2012/06/01 by ESA · 1 citation
Earth and Planetary Sciences · Environmental Science · Chemistry · #Ocean Acidification Effects and Responses #Marine Bivalve and Aquaculture Studies #Marine Biology and Ecology Research #Emiliania huxleyi #Coccolithophore #Ocean acidification #Coccolith #Total inorganic carbon #Phytoplankton #Population #Oceanography #Biology #Environmental science #Ecology #Seawater #Carbon dioxide #Carbonate #Chemistry #Geology #Nutrient
paper · pdf · doi:10.1890/i1540-9295-10-5-228
published in Frontiers in Ecology and the Environment 10(5), 228-232 (Wiley)
openalex publication_date 2012/06/01 · openalex created_date 2022/05/11 · openalex updated_date 2026/07/29
As oceans soak up atmospheric CO2 emissions, the resulting carbonic acid lowers water pH, compromising the growth and productivity of organisms that rely on calcium carbonate to make shells, scales, or skeletons. Until now, it was unclear whether these marine organisms would adapt to the new conditions over the long term. Researchers at the GEOMAR Helmholtz Centre for Ocean Research (Kiel, Germany) have published the first experimental evidence demonstrating that, after only 500 generations, the coccolithophore Emiliania huxleyi, an important phytoplankton species, can adapt to more acidic waters (Nat Geosci 2012; doi:10.1038/ngeo1441). Evolutionary biologist Thorsten Reusch and colleagues show that asexually reproducing populations of E huxleyi grown in cultures exposed to increased CO2 had both higher growth rates and 50% higher calcification rates than those of populations grown at ambient CO2 when both populations were tested in acidic waters. Electron microscope image of Emiliania huxleyi. “We were motivated to do this work because marine ecologists were overlooking the capacity for contemporary evolution when trying to predict future responses”, explains Reusch. He says E huxleyi is, arguably, the world's single most important calcifying organism because it is so productive and because it weighs down other organic material, improving transport of carbon from the surface to the depths of the ocean. But E huxleyi's short generation time likely enhances its adaptive capacity. “These findings are not totally unexpected because these are such fast reproducing organisms with large population sizes, but this is the first solid ‘proof of concept’ that growth and calcification rates can evolve in a high CO2 world”, comments Jennifer Sunday, a marine ecologist at Simon Fraser University (Burnaby, British Columbia). Last year, Sunday and colleagues demonstrated, by comparing genetic and phenotypic variation and population turnover rates, that a sea urchin species (Strongylocentrotus franciscanus) may have a faster evolutionary response than a mussel (Mytilus trossulus). “In my simulations, turnover rate is a good predictor of how quickly organisms may be able to evolve”, says Sunday. Genetic evidence suggests E huxleyi populations sexually reproduce in the oceans, yet don't in culture, for unknown reasons. “Our results likely underestimate the capacity for adaptation; future work is needed to see if a boost of sexual recombination would, as expected, accelerate adaptation”, concludes Reusch. Within the Yasuni National Park in eastern Ecuador lies the Ishpingo Tambococha Tiputini (ITT) oil field, containing an estimated 846 million barrels of oil. Even with the most advanced drilling techniques, extracting the oil would devastate one of the planet's most biodiverse places, which is also home to two isolated indigenous tribes. But the oil is worth US7.2 billion, a significant addition to the country's economy, which has long depended on crude oil as its primary export. To protect this special part of the Amazon rainforest – 1 ha of which contains more native tree species than are found in all of North America – the government of Ecuador has made a unique proposition. If the countries, corporations, and citizens of the world, as a show of goodwill and cooperation, contribute 50% of the market value of the oil – US3.6 billion – over the next 13 years, the government will forego extraction of the oil and save the Yasuni-ITT region from destruction. The plan emphasizes that developed countries need to pitch in to protect the ecological assets of poor countries, to make their conservation efforts realistic and sustainable. Ivonne Baki, Ecuador's Secretary of State, is leading the Yasuni-ITT Initiative. Says Baki, “Most programs provide funding for remediation and reforestation after natural areas have been destroyed. What we are doing with the Yasuni-ITT Initiative is saying that we don't want to take down the trees in the first place. We want to leave the oil in the ground and protect this special basin of life. This project represents a new way of thinking. It is a preventative measure to protect the forest and avoid significant greenhouse-gas emissions.” An estimated 407 million metric tons of CO2 emissions would be saved if the Yasuni-ITT oil were