Portal de Periódicos da CAPES

Dispatches

2015; Wiley; Volume: 13; Issue: 7 Linguagem: Inglês

10.1890/1540-9295-13.7.348

1540-9309

ESA,

Urban Agriculture and Sustainability

The Urban School Food Alliance – a coalition of the biggest school districts in the US: New York City, Los Angeles, Chicago, Miami-Dade, Dallas, and Orlando – recently announced that polystyrene trays in those schools' cafeterias will be replaced with newly designed compostable round plates. The rollout of the new plates has already begun in some schools, starting in May. The districts serve 2.5 million meals each school day, meaning the switch will prevent 225 million polystyrene trays from entering the waste stream every year. Polystyrene degrades extremely slowly in the natural environment; is widely found littering beaches and urban landscapes; and contains styrene and benzene, known toxic substances and suspected carcinogens. New compostable school-lunch plates provide health, cost, and environmental benefits. The need to stop serving food to children on polystyrene trays might seem clear, but it hasn't been easy to achieve. Compostable plates typically cost three times as much as polystyrene trays (12 cents and 4 cents each, respectively), which has made the former cost-prohibitive, given schools' tight meal program budgets. The six districts of the Alliance used their collective purchasing power (more than $550 million in food and supplies annually) to encourage manufacturers to develop a more affordable, environmentally friendly alternative to polystyrene. The new plates, manufactured in Maine by Huhtamaki North America (De Soto, KS), are made from pre-consumer recycled newspaper (recycled clippings left over when newspapers are cut) and are close in cost to the traditional polystyrene trays, at just under 5 cents each. Environmentalists applauded the move, saying that using compostable plates in place of polystyrene will reduce landfill waste, lessen plastic pollution in waterways, and generate rich compost. Eric Goldstein (New York, NY), Chairman of the Alliance, says: “While the compostable plates will help teach kids about environmental responsibilities, their use will also be a way for schools to encourage cities to fund and develop better composting facilities. Each school district is working with local municipalities to establish composting systems, and several schools from each district already have or are piloting composting programs.” The Alliance is also working to introduce compostable utensils. A vast warm water mass dubbed “the blob” – growing in the North Pacific Ocean since the fall of 2013 – underpins a series of odd events still underway. From the arrival of tropical plankton to a massive toxic algal bloom to large-scale die-offs of seabirds, sea stars, and salmon, the curious incidents are stacking up. The expanse of warm water prevents the normal upwelling of nutrient-rich waters off the Pacific Northwest coast that supports plankton and forage fish stocks that, in turn, fatten up migratory top predators such as salmon, tuna, and whales. But, according to researchers, these conditions are unprecedented. Such rapid ecosystem-level shifts may be a new normal –and fisheries management must adapt. “These events are a manifestation of increased climate variability”, warns Bill Peterson, an oceanographer at NOAA's Northwest Fisheries Science Center (Newport, OR). “All this weird stuff is beyond our experience.” The potential for widespread losses as a result of marine anomalies is causing concern. For example, in the summer of 2005, upwelling was delayed by a mere 2 months. As a result, the salmon fishery was closed for 2 years, costing the industry $200 million, says Peterson. Yet, managers continue to rely on fisheries models that focus predominantly on stock sizes to set catch limits. “We know that things like ocean productivity probably have a greater impact on stocks than fishing does, but we assess how stocks are affected and adjust catch limits accordingly”, says Kit Dahl, staff officer with the Pacific Fishery Management Council (Portland, OR). Dahl adds that while research is underway to incorporate changing ocean conditions into models, those efforts haven't yet evolved to the point where they can be a basis for tactical decision-making. Now that El Niño has returned, the ocean food-web impacts are even more uncertain. “We have two big oceanographic events that are causing sea surface temperatures to be anomalously high”, explains Steve Marx, policy analyst for the Pew Charitable Trusts (Portland, OR). Already, species that make up the middle of the food web – including krill, anchovies, and herring – are at historically low levels, he continues. “It looks bleak for the forage base.” Fortunately, says Marx, fisheries managers are getting better at accounting for the uncertainty that comes with changing ocean conditions, by taking a multi-species, ecosystem-based approach when setting catch levels. And perhaps this is just in the nick of time. “The rules are