engleski

The species composition and ecology of the genus Leptocylindrus Cleve in the Northern Adriatic Sea

The marine diatom genus Leptocylindrus Cleve is an important component of phytoplankton blooms in coastal ecosystems worldwide. However, only little is known about the ecology and species composition of this genus in the Adriatic Sea. Although Leptocylindrus danicus Cleve and L. minimus Gran have been reported from numerous studies conducted in the Adriatic Sea, there has been neither unequivocal species identification nor focused examination of the temporal abundance of Leptocylindrus in this region. In a recent reappraisal of Leptocylindrus by Nanjappa et al. (2013) five species and one new genus were identified using both morphological and molecular methods. We here describe the temporal distribution of the genus Leptocylindrus based on 45 years of records, revealing that this diatom is a key component of the seasonal phytoplankton cycle, with highest abundance in the spring and autumn periods. Using light and scanning electron microscopy as well as genetic analysis based on the nuclear- encoded rDNA regions and environmental meta-barcoding, our study unambiguously revealed three species new for the Adriatic Sea, Leptocylindrus hargravesii D. Nanjappa & A. Zingone, Leptocylindrus convexus D. Nanjappa & A. Zingone and Leptocylindrus aporus (F.W. French & Hargaves) D. Nanjappa & A. Zingone. Making use of the steep ecological gradients that characterize the Northern Adriatic Sea, we report here on the ecological circumstances under which those species thrive and how their respective populations are globally connected. The ecology, physiology and evolution of this significant diatom genus should be further investigated to improve our knowledge of its ecological significance in marine, planktonic ecosystems.

fitoplankton ; Jadransko more ; dijatomeje ; Leptocylindrus

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