left in the ground, and an additional 800 million metric tons of CO2 emissions would be avoided by preventing related deforestation. Should a future government want to remove the oil, citizens of Ecuador would first have to agree through a referendum, and donors who have contributed US50 000 or more would have to be repaid. The funds, to be invested in clean energy, reforestation, and other conservation efforts in Ecuador, are being managed by the UN Development Programme. More information, including updated fund totals and participating donors, is available at www.yasunisupport.org. The Yasuni-ITT Initiative will be prominently featured at the Rio+20 summit in June. Large-scale harvesting of forest biomass to meet current biofuel targets is neither carbon (C) neutral nor sustainable, according to a new analysis. The study (GCB Bioenergy 2012; doi:10.1111/j.1757-1707.2012.01169.x) examines the implications of increasing forest biomass harvesting to meet the goal of supplying 20% of total worldwide energy needs. The authors conclude that this would require fully 60% of the new growth created in forests each year. In reality, the impact could still be higher, because the 60% estimate includes root and leaf biomass that is of little value in bioenergy production. This strategy would likely fail to reduce greenhouse-gas (GHG) emissions, largely because it would deplete forest C pools, outweighing the benefits of biofuel use. The assumption that forest biomass harvesting is C neutral is therefore not valid, the analysis concludes, given that the reduction of C pools may take decades to centuries to be paid back – if it can be restored at all – by substituting biofuels for fossil fuels. “Previous reports on bioenergy were rather optimistic”, says lead author Ernst-Detlef Schulze (Max-Planck Institute for Biogeochemistry, Jena, Germany), “including the Intergovernmental Panel on Climate Change (IPCC) report on renewable energies (Renewable Energy Sources and Climate Change Mitigation, 2012). Our assessment, based on realistic numbers for biomass that is harvestable, accessible, and not under protection, comes to a different conclusion: there is not enough growth in forests to harvest the politically anticipated amounts in a sustainable manner.” Additional harvesting would also deplete soil fertility, requiring the addition of fertilizer that would further increase GHG emissions through the production of nitrous oxide. The authors also argue that increased biomass harvest would result in a loss of forest diversity and complexity, with forest composition shifting toward more homogeneous stands of younger trees. The analysis assumed a goal of supplying 20% of total energy needs because that represents policy targets in several developed nations, explains Schulze. The authors focused on the impacts of achieving this goal by increasing forest harvests, rather than growing biofuel crops on agricultural land, because using forest biomass avoids competition with food production. The research draws on data from several regional studies. One of these, conducted in forests along the west coast of the US, found that forest thinning for fire prevention and large-scale bioenergy harvest in areas with high fire risk would lead to 2–14% higher GHG emissions as compared with emissions from current management practices, says Beverly Law, a co-author of the GCB Bioenergy analysis. Tick diversity and dispersal may be getting a huge boost from seabird hosts, new research has shown. Seabirds such as the brown booby (Sula leucogaster) are known to travel vast distances between different breeding areas. The study (Biol Lett 2012; doi:10.1098/rsbl.2012.0179) finds that bird migration serves as an effective long-distance tick dispersal mechanism, greatly increasing the diversity of tick species on island archipelagos like Cape Verde, off the western coast of Africa. Lead author Elena Gómez-Díaz (Institute of Evolutionary Biology, CSIC-UPF, Barcelona, Spain) explains that “ticks from multiple and distant geographic origins, including colonies in the Indian, Atlantic, and Pacific Oceans, are mixed in Cape Verde. Our results indicate that this diversity originated by multiple and independent trans-oceanic colonizations of the islands by seabird hosts.” Given that tick mobility is determined by the host species, this work highlights the important role that seabirds may play in parasite dispersal. Seabirds like this brown booby (Sula leucogaster) and chick may be transporting parasites hundreds of miles. These findings have important conservation and epidemiological implications. Because ticks can negatively affect seabird behavior and reproductive success and can also serve as vectors for several diseases, monitoring tick dispersal is essential. According to Gómez-Díaz, “The fact that seabirds are able to carry ticks over large distances poses serious risks for the spreading and emergence of infectious agents worldwide”. Tracking the parasites can