| Title | The mesopelagic anoxic Black Sea as an unexpected habitat for Synechococcus challenges our understanding of global "deep red fluorescence" |
| Abstract | The Black Sea is the largest meromictic sea with a reservoir of anoxic water extending from 100 to 1000 m depth. These deeper layers are characterised by a poorly understood fluorescence signal called "deep red fluorescence", a chlorophyll a-(Chl a) like signal found in deep dark oceanic waters. In two cruises, we repeatedly found up to 10(3) cells ml(-1) of picocyanobacteria at 750 m depth in these waters and isolated two phycoerythrin-rich Synechococcus sp. strains (BS55D and BS56D). Tests on BS56D revealed its high adaptability, involving the accumulation of Chl a in anoxic/dark conditions and its capacity to photosynthesise when re-exposed to light. Whole-genome sequencing of the two strains showed the presence of genes that confirms the putative ability of our strains to survive in harsh mesopelagic environments. This discovery provides new evidence to support early speculations associating the "deep red fluorescence" signal to viable picocyanobacteria populations in the deep oxygen-depleted oceans, suggesting a reconsideration of the ecological role of a viable stock of Synechococcus in dark deep waters. |
| Source | The ISME journal (Print) 13 (7), pp. 1676–1687 |
| Keywords | microbial ecology |
| Journal | The ISME journal (Print) |
| Editor | Nature Publishing Group,, London, Regno Unito |
| Year | 2019 |
| Type | Articolo in rivista |
| DOI | 10.1038/s41396-019-0378-z |
| Authors | Callieri, Cristiana; Slabakova, Violeta; Dzhembekova, Nina; Slabakova, Nataliya; Peneva, Elisaveta; Cabello-Yeves, Pedro J.; Di Cesare, Andrea; Eckert, Ester M.; Bertoni, Roberto; Corno, Gianluca; Salcher, Michaela M.; Kamburska, Lyudmila; Bertoni, Filippo; Moncheva, Snejana |
| Text | 407737 2019 10.1038/s41396 019 0378 z ISI Web of Science WOS 000472152300004 microbial ecology The mesopelagic anoxic Black Sea as an unexpected habitat for Synechococcus challenges our understanding of global deep red fluorescence Callieri, Cristiana; Slabakova, Violeta; Dzhembekova, Nina; Slabakova, Nataliya; Peneva, Elisaveta; Cabello Yeves, Pedro J.; Di Cesare, Andrea; Eckert, Ester M.; Bertoni, Roberto; Corno, Gianluca; Salcher, Michaela M.; Kamburska, Lyudmila; Bertoni, Filippo; Moncheva, Snejana Natl Res Council CNR IRSA; Bulgarian Acad Sci; Sofia Univ St Kliment Ohridski; Univ Miguel Hernandez; Biol Certer CAS; Univ Zurich; Museum Nat Kunde The Black Sea is the largest meromictic sea with a reservoir of anoxic water extending from 100 to 1000 m depth. These deeper layers are characterised by a poorly understood fluorescence signal called deep red fluorescence , a chlorophyll a Chl a like signal found in deep dark oceanic waters. In two cruises, we repeatedly found up to 10 3 cells ml 1 of picocyanobacteria at 750 m depth in these waters and isolated two phycoerythrin rich Synechococcus sp. strains BS55D and BS56D . Tests on BS56D revealed its high adaptability, involving the accumulation of Chl a in anoxic/dark conditions and its capacity to photosynthesise when re exposed to light. Whole genome sequencing of the two strains showed the presence of genes that confirms the putative ability of our strains to survive in harsh mesopelagic environments. This discovery provides new evidence to support early speculations associating the deep red fluorescence signal to viable picocyanobacteria populations in the deep oxygen depleted oceans, suggesting a reconsideration of the ecological role of a viable stock of Synechococcus in dark deep waters. 13 Published version The mesopelagic anoxic Black Sea as an unexpected habitat for Synechococcus challenges our understanding of global deep red fluorescence s41396 019 0378 z.pdf Articolo in rivista Nature Publishing Group, 1751 7362 The ISME journal Print The ISME journal Print ISME j. Print The ISME journal Print International Society for Microbial Ecology journal Print roberto.bertoni BERTONI ROBERTO cristiana.callieri CALLIERI CRISTIANA gianluca.corno CORNO GIANLUCA andrea.dicesare DI CESARE ANDREA estermaria.eckert ECKERT ESTER MARIA |