changing”, says Peterson. “It makes you wonder what's going to happen next.” Since the US Environmental Protection Agency mandated cuts to mercury (Hg) emissions in the 1970s, air deposition of the toxic metal has plunged by over 40% along the US eastern seaboard. Despite this decrease, scientists have speculated it could take centuries for Hg concentrations in marine fish to decline, since the ocean is so vast and slow to change. However, a new study shows that Hg concentrations in the body tissues of bluefish (Pomatomus saltatrix) have kept pace with falling Hg inputs to the mid-Atlantic coast (Environ Sci Technol 2015; doi:10.1021/acs.est.5b01953). Released through the burning of coal and waste, inorganic Hg is converted into neurotoxic methylmercury – which bioaccumulates in aquatic food chains – by aquatic bacteria. About 10% of US women of childbearing age have methylmercury levels high enough to damage fetuses. The greatest source of Hg exposure is from eating contaminated marine fish. “It's widely recognized that declining mercury deposition drives decreasing mercury concentrations in freshwater fish, so we wondered if the same thing was happening in marine fish”, says Richard T Barber, a biological oceanographer at the Duke University Marine Laboratory (Beaufort, NC) and a coauthor of the paper. He and his team relied on a 1972 study that measured Hg levels in bluefish in North Carolina. In 2011, the scientists collected bluefish at the same place and month as the earlier investigation. They used measurements of Hg in mid-Atlantic bluefish from eight other studies conducted from 1973 to 2007 and calculated that average Hg concentration in fish filets declined by 43% over the 40-year period. This mirrors the change in estimated annual Hg inputs to the offshore study area from Massachusetts to North Carolina, which decreased by 37% over the same period. “These results show that mercury bioaccumulation in marine fish is tightly coupled to mercury inputs to ocean water”, Barber explains, adding that the findings run counter to earlier assumptions that the ocean responds slowly to Hg inputs. Although concentrations in bluefish have dropped to 0.33 μg of Hg per gram of fish tissue, pregnant women must still limit the amount they consume. “The study shows that if you clamp down on mercury emissions, you'll see positive results in a fairly short period of time”, says Susan Fisher, an environmental toxicologist at Ohio State University (Columbus, OH). However, she cautions that the declines in the US may not be permanent since global Hg emissions are climbing due to expansion of coal-fired power plants in Asia. The Welsh School of Architecture at Cardiff University in the UK is accelerating the future of energy-efficient housing with its new Solcer House design. Open since July, the three-bedroom home is both affordable and capable of exporting more energy to the electricity grid than it uses on an annual basis – a rare combination. The home, measuring 1000 square feet, was built in 16 weeks at a cost of £125 000 ($195 000). Energy-positive homes exist already, but they are rare and expensive, making them difficult to replicate. “The house we built is the first of this kind in the UK that is low cost”, says the project's lead architect, Ester Coma Bassas (Cardiff, UK). “We've developed a design that can be built for the masses, allowing optimization for cost and energy-efficiency.” The building's balance of components involves high levels of thermal insulation to reduce energy demand; fully integrated, glazed photovoltaic panels and solar air collectors to provide power and thermal energy; and dual thermal/battery storage systems. In collaboration with the Welsh government, the architects relied on local manufacturers, materials, and installers when possible, further reducing the building's carbon footprint while providing local jobs. “The individual items we used are nothing special”, explains Coma Bassas. “They are ‘off the shelf’, already existing on the market. But it's how we designed the house – as an integrated efficient system with all items, power and thermal, working together – that gives the concept its potential.” The energy-positive Solcer House, in Wales, UK. Relying on the nation's electricity grid for supplementary energy imports and surplus exports, the house generates £175 ($272) in exports for every £100 ($155) spent on electricity. Energy-positivity works best when there are ways to absorb surplus power, such as through the electric grid or electric cars, although that's not yet the case in many locales. The Solcer House provides proof of concept for energy-efficient building. “Its design is based on new priorities”, enthuses Eric Corey Freed (International Living Future Institute, Portland, OR). “The idea that you can have a low-cost net-positive house is exactly what we need. The rules that we took for granted on how we build our buildings are changing.” Conservation of endangered species requires accurate information about the organisms' daily lives. But the