Constantine Alexander's Journal

Tagging aquatic animals can disrupt natural behavior

Loggerhead turtle equipped with a 3-D logger. Credit: Tomoko Narazaki (Atmosphere and Ocean Research Institute, The University of Tokyo) 

American and Canadian researchers have for the first time quantified the energy cost to aquatic animals when they carry satellite tags, video cameras and other research instruments.

Studying fibreglass casts of sea turtles in a wind tunnel, the team found that while most commercially available tags increased drag by less than five per cent for large adult animals in the wild, these same devices increased drag by more than 100 per cent on smaller or juvenile animals.

"Many marine animals make yearlong breeding migrations crossing entire oceans, while others may rely on high speeds and acceleration – enabling them to catch prey or to escape predators," says T. Todd Jones, a scientist with the National Oceanic and Atmospheric Administration Pacific Islands Fisheries Science Center in Hawaii, who led the study while a doctoral fellow at the University of British Columbia.

"If the drag costs from carrying tags disrupts their natural behaviour, they may miss out on breeding and foraging seasons, be unable to catch enough food, or even end up becoming someone else's meal."

The study, published today in the journal Methods in Ecology and Evolution, also includes a universal formula that allows scientists to calculate drag for a wide range of marine species including turtles, mammals, fish, and diving birds to inform study design.

"In addition to the animal welfare and conservation implications, excessive drag may also impede the collection of research data in the wild," says Jones, whose previous research on leatherback sea turtle physiology has improved conservation practices.

"The guidelines we've developed can help ensure that the data collected accurately reflect the animals' natural behaviours in the wild, so we can devise conservation strategies accordingly." 

Contact: T. Todd Jones
[email protected]
808-366-9824
University of British Columbia

Listen up: Oysters may use sound to select a home

Oysters begin their lives as tiny drifters, but when they mature they settle on reefs. New research from North Carolina State University shows that the sounds of the reef may attract the young oysters, helping them locate their permanent home.

Larval oysters are planktonic, meaning that they cannot swim against or across currents. However, they do have the ability to move up and down within the column of water that they're in. As they mature, they develop a muscular "foot" that they can use to sense the terrain along the ocean floor. When they find the right spot, they attach themselves and remain there throughout their lives.

Ashlee Lillis, an NC State Ph.D. candidate in marine sciences, wondered how the tiny oysters knew when to drop down and start looking for a home. Scientists know that larval oysters and other bivalves, like clams, respond to some chemical and physical signals in seawater, but Lillis wondered if the sound of the reef played a role.

"When you're as small as these larvae, even if you're only 10 or 15 feet up in a water column you wouldn't have any real sense of where you were in terms of the seafloor beneath you," Lillis says. "But an ocean reef has very loud, distinct sounds associated with it. They're noisy enough to be heard by scuba divers and snorkelers. Even though oysters don't have ears and hear like we do, they might be able to sense the vibration from the sounds of the reef."

Lillis and her adviser David Eggleston, professor of marine sciences, decided to test the hypothesis. With help from NC State geophysicist Del Bohnenstiehl, the team first made underwater sound recordings of oyster reefs and the open seafloor. Then they tested larval oysters in the wild and in the lab to determine if the settlement rates increased when they were exposed to reef sounds versus those from further out.

The team found an increased settlement rate in both the lab and the wild when the larvae were exposed to reef sounds. Their results appear in PLOS ONE.

"The ocean has different soundscapes, just like on land," Lillis says. "Living in a reef is like living in a busy urban area: there are a lot of residents, a lot of activity and a lot of noise. By comparison, the seafloor is more like living in the quiet countryside.

"This research is the first step in establishing what normal, healthy reef environments sound like," Lillis adds. "If we can figure out how the noise impacts oysters it may give us strategies for establishing new oyster beds. It might also give us a noninvasive method for keeping tabs on the health of our undersea reefs."

