Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8886041 | Journal of Marine Systems | 2017 | 12 Pages |
Abstract
This study presents the results of the first field application of a flow-through multi-wavelength Fast Repetition Rate fluorometer (FRRF) equipped with two excitation channels (458 and 593Â nm). This device aims to improve the measurement of mixed cyanobacteria and algae community's photosynthetic parameters and was designed to be easily incorporated into existing ferrybox systems. We present a spatiotemporal analysis of the maximum photochemical efficiency (Fv/Fm) and functional absorption cross section (ÏPSII) recorded from April to August 2014 on a ship-of-opportunity commuting twice per week between Helsinki (Finland) and Travemünde (Germany). Temporal variations of Fv/Fm and ÏPSII differed between areas of the Baltic Sea. However, even though the Baltic Sea is characterized by several physico-chemical gradients, no gradient was observed in Fv/Fm and ÏPSII spatial distribution suggesting complex interactions between biotic and abiotic controls. ÏPSII was sensitive to phytoplankton seasonal succession and thus differed according to the wavelength used to excite photosystems II (PSII) pigments. This was particularly true in summer when high ÏPSII(593) values were observed later and longer than high ÏPSII(458) values, reflecting the role of cyanobacteria in photosynthetic light uptake measured at community scale. In contrast, Fv/Fm variations were similar after excitation at 458Â nm or 593Â nm suggesting that the adjustment of Fv/Fm in response to environmental factors was similar for the different groups (algae vs. cyanobacteria) present within the phytoplankton community.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Oceanography
Authors
Emilie Houliez, Stefan Simis, Susanna Nenonen, Pasi Ylöstalo, Jukka Seppälä,