| Green Column: Texas Clean Energy Hampered by Location Texas is by far the biggest producer of wind energy in the United States, but the industry is running into a significant constraint: There are too few transmission lines to carry the power. feeds.nytimes.com |
You've discovered a whacky wood-eating catfish? So what's new? | GrrlScientist The press has recently been abuzz with news of a newly discovered species of catfish that eats wood, of all thingsThe press has recently been abuzz with news of a newly discovered species of catfish that eats wood, of all things. But since at least the 1990s, scientists have known that some catfish species consume wood. The news stories I have read haven't done a particularly good job of describing why journalists are so intrigued by this discovery, beyond the obvious twist: a fish that eats wood. But these fish are popular pets: If you look at the tropical fishes available for sale in your local pet shop, then you have probably seen at least one of the dozen or so species that are placed into the genus, Panaque. (For example, today in my local pet shop, there were three Panaque species - all coyly hiding under submerged bits of wood, so I couldn't get a decent photograph to share with you.)Panaque are medium to large freshwater fish that are placed in the taxonomic family Loricariidae, a large group of catfishes that are united by several common characteristics: their powerful suckermouths and the tough plates covering their bodies. Whilst Loricariidae are found throughout tropical and subtropical rivers in Central and South America, the Panaque, which are the wood-eating specialists in the family, appear to be limited to the Magdalena, Orinoco and Amazon River basins. These fish go by a number of names. The genus name "Panaque" (pronounced "pan ack" in Britain and Europe, and as either "pan aki" or "pan a kay" in America), is the Latinisation of a native Venezuelan name for these fish. The local indigenous people, the Sharanahua, call it Ishgunmahuan - "large armored catfish." Indeed, the Sharanahua are quite familiar with this new Panaque species, because it is a popular item on the menu. The fish, which can reach 70cm (2ft 3in) in length, can be located by characteristic rasping sounds produced when they chew on submerged wood. "They seem to be really tough to find and catch. You have to catch them with gill nets or cast nets, or shoot them," explained Paulo Petry, who is formally describing the new species for science based on three individual fish that he and his colleague, Peruvian biologist Roberto Quispe, captured. "Since they eat wood, you're not going to catch them with a line." Dr Petry, a zoology professor at Harvard University is also the Nature Conservancy's freshwater specialist for Latin America. During this past summer, Dr Petry was part of a scientific expedition to one of the remotest places on the Amazon River; the Fitzgerald Arch, located in Peru. The trip was sponsored by the US National Science Foundation and took place between 21 July and 3 August. "Right now, it's fairly isolated there," said Dr Petry. "There are just two flights a month there from [the] Peruvian Air Force to provide supplies. The other way to get in is by river, which is a very long way. We chartered a flight in there, flying over the most pristine rainforest you will ever see."Even though this species of Panaque had been previously known only from dried pieces of several specimens that the locals captured, this was the first time that live specimens had been captured and studied by scientists. "The particular specimens that we captured are the first that are fresh specimens, so we have the entire fish from which to take tissue samples," said Dr Petry, thereby allowing scientists to formally describe the species. "The formal complete description of this species will be published in December in the Copeia magazine," Dr Petry added. That description will no doubt carefully document one of the features that is unique to the Panaque: their teeth. Even though it is common for the 700+ species of armoured catfishes to suck organic material -- such as insect larvae, algae, microbes and detritus -- from the surfaces of submerged objects, actually ingesting wood is apparently unique to Panaque. Thus, these fish evolved special "spoon-shaped teeth" especially for this job (see electron micrographs in top right and lower left panels in the figure below).But how did such a unique diet evolve in fish? Xylivory -- wood-eating -- likely evolved due to competition with other catfish species for food in the Amazon Basin rivers, said the researchers.Ecophysiologist Donovan German, who did not participate in the expedition, provided additional insight. Dr German is a postdoctoral researcher at the University of California at Irvine, but while a graduate student in biology at the University of Florida, he studied the digestive physiology of wood-eating catfish. These fish are not strong swimmers so they