Citation: Lillis A, Eggleston DB, Bohnenstiehl DR (2013) Oyster Larvae Settle in Response to Habitat-Associated Underwater Sounds. PLoS ONE 8(10): e79337. doi:10.1371/journal.pone.0079337

Contact: Tracey Peake
919-515-6142
North Carolina State University

Brussels Briefing on Energy: All you need to know for the month of November 2013

In this Brussels Briefing on Energy, leading journalist Hughes Belin provides an overview of the European Union’s most pressing energy issues:

• State intervention in the energy sector
• Unbundling of the electricity and gas distribution
• European Commission’s list of energy infrastructure projects
• Energy Efficiency Directive

Although Commissioner Günther Oettinger’s proposal on state intervention in the energy sector is still outstanding, the Commissioner for Competition Joaquim Almunia has withdrawn his proposal on state aid for nuclear energy. Nuclear state subsidy plans will therefore be examined on a case-by-case basis. Although it seems hard to argue that nuclear is an immature technology needing subsidies, Almunia seems quite open on the issue.

The EU Court of Justice ruled recently that Netherlands’ activities to unbundle the distribution of electricity and gas are compatible with EU treaties. Hereby, the Dutch government aims to separate the network management from generation, supply and trading of energy. The court says that consumer protection takes precedence over the restrictions on free movement of capital and, therefore, no treaty violations were determined.

Recently, the European Commission issued a list of 250 energy infrastructure projects of common interest. For these projects 5.8 billion Euros were set aside to finance studies as well as work where projects are recognized as necessary but not commercially viable.

The Energy Efficiency Directive was enforced a year ago. Nevertheless, it seems already quite likely that the EU will miss its 20% target for 2020.

 

Thawing permafrost: The speed of coastal erosion in Eastern Siberia has nearly doubled

This photo illustration shows the erosion of the east-Siberian island Muostakh. The blue line marks ist coastal line in the year 1951, the red line presents its status in the year 2012. In the upper right corner one can see an aerial picture of the island's northern tip, taken in the year 2012. At its narrowest point the island is shrinking more than four meters per year. Credit: © F. Guenther, Alfred Wegener Institute

The high cliffs of Eastern Siberia – which mainly consist of permafrost – continue to erode at an ever quickening pace. This is the conclusion which scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have reached after their evaluation of data and aerial photographs of the coastal regions for the last 40 years. According to the researchers, the reasons for this increasing erosion are rising summer temperatures in the Russian permafrost regions as well the retreat of the Arctic sea ice. This coastal protection recedes more and more on an annual basis. As a result, waves undermine the shores. At the same time, the land surface begins to sink. The small island of Muostakh east of the Lena Delta is especially affected by these changes. Experts fear that it might even disappear altogether should the loss of land continue.

The interconnectedness is clear and unambiguous: The warmer the east Siberian permafrost regions become, the quicker the coast erodes. "If the average temperature rises by 1 degree Celsius in the summer, erosion accelerates by 1.2 meters annually," says AWI geographer Frank Günther, who investigates the causes of the coastal breakdown in Eastern Siberia together with German and Russian colleagues, and who has published his findings in two scientific articles.

In these studies, he and his team evaluated high-resolution air and satellite photos from 1951 to 2012 as well as measurements of the past four years. In addition, the researchers surveyed four coastal sections along the Laptev Sea (see map) and on the island of Muostakh.

One example of the changes documented in their research are the warming summers. While the temperatures during the period of investigation exceeded zero degrees Celsius on an average of 110 days per year, the scientists counted a total of 127 days in the years 2010 and 2011. The following year, 2012, the number of days with temperatures above freezing increased to 134.

This increase in temperature is not without consequences. Whereas a thick layer of sea ice used to protect the frozen soil almost all year round, it now recedes in this part of the Arctic for increasing periods of time during the summer months. The number of summer days on which the sea ice in the southern Laptev Sea vanishes completely grows steadily. "During the past two decades, there were, on average, fewer than 80 ice-free days in this region per year. During the past three years, however, we counted 96 ice-free days on average. Thus, the waves can nibble at the permafrost coasts for approximately two more weeks each year," explains AWI permafrost researcher Paul Overduin.

