Quiz on SDG 14 “Life Below Water”

Take this quiz and learn more about SDG 14 - Life Below Water.

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Q. 1 What percentage of carbon dioxide does the ocean absorb?

Answer Detail: Oceans absorb about 30% of carbon dioxide produced by humans, buffering the impacts of global warming. Coastal and shallow-waters contain some of the world’s most diverse and productive ecosystems, such as mangroves, coral reefs and seagrass beds.

Q. 2 Fill in the blanks -

Coral Reefs support __% of ocean life.

Answer Detail: Coral reefs support a quarter of all ocean life, i.e. 25%, and one billion people rely on them for food and income. The ecosystem also contributes $375 billion per year to the global economy through tourism, medicine, and livelihoods. However, 50% of the world’s corals have died in the past 50 years and, according to reports by the Intergovernmental Panel on Climate Change, up to 90% could be lost by 2050 due to global warming.

Q. 3 Fill in the blanks -

Oceans cover __% of the Earth’s surface.

Answer Detail: Oceans cover 71% of the Earth's surface and absorb about 30% of Carbon Dioxide (CO2) produced by humans, buffering the impacts of global warming.

Q. 4 When is World Wetlands Day celebrated every year?

Answer Detail: On 30 August 2021, the UN General Assembly proclaimed 2 February as World Wetlands Day to raise awareness of the urgency of reversing the accelerating loss of wetlands and to promote their conservation and restoration. The day marks the date of the adoption of the "Convention on Wetlands of International Importance" held in 1971 in the Iranian city of Ramsar on the shores of the Caspian Sea.

Q. 5 Fill in the blank -

Over ___ billion people depend on marine and coastal biodiversity for their livelihoods.

Answer Detail: More than 3 billion people are dependent on marine and coastal biodiversity for their livelihoods.

Q. 6 Oceans help produce what percentage of the Earth’s oxygen?

Answer Detail: Scientists estimate that 50-80% of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth. But this little bacteria produces up to 20% of the oxygen in our entire biosphere. That’s a higher percentage than all of the tropical rainforests on land combined.

Calculating the exact percentage of oxygen produced in the ocean is difficult because the amounts are constantly changing. Scientists can use satellite imagery to track photosynthesizing plankton and estimate the amount of photosynthesis occurring in the ocean, but satellite imagery cannot tell the whole story. The amount of plankton changes seasonally and in response to changes in the water’s nutrient load, temperature, and other factors. Studies have shown that the amount of oxygen in specific locations varies with time of day and with the tides

Q. 7 What is the significance of plankton in the ocean? (Plankton are marine drifters — organisms carried along by tides and currents. The word “plankton” comes from the Greek for “drifter” or “wanderer.” An organism is considered plankton if it is carried by tides and currents, and cannot swim well enough to move against these forces.)

Answer Detail:

Plankton are an essential component of life on Earth. Marine plankton, found in all ocean ecosystems, play a critical role in maintaining the health and balance of the ocean and its complex food webs. The oxygen, nutrients, and biomass they produce also sustain terrestrial life—from the food we eat to the air we breathe. 

The number of marine phytoplankton, the microscopic organisms that gobble greenhouse gases and directly or indirectly feed every animal in the ocean, has been declining by about 1% of the global average per year, according to a new study. If the trend continues, it could decimate ocean food chains and accelerate global warming.

The loss of phytoplankton is a huge problem for marine food chains because every creature in the ocean either eats phytoplankton or eats other organisms that depend on it. If their numbers start to decrease, the populations of these species would drop as well.