|Spatial and temporal variations in Antarctic and subantarctic bacterioplankton|
Bouvy, M.; Delille, D. (1988). Spatial and temporal variations in Antarctic and subantarctic bacterioplankton. Neth. J. Sea Res. 22(2): 139-147
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579, more
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One major difficulty in the interpretation of short-term variations in bacterioplankton is that variability in time is closely entwined with variability in space. In order to clarify this problem, two series of investigations were carried out in Antarctic and subAntarctic coastal surface waters during the summer of 1986. Each series included temporal (on hourly and daily scales) and spatial surveys, using standard parameters such as total and viable counts, and estimations of the frequency of dividing cells. Our results showed spectacular gradients in bacterial concentrations. To explain the observed decreases from the shore to the open sea, we suggest a relation with: (1) the degradation processes of macrophytes in the subAntarctic area, and (2) the presence of penguin faeces in the Antarctic area. These organic matter sources appear responsible for the formation of bacterial patches along the gradients. Storm-induced modifications of the spatial distribution of bacterioplankton appeared sufficient to explain the hourly changes in bacterial concentrations; this fact was confirmed by measurements of some nutrient parameters (POC, pigment, seston). On daily scales, other phenomena, probably linked to trophic food chains (e.g. bacterial growth, grazing), must be considered to explain the bacterioplankton changes.