215
Further, the microbes are treated as being devoid of behavioral responses to nutrient and
predator-prey fields.
Recent focus on oceanic biogeochemical cycles has made the status quo untenable, by seeking
to understand how the biochemical forces influence the spatial-temporal patterns of the
distribution of N, P, and C atoms. True, biogeochemists are interested in variability at large
space and time scale. However, one can justifiably assert (and this is an argument developed in
this paper) that the metabolic activities of individual cells of phytoplankton, bacteria and
protozoa, in large part, form the basis of the ocean basin scale features of biogeochemical
dynamics. It is self-evident, for instance, that primary productivity is not a mesoscale process;
it is the activity of individual phytoplankton cells, and as such it is regulated at the single cell
level by the physicochemical environment in which a particular phytoplankton cell occurs at a
given time. Interestingly, our acceptance of the importance of micro scale processes is also
"patchy". For example, no self-respecting phytoplankton ecologist today would assume that
phytoplankton cells are exposed to a constant light field during the light period. On the other
hand, paradoxically, our conceptual models still ignore that, in all probability, individual
phytoplankton cells experience remineralized nutrient fields quite different than those in the
bulk-phase. This is in spite of the knowledge that much of the nutrient remineralization is done
by bacteria and protozoa and therefore their microscale distribution in relation to the
phytoplankton influences the remineralized nutrient field experienced by the phytoplankton cell.
Microbes do not interact at mesoscale space; their metabolic interactions occur in spatially
intimate microenvironments, and this should result in spatial heterogeneity in the intensity of
metabolic processes.
In this paper we examine the proposition that the variability of ecosystem roles of bacteria
results from bacteria being in microzones of different nutrient statuses. We suggest that
micro scale variations in bacterial environments are caused by the presence of discrete loci of
organic matter, notably phytoplankton cells and organic particles. We stress the need to focus
on the biochemical and behavioral adaptations of bacteria in an ecosystem context, rather than
piecemeal study of particular activities of bacteria, if we are to develop a unified concept of the
role of bacteria in pelagic marine ecosystems. In other words, the ecosystem role of bacteria
Further, the microbes are treated as being devoid of behavioral responses to nutrient and
predator-prey fields.
Recent focus on oceanic biogeochemical cycles has made the status quo untenable, by seeking
to understand how the biochemical forces influence the spatial-temporal patterns of the
distribution of N, P, and C atoms. True, biogeochemists are interested in variability at large
space and time scale. However, one can justifiably assert (and this is an argument developed in
this paper) that the metabolic activities of individual cells of phytoplankton, bacteria and
protozoa, in large part, form the basis of the ocean basin scale features of biogeochemical
dynamics. It is self-evident, for instance, that primary productivity is not a mesoscale process;
it is the activity of individual phytoplankton cells, and as such it is regulated at the single cell
level by the physicochemical environment in which a particular phytoplankton cell occurs at a
given time. Interestingly, our acceptance of the importance of micro scale processes is also
"patchy". For example, no self-respecting phytoplankton ecologist today would assume that
phytoplankton cells are exposed to a constant light field during the light period. On the other
hand, paradoxically, our conceptual models still ignore that, in all probability, individual
phytoplankton cells experience remineralized nutrient fields quite different than those in the
bulk-phase. This is in spite of the knowledge that much of the nutrient remineralization is done
by bacteria and protozoa and therefore their microscale distribution in relation to the
phytoplankton influences the remineralized nutrient field experienced by the phytoplankton cell.
Microbes do not interact at mesoscale space; their metabolic interactions occur in spatially
intimate microenvironments, and this should result in spatial heterogeneity in the intensity of
metabolic processes.
In this paper we examine the proposition that the variability of ecosystem roles of bacteria
results from bacteria being in microzones of different nutrient statuses. We suggest that
micro scale variations in bacterial environments are caused by the presence of discrete loci of
organic matter, notably phytoplankton cells and organic particles. We stress the need to focus
on the biochemical and behavioral adaptations of bacteria in an ecosystem context, rather than
piecemeal study of particular activities of bacteria, if we are to develop a unified concept of the
role of bacteria in pelagic marine ecosystems. In other words, the ecosystem role of bacteria