Microbially mediated nutrient cycles in marine sponges.

Area of Science:

• Marine Biology
• Microbial Ecology
• Ecosystem Science

Background:

• Coral reef ecosystems rely on efficient nutrient cycles, with marine sponges playing a key role as habitat formers harboring abundant microbial symbionts.
• Despite their importance, microbially mediated nutrient cycling processes within marine sponges remain under-reviewed.

Purpose of the Study:

• To review and synthesize current knowledge on microbially mediated carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) cycles in marine sponges.
• To propose a conceptual model for interactions and constraints within sponge nutrient cycles.
• To highlight the influence of host behavior, such as sponge pumping, on symbiotic microbial communities and nutrient cycling.

Main Methods:

• Literature review synthesizing existing knowledge and recent advances in sponge microbial nutrient cycling.
• Development of a conceptual model illustrating nutrient cycle interactions and constraints.
• Analysis of the impact of host behavior (e.g., pumping) on microbial symbiont activity.

Main Results:

• Comprehensive summary of microbial roles in C, N, P, and S cycling within sponges.
• A conceptual model is proposed, emphasizing interactions and constraints in sponge nutrient cycling.
• Sponge pumping behavior significantly influences symbiotic microbial communities and nutrient cycling dynamics.

Conclusions:

• Sponge microbiomes are critical drivers of nutrient cycles in coral reef ecosystems.
• Further research is needed on spatial-temporal variations and host behavior to fully understand these cycles.
• Shifting redox states, influenced by host activity, are key regulators of symbiotic microbial functions in nutrient cycling.