Nitrogen Fixation Influenced by Phosphorus and Nitrogen Availability in the Benthic Bloom‐forming Cyanobacterium Hydrocoleum sp. Identified in a Temperate Marine Lagoon. Issue 3 (26th March 2022)

• Record Type: Journal Article
• Authors: Moisander, Pia H.; Daley, Meaghan C.; Shoemaker, Katyanne M.; Kolte, Vaishnavi; Sharma, Gaurav; Garlick, Kelsey
• Editors: Palenik, B.
• Is Part Of: Journal of phycology. Volume 58:Issue 3(2022)
• Page Start: 377
• Page End: 391
• Publication Date: 2022-03-26
• Subjects: coralline algae -- cyanobacteria -- diazotroph -- gene expression -- microphytobenthos -- nitrogen fixation -- nutrients -- systematics -- Trichodesmium; Algae -- Periodicals; 579.8
• DOI: 10.1111/jpy.13244
• Languages: English
• ISSNs: 0022-3646

Abstract

Abstract : The nitrogen‐fixing, non‐heterocystous cyanobacterium Hydrocoleum sp. (Oscillatoriales) is a common epiphytic and benthic bloom‐former in tropical and subtropical shallow water systems but shares high phylogenetic similarity with the planktonic, globally important diazotroph Trichodesmium . Multiphasic observations in this study resulted in unexpected identification of Hydrocoleum sp. in mass accumulations in a coastal lagoon in the Western temperate North Atlantic Ocean. Hydrocoleum physiology was examined in situ through measurements of N2 and CO2 fixation rates and expression of genes involved with N2 fixation, CO2 fixation, and phosphorus (P) stress. Bulk N2 fixation rates and Hydrocoleum nif H expression peaked at night and were strongly suppressed by dissolved inorganic nitrogen (DIN). The expression of high affinity phosphate transporter ( pst S) and alkaline phosphatase ( pho A) genes of Hydrocoleum was elevated during the night and negatively responded to phosphate amendments, as evidence that these mechanisms contribute to P acquisition during diazotrophic growth of Hydrocoleum in situ. This discovery at the edge of the previously known Hydrocoleum habitat range in the warming oceans raises intriguing questions about diazotrophic cyanobacterial adaptations and transitions on the benthic‐pelagic continuum.