IRON, MANGANESE, AND NICKEL IN SKELETONS AND FOOD OF THE SEA URCHINS TRIPNEUSTES ESCULENTUS AND ECHINOMETRA LUCUNTER1

Abstract

Levels of the trace elements Fe, Ni, and Mn were determined in the skeletons of the sea urchins Tripneustes esculentus (Leske) and Echinometra lucunter (L.) and compared between animals of the same species collected at Punta Higuero and at La Parguera, Puerto Rico. Differences between species were also compared. Levels of Mn and Ni were higher in E. lucunter than in T. esculentus, reflecting a species difference. Levels of Fe in T. esculentus from Punta Higuero were significantly higher than in those from La Parguera. The trace element contents of Padina gymnospora, the principal forage plant of T. esculentus at Punta Higuero and of Thalassia testudinum, the principal forage plant of T. esculentus at La Parguera were compared. P. gymnospora contained significantly more Fe than T. testudinum, showing a relationship between the amount of Fe in the skeletons of T. esculentus and their food. The higher levels of Mn and Ni in P. gymnospora were not reflected in the urchin skeletons. Relationships between food, temperature, and salinity are discussed in relation to the trace element content of the urchins.