Diversity and distribution of the planktonic diatom genus Chaetoceros (Bacillariophyceae) in the Golden Horn Estuary (Sea of Marmara)

Abstract

The diversity and distribution of the diatom genus Chaetoceros (Bacillariophyceae) was studied at monthly, bi-weekly and weekly intervals over two periods (2009–2010, 2013–2014) in the Golden Horn Estuary. Chaetoceros was the most diverse genus in the diatom assemblage of the study area. A total of 23 Chaetoceros species were identified based on light and scanning electron microscopy. Three taxa, Chaetoceros aequatorialis, C. contortus and C. lorenzianus f. forceps were recorded for the first time in Turkish seas. The most common species were C. affinis, C. curvisetus, C. decipiens and C. holsaticus. The contribution of Chaetoceros species to the number of total phytoplankton species was between 15% and 17%. The highest abundance of Chaetoceros species was 507 × 10³ cells L⁻¹, dominated by C. affinis, C. constrictus, C. holsaticus, C. lauderi in the middle estuary in spring. Chaetoceros species were more abundant in the middle and lower estuary in April and May. In the upper estuary (UE), Chaetoceros species were rarely observed due to low water transparency caused by suspended particulate materials. Light limitation may be considered one of the most important factors affecting the diversity and spatial distribution of these species in the UE. The present work is the first detailed study on the diversity and distribution of Chaetoceros species for Turkish seas.

Keywords:

• diatoms
• Chaetoceros
• biodiversity
• Sea of Marmara
• Golden Horn Estuary

Acknowledgements

The authors would like to thank Dr Ahsen Yuksek, Dr Noyan Yilmaz, Dr Fuat Dursun, MSc. Elif Murat Dalkara, MSc. Duysen Kus and MSc. Turgay Durmus for their help and efforts during these projects and Dr Nina Lundholm for her constructive suggestions during the preparation of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Seyfettin Tas http://orcid.org/0000-0002-4660-3937

David Uriel Hernández-Becerril http://orcid.org/0000-0002-3169-6886

Additional information

Funding

This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK – project numbers: 109Y046 and 113Y091).