The waves dig deep recesses into the base of the high coasts. The result: The undermined slopes break off bit by bit. During the past 40 years, the coastal areas surveyed retreated on average 2.2 meters per year. "During the past four years, this value has increased at least 1.6 times, in certain instances up to 2.4 times to reach 5.3 meters per year," says Paul Overduin.

For the little island of Muostakh east of the harbour town of Tiksi, this may well mean extinction. "In fewer than one hundred years, the island will break up into several sections, and then it will disappear quickly," predicts Frank Günther. On its northern tip, the island shows fluctuating annual erosion rates between 10 and 20 meters per year, and it has already lost 24 per cent of its area in the past 60 years. Because the subsurface here consists of more than 80 per cent of ice that has formed within the soil, and since the ice is gradually melting, the island's surface collapses as well. The scientists speak of a 34 per cent loss in volume. "If one bears in mind that it took tens of thousands of years for the island to form through sedimentary deposition, then its disintegration is proceeding at a very rapid pace," says Paul Overduin.

In addition, long-term studies conducted by AWI scientists show the impact of coastal erosion for the sea as well. Depending on the kind of erosion and the particular structure of the coast, between 88 and 800 tons of plant-, animal, and microorganism-based carbon are currently washed into the sea per year and kilometre of coastline – these are materials that had been sealed in the permafrost thus far. With regard to the Laptev Sea, this translates into approximately one eighth of the organic carbon that is transported by the Lena River annually – and the Lena is a river that encompasses a drainage basin the size of the Mediterranean. "We can, however, assume larger quantities if this accelerating coastal erosion we currently observe continues," the scientists write in their subject-specific paper for the Biogeosciences special volume: "Interactions between the land and sea in the Lena Delta Region." Once in the water, carbon may turn into carbon dioxide and, as a result, contribute to the acidification of the oceans: the composition of our oceans becomes less alkaline. 

These studies were conducted as part of the PROGRESS project which is funded by Germany's Federal Ministry of Education and Research. PROGRESS is the acronym for Potsdamer Forschungs- und Technologieverbund für Naturgefahren, Klimawandel und Nachhaltigkeit (Potsdam Research Cluster for Georisk Analysis, Environmental Change and Sustainability). In addition to the Alfred Wegener Institute, sectors of the Deutsches GeoForschungsZentrum (German Geo Research Center), the Potsdam-Institut für Klimafolgenforschung (Potsdam Institute for the Study of Climate Change), as well as the Hasso-Plattner-Institut für Softwaresystemtechnik (Hasso Plattner Institute for Software System Technology) are participating in this project. 

Contact: Sina Loeschke
49-471-483-12008
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Scientists find that dolphin in Australian waters is a new species

Study of humpback dolphin in Atlantic, Indian, and Pacific waters finds as-of-yet unnamed species

Two individual animals from an as-of-yet unnamed species of humpback dolphin are shown in the waters off northern Australia. Photo credit: Guido Parra

A species of humpback dolphin previously unknown to science is swimming in the waters off northern Australia, according to a team of researchers working for the Wildlife Conservation Society, the American Museum of Natural History, and numerous other groups that contributed to the study.

The humpback dolphin grows up to 8 feet in length and ranges from dark gray to pink and/or white in color. The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian and Pacific oceans to the coasts of Australia. The Atlantic humpback dolphin is considered "Vulnerable" according to the IUCN Red List, whereas the Indo-Pacific dolphin species Sousa chinensis is listed as "Near Threatened." Humpback dolphins are threatened by habitat loss and fishing activity. 

To determine the number of distinct species in the family of humpback dolphins (animals named for a peculiar hump just below the dorsal fin), the research team examined the evolutionary history of this family of marine mammals using both physical features and genetic data. While the Atlantic humpback dolphin is a recognized species, this work provides the best evidence to date to split the Indo-Pacific humpback dolphin into three species, one of which is completely new to science.

