Distribution of phytoplankton community in Kotor Bay (south-eastern Adriatic Sea)

Abstract

The goal of this paper was to explain variability of phytoplankton in a shallow coastal area in relation to physico-chemical parameters. Temporal variability and composition of phytoplankton were investigated in the Kotor Bay, a small bay located in the south-eastern part of the Adriatic Sea. Samplings were performed weekly from February 2008 to January 2009 at one station in the inner part of the Kotor Bay, at five depths (0 m, 2 m, 5 m, 10 m, 15 m). Phosphates, nitrites and nitrates ranged from values under the level of detection to the maximum values of 1.54, 1.53 and 23.91 µmol l−1, respectively. The phytoplankton biomass — represented by chlorophyll a concentration — ranged from 0.12 to 6.78 mg m−3, reaching a maximum in summer. Diatoms were present throughout the whole sampling period, reaching the highest abundance in March (3.42×105 cells l−1at surface). The peak of dinoflagellates in July (2.2×106 cells l−1 at surface) was due to a single species, Prorocentrum micans. The toxic dinoflagellate Dinophysis fortii occurred at a concentration of 2140 cells l−1 in May. The present results of phytoplankton assemblages and distribution provide valuable information for this part of the south-eastern Adriatic Sea where data is currently absent.

Untitled

“…The maximum microplankton abundance in current research was lower than the values found in the Boka Kotorska Bay (Drakulović et al, 2012;Bosak et al, 2012) and similar with the data recorded in the northeastern Adriatic Sea (Lim Bay and Zrmanja Bay) (Burić et al, 2007;Bosak et al 2009). Also the value was lower compared to with microplankton abundance in the northwestern Adriatic Sea (Aubry et al, 2004), which is influenced by two important rivers (Po and Adige) that caused modification of local circulation with wind stress.…”

“…Negative significant correlation between nitrate and silicate on one side and salinity on other indicates an influence of river runoff during periods of high precipitation. The same correlation was noticed in other Adriatic estuaries (Burić et al, 2007;Aubry, Berton, Bastianini, Socal, & Acri, 2004), while in previous study of the Bay correlation was positive (Drakulović et al, 2012).…”

“…In this research, diatoms were present with 42 taxa, dinoflagellates with 50 taxa which is different from the result noted by Bosak et al (2012) and similar with data noted by Drakulović et al (2012). In the northwestern Adriatic Sea, as expected in a nutrientenriched system, the community structure was dominated by diatoms over most of the year (Aubry et al, 2004).…”

“…The present result is slightly different from the results recorded in the Zrmanja estuary (Burić et al, 2007) and in the south-eastern Adriatic (Krivokapić et al, 2011), where a chlorophyll a peak was noticed in late winter and spring when the water column is rich with regenerated nutrients and solar radiation is increasing. The chlorophyll a values in this study were significantly lower than those in the previous study of Boka Kotorska Bay (Drakulović et al, 2012). Numerous studies emphasize that that concentration of chl decreases as phytoplankton standing stocks increase (Desortova, 1981;ChowFraser, Trew, Findley, & Stainton, 1994;Sandu, Iacob, & Nicolescu, 2003;Kiss, Devai, Tothmeresz, & Szabo, 2006).…”

“…In order to make their scales comparable, both biological and hydrological variables were scaled to unit variance. (Drakulović, Pestorić, Cvijan, Krivokapić, & Vuksanović, 2012). Generally, in the Adriatic Sea (Burić et al, 2007;Viličić et al, 2008), limited nutrient is phosphate almost throughout the year, while nitrogen availability is sporadically limited in the summer.…”