Evidence for coupling the vertical flux of phytodetritus to the diet and seasonal life history of the deep-sea echinoid Echinus affinis

Data from a temporal sampling programme at 2200 m depth provide evidence for a relationship between the diet of the deep-sea echinoid Echinus affinis and deposition of phytodetritus. Nonlinear regression and “lack of fit” analysis resulted in the identification of a number of seasonal fluctuations in the organ and gut content indices of E. affinis. The amount of gut contents were low in winter and high during spring and summer months. The proportionof organic matter in the gut contents, however, did not show a significant seasonal variation. Planktonic and benthic material was identified from the gut contents using electron microscopy. All these data support the hypothesis that the seasonal deposition of phytodetritus provides energy for growth and reproduction.