title: Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges.
abstract: Marine sponges are major habitat-forming organisms in coastal benthic communities and have an ancient origin in evolution history. Here, we report significant accumulation of polyphosphate (polyP) granules in three common sponge species of the Caribbean coral reef. The identity of the polyP granules was confirmed by energy-dispersive spectroscopy (EDS) and by the fluorescence properties of the granules. Microscopy images revealed that a large proportion of microbial cells associated with sponge hosts contained intracellular polyP granules. Cyanobacterial symbionts cultured from sponges were shown to accumulate polyP. We also amplified polyphosphate kinase (ppk) genes from sponge DNA and confirmed that the gene was expressed. Based on these findings, we propose here a potentially important phosphorus (P) sequestration pathway through symbiotic microorganisms of marine sponges. Considering the widespread sponge population and abundant microbial cells associated with them, this pathway is likely to have a significant impact on the P cycle in benthic ecosystems.
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD 21202; and.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD 21202; and.
authors.forename: Leah C
authors.initials: LC
authors.lastname: Blasiak
authors.affiliation: Institute of Fluorescence, University of Maryland Baltimore County, Baltimore, MD 21202.
authors.forename: Jan O
authors.initials: JO
authors.lastname: Karolin
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD 21202; and.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Powell
authors.affiliation: Institute of Fluorescence, University of Maryland Baltimore County, Baltimore, MD 21202.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Geddes
authors.affiliation: Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD 21202; and hill@umces.edu.
authors.forename: Russell T
authors.initials: RT
authors.lastname: Hill
mesh_terms: D000818:Animals; D001426:Bacterial Proteins; D044822:Biodiversity; D057894:Coral Reefs; D000458:Cyanobacteria / Q000378:metabolism*; D017753:Ecosystem; D005431:Florida; D008164:Luminescent Proteins; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010758:Phosphorus / Q000737:chemistry / Q000502:physiology*; D011122:Polyphosphates / Q000737:chemistry; D011161:Porifera / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013045:Species Specificity; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D011122:Polyphosphates; D012336:RNA, Ribosomal, 16S; C054562:yellow fluorescent protein, Bacteria; D010758:Phosphorus
keywords: microbial symbionts; phosphorus sequestration; polyphosphate; sponge