A new as-of-yet unnamed species of humpback dolphin is shown off the coast of northern Australia. Photo credit: Guido Parra

 "Based on the findings of our combined morphological and genetic analyses, we can suggest that the humpback dolphin genus includes at least four member species," said Dr. Martin Mendez, Assistant Director of WCS's Latin America and the Caribbean Program and lead author of the study. "This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species."

The authors propose recognition of at least four species in the humpback dolphin family: the Atlantic humpback dolphin (Sousa teuszii), which occurs in the eastern Atlantic off West Africa; the Indo-Pacific humpback dolphin (Sousa plumbea), which ranges from the central to the western Indian Ocean; another species of Indo-Pacific humpback dolphin (Sousa chinensis), which inhabits the eastern Indian and western Pacific Oceans; and a fourth Sousa species found off northern Australia yet to be named (the formal adjustment of the naming and number of species occurs through a separate and complementary process based on these findings).

"New information about distinct species across the entire range of humpback dolphins will increase the number of recognized species, and provides the needed scientific evidence for management decisions aimed at protecting their unique genetic diversity and associated important habitats," said Dr. Howard Rosenbaum, Director of WCS's Ocean Giants Program and senior author on the paper. 

Two dolphins from the as-of-yet unnamed species of humpback dolphin are shown off northern Australia. Photo credit: Guido Parra

Working to bring taxonomic clarity to a widespread yet poorly known group of dolphins, the authors assembled a large collection of physical data gathered mostly from beached dolphins and museum specimens. Specifically, the team examined features from 180 skulls covering most of the distribution area of the group in order to compare morphological characters across this region.

The researchers also collected 235 tissue samples from animals in the same areas, stretching from the eastern Atlantic to the western Pacific Oceans, analyzing both mitochondrial and nuclear DNA for significant variations between populations. 

The study appears in the latest edition of Molecular Ecology. The authors are: Martin Mendez and Howard C. Rosenbaum of the Wildlife Conservation Society and American Museum of Natural History; Thomas J. Jefferson of Clymene Enterprises, Lakeside, California; Sergios-Orestis Kolokotronis of Fordham University; Michael Krützen of the University of Zurich, Switzerland; Guido J. Parra of Flinders University, Adelaide, Australia; Tim Collins of the Wildlife Conservation Society and the Environment Society of Oman; Giana Minton of the Environment Society of Oman and the University Malaysia Sarawak; Robert Baldwin of the Environment Society of Oman; Per Berggren of Newcastle University, Newcastle-upon-Tyne, United Kingdom; Anna Särnblad of Stockholm University, Sweden; Omar A. Amir of the University of Dar es Salaam, Zanzibar, Tanzania; Vic M. Peddemors of the School of Biological and Conservation Sciences, Durban, South Africa and the Cronulla Fisheries Research Centre, Australia; Leszek Karczmarkski of the University of Hong Kong; Almeida Guissamulo of the Museu de Historia Natural, Mozambique; Brian Smith of the Wildlife Conservation Society; Dipani Sutaria of James Cook University, Australia; and George Amato of the American Museum of Natural History. 

Contact: John Delaney
718-220-3275
Wildlife Conservation Society

New study suggests coral reefs may be able to adapt to moderate climate change

Coral Reef in Florida by Jerry Reid, WO-3540-CD42A, U.S. Fish and Wildlife Service (CC)

Coral reefs may be able to adapt to moderate climate warming, improving their chance of surviving through the end of this century, if there are large reductions in carbon dioxide emissions, according to a study funded by NOAA and researched by the agency's scientists and its academic partners. Results further suggest corals have already adapted to part of the warming that has occurred.

"Earlier modeling work suggested that coral reefs would be gone by the middle of this century. Our study shows that if corals can adapt to warming that has occurred over the past 40 to 60 years, some coral reefs may persist through the end of this century," said study lead author Cheryl Logan, Ph.D., an assistant professor in California State University Monterey Bay's Division of Science and Environmental Policy. The scientists from the university, and from the University of British Columbia, were NOAA's partners in the study.

