A single trophic interaction between two major biotic components within similar ecosystems can reveal high variability. In fact, in situ measurements of the trophic interactions, as provided by the field application of stable isotopes, are likely to reveal strong differences in patterns. An illustration of such a geographical plasticity is provided when regarding the trophic interaction between two major components of intertidal habitats namely, the oyster Crassostrea gigas and the microphytobenthos. The contribution of benthic diatoms to oysters' diets ranged from 4.4±3.5% in the Mont St Michel bay to 69.6±1.1% in the Marennes-Oléron bay, as estimated from δ13C and δ15N analyses. Concerning food web investigations, these results point out serious limits for extrapolating qualitative and quantitative observations related to the major trophic links between identical food sources and consumers inhabiting similar ecosystems.

The current study presents both longitudinal behavioral data and functional activation data documenting the effects of early focal brain injury on the development of spatial analytic processing in two children, one with prenatal left hemisphere (LH) injury and one with right hemisphere (RH) injury. A substantial body of evidence has shown that adults and children with early, lateralized brain injury show evidence of spatial analytic deficits. LH injury compromises the ability to encode the parts of a spatial pattern, while RH injury impairs pattern integration. The two children described in this report show patterns of deficit consistent with the site of their injury. In the current study, their longitudinal behavioral data spanning the age range from preschool to adolescence are presented in conjunction with data from a functional magnetic resonance imaging (fMRI) study of spatial processing. The activation results provide evidence that alternative profiles of neural organization can arise following early focal brain injury, and document where in the brain spatial functions are carried out when regions that normally mediate them are damaged. In addition, the coupling of the activation with the behavioral data allows us to go beyond the simple mapping of functional sites, to ask questions about how those sites may have come to mediate the spatial functions. (JINS, 2003, 9, 604–622.)