more elusive or rare the species, the harder it is to obtain baseline ecological data. Marine mammals can be particularly difficult to study, as their underwater nature puts them out of reach of land-dwelling scientists. However, they do produce readily available samples that can provide valuable information: feces. Fecal matter contains remnants of recent meals. Traditionally, scientists look for evidence of food items like beaks and bones, which help to identify key prey species, in turn giving clues as to habitat usage. But when Kristian Peters (South Australia Department of Environment, Water and Natural Resources, Adelaide) hand-sifted through about six hundred freshly collected samples from Australian sea lions (Neophoca cinerea) – a charismatic and endangered species – he couldn't find much. “Sea lions have these sloppy poos”, Peters explained. “We don't find many samples with remains because most are digested, making it difficult to determine what they eat.” Waiting for a sample. Peters and his colleagues decided to use alternative molecular DNA techniques to fill in the blanks. Genetic analysis of fecal matter has become an increasingly popular technique for studying diet in recent years, because it allows for finer resolution when stomach contents and fecal samples fall short. Nevertheless, ensuring that such protocols accurately reflect prey composition can be a challenge. Peters and his colleagues therefore tested their methods in a closed system first, sequencing genetic evidence from the feces of captive animals that consumed a known diet (Marine Ecology 2014; doi:10.1111/maec.12242). They then amplified DNA from wild sea lion stool samples, using small regions of the mitochondrial 16S gene to identify prey species. In a separate paper (Marine Ecology 2014; doi:10.1111/maec.12145), Peters et al. describe the first fine-scale DNA dietary analysis for Australian sea lions, identifying about 30 prey species not previously reported in the animals' diet. These included organisms that frequent seagrass beds, rocky reefs, and mixed sandy bottoms, “which suggests that all these habitats are really important for the sea lions”, says Peters. These results further underscore the usefulness of DNA sequencing as a non-invasive method of diet analysis in imperiled species. Non-native invasive mammals have driven dozens of endemic species to extinction in Mexico and Australia, two countries currently taking action to protect native wildlife. Recent successes include the eradication of rats from Banco Chinchorro (a large coral atoll composed of three islands off the Yucatan Peninsula) and the launch of Australia's first national Threatened Species Strategy – a key component of which is a plan to cull two million feral cats nationwide by 2020. In cooperation with the federal government, the nongovernmental organization Grupo de Ecología y Conservación de Islas (GECI) has cleared 57 invasive mammal populations from 37 Mexican islands, including the newly rat-free Banco Chinchorro. According to the director general of GECI, Alfonso Aguirre (Ensenada, Mexico), the work on Banco Chinchorro's largest island, Cayo Centro, represents a conservation benchmark. The removal marks the first rodent eradication from a tropical, wet island of its size (539 ha), releasing important migratory bird species from predation by rats. To achieve this, GECI staff had to adapt to novel conditions: for instance, kayaking through dense mangroves to tie “piñatas” of poison bait above the intertidal zone, and temporarily corralling many of the island's native iguanas to reduce bait interference. Culling invasive mammals is “actually a very common conservation tool”, explains James Russell, rodent eradication specialist at the University of Auckland (Auckland, New Zealand). “There have been about 1000 [non-native] mammal eradications from islands around the world.” Russell believes that the reason for the approach's success lies in its relative simplicity: unlike many other environmental challenges where solutions are neither obvious nor easy to implement, rodents can be eradicated by baiting alone. “We've got it down to a fine art”, he says. Feral cats, however, are another story. “To date we don't have a technique for controlling cats”, admits John Read (University of Adelaide, Adelaide, Australia). Existing management methods are labor-intensive (leg-hold and cage traps require inspections, and building long fences requires time and resources) or ineffective (cats would rather hunt bandicoots than scavenge bait). Even when campaigns manage to reduce cat numbers, a few wary individuals usually evade the culling, continues Read, who is developing a solution with funding provided under the new national Strategy. His humane grooming “traps” do not restrain but rather will detect a cat based on body size and shape, then spray its coat with toxin that the animal will ingest when it grooms itself. Read emphasizes that cat control is imperative; several populations of native Australian mammals are still