also provide migratory information about the seabirds. “A bird may visit a distant colony [without reproducing there] and return to its natal colony or region for mating. In this scenario, parasites can be [better] markers of large-scale movements in birds than their own DNA.” Gómez-Díaz and her colleagues continue to investigate many questions surrounding parasite dispersal and diversity, such as whether similar patterns occur in other geographic areas and how easily ticks may be able to switch to different host species. “This work further emphasizes that parasite biodiversity has been largely underestimated, and encourages future study in this and other parasite systems to uncover the true contribution of parasitic organisms to global biodiversity”, she concludes. India has launched a new experiment that combines solar energy with irrigation canals to achieve faster rollout of solar power. A one megawatt (MW) solar power project unveiled at Chandrasan (Gujarat, India) uses solar panels fixed over a 750-m stretch of an irrigation canal. Unlike new solar projects that require a minimum of 5 acres (2.02 ha) of land to produce one megawatt of power, no additional land had to be acquired for this project. For developers, acquiring the necessary land for solar power plants involves high upfront costs and complicated changes to land-use and settlement claims. Besides saving time and money with land acquisition, canal-top solar arrays would also minimize irrigation water evaporation; the Chandrasan project, for instance, is projected to save nine million liters of water per year. If the experiment is successful, the local government plans to implement similar projects along a 458-km stretch of the Narmada Canal, a major irrigation canal in Gujarat, in the future. Canal-top solar power projects can reduce energy costs. Many Indian states have extensive networks of irrigation canals; the total length of these channels in Gujarat alone is 19 000 km. “Even if [only] 10% of this network is used for deploying solar panels, we can generate 2400 MW of solar power and eliminate the need to acquire about 10 000 acres (~4047 ha) of land for power generation”, points out Gurdeep Singh (Gujarat State Electricity Corporation Limited, Ahmedabad, India). Another Indian state, Punjab, also plans to harness canal-top solar power. However, the success of such efforts would depend on factors such as canal location, the availability of grid access, and coordination between irrigation and power utilities. In addition, says independent consultant Jami Hossain (Gurgaon, India), maintenance of both solar panels and irrigation channels could pose problems unless specific provisions are enacted. India's Jawaharlal Nehru National Solar Mission is a related effort, intended to boost solar energy production throughout the nation. The Mission entails achieving 20 000 MW of solar capacity by 2022, up from the present installed capacity of 979 MW. With 300 sunny days a year occurring in most parts of the country, coupled with favorable policies, the Indian Government believes that this target could easily be met. Conservationists are urging the Australian Federal Government to consider National Heritage listing for Tasmania's 447 000-ha Tarkine rainforest before they decide whether to approve 10 new mines in the region. “The Tarkine – the second largest temperate rainforest on Earth – is sited above the world's second largest undeveloped tin reserve”, explains Tarkine National Coalition spokesman Scott Jordan (Burnie, Tasmania). While the tin deposits have been known about for some time, rising global tin prices over the past year have made their extraction a viable economic prospect. Much of the Tarkine's native forest is already slated to be spared from logging under a federal–state forests agreement, but the National Heritage deferral would mean the mine applications were not assessed against natural or indigenous cultural values under national protection laws. The Australian Heritage Council reportedly recommended listing the Tarkine in 2010, but the Federal Government deferred a decision on the grounds that the region's values are still being assessed. Biologists are concerned about the impact that the proposed mines will have on the last remaining region where Tasmanian devil (Sarcophilus harrisii) populations remain healthy, particularly since three devils suffering from devil facial tumor disease (DFTD) were discovered nearby. “The largest impact, behind habitat destruction at the mine site itself, is the increased traffic and building of new roads to the mines”, says Jordan. “The Tasmanian devil survives mainly by scavenging, so the increased roadkill will be like a magnet for them. Lots of devils are killed on roads, so the impact of the new roads would be enormous, let alone when combined with the disease.” Road construction may also facilitate the spread of DFTD, which has radiated from its original source in northeastern Tasmania at a rate