Aggregation and sedimentation of Thalassiosira weissflogii (diatom) in a warmer and more acidified future ocean.

Increasing Transparent Exopolymer Particle (TEP) formation during diatom blooms as a result of elevated temperature and pCO2 have been suggested to result in enhanced aggregation and carbon flux, therewith potentially increasing the sequestration of carbon by the ocean. We present experimental results on TEP and aggregate formation by Thalassiosira weissflogii (diatom) in the presence or absence of bacteria under two temperature and three pCO2 scenarios. During the aggregation phase of the experiment TEP formation was elevated at the higher temperature (20°C vs.

Development of a genetic system for Marinobacter adhaerens HP15 involved in marine aggregate formation by interacting with diatom cells.

Diatom aggregation is substantial for organic carbon flux from the photic zone to deeper waters. Many heterotrophic bacteria ubiquitously found in diverse marine environments interact with marine algae and thus impact organic matter and energy cycling in the ocean. In particular, Marinobacter adhaerens HP15 induces aggregate formation while interacting with the diatom, Thalassiosira weissflogii.

Marinobacter adhaerens sp. nov., isolated from marine aggregates formed with the diatom Thalassiosira weissflogii.

A Gram-negative, motile, rod-shaped bacterial strain, HP15(T), was isolated from aggregates taken from surface waters of the German Wadden Sea (German Bight). Of 82 marine isolates, HP15(T) was chosen for further study because of its high potential to induce production of transparent exopolymeric particles and aggregate formation while interacting with the diatom Thalassiosira weissflogii. HP15(T) grew optimally at 34-38 °C and pH 7.

Complete genome sequence of Marinobacter adhaerens type strain (HP15), a diatom-interacting marine microorganism.

Marinobacter adhaerens HP15 is the type strain of a newly identified marine species, which is phylogenetically related to M. flavimaris, M. algicola, and M.