Phytoplankton distribution and environmental characteristics were determined in a shallow, highly stratified and oligotrophic estuary (Zrmanja, eastern Adriatic). Samples were collected in two ...contrasting seasons; winter (February 2000), when river discharge was high, and in summer (July 2003), a period of drought. Phytoplankton distribution was closely related to salinity gradients, nutrient levels, and water residence time. Microscopic analysis revealed that phytoplankton was composed mainly of marine diatoms, dinoflagellates, cryptophytes, green flagellates, and coccolithophorids. The dominant biomarker pigments were fucoxanthin, alloxanthin and 19'-hexanoyloxyfucoxanthin, while lower, but indicative contributions of peridinin and chlorophyll b were also noted. Maximum abundance and biomass were found in the middle estuary in winter and in the upper estuary in summer. The estuary is mostly P-limited. Development of chain-forming marine diatoms was evident in winter. Due to the reduced nutrient input in summer, the biomass accumulated in the upper estuary (1,000 ng chlorophyll a l⁻¹) was composed mostly of nanoplanktonic unicellular diatoms, nanoplanktonic marine dinoflagellates, cryptophytes, and chlorophytes. The concentrations of about 200 ng l⁻¹ hex-fuco, suggested that the contribution of prymnesiophytes to total biomass was comparable to that of diatoms and dinoflagellates. In the middle estuary and coastal sea, PO₄ and TIN were 3.5 times lower, resulting in a fivefold decrease in biomass (<100 ng chlorophyll a l⁻¹). The oligotrophic Zrmanja and other karstic rivers discharging in the eastern Adriatic Sea, provide insufficient source of nutrients and low productivity of the eastern Adriatic Sea.
Based on our own research carried out from 2013 to 2019 and literature data, this study presents for the first time a comprehensive floristic list of Mt Svilaja (max. 1508 m a.s.l.). It contains 1285 ...taxa classified within 502 genera and 109 families. Of these, 552 taxa are listed for the first time for Svilaja. Out of 733 taxa recorded previously, the presence of 128 taxa has not been confirmed. Poaceae (8.79%), Asteraceae and Fabaceae (8.72% each) had the highest number of taxa, with the largest number of taxa within the genera Trifolium (23 taxa), Carex (20) and Centaurea (17). Hemicryptophytes (43.35%) and therophytes (25.45%) prevailed, and Mediterranean (23.27%), southern European (20.83%) and Eurasian (17.43%) plant taxa dominated. Altogether, there were 76 endemics (5.91%), mostly of Illyrian-Adriatic origin, 34 endangered (CR, EN, VU) taxa (2.65%), and 155 strictly protected taxa according to Croatian law (12.06%). Among the endemics, the presence of Scabiosa delminiana Abadžić must be stressed. Mt Svilaja is characterized by rich orchid flora (51 taxa, 3.97%), and features Epipactis placentina Bongiorni & Grünanger, the only site found in Croatia that does. Although as many as 34 invasive taxa have been recorded, their presence is mostly limited to anthropogenic habitats.
U travnju 2020. istraživana je flora ulica i pločnika u staroj gradskoj jezgri u Dubrovniku tijekom razdoblja karantene uslijed epidemije COVID-19. U radu su opisane florističke značajke temljem ...analize taksonomskog sastava, životnih oblika, flornih elemenata i fitocenološke pripadnosti biljnih svojti na osam lokaliteta te na transektu uzduž Straduna. Ukupno je pronađeno 57 biljnih vrsta i tri podvrste. Najveći udio u flori imali su terofiti, kozmopoliti te svojte svojstvene vegetacijskim razredima Papaveretea rhoeadis i Chenopodietea. Studija ističe važnost istraživanja flore i vegetacije u povijesnoj jezgri grada Dubrovnika.
Deep chlorophyll a maximum (DCM) was found in the 80-110 m deep northeastern coastal Adriatic (Pag and Velebit Channels) in July 2007. Eight times higher concentrations of chlorophyll were determined ...in the 50 to 60 m DCM layer (0.81 to 0.91 mu gL super(-1)) relative to the surface waters. According to thermohaline conditions and phytoplankton biomass distribution, over the greater part of the considered area the water column was separated into three layers (the surface layer approximately 10 m deep, the subsurface layer extending between 10 and 50 m, and the deep layer found below 50 m depth) and three distinctive regimes were detected (in the South Velebit Channel, the Middle Velebit Channel, and the Pag Channel). This is the first evidence of the deep chlorophyll maximum in the eastern coastal Adriatic Sea. Deep chlorophyll maxima were composed of picoplanktonic, rounded cells, probably cyanobacteria (1.2 mu m in size, 8 x 10 super(3) - 1 x 10 super(4) cells mL super(-1)).
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