of 5–10 km per year since its emergence in 1996. Despite increased knowledge about the disease, which has wiped out an estimated 84% of devils in the wild, the only current option for breaking the cycle of disease transmission is to move healthy devils to mainland and island sanctuaries where they will not encounter infected individuals. The Tasmanian Minerals Council has rejected claims that mining activity will promote the spread of DFTD. “Mining leases don't [include] foot traffic”, says the Council's executive director, Terry Long (Hobart, Tasmania). “They don't allow hunting and they're generally remote from human populations, and for that reason they're regarded by the devil protection experts as being ideal refuges, probably the best available in Tasmania.” Analysis of DNA harvested from the blood meals of leeches could help conservationists survey mammalian diversity in tropical forests, suggests new research published in the April 24 issue of Current Biology (2012; doi: 10.1016/j.cub.2012.02.058). “We found non-primate mammalian mitochondrial DNA in 21 out of 25 leech samples collected in the Central Annamite region of Vietnam”, explains Thomas Gilbert (University of Copenhagen, Denmark). “Most excitingly, we identified DNA from several shy or cryptic species, including two only recently described for the first time.” Monitoring mammals in tropical forests with conventional approaches, such as tracking and camera trapping, can be laborious. Consequently, many researchers are turning to analysis of DNA in resources such as mosquito blood meals and predator feces as alternative ways of assessing mammalian biodiversity. Gilbert and his colleagues at the Copenhagen Zoo got the idea of using leeches to screen for biodiversity after being attacked by these blood suckers while doing field work. To test the approach, they examined how long goat DNA persisted in medicinal leeches (Hirudo spp) fed on goat blood. “We actually ran out of leeches to test before the goat DNA had disappeared from the leeches”, says Gilbert, “a result that suggested we would not have to collect leeches immediately after a blood meal to find mammalian DNA”. The researchers then looked for mammalian DNA in wild Haemadipsa spp leeches collected from a densely forested biotope in Vietnam. “Remarkably, although some of the leeches contained DNA from cows and pigs, we also detected DNA from forest species for which there were no confirmed local records, such as the Annamite striped rabbit and the small toothed ferret-badger”, notes Gilbert. “Leeches may be useful in some circumstances”, comments George Amato of the American Museum of Natural History (New York, NY), “but I am skeptical that this approach will provide significant information on rare or shy animals”. Instead, Amato favors comprehensive scat collection to recover DNA from forest mammals. Gilbert agrees that leeches are not the only way to survey mammalian diversity in forests, but, he points out, “leech sampling is simple and cheap, so we would encourage conservationists to give our approach a try”. There was a point in the mid-20th century when many science-fiction writers predicted that almost everything in the future would be done via osmosis, so a press release from the American Chemical Society (ACS) last month seemed almost fictional, too. A team of ACS scientists had calculated exactly how much electrical power could be produced using osmosis near estuaries. Generating electricity by osmosis is indeed already underway at a prototype power plant in Norway. It works like this: when fresh and salt water converge in a typical estuary, a salinity gradient is formed. If a semi-permeable membrane is placed between the two, an increase in pressure occurs that can be used to drive a turbine and generate electrical energy. Known as pressure-retarded osmosis (PRO), this method may represent an exceptionally environmentally friendly way to produce power. In their paper, Menachem Elimelech and Ngai Yin Yip (Yale University, New Haven, CT) conclude that just one-tenth of the globe's current river water flow into the oceans could produce enough power to meet the electrical demands of 520 million people – greenhouse-gas (GHG) emissions 2012; doi: if power plants were used for that over one billion metric tons of would be used for power are pressure the of the has not been in these energy In to those be yet require additional energy as as and “This at one Yip A analysis is still have also been about changes to water and salinity near on the conditions where have power says an from the Institute for If the water being used is he then may be needed for the but a new building where the water source is clean land-use the other plants to where large already more “This is still in its but the we more people will be to got more protection than just their on April after the State their The is a biodiversity for with alone home to some species. 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