around only because of feral cat management. When used responsibly, antibiotics can stop bacterial infections and save lives. However, an overreliance on such treatments can lead to drug-resistant microbial strains, threatening both human and animal health. In a new study (J Wildlife Dis 2015; doi:10.7589/2014-11-257), scientists from Virginia Tech (Blacksburg, VA) measured antibiotic resistance in intestinal microbes from different mammalian and avian species in northern Botswana, with the goal of better understanding how resistant bacteria contaminate and move through the environment. As author Kathleen Alexander explains, “Each animal species has its own unique way of interacting with the environment”. Tracking these species' differences provided clues about how resistance to antimicrobials infiltrates ecosystems, prompting Alexander and her team to ask why the gut flora of some species exhibit higher levels of drug resistance than others. In fecal samples collected from 19 different wild and domestic species, the researchers isolated and tested Escherichia coli – a common intestinal bacterium – for resistance to 10 antibiotic drugs. Of the 150 samples, over 40% contained E coli displaying resistance to one or more antibiotics and 13% contained E coli resistant to three or more antibiotics. Multidrug resistance (MDR) is a major concern because it indicates that bacteria are becoming less responsive to available antimicrobial treatments. The team also found links between the E coli's resistance and its host's habitat use and position in the food web, with a particular susceptibility among aquatic species like hippopotamus. According to Alexander, “wildlife species living with humans and top predators were significantly associated with MDR. But, intriguingly, animals living in water had higher levels of MDR than species that did not.” Alexander and her colleagues are now interested in the relationship between water and microbial resistance – so much so that the focus of their fieldwork has shifted to the region's waterways. “The work on the river is difficult, as it's filled with hippopotamus and crocodiles and other dangerous animals”, says Alexander. “But, we now know that water contamination – even in the national park – is an important factor contributing to accumulation of MDR.” Her team currently runs the only laboratory in the region for this type of work, so getting supplies and equipment to their remote study areas is often a challenge. Nevertheless, their monitoring efforts across landscapes provide critical insight into exposure and accumulation of multidrug-resistant bacteria that can be applied to other ecosystems. “Our work here has global implications”, Alexander concludes. A 93-m2, solar-powered geodesic dome almost 2500 m up the lava rock-jumbled slopes of Hawaii's Mauna Loa – the world's largest subaerial volcano – will be home to six scientists living together in isolation for a full year. The NASA-funded Hawaii Space Exploration Analog and Simulation project (HI-SEAS; http://hi-seas.org) began its fourth and longest mission on August 28. The project's primary focus, similar to the three before it, is to gather new psychological and sociological data on individuals living in isolated environments in order to predict the experience of astronauts on a 3-year expedition to Mars. “Mauna Loa is one of the most Mars-like places on Earth in terms of its physical geology. It's a shield volcano, and similar in both surface appearance and underlying geology to Mars”, says Kim Binsted, HI-SEAS Mission IV Principal Investigator (Manoa, HI). “Unlike other analogs, such as those in Antarctica, [Mauna Loa] has this really nice combination of being isolated yet accessible.” Mauna Loa, HI, will provide mission scientists with a Mars-like experience. The mission scientists – who bring varied backgrounds to the project: from soil science to astrobiology to neuroscience and even architecture – will conduct individual experiments to better understand the complexities of sustaining an Earth-like ecosystem for space travelers. “We take for granted the quality of our soil and agricultural resources here on Earth”, says crew commander and soil scientist Carmel Johnston (Whitefish, MT). Planned experiments include growing vegetables in simulated Martian soil – ie without Earth's biotic components – as well as using aquaponics, hydroponics, and bioponics. Unlike previous efforts, such as the Mars 500 Program (Russian Academy of Sciences' Institute of Biomedical Problems, Moscow, Russia) and the unsuccessful 1991 Biosphere 2 mission (Columbia University, Oracle, AZ), the HI-SEAS crew will be allowed out of the habitat, but only in full space attire. A rover will aid exploration of the surrounding lava rock. “Earth is a magical planet that is traveling through the solar system with the perfect conditions to support human life”, says Johnston. “Many things that we learn…will teach us about Mars, but will also give us great insight into our own relationship with Earth. Hopefully this