SBI Junior Associate 2020 · Question 147 of 290

Read the given passage and answer the questions given below. Some words may be highlighted. Plastics, chemicals and oil management (1) pollute and endanger marine ecosystems. Yet cleaning up the ocean is rarely, if ever, possible. Solutions must therefore consist in reducing waste and other hazardous materials. For decades, waste and hazardous materials have been dumped into the ocean as a result of human activity. Covering more than two-thirds of the Earth’s surface, the ocean is so vast that human carelessness seemed unlikely ever to affect it. But it is now a known fact that, in addition to overfishing, warming caused by climate change, ever-increasing maritime transport, and ocean acidification, pollution is a threat to marine organisms and their habitats. One of the key aiding factors to this is vast scale pollution is the dumping of plastic. By its sheer scale, plastic contamination symbolises the human impact on the environment, above all other forms of man-made pollution. Due to poor waste spills (2), it is estimated that every year, 10 million tonnes of plastic are dumped into the sea, 80% of which comes from inland, mainly via rivers. “From coastal regions to the poles, and from the ocean surface to the seafloor, no area of the ocean is free from this pollution. As a result, all the essential services provided by the ocean to the planet and to humankind are likely to be seriously disrupted. The world’s population depends to a large extent on marine resources, not only for food but also for economic purposes, from tourism to the transport of goods. The ocean is also vital to the climate since it absorbs 25% of the CO2 emitted by human activity into the atmosphere every year. Deep-sea organisms also play a key role in the functioning of this biological carbon pump where phytoplankton, at the bottom of the marine food chain, use CO2 and transform it into organic matter, part of which sinks to the ocean floor. In the process, these microscopic algae and bacteria provide half the oxygen produced on Earth. The whole food result (3) is impacted, from zooplankton to whales,” points out Ika Paul-Pont of the Laboratory of Environmental Marine Sciences. In addition to larger waste such as bags and bottles, which can cause the death of animals by entanglement or intestinal obstruction when ingested, plastic pollution turns out to be particularly insidious, as it is made up of billions of particles, sometimes less than a few millimetres in diameter, produced by the decomposing of plastic caused by UV radiation and wave action. These microplastics, as they are known, are ingested by all marine fauna, even the very smallest organisms, with a wide range of effects. Once swallowed (4), these pollutants can prevent animals from feeding normally, which affects their growth, reproduction and immune defences. “We exposed oysters to microplastics in the laboratory. These molluscs feed on microalgae by filtering water, ingesting plastic in the process. The presence of the polymer means the shellfish have to devote more energy to filtration – and therefore less to reproduction. As a chain (5), we’ve observed a 40% drop in the hatching rate compared to uncontaminated oysters,” Paul-Pont explains. More recently, scientists, including CNRS researchers, have also discovered that microplastics continue to break down into even smaller, nanometre-sized particles. They are able to cross cell membranes and may pose an even greater toxicity hazard. Although this field of research is still in its infancy, its findings are eagerly awaited. Ocean ecosystems are indeed not the only ones exposed to such pollution, since marine wildlife eventually ends up in our plates! What is a suitable title for the passage?

reading-comprehension

1. A(A) Ocean- a blessing for humankind
2. B(B) The plastic plagueCorrect
3. C(C) Endangered ecosystems
4. D(D) Pollution- a marine threat
5. E(E) Dangers of overfishing