USING NONLINEAR-ANALYSIS TO COMPARE THE SPATIAL STRUCTURE OF CHLOROPHYLL WITH PASSIVE TRACERS

A form of non-linear analysis, termed the near-neighbour algorithm, wa s applied to transects of chlorophyll and salinity collected off easte rn Antarctica in the Austral summer of 1995/96. The near-neighbour alg orithm was initially developed to detect chaos in time series, but was applied here to compare the spatial structure of chlorophyll, a non-c onservative tracer, with that of a conservative tracer, salinity. The validity of such an application is discussed in the context of the lit erature and as a complementary approach to traditional methods such as autocorrelation and spectral analysis. The results indicate that the spatial structure of salinity could be classified as non-linear in nat ure. The structure of chlorophyll at corresponding spatial scales cont ains a stochastic component, and it is postulated that this is caused by biological factors, specifically net phytoplankton growth. The pote ntial for expanded, more detailed analyses is discussed, and parallels are drawn between the current state of non-linear analysis in biologi cal oceanography and the development of spectral analysis over the las t three decades.