Warm water can contribute to a potentially fatal process known as coral "bleaching," in which reef-building corals eject algae living inside their tissues. Corals bleach when oceans warm only 1-2°C (2-4°F) above normal summertime temperatures. Because those algae supply the coral with most of its food, prolonged bleaching and associated disease often kills corals.

The study, published online in the journal Global Change Biology, explores a range of possible coral adaptive responses to thermal stress previously identified by the scientific community. It suggests that coral reefs may be more resilient than previously thought due to past studies that did not consider effects of possible adaptation.

The study projected that, through genetic adaptation, the reefs could reduce the currently projected rate of temperature-induced bleaching by 20 to 80 percent of levels expected by the year 2100, if there are large reductions in carbon dioxide emissions.

"The hope this work brings is only achieved if there is significant reduction of human-related emissions of heat-trapping gases," said Mark Eakin, Ph.D., who serves as director of the NOAA Coral Reef Watch monitoring program, which tracks bleaching events worldwide. "Adaptation provides no significant slowing in the loss of coral reefs if we continue to increase our rate of fossil fuel use."

"Not all species will be able to adapt fast enough or to the same extent, so coral communities will look and function differently than they do today," CalState's Logan said.

While this paper focuses on ocean warming, many other general threats to coral species have been documented to exist that affect their long-term survival, such as coral disease, acidification, and sedimentation. Other threats to corals are sea-level rise, pollution, storm damage, destructive fishing practices, and direct harvest for ornamental trade.

According to the Status of Coral Reefs of the World: 2000 report, coral reefs have been lost around the world in recent decades with almost 20 percent of reefs lost globally to high temperatures during the 1998-1999 El Niño and La Niña and an 80 percent percent loss of coral cover in the Caribbean was documented in a 2003 Science paper. Both rates of decline have subsequently been documented in numerous other studies as an on-going trend.

Tropical coral reef ecosystems are among the most diverse ecosystems in the world, and provide economic and social stability to many nations in the form of food security, where reef fish provide both food and fishing jobs, and economic revenue from tourism. Mass coral bleaching and reef death has increased around the world over the past three decades, raising questions about the future of coral reef ecosystems.

In the study, researchers used global sea surface temperature output from the NOAA/GFDL Earth System Model-2 for the pre-industrial period though 2100 to project rates of coral bleaching.

Because initial results showed that past temperature increases should have bleached reefs more often than has actually occurred, researchers looked into ways that corals may be able to adapt to warming and delay the bleaching process.

The article calls for further research to test the rate and limit of different adaptive responses for coral species across latitudes and ocean basins to determine if, and how much, corals can actually respond to increasing thermal stress.

Citation: Cheryl A. Logan, John P. Dunne, C. Mark Eakin, Simon D. Donner; Incorporating adaptive responses into future projections of coral bleaching; Global Change Biology DOI: 10.1111/gcb.12390

NOAA's Coral Reef Conservation Program funded the study. 

Contact: Ben Sherman
301-713-3066
NOAA Headquarters

UCLA report urges new global policy effort to tackle crisis of plastic litter in oceans

Plastic litter and other trash on the coastline of Green Island, Kure Atoll, Hawaii (2006). Image courtesy of Claire Fackler, CINMS, NOAA/NOAA Photo Library.

Plastic litter is one of the most significant problems facing the world's marine environments. Yet in the absence of a coordinated global strategy, an estimated 20 million tons of plastic litter enter the ocean each year.

A new report by authors from UCLA School of Law's Emmett Center on Climate Change and the Environment and UCLA's Institute of the Environment and Sustainability explores the sources and impacts of plastic marine litter and offers domestic and international policy recommendations to tackle these growing problems — a targeted, multifaceted approach aimed at protecting ocean wildlife, coastal waters, coastal economies and human health.

In addition to summarizing the economic, public health, public property and ecological risks posed by marine debris, the report identified the legal shortcomings on efforts to solve the global marine plastic litter crisis. An estimated 20 million tons of plastic litter enter the ocean every year and has been known to impact more than 600 species of marine life.  Recent EPA estimates of the economic cost of marine litter range in the $500 million a year range: an average cost of over $13 per person per year.

