Original scientific paper

https://doi.org/10.1515/botcro-2015-0031

Diatoms in an extreme euxinic environment (Rogoznica Lake, eastern Adriatic coast)

Nikola Malešević ; University of Zagreb, Faculty of Science, Division of Biology, Rooseveltov trg 6, 10000 Zagreb, Croatia
Irena Ciglenečki ; Ruđer Bošković Institute, Division of Marine and Environmental Research, Bijenička cesta 54, 10000 Zagreb, Croatia
Elvira Bura-Nakić ; Ruđer Bošković Institute, Division of Marine and Environmental Research, Bijenička cesta 54, 10000 Zagreb, Croatia
Marina Carić ; University of Dubrovnik, Institute for Marine and Coastal Research, Kneza Damjana Jude 12, 20000 Dubrovnik, Croatia
Iris Dupčić ; University of Dubrovnik, Institute for Marine and Coastal Research, Kneza Damjana Jude 12, 20000 Dubrovnik, Croatia
Enis Hrustić ; University of Dubrovnik, Institute for Marine and Coastal Research, Kneza Damjana Jude 12, 20000 Dubrovnik, Croatia
Damir Viličić ; University of Zagreb, Faculty of Science, Division of Biology, Rooseveltov trg 6, 10000 Zagreb, Croatia
Zrinka Ljubešić ; University of Zagreb, Faculty of Science, Division of Biology, Rooseveltov trg 6, 10000 Zagreb, Croatia

Abstract

The Rogoznica Lake marine system is a small, karstic, naturally eutrophic and euxinic marine environment. Abundance and temporal distribution of phytoplankton was investigated in relation to environmental conditions in the period from 1998 to 2013. The 36 determined diatoms contributed 90% of the total phytoplankton abundance. The diatom composition is characterized by low species diversity and high single species abundance (up to 107 cells L–1). There were, on average, 2.6 diatom species per sample (maximum 14 diatom species per sample) reflecting extreme environmental conditions. Dominant diatoms Thalassionema nitzschioides, Cyclotella choctawhatcheeana, Dactyliosolen fragilissimus and Chaetoceros curvisetus occurred repeatedly and were alternately dominant in the lake during the whole research period. Some diatoms were dominant only in limited period, like Cyclotella choctawhatcheeana (evident since 2001), and Pseudo-nitzschia spp. (evident in the period 2002 to 2009). It appears that the interplay of environmental conditions such as variability in thermohaline and redox conditions, nutrient and reduced sulphur concentration influence the phytoplankton development and abundance in the lake.

Keywords

diatoms; extreme environmental conditions; marine lake; phytoplankton

Hrčak ID:

146032

URI

https://hrcak.srce.hr/146032

Publication date:

1.10.2015.

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