Project description:Seamounts, often rising hundreds of metres above the surrounding seafloor, obstruct the flow of deep-ocean water. While the resultant entrainment of deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered by the large scale and slow rate of the interaction. To overcome these limitations we use the growth of planktonic bacteria to assess the interaction rate. The selected study site, Tropic Seamount, in the North-Eastern Atlantic represents the majority of isolated seamounts, which do not affect the surface ocean waters. We prove deep-water is entrained by the seamount by measuring 2.3 times higher bacterial concentrations in the seamount-associated or ‘sheath’ water than in deep-ocean water unaffected by seamounts. Genomic analyses of the dominant sheath-water bacteria confirm their planktonic origin, whilst proteomic analyses indicate their slow growth. According to our radiotracer experiments, the doubling time of sheath-water bacterioplankton is 1.5 years. Therefore, for bacterioplankton concentration to reach 2.3 times higher in the ambient seawater, the seamount would need to retain deep-ocean water for more than 3.5 years. We propose that turbulent mixing of the retained sheath-water could stimulate bacterioplankton growth by increasing the cell encounter rate with the ambient dissolved organic molecules. If some of these molecules chelate hydroxides of iron and manganese, bacterioplankton consumption of the organic chelators would result in precipitation of insoluble hydroxides. Hence precipitated hydroxides would form ferromanganese deposits as a result of the bacterioplankton-mediated deep-water seamount interaction.
Project description:Transcriptional profiling of populations in the clam Ruditapes decussatus determined differentiation in gene-expression along parallel temperature gradients and between races of the Atlantic Ocean and West Mediterranean sea.
Project description:This project presents field metaproteomics data from Trichodesmium colonies collected from the surface ocean. Most were collected from the tropical and subtropical Atlantic ocean, but there is also data from the long term Bermuda Atlantic Time Series and Hawaii Ocean Time Series. Trichodesmium is a globally important marine microbe and its growth and nitrogen fixation activity is limited by nutrient availability in the surface ocean. This dataset was generated to answer questions about limitations on Trichodesmium's growth and activity in the nature.
Project description:We provide a comprehensive map of the subcellular localization of mRNAs in mature neurons and reveal that transcripts stably retaining introns are broadly targeted for nuclear retention. We systematically probed the fate of nuclear transcripts upon neuronal stimulation and found that sub-populations of transcripts are bi-directionally regulated in response to neuronal cues: some are targeted for degradation while others undergo splicing completion to generate fully mature mRNAs which are exported to the cytosol.
