Balancing photosynthesis and respiration in North Pacific protist communities.

Higher TiP values in North Pacific plankton communities correlate with nutrient-rich conditions and larger phototrophic taxa, indicating increased primary productivity.

• Why it matters: Understanding how different protist taxa balance photosynthesis and respiration is crucial for linking community composition to ecosystem function, especially under varying nutrient conditions.
• What they did: Researchers developed the Transcript-informed Productivity (TiP) metric from metatranscriptomes and applied it across size classes and taxa during three expeditions, integrating flow cytometry and 18S rRNA data.
• The result: The study revealed that nutrient-rich areas favor larger phototrophs with higher TiP, while nutrient-limited zones show reduced TiP and greater reliance on respiration, aiding in ecosystem metabolic assessments.