Methanopyrus kandleri is a species of archaea that lives in the hydrothermal vents of the Pacific Ocean. This species' optimal temperatures are between 100-122 ºC. This species also does not require oxygen, as it survives off of hydrogen gas and releases methane gas. What environmental classifications would this archaeal species fit into?

• A. Mesophile & Obligate Aerobe.
• B. Non-halotolerant & Psychrophile.
• C. Neutrophile & Facultative Aerobe.
• D. Hyperthermophile & Obligate Anaerobe.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the environmental conditions where Methanopyrus kandleri thrives. It lives in hydrothermal vents with temperatures between 100-122 ºC and does not require oxygen, using hydrogen gas and releasing methane gas.
2. Step 2: Define the term 'Hyperthermophile'. Hyperthermophiles are organisms that thrive at extremely high temperatures, typically above 80 ºC. Methanopyrus kandleri fits this classification due to its optimal temperature range.
3. Step 3: Define the term 'Obligate Anaerobe'. Obligate anaerobes are organisms that cannot survive in the presence of oxygen. Methanopyrus kandleri fits this classification as it does not require oxygen and survives off hydrogen gas.
4. Step 4: Compare the characteristics of Methanopyrus kandleri with the given options. Mesophiles thrive at moderate temperatures, psychrophiles at cold temperatures, and neutrophiles prefer neutral pH environments. None of these match the high-temperature preference of Methanopyrus kandleri.
5. Step 5: Conclude that Methanopyrus kandleri is best classified as a Hyperthermophile & Obligate Anaerobe based on its temperature preference and anaerobic nature.