The role of bacteria in the fluxes of matter

  JP Torréton, IRD

The involvement of bacteria in the fluxes of matter occurring in the Tuamotu atoll lagoons is described in detail in the 6 pages which can be accessed by clicking on the links in the following figure.

Some important introductory comments:

From the spatial point of view, the lagoons can be said to be quite homogeneous, both vertically and horizontally speaking. This homogeneity has resulted from two processes. First, the prevailing south-easterly trade winds, which have a mean annual force of 5 m.s^-1, suffice to constantly mix the water column.

Secondly, the possible inputs are restricted because both the coral ring and the surrounding ocean waters are so poorly endowed with organic and mineral components. In addition, these inputs are quite diffusely distributed around the ring in the case of the terrestrial inputs, and widely spread across the ring by the hoas in the case of the oceanic inputs.

From the temporal point of view, it is worth noting the consistency of the bacterial processes, whether they are observed on the scale of a single day, a month or a whole season. This can be seen from the figure below :

Abundance and productivity of the bacteria during various field campaigns  carried out on Tikehau. The primary production data are reproduced from Charpy & Charpy-Roubaud (1990).  The large symbols give the means and standard errors for each campaign. The 2 campaigns carried out in Nov. 91 and Nov. 92 have been given different colours.

The great homogeneity of the bacterial stocks and processes in time and space was confirmed by all the data obtained in this study on 12 of the Tuamotu atolls.

References

Torréton JP, Dufour P (1996b) Temporal and spatial stability of bacterioplankton biomass and productivity in an atoll lagoon. Aquatic Microbial Ecology 11:251-261

Torréton J-P, Pagès J, Talbot V (soumis.) Bacterioplankton and phytoplankton biomass and production in Tuamotu atoll lagoons.