Which of the following best describes the production of dimethylsulfoniopropionate (DMSP) by coral and their symbiotic algae?

• A. DMSP is only produced when corals are exposed to high levels of carbon dioxide.
• B. DMSP is a waste product excreted by corals during respiration.
• C. DMSP is primarily produced by the symbiotic algae (zooxanthellae) within coral tissues as a byproduct of photosynthesis.
• D. DMSP is synthesized exclusively by the coral animal and not by its symbionts.

Answer: (C)

Verified step by step guidance

1. Understand the context: DMSP (dimethylsulfoniopropionate) is a sulfur-containing compound that plays a role in the marine sulfur cycle and is associated with coral reef ecosystems. It is important to identify the source of DMSP production in this context.
2. Recognize the symbiotic relationship: Corals have a mutualistic relationship with symbiotic algae called zooxanthellae. These algae reside within coral tissues and perform photosynthesis, providing energy to the coral.
3. Evaluate the options: Analyze each statement provided in the problem. For example, the first option suggests DMSP is only produced under high CO2 conditions, which is incorrect because DMSP production is not limited to such conditions. The second option incorrectly identifies DMSP as a waste product of coral respiration.
4. Focus on photosynthesis: Zooxanthellae, the symbiotic algae, produce DMSP as a byproduct of their photosynthetic activity. This aligns with the correct answer provided in the problem.
5. Clarify the role of the coral animal: The coral animal itself does not synthesize DMSP exclusively; rather, it is primarily produced by the symbiotic algae within the coral tissues. This distinction is key to understanding the correct answer.