will allow us to be better stewards of our own planet while we explore the potentials of Mars.” In July, the Doñana National Park, in southern Spain's region of Andalucia, was awarded IUCN Green List status, making it one of 24 protected areas (others include Italy's Gran Paradiso National Park, Colombia's Gorgona National Park, and Kenya's Ol Pejeta Conservancy) recognized for their successful conservation efforts. Covering over 200 km2 of pine forests, marshlands, lagoons, sand dunes, and beaches, Doñana is one of Europe's most biodiverse areas. Greater flamingoes (Phoenicopterus roseus), spoonbills (Platalea leucorodia), huge concentrations of waterfowl (over 500 000), the Iberian imperial eagle (Aquila adalberti), and the Iberian lynx (Lynx pardina) top the bill among a cast of 360 species of birds, 37 mammal species, over 30 species of reptiles and amphibians, and nearly 900 species of flora. The listing adds to Doñana's other accolades: UNESCO World Heritage Site and Biosphere Reserve, RAMSAR Wetland of International Importance, and European Union Special Protection Area. Doñana National Park Being appointed to the Green List, which was launched in November 2014 at the IUCN World Parks Congress in Sydney, Australia, is a sign of having met global standards in protected area management. As James Hardcastle, Manager of the IUCN Green List of Protected Areas (Gland, Switzerland) explains, it “celebrates that biodiversity and ecosystem services are being maintained, that conservation efforts are achieving intended goals, and that the costs and benefits of protection are equally shared [by stakeholders]”. Doñana has made a major contribution to the recovery of the Iberian lynx, increasing its population within the Park boundaries from 41 in 2002 to 94 in 2013. It has also been involved in its captive breeding, helping to raise numbers across Spain to over 300. As a result, the species was recently downgraded from Critically Endangered to Endangered on the IUCN's Red List. “The lynx and Iberian imperial eagle recovery programs are possibly our best-known projects”, says Park Director Juan Pedro Castellano Domínguez, “but making the Green List is also recognition of our [other conservation efforts] and exertions in managing this space, while taking into consideration human activities within it and [the needs] of its local communities”. Remaining on the list, however, requires that parks maintain standards and respond to threats, with inspections undertaken by the IUCN every 2 years. Although Spain's Supreme Court recently ruled against the dredging of the Guadalquivir River (which borders Doñana) to accommodate ocean-going shipping, the use of water for agriculture around the Park, as well as external mining projects, remain major threats. Four years of extreme drought have forced California to take drastic measures. Last year, Governor Jerry Brown asked cities to cut water use by 20%, but this voluntary approach failed. So this spring he ordered municipalities to reduce water consumption by 25% and, over the summer, the state launched a website for people to anonymously report suspected instances of water squandering. “Leaks and overwatering are a huge source of waste”, says George Kostyrko, head spokesman for the State Water Resources Control Board (SWRCB) in Sacramento. Some cities already have water waste reporting programs, but many don't. “The new site bridges the gap”, Kostyrko explains, adding that to his knowledge this is the first state-level tool for recording inefficient use or misuse of water. California's emergency regulations for water conservation target outdoor use, limiting irrigation to twice weekly and banning runoff onto sidewalks and down gutters. There is evidence that some Californians are likely to embrace the site (http://savewater.ca.gov), which sends allegations of waste to 1400 water agencies statewide. According to a recent poll by the San Francisco-based Public Policy Institute of California, 60% of residents say their neighbors aren't doing enough to respond to the drought. “Water is a finite resource”, Kostyrko points out. “We need to get people thinking about how they're using it.” Education often prompts people to do the right thing, but there are still plenty of scofflaws, and water agencies lack the manpower to find them all. “Neighbors ratting out neighbors is like having free ‘water cops’”, explains Mark Lubell, director of the University of California–Davis Center for Environmental Policy and Behavior (Davis, CA). Being caught makes most water wasters comply, but the unrepentant face fines of $500 per day. “It's just like drivers disobeying the speed limit –some people only respond if they get a ticket”, continues Lubell. The new website comes as California begins its hottest months, when conserving water is the most challenging – and the most essential. “Every drop saved will help stretch the state's limited supply”, SWRCB chair Felicia Marcus cautioned in a statement. “We don't know whether next year will be a fifth year of drought.”