engleski

The ecology of the genus Leptocylindrus in a highly structured ecosystem, the northern Adriatic

The marine diatom genusLeptocylindrusis a major component of phytoplankton blooms in coastal ecosystems worldwide, however, little is known about the ecology and meticulous species composition of this genus in the Adriatic Sea. Although Leptocylindrus danicus andL. minimus have been reported from numerous studies conducted in Adriatic, 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 markers. 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 greatest abundance in the spring and autumn. Using light and scanning electron microscopy as well as genetic analysis based on the nuclear- encoded rDNA regions, our study unambiguously revealed three species new for the Adriatic Sea, Leptocylindrus hargravesii, Leptocylindrus convexus and Leptocylindrus aporus. Furthermore, we investigated the growth, auxospore and resting spore formation of one of the Leptocylindrus species under different nutrient regimes. The ecology, physiology and evolution of this significant diatom genus should be further investigated.

phytoplankton, Adriatic sea, diatoms, Leptocylindrus

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