Emergence in pelagic communities

Pelagic systems, those based on the open waters of large lakes and seas, provide excellent opportunities for ecological study. This is because, the vastness of the oceans apart, pelagic ecosystems operate on short space and time scales. This affords important opportunities to study the emergence of ecosystems and the basis of striking high-order patterns of ecosystem behaviour. The essay seeks an outline of the processes by which the biologies of individual organisms - the largest functional, controlled units in the ecosystem - interact and bias the outcomes in favour of particular network structures recognised by ecologists. Populations build, communities assemble, ecosystems function but always in ways that relate to the match between the adaptations 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 advantages of absolutely short generation times among the producers, consumers and heterotrophs of the pelagic, I seek to sample the ascendant pathways of ecosystem synthesis, noting the energetic decisions which select for particular outcomes. However, the simple organisational state of many pelagic communities 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 attempts to re-affirm what is known about organisational hierarchies; then, using approximate quantities, the points of bifurcation between alternative organisational structures are nominated; drawing upon suppositions about the dissipation of energy, the organisational underpinning of function at the level of the whole ecosystem is proposed. Corroboration from observations from the real world is sought throughout.