Microbial trace metal trafficking on marine particles

Science Highlights

28 September 2021

Marine particles contain metals that can quantitatively equal or exceed the dissolved pool, but whether particulate matter presents a source for microorganism remains largely unexplored.  Debeljak and colleagues (2021, see reference below) have addressed this question by a double approach, the chemical characterization and the ‘metallo’-metatranscriptome of a diverse prokaryotic community inhabiting particles in the Southern Ocean. Their study shows that the ratios of multiple metals to phosphorus are higher in particles as compared to those in heterotrophic prokaryotes, identifying particulate matter as a potential source of these elements. Using a comparative metatranscriptomics approach, Debeljak and colleagues reveal an enhanced expression of genes for the uptake of metals through various mechanisms in prokaryotes inhabiting particles. But concurrently genes involved in the control of resistance to metal toxicity, storage, sensing and regulation were also highly expressed by particle-attached prokaryotes. Their study provides evidence for the processing of nine particulate trace metals in multiple manners by diverse microbial communities. To explain these enhanced transcript inventories of distinct metal-related genes in particle-attached heterotrophic prokaryotes, the authors suggest an overarching biological property essential for life, homeostasis, as a conceptual framework.

Figure: Enrichment of trace metal related gene transcripts in particle-associated prokaryotes
Fold changes of normalized transcript counts of KEGG orthologous genes in prokaryotic communities attached to particles as compared to those in particle-free incubations (given in Log2Fold). Significantly higher expressed transcripts (adjusted p-value <0.05) are indicated by an asterisk (*) and genes potentially implicated in the transport of multiple metals are indicated by the letter M (for multiple). Transporters for organically-bound Fe are shown separately from those for Fe 2+ and Fe 3+.

This study is published in Limnology and Oceanography and illustrated by the following Video Abstract:

Reference:

Debeljak, P., Blain, S., Bowie, A., Merwe, P., Bayer, B., & Obernosterer, I. (2021). Homeostasis drives intense microbial trace metal processing on marine particles. Limnology and Oceanography, lno.11923. DOI: https://doi.org/10.1002/lno.11923

Latest highlights

Continuous record of the Antarctic Circumpolar Current latitude over the last glacial-interglacial cycles

The meridional positions of the oceanic fronts separating subtropical and Antarctic waters are key to constraining the mechanisms that drive the degassing of deeply-stored CO2 at the end of the glacial periods…

23 Million Years of iron sources reconstructed in the Northwest Pacific Ocean using iron isotopes in a ferromanganese crust

Using iron isotopes and elemental records, Chu and co-workers analysed an iron-manganese crust recovered from the Hongyan Seamount, and reconstructed the sources of dissolved Fe to the Northwest Pacific Ocean…

Variability of the past deep-water masses in the Arabian Sea over the last 41ka

Shukla and colleagues propose a high-resolution authigenic ƐNd record measured from a sediment core located in the eastern Arabian Sea…

Arctic outflows to Davis Strait and the Labrador Sea traced by radionuclide distributions

This study demonstrates that Arctic outflows through the Canadian Arctic Archipelago play a much more significant role than previously recognised.

Rechercher