"Stemming the Tide of Plastic Marine Litter: A Global Action Agenda," the Emmett Center's most recent Pritzker Environmental Law and Policy Brief, documents the devastating effects of plastic marine litter, detailing how plastic forms a large portion of our waste stream and typically does not biodegrade in marine environments. Plastic marine litter has a wide range of adverse environmental and economic impacts, from wildlife deaths and degraded coral reefs to billions of dollars in cleanup costs, damage to sea vessels, and lost tourism and fisheries revenues. The brief describes the inadequacy of existing international legal mechanisms to resolve this litter crisis, calling on the global community to develop a new international treaty while also urging immediate action to implement regional and local solutions.

"Plastic marine litter is a growing global environmental threat imposing major economic costs on industry and government," said report co-author Mark Gold, an associate director of the Institute of the Environment and Sustainability. Marine plastic pollution slowly degrades and has spread to every corner of the world's oceans, from remote islands to the ocean floor. Voluntary half-measures are not preventing devastating global impacts to marine life, the economy and public health. Although there is no one panacea, we have identified the top 10 plastic pollution–prevention actions that can be implemented now to begin drastically reducing plastic marine litter."

In "Stemming the Tide of Plastic Marine Litter," the authors review the universe of studies, policies and international agreements relevant to the problem and provide a suite of recommendations to achieve meaningful reductions in plastic marine litter. The report's "Top 10" list of recommended actions includes a new international treaty with strong monitoring and enforcement mechanisms; domestic and local regulatory actions, such as bans of the most common and damaging types of plastic litter; extended producer-responsibility programs; and the creation of an "ocean friendly" certification program for plastic products.

"Because global mismanagement of plastic is fueling the growing marine litter problem, policy responses are needed at all levels, from the international community of nations down to national and local communities," said report co-author Cara Horowitz, executive director of the Emmett Center on Climate Change and the Environment. "We can act now to rapidly scale up effective policies and programs to address plastic marine litter. And hopefully, international collaboration to reduce plastic litter will lay a foundation for broader cooperation on other significant issues affecting the health of our oceans."

Plastic marine litter has its origins in both land- and ocean-based sources, from untreated sewage and industrial and manufacturing sites to ships and oil and gas platforms. Pushed by the natural motion of wind and ocean currents — often over long distances — the litter is present in oceans worldwide, as well as in sea floor sediment and coastal sands. As the particles break down and disperse, they have a wide range of adverse environmental, public health and economic consequences with the potential to kill wildlife, destroy natural resources and disrupt the food chain.    

• Download Stemming the Tide of Plastic Marine Litter - A Global Action Agenda - UCLA Report

The Pritzker Environmental Law and Policy Briefs are published by UCLA School of Law and the Emmett Center on Climate Change and the Environment in conjunction with researchers from a wide range of academic disciplines and the broader environmental law community. They are made possible through a generous donation by Anthony "Tony" Pritzker, managing partner and co-founder of The Pritzker Group. The briefs provide expert analysis to further public dialogue on issues impacting the environment.

UCLA School of Law, founded in 1949, is the youngest major law school in the nation and has established a tradition of innovation in its approach to teaching, research and scholarship. With approximately 100 faculty and 1,100 students, the school pioneered clinical teaching, is a leader in interdisciplinary research and training, and is at the forefront of efforts to link research to its effects on society and the legal profession.  

Contact: Sara Rouche
310-206-2221
University of California - Los Angeles

The people's choice: Americans would pay to help monarch butterflies

Americans place high value on butterfly royalty. A recent study suggests they are willing to support monarch butterfly conservation at high levels, up to about 6 ½ billion dollars if extrapolated to all U.S. households.

If even a small percentage of the population acted upon this reported willingness, the cumulative effort would likely translate into a large, untapped potential for conservation of the iconic butterfly.

Monarch butterfly populations have been declining across Mexico, California and other areas of the United States since 1999. A 2012 survey at the wintering grounds of monarchs in Mexico showed the lowest colony size ever recorded.

