Temporal variation of surface chlorophyll a in the Romanian near-shore waters

Abstract

Chlorophyll a (Chl a) dynamics in the near-shore waters of the NW Black Sea was investigated between 2002 and 2010 in the Mamaia Bay (north of Constanta, Romania) in relation to some physical-chemical parameters. Chl a ranged from values below detection limit (0.17 µg ) to 76.13 µg . l -1 , and showed large temporal variability (CV = 142.3%), strongly related to the Danube's discharges, meteorological conditions, and anthropogenic pressures.Seasonally, Chl a showed a winter/early spring maximum, sometimes followed by a stronger one in April/early May, closely linked to the Danube's higher discharges in spring. After significantly lower concentrations in late spring/early summer, Chl a exhibited its strongest maximum in summer (July-August), followed by another one in autumn (late September-October).Interannual variation of Chl a seems to be controlled by the hydrometeorological conditions in summer. Thus, the highest annual Chl a means were observed in 2006 (8.56 ± 8.35 µg . l -1 ) and 2010 (9.20 ± 11.72 µg . l -1 ), when, also, the summer Chl a concentrations were maximal due to the large riverine discharges. The lowest annual Chl a mean was observed in 2004 (4.57 ± 9.81 µg . l -1 ), closely linked to minimal summer Chl a resulted from a strong P limitation during summertime.

Quantifying importance and scaling effects of atmospheric deposition of inorganic fixed nitrogen for the eutrophic Black Sea

“…The influence of atmospheric deposition of IFN at the concentration of chlorophyll a in the surface waters in the Black Sea has never been studied. The previously published data have attributed spatial anomalies in the distribution of chlorophyll a to coastal sources of nutrients (Vasiliu et. al., 2012), physical flux of nutrients (Yunev et al, 2002), and dust deposition (Katara et al, 2008).…”

Distributions and compound-specific isotopic signatures of sedimentary chlorins reflect the composition of photoautotrophic communities and their carbon and nitrogen sources in Swiss lakes and the Black Sea

“…The core covers the typical Black Sea unit 1 (Piper and Calvert, 2011;Ross and Degens, 1974). The phytoplankton communities in the western Black Sea are typically dominated by dinoflagellates in spring, and diatoms and coccolithophores in fall (Eker et al, 1999;Moncheva et al, 2001), although the Romanian Shelf is generally dominated by diatoms with exceptions of blooms comprising cyanobacteria and dinoflagellates (Vasiliu et al, 2012). GSB have been reported from the chemocline of the Black Sea (e.g.…”

Quantifying importance and scaling effects of atmospheric deposition of inorganic fixed nitrogen for the eutrophic Black Sea

“…In order to analyse spatial and temporal variations in the input of IFN to the Black Sea with atmospheric precipitations and to scale the effect of this input, we have followed Vautz et al (2003) to parameterize the concentration of IFN as a function of meteorological variables. A multiple regression equation is used in this model to bind meteorological parameters (daily data of the precipitations amount, wind direction, season and preceding dry period) with the flow of contaminants from the atmosphere.…”

“…In order to reconstruct a multiple nonlinear regression equation for the IFN concentration as a function of meteorological parameters, we have followed the approach discussed by Vautz et al (2003) and suggested by Brandon (1959). The method is based on (i) identification of regressions between the concentration of IFN and individual statistically significant meteorological variables and (ii) successive introduction of these individual regressions to the multiple regression equation.…”