have to attach themselves to a solid object with their powerful sucking mouth to avoid being washed downstream. "There're not a lot of rocks in the Amazonian Basin, where these fishes live," explained Dr German. "There's mud and water, and the one consistent substrate at the bottom is wood. It's [also] the one place where fish can go to get food off a surface." But are Panaque species true xylivores -- are they actually digesting the wood they consume, as do beavers, porcupines and termites? The same question occurred to Dr German while he was in graduate school. To better understand the structure and function of the gastrointestinal (GI) tracts of wood-eating catfishes, Mr German conducted a series of comparisons between the intestinal structure of wild-caught Panaque and a closely-related species detritus-feeding fish that does not consume wood. In short, Mr German found that Panaque digestive tracts are similar in shape and size to those of detritivorous fish. Panaque had none of the special anatomical features that other wood-eating animals possess for providing a home for beneficial bacteria that break down wood so the fish may then absorb the nutrients. [DOI: 10.1007/s00360-009-0381-1]"People think they must have an amazing consortium of microbes in their guts to help the fish digest wood, but that isn't really what I've found," Dr German pointed out. Earlier work that attempted to isolate gut microbes and identify digestive enzymes that break down various components of wood provided ambiguous results. [DOI: 10.1111/j.1095-8649.1999.tb00858.x] The other key factor suggesting that Panaque probably do not digest wood is their rapid gut transit time, which reduces the numbers of wood-digesting bacteria that can reside in their intestinal tract. "The fish pass wood through their guts in less than four hours, which is incredibly fast for an animal that supposedly digests wood," remarked Dr German. Wood-digesting animals typically retain wood in their GI-tracts for longer than 24 hours. At this time, it is thought that wood-eating catfish are not digesting wood at all but, by chewing up rotting wood into tiny pieces, they are digesting the organic matter, microbes, and microbial byproducts that reside in the spaces between wood fibers. The wood itself is excreted as waste. "The amazing microbes are in the river, on the wood itself."Due to their feeding behavior, Panaque catfishes appear to play a valuable role in the ecology of the Amazonian rainforest. By reducing large chunks of wood into microscopic fragments they are speeding up the process of decay and carbon recycling within the environment. According to Dr Petry, these fish are found in an area that is filled-to-bursting with biodiversity -- a poorly-known area that is under threat from development. "There are several proposed infrastructure development projects and roads -- with them will come lumber extraction, cattle ranching and slash-and-burn agriculture," stated Dr Petry. He also noted that on average, over 100 new fish species are discovered every year in South America. This year alone, 69 new species have been described thus far. "These numbers show very clearly that we are far from knowing the number of freshwater species in South America."This makes me wonder how many species will disappear before we even know they are there? And how will this loss of biodiversity affect these ecosystems?Sources:Nelson, J., Wubah, D., Whitmer, M., Johnson, E., & Stewart, D. (1999). Wood-eating catfishes of the genus Panaque: gut microflora and cellulolytic enzyme activities Journal of Fish Biology, 54 (5), 1069-1082 DOI: 10.1111/j.1095-8649.1999.tb00858.xGerman, D. (2009). Inside the guts of wood-eating catfishes: can they digest wood? Journal of Comparative Physiology B, 179 (8), 1011-1023 DOI: 10.1007/s00360-009-0381-1Quotes:Nature Conservancy interview [30 August 2010]GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Science funding cuts: We won't fill the gaps, say firms and charities Big R&D spenders say they won't step up funding of university research in the UK to make up for science funding cutsAlok JhaCompanies and charities that spend billions of pounds on research and development in the UK have said it is not their job to fill the gaps in university funding that will be left if the government's proposed cuts to the science budget go ahead.The private sector spends around £13bn a year on R&D in the UK, and a significant portion is spent in partnership with universities to fund basic science or to turn ideas into commercial products. But all that investment is dependent on a strong, publicly funded university system, said company and charity chiefs."The private and charitable sector fund in the UK because we have a good partnership with government," said Mark Walport, director of the Wellcome Trust, a biomedical charity that spends £450m a year on research. "We're not here in order to substitute for government, we can't do that. It sends the pharmaceutical