Mycosporine-like amino acids (MAAs) in phytoplankton, a herbivorous pteropod (Limacina helicina), and its pteropod predator (Clione antarctica) in McMurdo Bay, Antarctica

Abstract.

Mycosporine-like amino acids (MAAs) present in a natural phytoplankton assemblage, a herbivorous pteropod, Limacina helicina (Phipps), and a predatory pteropod, Clione antarctica (Smith), that feeds exclusively on L. helicina were investigated in a coastal Antarctic system during January 2000. This study used a novel approach in MAA analysis by incorporating mass spectrometry (LC/MS and LC/MS/MS) to provide the molecular weight and unique fragmentation pattern for each MAA. HPLC and LC/MS analyses of samples collected in the vicinity of McMurdo Station, Antarctica revealed the presence of two MAAs in the phytoplankton assemblage (shinorine and porphyra-334) and five MAAs in each of the pteropods (mycosporine-glycine, shinorine, porphyra-334, palythenic acid, and palythine). If the MAAs present in the phytoplankton represent what was dietarily obtained by the pteropods, concentration factors of 4.8 and 2.4 attend the first and second trophic transfers, respectively. A theoretical reaction scheme is described for the production of mycosporine-glycine, palythenic acid, and palythine from the shinorine and porphyra-334 via microbial and chemical reactions previously observed in other systems. These findings point to the potential for MAAs (and thereby UV-photoprotection) to be transferred, not just from primary producers to primary consumers, but also to the second trophic level of secondary consumers.