"The multigenerational migration of the monarch butterfly is considered one of the world's most spectacular natural events," said Jay Diffendorfer, a USGS scientist and the study's lead author. "However, managing migratory species is difficult because they can cross international borders and depend on many geographic areas for survival."

Much of the decline in monarch numbers has been blamed on the loss of milkweed, the native plants on which monarch caterpillars feed.

"While many factors may be affecting monarch numbers, breeding, migrating, and overwintering habitat loss are probably the main culprits," said Karen Oberhauser, a monarch biologist at the University of Minnesota and a co-author of the study. "In the U.S., the growing use of genetically-modified, herbicide-tolerant crops, such as corn and soybeans, has resulted in severe milkweed declines and thus loss of breeding habitat."

The authors suggest that the universal popularity of monarchs could encourage a market for monarch-friendly plants.

"This is the first nation-wide, published, economic valuation survey of the general public for an insect. The study indicates that economic values of monarch butterflies are potentially large enough to mobilize people for conservation planting and funding habitat conservation," said John Loomis, the lead economist on the study from Colorado State University.

"The life cycle of monarchs creates opportunities for untapped market-based conservation approaches," Diffendorfer continued. "Ordinary households, conservation organizations, and natural resource agencies can all plant milkweed and flowering plants to offset ongoing losses in the species' breeding habitat."

According to the annual survey of the National Gardening Association, households that identify as "do-it-yourself lawn and gardeners" spent $29.1 billion in related retail sales in 2012.

"By reallocating some of those purchases to monarch-friendly plants, people would be able to contribute to the conservation of the species as well as maintain a flower garden," said Oberhauser. "Helping restore the monarch's natural habitat, and potentially the species' abundance, is something that people can do at home by planting milkweed and other nectar plants."

Unfortunately, many plants purchased by gardeners have been treated with systemic insecticides that can kill both pollinators that consume the nectar, and caterpillars, like monarchs, that eat the leaves.

"This study shows that not only might consumers pay more for monarch-friendly milkweeds grown without systemic insecticides in the potting soil, but also that consumers might be more interested overall in buying nectar-producing plants or milkweeds if they knew a small percentage of sales will be donated to habitat conservation," said Diffendorfer.

The study, released today in Conservation Letters, was authored by researchers with the USGS, Colorado State University, the University of Minnesota, and others, who participated in a USGS John Wesley Powell Center for Analysis and Synthesis working group.

Monarchs are very popular in both society and throughout education. The monarch butterfly is currently the official insect or butterfly of seven different U.S. states, and is celebrated in festivals held across North America. Monarchs have been the focus of many school's science curricula as well as the subjects of multiple citizen-science projects. 

Contact: Ethan Alpern
703-648-4406
United States Geological Survey

Melting Arctic sea ice could increase summer rainfall in northwest Europe suggests new study

This shows the average location of the jet stream during wet summer months over northwest Europe. The arrows represent the winds at roughly 10 kilometers above the Earth's surface. The orange and red arrows show the strongest winds that make up the jet stream. Credit: James Screen, University of Exeter

A new study offers an explanation for the extraordinary run of wet summers experienced by Britain and northwest Europe between 2007 and 2012. The study found that loss of Arctic sea ice shifts the jet stream further south than normal resulting in increased rain during the summer in northwest Europe.

Dr James Screen from the University of Exeter used a computer model to investigate how the dramatic retreat of Arctic sea ice influences the European summer climate. He found that the pattern of rainfall predicted by the model closely resembles the rainfall pattern of recent summers. The study is published in the journal Environmental Research Letters.

Dr Screen said: "The results of the computer model suggest that melting Arctic sea ice causes a change in the position of the jet stream and this could help to explain the recent wet summers we have seen.

"The study suggests that loss of sea ice not only has an effect on the environment and wildlife of the Arctic region but has far reaching consequences for people living in Europe and beyond."

Jet streams are currents of strong winds high in the atmosphere – around the height at which aeroplanes fly. These winds steer weather systems and their rain. Normally in summer the jet stream lies between Scotland and Iceland and weather systems pass north of Britain. When the jet stream shifts south in summer, it brings unseasonable wet weather to Britain and northwest Europe causing havoc for tourism and farming. 

