? Until the mid-20th century, many researchers thought that birds had no sense of smell. The main author of the paper wrote in an email: "Scientists have found that most birds have a sense of smell, and some birds have an extraordinary sense of smell. Seabirds need a good sense of smell because their food is in the vast ocean. In other words, they hunt like looking for a needle in a haystack. " If plastic fragments smell like appetizers, there is no reason not to attract birds, although seabirds may have to swallow them for other reasons.
Savoca said: "Birds use their extraordinary sense of smell to locate food before they see it. Our work found that these plastic wastes look very similar to those of seabirds, and the perspective of seabirds is a very important consideration for us. " During the experiment, the researchers put plastic waste (which is easy to clean in a net bag) in the ocean for three weeks. Later, chemical analyzers were used to check the remaining plastic wastes. They found that these plastic wastes gave off the smell of a compound called dimethyl sulfide (DMS).
? This discovery is very important because DMS is an important chemical signal from algae, indicating that tiny crustaceans are already eating themselves, and seabirds like to chew them very much. Seabirds have a keen sense of smell. If the DNS smell indicates that krill is preying in a certain area, it means that seabirds should have dinner. This discovery may help explain why seabirds tend to mistake plastic for their own food when looking for food. The effects of plastics in seabirds on their health are still under study, but these plastic fragments will occupy the stomach space of seabirds, leading to malnutrition in infants or damage to internal organs.
? Researchers still don't know why these plastics emit such a strong DNS smell. But algae will grow on rocks, and some plastics eaten by krill and other organisms will cover the algae to attract seabirds. Or dry dead algae floating on the water give the same chemical signal. Reducing plastic waste is helpful to reduce the problem of seabirds eating plastic, and a large amount of plastic waste is not conducive to the growth of seaweed. The research in this field is still in progress. Next, as part of the paper, Savoca plans to conduct behavioral experiments on seabirds and other marine life to test whether they are really attracted by DMS emitted by plastics.
? Pacific garbage patch is a garbage vortex; The vortex captured in the ocean current is spinning. Although it is not a garbage island in the literal sense sometimes described by the media, its waters are scattered with large floating debris. Due to the agitation of waves, debris floats up and down in the water column and circulates with the water flow. Invasive species travel to water in plastic and never intend to enter their occupations. Seabirds, marine mammals and fish mistakenly put floating chunks on food and fill their stomachs with indigestible garbage. When shaking mercilessly and rubbing tiny plastic fragments and toxic chemicals in water, these fragments will still wear away.
According to scientific research, the smell of plankton on the surface of plastic garbage is similar to that of rotten algae, so seabirds such as albatrosses will mistake them for food and swallow them. About 90% seabirds have eaten plastic garbage, which is harmful to their health. Global plastic pollution is on the rise. In just 20 14 a year, 250 million tons of garbage drifted into the ocean.
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