Emergence in pelagic communities

Pelagic systems, those based on the open waters of large lakes and seas, pr ovide excellent opportunities for ecological study. This is because, the va stness of the oceans apart, pelagic ecosystems operate on short space and t ime scales. This affords important opportunities to study the emergence of ecosystems and the basis of striking high-order patterns of ecosystem behav iour. The essay seeks an outline of the processes by which the biologies of individual organisms the largest functional, controlled units in the ecosy stem - interact and bias the outcomes in favour of particular network struc tures recognised by ecologists. Populations build, communities assemble, ec osystems function but always in ways that relate to the match between the a daptations and performances of individual species and the capacities of the environments in which they find themselves. The paper attempts to discern the linkages between the biology of individual and the ways that ecosystems are put together, between organisms and organisation. Drawing on the advan tages of absolutely short generation times among the producers, consumers a nd heterotrophs of the pelagic, I seek to sample the ascendant pathways of ecosystem synthesis, noting the energetic decisions which select for partic ular outcomes. However, the simple organisational state of many pelagic com munities reminds us that ascendancy is frequently restrained by a scarcity of resources and tempered by the frequent intervention of abiotic factors. The presentation does not seek to prove any point about systems: it attempt s to reaffirm what is known about organisational hierarchies; then, using a pproximate quantities, the points of bifurcation between alternative organi sational structures are nominated; drawing upon suppositions about the diss ipation of energy, the organisational underpinning of function at the level of the whole ecosystem is proposed. Corroboration from observations from t he real world is sought throughout.