 

The model suggests that while summer rainfall increases in northwest Europe, Mediterranean regions will receive less rain. The effects are not limited to Europe - weather systems as far as North America could also be influenced.

The annual average extent of Arctic sea ice is currently declining at about half a million square kilometres per decade – equivalent to about twice the area of the UK. The study compared weather patterns during low sea ice conditions as seen in recent years to weather patterns during high sea ice conditions typical of the late 1970s. The model did not use estimates of how much sea ice there will be in the future, and so this study cannot predict future weather. The results do suggest however that if sea ice loss continues as it has over recent decades, the risk of wet summers may increase.

 

Citation: J A Screen; Influence of Arctic sea ice on European summer percipitation; 2013 Environ. Res. Lett. 8 044015, doi:10.1088/1748-9326/8/4/044015

Other studies have suggested that recent ocean warming of the North Atlantic could also be responsible for more summer rain in northwest Europe. It is likely that several other factors, combined with the impact of melting Arctic sea ice, explain the recent run of wet summers.

The next step is to use estimates of future sea ice loss to make predictions of how further melting could influence summer rainfall in Europe in the years to come.

Contact: Jo Bowler
44-013-927-22062
University of Exeter 

Urban Underground Holds Sustainable Energy

Groundwater Aquifers in Conurbations Hold Geothermal Energy – Researchers Develop Model of Heat Flux into the Underground.

By Monika Landgraf

Where does the heat in the underground of large cities come from? Researchers analyzed various factors. (Graphics: AGW/KIT)

Vast energy sources are slumbering below big cities. Sustainable energies for heating in winter and cooling in summer may be extracted from heated groundwater aquifers. Researchers from KIT and ETH Zurich developed an analytical heat flux model and found that increasing heat in the underground is mainly caused by an increase in surface temperatures and heat release from buildings. 

Temperatures in big cities are far above those in the surrounding rural area: Dense settlement, surface sealing, industry, traffic, and lacking vegetation cause an urban microclimate with increased temperatures in the atmosphere. Temperature anomalies also develop in the underground. They spread laterally and vertically. In the past decades, groundwater in conurbations heated up considerably. “In Karlsruhe, the average heat flux density into subsurface aquifers was 759 milliwatts per square meter in 1977. In 2011, a heat flux density of 828 milliwatts per square meter was reached,” says Junior Professor Philipp Blum, Head of the Engineering Geology Division of the KIT Institute of Applied Geosciences (AGW). “This amount of heat corresponds to 1 petajoule per year and would suffice to supply at least 18,000 households in Karlsruhe with heat.“

In cooperation with Kathrin Menberg and Axel Schaffitel from KIT and Dr. Peter Bayer from ETH Zurich, Philipp Blum also studied the origin of heat in the underground of conurbations. The scientists developed an analytical heat flux model to examine factors, such as the increase in temperatures of sealed surfaces, heat release from buildings, sewage ducts, and underground district heating networks as well as discharge of thermal waste water. By modeling anthropogenic heat fluxes into the underground of the city of Karlsruhe, the researchers determined long-term trends of heat flux processes. They found that the increased surface temperature and heat release from buildings in particular are responsible for the increase in temperatures in the subsurface area.

The energy from close-to-surface groundwater aquifers might be used for heating in winter and cooling in summer via geothermal heat pumps and groundwater heat pumps. Use of this geothermal potential would not only cover part of the growing demand for energy, but also reduce the emission of greenhouse gases, which would counteract heating of the cities.

Citation: Kathrin Menberg, Philipp Blum, Axel Schaffitel, and Peter Bayer: Long-Term Evolution of Anthropogenic Heat Fluxes into a Subsurface Urban Heat Island. Environmental Science and Technology, 2013, 47 (17), pp 9747–9755. DOI: 10.1021/es401546u.

Contact: Kosta Schinarakis
PKM, Themenscout