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Documentation of long-term change in benthic ecosystems is important for assessing and managing the effects of such change on: 1) secondary production, particularly leading to commercially important food webs, 2) pollutant transfer within the food web, 3) the ability of the 'new' assemblage to metabolically burnoff labile detritus that might otherwise accumulate, contributing to long-term hypoxia, and 4) recyling of nutrients from the seafloor back to primary producers.Organism-sediment relationships which accompany benthic disturbances have predictable features. Although participating species may vary regionally or seasonally, their life-history attributes and functional relationships to the associated sediment appear to be universal. Pioneering seres are near-surface dwelling, productive, and are readily available to demersal predators. However, these taxa may be potential pollutant vectors. Dense tube mats may promote the deposition and retention of high BOD organic matter. Late successional stage seres are represented by deeply bioturbating 'head-down' deposit feeders. The deep cryptic infaunal habitat of these species may make them less important as prey for epifaunal predators. Sediments populated by these equilibrium assemblages are characteristically low in labile crrnanic matter, sedimentary sulphides, and oxygen demand. Nutrients (N, P, Si) are returned to primary producers by biogenic irrigation of sediment pore water.Mapping of successional mosaics is important for documenting major long-term change in benthic community structure and associated biogenic processes. Our mapping tool consists of a vessel-deployed sediment-profile camera; organism-sediment relationships can be imaged in situ with this instrument. Such a mapping protocol is not intended to replace traditional sampling. Rather, the successional maps are used to efficiently detect change in a system, design a cost-efficient sampling grid for obtaining geochemical and biological ground-truth samples, and to construct hypotheses about how the change might answer the four outlined management questions.

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This paper approaches ecological data analysis from a different vantage point and has implications for ecological risk assessment. Despite all the advances in theoretical ecology over the past four decades and the huge amounts of data that have been collected in various marine monitoring programs, we still do not know enough about how marine ecosystems function to be able to make valid predictions of impacts before they occur, accurately assess ecosystem ``health,'' or perform valid risk assessments. Comparisons are made among the fields of psychology, social science, and ecology in terms of the applications of decision theory or approach to problem diagnosis. In all of these disciplines, researchers are dealing with phenomena whose mechanisms are poorly understood. One of the biggest impediments to the interpretation of ecological data and the advancement of our understanding about ecosystem function is the desire of marine scientists and policy regulators to cling to the ritual of null hypothesis significance testing (NHST) with mechanical dichotomous decisions around a sacred 0.05 criterion. The paper is divided into three main sections: first, a brief overview of common misunderstandings about NHST; second, why diagnosis of ecosystem health is and will be such a difficult task; and finally, some suggestions about alternative approaches for ecologists to improve our "diagnostic accuracy'' by taking heed of lessons learned in the fields of clinical psychology and medical epidemiology. Key words: statistical significance, Bayesian statistics, risk assessment