Questão de Língua Inglesa

TEXT li Read the text below and answer questions 27 and 28. Welcome to the 'plastisphere': the synthetic ecosystem evolving at sea [1] Plastic bottles dominate waste in lhe ocean, with an estimated 1m of !hem reaching lhe sea every minute. The biggest culprit is polyethylene terephthalate (Pet) bottles. [2] Las! month, a study found two bacteria capable of breaking down Pet - or, as lhe headlines put it, "eating plastic". Known as Thioclava sp. BHET1 and Bacillus sp. BHET2, thê:, bacteria were isolated in a laboratory - but they were dfscovered in lhe ocean. [3] The bacteria are lhe lates! example of new organisms that appear to be growing in a unique environment: lhe vast amounts of plastic at sea. [4] Like lhe atmosphere, magnetosphere and hydrosphere, the plastisphere is a region. But it is also an ecosystem, like the Siberian steppe or coral reefs - a plasticised marine environment. The best-known concentration of seaborne plastic waste is lhe Great Pacific garbage patch, a sort of plastic soup spread over an area roughly twice lhe size of France, but plastic is everywhere. [5] First described in a 2013 study to reter to a collective of plastic-colonising organisms, including bacteria and fungi, the term has since expanded. li now loosely encompasses larger organisms, from crabs to jellyfish, which float across oceans on marine plastics. The term was coined by Linda Amaral-Zettler, a marine microbiologist ai lhe Royal Netherlands lnstitute for Sea Research. [6] Although the term may be recent, the phenomenon is not. "The plastisphere has been around for as long as plastic has existed," Amaral-Zettler says. [7] What is new is our understanding of just how complex an ecosystem lhe world of plastic can be. ln lhe plastisphere there are organisms that photosynthesise; there are predators and prey; symbionts and parasites, allowing for "a full range of interactions possible, as in other ecosystems", says Amaral-Zettler. [8] Another unique feature of the plastisphere is that humans invented it. Every other ecosystem has evolved over millions of years. The meaning of that is not yet clear. Wright believes "it's more an issue of scale" because unlike most naturally occurring materiais, plastic is highly durable and persistent, allowing lhe growth and spread of attached organisms over a massive area. [9] There are also concerns about plastic-colonising organisms that can travei around lhe world. Amaral- Zettler's 2013 study discovered Vibrio, a type of bacteria known to contain several species of pathogens, including some associated with gastroenteritis. [1 O] For lhe scientists, lhe plastisphere's presence is a less obvious concern than its potential health dangers. Most plastic ends up in landfill, but nearly a third of it ends up in lhe sea. The majority sinks, but a lot does not, becoming a home for all sorts of microbes that might no! otherwise have a home. [11] "AI lhe moment that's still very much an aclive area of research," Wright says. There are two main fields of investigation: potential pathogens in lhe plastisphere, and lhe potential for some microbes to biodegrade hydrocarbons, such as lhe plastic-eaters identified las! month. [12] Those are not unique to lhe ocean. ln 2016, scientists in Japan discovered ldeonella sakaiensis, a species of bacteria at a rubbish tip that had evolved an enzyme that enabled it to eat plastic. [13] But another study in lhe sarne year found that, compareci with bacteria in the surrounding waters, those in lhe plastisphere possessed an enriched collection of genes, suggesting that they had adapted for a "surfaceattached lifestyle". [14] Could lhe plastisphere evolve in such a way that bacteria would essentially eat it, or at least help us identify ways to break down our plastic waste? "l'd definitely agree that [microbes on] plastics are going to be the key place to look in the fight against plastic," says Wright. (Adapted from: https://www.theguardian.com) Página: 9/12