Abstract: As a part of marine algae, marine macroalgae, whose edible and medicinal values are widely applied, participate in
global CO2 and O2 turnover through photosynthesis. Therefore, when viewed from ecology as well as economics, the process of
photosynthetic CO2 fixation and metabolism in marine macroalgae is of great significance. Up to the present, metabonomics and
enzymology researches on photosynthetic carbon metabolism in marine macroalgae have proved the existence of the PEPCK- or
PEPC-type C4 pathway as well as the CAM pathway in addition to the C3 pathway, although the integrality of the pathways is still
unknown. Moreover, the results of photosynthetic gas exchange indicate that the photosynthetic carbon metabolism pathway in
macroalgae performs the C4-like type on the whole. This situation resembles some terrestrial C3 plants with additional C4 pathway.
Therefore, researches on photosynthetic carbon metabolism pathways in macroalgae remain to be explored in depth in the future.

Key words: marine macroalgae, photosynthesis, carbon metabolism type