community and the medical charity community an extremely bad signal if government cuts this area of funding. The government knows very well that the Wellcome Trust believes this is about synergy not substitution."Mike Bushell, principal scientific adviser at the agrochemical company Syngenta, said it was "extremely unlikely" that private industry would step in to make up the shortfalls if the government cuts science funding. "The government does have to make cuts, everybody accepts that. It shouldn't be an across-the-board bacon slice, they have to set some clear national priorities and make sure that the impact of the investment they make really is felt as soon as it can in economic advantage for the country."Syngenta spends around $1bn globally on R&D every year, around a fifth of that being spent in the UK. "We've got hundreds of individual collaborations on at any time, we fund about 50-60 PhD studentships at any one time across a range of different disciplines," said Bushell. "There are also good links between the best university departments and our research groups in the UK."In 2008/09, the government supplied funding for university research to the tune of £3.3bn via the research councils and £2.2bn via the higher education funding councils, and most of this was for curiosity-driven science. Research council funding is distributed through competitive grants for specific research projects and it pays for equipment and PhD and postdoctoral students. Higher education funds are distributed to universities for basic infrastructure.All government departments have been asked to prepare for cuts of 25% or more in their budgets as part of the government's austerity drive. Scientists have warned that such deep cuts to the UK's science infrastructure would have devastating long-term effects, forcing the country out of the "premier league" in many fields of research and leading to the loss of a generation of scientists from the UK. In a worst-case scenario, up to £1bn in total could be wiped off annual budgets.Richard Barker, director general of the Association of the British Pharmaceutical Industry, said said he would be "very disappointed" to see cuts of the order of 25% and warned that, even in such a scenario, there would be no reason for companies to step in to replace government funds. "The UK has been an attractive site for R&D because of the very strong basic science base. The vast majority of the UK research base is very competitive internationally and some of it is globally leading. Over a long-ish period of time [after spending cuts], companies would drift away. Any change you make to basic research, particularly basic life sciences research, the results will play out over 10-20 years."If major cuts do occur and the UK's university base starts to erode, charities and companies are likely to look elsewhere to invest their money. At present the Wellcome Trust spends around 80% of its annual research budget in the UK, but Walport stressed the charity's global reach. "We have a clear strategy, which says we are a global funder and international help is an increasing part of our portfolio. I hope the UK will remain a powerful environment for conducting medical research."Imran Khan, director of the Campaign for Science and Engineering, said: "Industry leaders have consistenly said their private sector investment depends on public support for science. If that support disappears, they will have no other choice but to look abroad for their raw materials: world class research and talented scientists and engineers."He added: "As a nation we don't have any choice but to gear up to having a high-tech, high-skills economy. With our international competitors increasing their investment in science and engineering, this would be the worst possible time to lower our own ambitions – it could take decades to rebuild our technological base to its world-class status."The comments by business and charity leaders echo the conclusions of a report, to be published next week, by Research Councils UK, which looks at the role of science in the UK's future prosperity. "Continued public investment in scientific endeavour is essential for the success of UK business and industry – and, more broadly, for a productive economy, a healthy society and a sustainable world. Estimates of the impact of research council spending on the UK's national output suggest that a cut of £1bn in annual spending would lead to a fall in GDP of £10bn," the report will say.Science funding crisisScience policyResearch and developmentResearchHigher educationAlok Jhaguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Turtle nesting season starts early The turtle nesting season has begun early at Mon Repos, east of Bundaberg, with the arrival of a female flatback. abc.net.au |
Female snails growing penises FEMALE marine snails off the Perth coast are growing male sex organs on their heads after exposure to the chemical TBT, according to researchers. news.com.au |