title: Salinity tolerance of the chlorophyll b-synthesizing cyanobacterium Prochlorothrix hollandica strain SAG 10.89.
abstract: Ecophysiological investigations on the salinity acclimation of the cyanobacterium Prochlorothrix hollandica SAG 10.89 led to significantly revised salinity tolerance limits. Besides potential effects of cultivation techniques, clear ion composition effects mainly explain formerly described hypersensitivity to NaCl-mediated salinity and lack of osmolyte detection. An extraordinarily broad plasticity of cellular chlorophyll a/b ratios occurred with variations of NaCl-induced salinity. Photosynthesis characteristics, pigment regulation, respiration, and biomass yield in growth medium with field-like ion composition indicated generally reduced acclimation pressure. A simultaneously significant increase in osmolyte (sucrose) accumulation indicated more efficient osmotic acclimation. Minor growth inhibition up to salinities of 10 practical salinity units enlarged the potential habitat of P. hollandica but at the most to about 300,000 km2 in the Baltic Sea. This supports probable observations of Prochlorothrix sp. in phytoplankton assemblages of open waters in Baltic Sea-monitoring studies. Brackish habitats differ from so far known habitats of Prochlorothrix spp. in turbidity, productivity, and plankton composition. Adjusted physiological features dispel fundamental doubts on the establishment of filamentous prochlorophytes in brackish waters.
authors.affiliation: Institute of Biosciences, Aquatic Ecology, University of Rostock, Rostock, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Bergmann
authors.forename: Ulrike
authors.initials: U
authors.lastname: Geiss-Brunschweiger
authors.forename: Martin
authors.initials: M
authors.lastname: Hagemann
authors.forename: Arne
authors.initials: A
authors.lastname: Schoor
mesh_terms: D018533:Biomass; D002734:Chlorophyll / Q000096:biosynthesis*; D003470:Culture Media; D009994:Osmolar Concentration; D010788:Photosynthesis / Q000187:drug effects; D019692:Prochlorothrix / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D054712:Salinity; D012965:Sodium Chloride / Q000494:pharmacology*; D013395:Sucrose / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D003470:Culture Media; D002734:Chlorophyll; D012965:Sodium Chloride; D013395:Sucrose; C037184:chlorophyll b