Brevet 2022: the answer key for the science test (SVT and Technology)

The latest 2022 Patent Answer Key is ready and available for Science, Technology and SVT for General Series candidates.

Date: Friday, July 1, 2022 from 1:30 p.m. to 2:30 p.m.

Patent: General Series – see here the answer key for the pro series

Scoring: 50 points

Duration of the test: 1 hour

Patent 2022 / Corrected / SVT

Interesting subject, well conducted but very long to be treated correctly in 30 minutes.

Issue 1:

Coral corresponds to an association between zooxanthellae and polyps. Zooxanthellae bring carbon-rich molecules and oxygen to the polyps. Zooxanthellae benefit from an environment protected from browsing by predators and stable conditions for their multiplication and they use the nitrogenous and phosphate waste products of the polyp as a source of mineral elements. There are therefore reciprocal benefits between polyps and zooxanthellae, characteristics of a symbiotic association.

Issue 2:

We note that when the water temperature is 27°C, the number of Zooxanthellae is 0.5 million per cm2 of polyp and when the temperature is 32°C the number of Zooxanthellae decreases, it goes to 0, 2 million per cm2 of polyp. So when the temperature increases, the number of zooxanthellae decreases.

Issue 3:

Here is the experimental protocol for selecting corals resistant to a surface water temperature of 32°C:

– 1 aquarium at 32°C containing corals harboring zooxanthellae of species A.

– 1 aquarium at 32°C containing corals harboring zooxanthellae of species B.

– 1 aquarium at 32°C containing corals harboring zooxanthellae of species C.

– All aquariums contain seawater and the temperature is monitored (thermostat baths and thermometer) to be maintained at 32°C throughout the experiment.

– Observe results (whitening) after a few weeks.

Issue 4:

I will show that a change on a planetary scale can influence local biodiversity and human activities.

Current global warming is causing an increase in the temperature of the surface waters of the oceans, and coral reefs live in these surface waters. Corals correspond to a symbiotic association between polyps (animals) and zooxanthellae (algae), and these zooxanthellae carry out photosynthesis (document 1) and are responsible for the color of the coral.

However, an increase in water temperature decreases the number of zooxanthellae in the polyps (documents 2 and 3), causing the death of the polyps and thus the bleaching of the corals. But this is not the only consequence, the bleaching of the corals and therefore the death of the reefs has an impact on the fish, because the reefs constitute a spawning and nursery area. This also impacts fishing, which is the main resource for the poorest families.

We can also mention another consequence on human activities: these coral reefs protect the coasts from the swell and thus prevent the degradation of coastal habitats. However, the coast attracts a lot of tourists from Reunion Island (beaches, coastal sports, diving clubs, etc.) and thus represents a very important source of income for the island (tourism represents 350 million euros each year on the island).

Thus, as we have just seen with Reunion Island, global climate change (rise in water temperature) can degrade local biodiversity (corals, fish, rare and endangered species) and thus impact human activities ( fishing, tourism, source of income). In order to limit these consequences, attempts are being made to introduce zooxanthellae which are resistant to surface water temperatures of 32°C (document 3).

Patent 2022 / Corrected / Technology

coming very soon!

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