Dissolved organic carbon and surface active substances in the northern Adriatic Sea: Long-term trends, variability and drivers

Ciglenečki, Irena; Vilibić, Ivica; Dautović, Jelena; Vojvodić, Vjeročka; Ćosović, Božena; Zemunik, Petra; Dunić, Natalija; Mihanović, Hrvoje

doi:10.1016/j.scitotenv.2020.139104

Cited by 27 publications

(20 citation statements)

References 101 publications

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“…The abundance and species within the Adriatic zooplankton communities have also been connected to the BiOS by Batistić et al (2014). More recently, Peharda et al (2018) found a consistent anticorrelation between the bivalve chronology in the northern Adriatic Sea and the BiOS regimes while Vilibić et al (2020) and Ciglenečki et al (2020) strongly correlated bottom salinity and the surface active substances fraction of the dissolved organic carbon in the northern Adriatic to the delayed BiOS index. However, no numerical study has ever quantified the impact of the BiOS regimes on the decadal variability of the Adriatic Sea as the available long-term ocean runs were not properly simulating the dense water formation, spreading and storage within the Adriatic basin (Dunić et al 2018).…”

Section: Introductionmentioning

confidence: 88%

“…This predominant lack of long-term variability can be probably explained by the influence of the Po River plume, which affects the full transect, even the eastern stations (Vilibić et al 2019). For example, dissolved salinity and organic carbon measured at the easternmost station have been strongly correlated to the longterm variability of the Po River discharge (Vilibić et al 2020;Ciglenečki et al 2020). The impact of the Po River plume is also seen on the spatial patterns of the salinity EOF 1 (66.2% of the signal) which highlight a difference in the strength of EOF signals between the upper layer up to 10 m depth and the rest of the profile (i.e.…”

Section: Evaluation Along the Long-term Monitoring Adriatic Transectsmentioning

confidence: 99%

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Modes of the BiOS-driven Adriatic Sea thermohaline variability

et al. 2022

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In this study the impact of the Adriatic-Ionian Bimodal Oscillating System (BiOS) on the interannual to decadal variability of the Adriatic Sea thermohaline circulation is quantified during the 1987-2017 period with the numerical results of the Adriatic Sea and Coast (AdriSC) historical kilometer-scale climate simulation. The time series associated with the first five Empirical Orthogonal Functions (EOFs) computed from the salinity, temperature and current speed monthly detrended anomalies at 1-km resolution are correlated to the BiOS signal. First, it is found that the AdriSC climate model is capable to reproduce the BiOS-driven phases derived from in-situ observations along a long-term monitoring transect in the middle Adriatic. Then, for the entire Adriatic basin, high correlations to the 2-year delayed BiOS signal are obtained for the salinity and current speed first two EOF time series at 100 m depth and the sea-bottom Finally, the physical interpretation of the EOF spatial patterns reveals that Adriatic bottom temperatures are more influenced by the dense water circulation than the BiOS. These findings confirmed and generalized the known dynamics derived previously from observations, and the AdriSC climate model can thus be used to better understand the past and future BiOS-driven physical processes in the Adriatic Sea.

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Section: Introductionmentioning

confidence: 88%

Section: Evaluation Along the Long-term Monitoring Adriatic Transectsmentioning

confidence: 99%

Modes of the BiOS-driven Adriatic Sea thermohaline variability

et al. 2022

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“…Indeed, during the stratification in eutrophic NA waters all dominant diatom species expressed APA and P turnover time mediated by APA was shorter than 5 h [33], indicating P limitation [81]. Consequently, the lowest DOP concentration was found, in spite of the enhanced production of dissolved organic matter in these low-salinity waters [52].…”

Section: Eutrophic Eventsmentioning

confidence: 91%

“…Since stable pycnoclines do not permit the upward flux of nutrients from deeper waters, nutrient availability in upper waters mainly depends on the recycling of organic matter. However, these waters are characterized with high levels of organic matter produced during freshwater inputs [52]. Persistent high concentrations of dissolved organic carbon (DOC) are constituted mainly of compounds, transformed by bacteria, microzooplankton, and viruses [53].…”

Section: Area Description and Main Case Studymentioning

confidence: 99%

Ecological Importance of Alkaline Phosphatase Activity in Changing Marine Environmental Conditions

