title: Bio-optical characterization of selected cyanobacteria strains present in marine and freshwater ecosystems.
abstract: The optical properties, i.e., absorption and scattering spectra of ten strains of cyanobacteria from the Baltic Sea and Pomeranian lakes (Aphanizomenon flos-aquaeKAC 15,Microcystis aeruginosaCCNP 1101,Anabaenasp. CCNP 1406,Synechocystis salinaCCNP 1104,Phormidiumsp. CCNP 1317,Nodularia spumigenaCCNP 1401,Synechococcussp. CCNP 1108,Nostocsp. CCNP 1411,Cyanobacteriumsp. CCNP 1105,Pseudanabaena cf. galeataCCNP 1312) grown under low light conditions were investigated. Moreover, the chlorophylls, carotenoids, and phycobilin composition as well as the size structure of chosen cyanobacteria were measured. Studied species revealed high diversity both in optical properties with the absorption spectra similarity index ranging from 0.67 to 0.94 and the pigment composition. The chlorophyll-specific absorption coefficient at 440 nmaph*(440) varied between 0.017 and 0.065 m2mg-1. The influence of the package effect was only observed in the case of large filamentous cyanobacteria likeN. spumigenaorNostocsp. Interestingly, the package effect factorQa*(675) for large-celledAnabaenasp. was 0.92. Besides chlorophylla, only echinenone,β-carotene, and phycocyanin were present in all analyzed cyanobacteria strains. Zeaxanthin, which is widely used as a marker pigment for cyanobacteria, was absent in the toxicN. spumigenaandAnabaenasp., which are the species that occur in the Baltic Sea most frequently causing summer cyanobacterial blooms. The investigation also showed that the sample preservation technique can introduce some major errors within the absorption band affected by the phycocyanin absorption.
authors.affiliation: Department of Physical Oceanography, Institute of Oceanography, University of Gdańsk, Marszałka Piłsudskiego 46, 81-378 Gdynia, Poland ; CSIRO Oceans and Atmosphere, Floreat, WA Australia.
authors.forename: Bożena
authors.initials: B
authors.lastname: Wojtasiewicz
authors.affiliation: Marine Physics Department Polish Academy of Sciences, Powstańców Warszawy 55, 81-712 Sopot, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Stoń-Egiert
keywords: Absorption; Carotenoids; Chlorophyll; Cyanobacteria; Phycobilins; Size structure