AB 2:131-141(2008) - doi: 10.3354/ab00042
Copepod feeding stimulates bacterioplankton activities in a low phosphorus system
Josefin Titelman1,*,**, Lasse Riemann2,**, Karin Holmfeldt2, Trygve Nilsen3
**J.T. and L.R. contributed equally to this article
ABSTRACT: Zooplankton sloppy feeding releases high-quality dissolved organic matter, which is readily used by microbes. We hypothesized that in phosphorus (P) limited environments, released dissolved DNA may be a particularly important source of P for bacteria. In an incubation experiment with water from the Bothnian Bay, Sweden, we investigated the short-term effect of copepod feeding activity on bacterial production, DNA uptake and phosphatase activity. Consistent patterns in bacterial activity measures suggested that copepod feeding activity stimulated phosphatase activity, DNA uptake and production. The P taken up as dissolved DNA exceeded cellular P requirements. We speculate that bacterioplankton cells in the Bothnian Bay store excess P intracellularly during times of extensive sloppy feeding, which may then subsequently be utilized to prevent P limitation of growth.
KEY WORDS: Bacteria · Copepod · DNA uptake · Phosphorus · Alkaline phosphatase · Dissolved DNA · Bothnian Bay
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