Marimo (Japanese Algae Balls) - Advanced Quiz

Questions

1. What is the scientific name for Marimo algae balls? a) Aegagropila linnaei b) Cladophora aegagropila c) Chaetomorpha linum d) Spirogyra maxima

2. In which specific lake in Japan are wild Marimo considered a national treasure? a) Lake Biwa b) Lake Akan c) Lake Towada d) Lake Chuzenji

3. What unique wave action is primarily responsible for the spherical shape of wild Marimo? a) Tidal oscillations b) Thermal currents c) Seiche waves d) Wind-driven circulation

4. At what depth range do wild Marimo typically grow in their natural habitat? a) 0.5-2 meters b) 2-2.5 meters c) 5-8 meters d) 10-15 meters

5. What is the approximate growth rate of Marimo in optimal conditions? a) 1-2 mm per year b) 5 mm per year c) 1 cm per year d) 2-3 cm per year

6. Which country besides Japan has significant wild Marimo populations? a) South Korea b) Iceland c) Scotland d) All of the above

7. What is the primary method of reproduction for Marimo in the wild? a) Sexual reproduction through gametes b) Fragmentation and vegetative growth c) Spore formation d) Binary fission

8. What water temperature range is optimal for Marimo growth? a) 18-25°C (64-77°F) b) 10-20°C (50-68°F) c) 5-15°C (41-59°F) d) 25-30°C (77-86°F)

9. What causes the distinctive green color to fade in cultured Marimo? a) Lack of carbon dioxide b) Insufficient light or poor water quality c) Excess nutrients d) High water temperature only

10. In Japanese folklore, what do Marimo symbolize? a) Eternal youth b) Good fortune and lasting love c) Protection from evil spirits d) Connection to ancestors

11. What is the estimated lifespan of a wild Marimo? a) 50-100 years b) 100-200 years c) 200-300 years d) Over 500 years

12. Which mineral is particularly important for healthy Marimo growth? a) Iron b) Calcium c) Magnesium d) Phosphorus

13. What happens to Marimo during winter in their natural habitat? a) They die and regrow in spring b) They sink to the bottom and become dormant c) They continue growing at the same rate d) They fragment into smaller pieces

14. What is the primary threat to wild Marimo populations? a) Overharvesting b) Climate change and lake warming c) Invasive species d) Water pollution from agriculture

15. In what year were Marimo first scientifically described? a) 1823 b) 1897 c) 1921 d) 1952

16. What is the maximum recorded size of wild Marimo? a) 15 cm (6 inches) b) 20 cm (8 inches) c) 30 cm (12 inches) d) 43 cm (17 inches)

17. Which lake system outside of Japan has the most genetically diverse Marimo population? a) Lake Mývatn, Iceland b) Loch Aegir, Scotland c) Lake Saimaa, Finland d) Lake Akan system has the most diversity

18. What pH level is optimal for Marimo cultivation? a) 6.0-6.5 (slightly acidic) b) 7.0-8.5 (neutral to slightly alkaline) c) 8.5-9.0 (alkaline) d) 5.0-6.0 (acidic)

19. How do wild Marimo obtain nutrients in their oligotrophic lake environment? a) Through symbiotic relationships with bacteria b) By filtering microscopic organisms from water c) Through photosynthesis and absorption of dissolved minerals d) By decomposing organic matter on the lake floor

20. What conservation status do wild Marimo hold in Japan? a) Vulnerable species b) Special Natural Monument c) Critically endangered d) Protected cultural artifact

Answer Key

1. a) Aegagropila linnaei - This is the current accepted scientific name, though it was formerly classified as Cladophora aegagropila.
2. b) Lake Akan - Located in Hokkaido, this lake’s Marimo were designated as a Special Natural Monument in 1952.
3. c) Seiche waves - These standing wave oscillations in the lake create the gentle, consistent rolling motion that shapes Marimo into perfect spheres.
4. b) 2-2.5 meters - This specific depth range provides optimal light levels while protecting from surface turbulence.
5. b) 5 mm per year - Wild Marimo grow extremely slowly, making large specimens potentially centuries old.
6. d) All of the above - Marimo populations exist in Iceland (Lake Mývatn), Scotland (lochs), and other northern locations, though Japan’s are most famous.
7. b) Fragmentation and vegetative growth - Pieces that break off can develop into new spherical colonies under proper conditions.
8. b) 10-20°C (50-68°F) - Marimo prefer cool water temperatures typical of northern lakes.
9. b) Insufficient light or poor water quality - Low light reduces photosynthesis, while poor water quality affects overall health.
10. b) Good fortune and lasting love - In Japanese culture, Marimo are often given as gifts to symbolize enduring relationships.
11. b) 100-200 years - Some large specimens may be even older, making them among the longest-lived simple organisms.
12. a) Iron - Iron is crucial for chlorophyll production and overall algae health.
13. b) They sink to the bottom and become dormant - Reduced light and cold temperatures cause them to settle and slow their metabolism.
14. b) Climate change and lake warming - Rising temperatures threaten the cool water conditions Marimo require.
15. b) 1897 - Japanese botanist Takiya Kawakami first described them scientifically, though they were known in folklore much earlier.
16. c) 30 cm (12 inches) - The largest wild specimens can reach this impressive size after centuries of growth.
17. a) Lake Mývatn, Iceland - This population shows remarkable genetic diversity and adaptation to local conditions.
18. b) 7.0-8.5 (neutral to slightly alkaline) - This range mimics their natural lake environment.
19. c) Through photosynthesis and absorption of dissolved minerals - As photosynthetic organisms, they produce their own food and absorb nutrients from the water.
20. b) Special Natural Monument - This is Japan’s highest level of natural protection, granted in 1952.