Ivančić

Kraus

Najdek

et al. 2021

Water

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The effects of changing hydrological and climatic conditions on the dynamics of phosphorus (P) were studied in the Northern Adriatic Sea (NA), a coastal system currently affected by these changes. P limitation is one of the key stresses in the NA and it is a globally important phenomenon in aquatic ecosystems. Therefore, the response to P stress by inducing alkaline phosphatase activity (APA) was studied in characteristic water types in the NA, formed by the changing freshwater input in different thermic conditions. APA was important in providing P for microbial growth in upper waters dominated by assimilation during the warmer part of the year in stratified conditions. Contrarily, APA was not important during mixing in the colder part of the year, as well as in waters dominated by regeneration. In waters influenced by freshwater, temperature had no effect on APA, while in high-salinity waters, temperature was an important factor for APA increase. The highest APA occurred during riverine nutrients supply, indicating that the alteration of anthropogenic nutrient loads might strongly change P status in this coastal system. Furthermore, predicted increases in winter sea temperature and summer Po River discharge could delay the water column mixing, prolonging periods of P limitation.

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“…The final negative effect of the SAS influence is the inaccuracy of speciation parameters ( Louis et al, 2008 ). Given that SAS is a significant fraction of DOM in seawater ( Ciglenečki et al, 2020 ), the analysis of samples with high DOM content is particularly challenging. At potentials < −1.4 V, desorption of SAS from the electrode surface occurs ( Sahlin and Jagner, 1996 ).…”

Section: Introductionmentioning

confidence: 99%

Organic Copper Speciation by Anodic Stripping Voltammetry in Estuarine Waters With High Dissolved Organic Matter

et al. 2021

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The determination of copper (Cu) speciation and its bioavailability in natural waters is an important issue due to its specific role as an essential micronutrient but also a toxic element at elevated concentrations. Here, we report an improved anodic stripping voltammetry (ASV) method for organic Cu speciation, intended to eliminate the important problem of surface-active substances (SAS) interference on the voltammetric signal, hindering measurements in samples with high organic matter concentration. The method relies on the addition of nonionic surfactant Triton-X-100 (T-X-100) at a concentration of 1 mg L−1. T-X-100 competitively inhibits the adsorption of SAS on the Hg electrode, consequently 1) diminishing SAS influence during the deposition step and 2) strongly improving the shape of the stripping Cu peak by eliminating the high background current due to the adsorbed SAS, making the extraction of Cu peak intensities much more convenient. Performed tests revealed that the addition of T-X-100, in the concentration used here, does not have any influence on the determination of Cu complexation parameters and thus is considered "interference-free." The method was tested using fulvic acid as a model of natural organic matter and applied for the determination of Cu speciation in samples collected in the Arno River estuary (Italy) (in spring and summer), characterized by a high dissolved organic carbon (DOC) concentration (up to 5.2 mgC L−1) and anthropogenic Cu input during the tourist season (up to 48 nM of total dissolved Cu). In all the samples, two classes of ligands (denoted as L1 and L2) were determined in concentrations ranging from 3.5 ± 2.9 to 63 ± 4 nM eq Cu for L1 and 17 ± 4 to 104 ± 7 nM eq Cu for L2, with stability constants logKCu,1 = 9.6 ± 0.2–10.8 ± 0.6 and logKCu,2 = 8.2 ± 0.3–9.0 ± 0.3. Different linear relationships between DOC and total ligand concentrations between the two seasons suggest a higher abundance of organic ligands in the DOM pool in spring, which is linked to a higher input of terrestrial humic substances into the estuary. This implies that terrestrial humic substances represent a significant pool of Cu-binding ligands in the Arno River estuary.

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Dissolved organic carbon and surface active substances in the northern Adriatic Sea: Long-term trends, variability and drivers

Cited by 27 publications

References 101 publications

Modes of the BiOS-driven Adriatic Sea thermohaline variability

Modes of the BiOS-driven Adriatic Sea thermohaline variability

Ecological Importance of Alkaline Phosphatase Activity in Changing Marine Environmental Conditions

Organic Copper Speciation by Anodic Stripping Voltammetry in Estuarine Waters With High Dissolved Organic Matter

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