Caught in the food web: complexity made simple?

Abstract

SUMMARY: Several historically separate lines of food-web research are merging into a unified approach. Connections between microbial and metazoan food webs are significant. Interactions of control by predators, defenses against predation, and availability of organic and inorganic nutrition, not any one of these, shape food webs. The same principles of population ecology apply to metazoans and microorganisms, but microorganisms dominate the flux of energy in both marine and terrestrial systems. Microbial biomass often is a major fraction of total biomass, and very small organisms have a very large ratio of production and respiration to biomass. Assimilation efficiency of bacteria in natural systems is often not as high as in experimental systems, so more primary production is lost to microbial respiration than had been thought. Simulation has been a highly useful adjunct to experiments in both population theory and in studies of biogeochemical mass balance, but it does not fully encompass the complexity of real systems. A major challenge for the future is to find better ways to deal with the real complexity of food webs, both in modeling and in empirical observations, and to do a better job of bringing together conceptually the dynamics of population processes and biogeochemistry.

Fisheries oceanography and the ecology of early life histories of fishes: a perspective over fifty years

“…Nixon, 1988;Houde and Rutherford, 1993;Nielson and Richardson, 1996), in part because of the varying and complex food webs of the pelagia (e.g. Greve and Parsons, 1977;Olsen et al, 2001;Biktashev et al, 2003; but also see Pomeroy, 2001). Moreover, it is apparently new primary production, not primary production in toto, that comes into play in the match-mismatch postulate (Richardson, 2002).…”

Temporal variation of phytoplankton growth and grazing loss in the west coast of Peninsular Malaysia

“…The simplifications used in the dilution method do not approach the complexity of an actual food web (Pomeroy 2001) where composition and population dynamics of both prey and grazer may influence the rates measured (Modigh and Franzé 2009). However dilution experiments done in large numbers can be used to describe the process interactions and relationships in natural systems (Landry 2014).…”

Building bridges across subdisciplines in marine ecology

“…1). Because metabolic rate and production of biomass increase by about 1.75 per order of magnitude decrease in body size (Banse and Mosher, 1980), the dominance of microorganisms in consumption and production is even greater than that of their biomass (Pomeroy, 2001). It is important to note that microbial dominance of community metabolic processes is the natural condition, and there is no reason to believe that current microbial dominance is the recent result of some of the anthropogenic changes in communities discussed above.…”

“…When we measure rates of primary production by either uptake of 14 C or oxygen evolution, we do not distinguish between prokaryotic picoplankton and larger diatoms. Microbial processes are also frequently underestimated in studies of terrestrial systems, because most of the microbial activity is in soils, the study of which tends to be a separate discipline (Pomeroy, 2001). …”

“…At the same time, saturation of these environments with nutrients has increased primary production (Boynton et al, 1995). While unexploited invertebrates and some vertebrate species have undoubtedly increased to fill vacant niches, such as filter-feeding, bacteria probably have increased relatively little in numbers or biomass but have increased their metabolism and production rates (Pomeroy, 2001). This latter postulate must be based on observations of current research, since there are no historical data.…”