, and the landslide risk. Because information regarding large dams is restricted under the Chinese State Secrets Act, Kibler modeled the potential effects of the four large dams using publically-available information from hydropower companies, development agencies, and academic literature.

After evaluating data from the field, hydrological models, and Environmental Impact Assessment reports about the small dams, Kibler and Tullos concluded that impacts of the small dams exceeded those of large dams on 9 out of the 14 characteristics they studied.

One particularly detrimental impact of the small dams observed in this study is that they often divert the flow of the river to hydropower stations, leaving several kilometers of river bed dewatered, Kibler explained.

From its headwaters in the Tibetan Plateau, the Nu River flows through China, Myanmar (Burma) and Thailand. "While the number of small hydropower dams in operation or planned for tributaries to the Nu River is unreported," the authors note in this study, "our field surveys indicate that nearly one hundred small dams currently exist within Nujiang Prefecture alone."

Thirteen large hydropower dams are proposed for the main stream of the Nu River in Tibet and Yunnan Province in China. "No large dams have been built, but there have been reports that site preparations have begun at some proposed dam sites," Kibler said.

Environmental, social, and economic factors make the Nu River basin extremely sensitive to hydropower installations. In addition to supporting several protected species, the region is home to a large proportion of ethnic minorities and valuable natural resources, the authors report in the study. Parts of the Nu River are also designated as a World Heritage site and the Nature Conservancy and Conservation International have delineated stretches of this river and its tributaries as biodiversity hotspots. But proposed hydropower projects are threatening these statuses, according to Kibler.

While large hydropower projects are managed by the central government, and both large and small hydropower projects undergo environmental impact assessments, decisions about small hydropower projects are made at a provincial or other regional level and receive far less oversight, Kibler and Tullos state in their paper.

Small dams in China "often lack sufficient enforcement of environmental regulations" because they are "left to the jurisdiction of the province," said Guy Ziv, lead scientist for the Natural Capital Project, an organization which develops tools to assess and quantify natural resources, and a researcher for the Woods Institute for the Environment at Stanford University. This study, he added, is "an important contribution to the field of natural resource management."

The lack of regulation paired with a dearth of communication between small dam projects in China allows for the impacts to multiply and accumulate through several dam sites, the study authors write.

In order to mitigate the detrimental effects of small dams, there is a "need for comprehensive planning of low-impact energy development." Kibler and Tullos note.

Policies supporting growth in the small hydropower sector are often crafted at the national or international level, Kibler noted. For example, many of the small dams investigated in the new study were supported by the Kyoto Protocol, a 1997 agreement to reduce greenhouse gas emissions.

"The lack of comprehensive analysis regarding cumulative impact of small hydropower," Kibler said, "is a significant research gap with important policy implications."

Contact: Peter Weiss
[email protected]
202-777-7507
American Geophysical Union