Spatial, temporal, and vertical variability of nutrients in the Southeastern Black Sea

Alkan, Ali; Serdar, Serkan; Fidan, Dilek; Akbaş, Ufuk; Zengin, Bayram; Kiliç, M. Baran

doi:10.1016/j.chemosphere.2022.134809

Cited by 9 publications

(4 citation statements)

References 43 publications

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“…In 2010, the DIP levels were significantly higher in the inner bay than in the upper bay because of the transport of large amounts of phosphate from various factories and sewage discharge points (Zhang et al, 2021). In addition, DIN levels in ZJB are mainly caused by the discharge of urban agricultural fertilizers and industrial and domestic wastewater (Li et al, 2020;He et al, 2023;Zhang et al, 2023a), which is consistent with other offshore waters such as the Black Sea (Alkan et al, 2022), the Chinese coast (Wang et al, 2020) and the Elbe estuary in Germany (Dähnke et al, 2008). Freshwater runoff is the primary source of terrestrial DIN in the upper bay, with N fertilizer and soil N contributing approximately 70%, and sewage and feces contributing the remaining 30% (Li et al, 2020).…”

Section: Terrigenous Input Contributes To Eutrophicationsupporting

confidence: 66%

Unveiling the eutrophication crisis: 20 years of nutrient development in Zhanjiang Bay, China

Liang,

Zhang,

Zhang

et al. 2024

Front. Mar. Sci.

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Coastal eutrophication is a major issue of marine pollution. The main factors controlling eutrophication must be identified to ensure effective marine environmental management according to the respective local conditions. Zhanjiang Bay (ZJB), located northwest of the South China Sea, is a semi-closed bay influenced by complex water flows and the development of surrounding cities. In this study, we investigated the development of nutrient concentrations and compositions in ZJB seawater over the past 20 years and the factors influencing eutrophication based on several field investigations from 2006 to 2022 and historical data. High concentrations of dissolved inorganic phosphorus (DIP) and dissolved inorganic nitrogen (DIN) were the main contributors to the severe long-term eutrophication in ZJB; however, light eutrophication was observed in the outer bay, primarily caused by chemical oxygen demand (COD) and DIP. The primary sources of COD and nutrients were riverine freshwater, sewage outfalls, mariculture and domestic effluents carried by rivers. Tidal effects diluted the nutrient concentrations in the bay with seawater from the outer bay, thereby playing a key role in nutrient redistribution. The DIN: DIP ratio of ZJB showed long-term nitrogen restriction and excess phosphorus, primarily owing to mariculture activities. Marine undertakings can exert various impacts on water quality. Eliminating illegal aquaculture and launching aquaculture tailwater treatment can improve water quality, whereas practices such as channel dredging may worsen it. This study demonstrates the intricate dynamics of the ZJB ecosystem and offers valuable insights for effective environmental management and conservation efforts.

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Section: Terrigenous Input Contributes To Eutrophicationsupporting

confidence: 66%

Unveiling the eutrophication crisis: 20 years of nutrient development in Zhanjiang Bay, China

Liang,

Zhang,

Zhang

et al. 2024

Front. Mar. Sci.

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“…(2020) imply that selective environmental forces act more strongly on the otolith width than on the anterior notch and show the weakest correlations with neutral genetic differentiation. The Aegean Sea differs significantly from the Black Sea as well as the Sea of Marmara in hydrology and geomorphology (Alkan et al ., 2022; Altuğ et al ., 2011; Siokou‐Frangou et al ., 2004), which is also reflected in otolith and body shape differences between the Aegean stock and the other stocks (Figure 9).…”

Section: Discussionmentioning

confidence: 99%

Using otolith and body shape to discriminate between stocks of European anchovy (Engraulidae: Engraulis encrasicolus) from the Aegean, Marmara and Black Seas

Khan

Bal

Battal

et al. 2022

Journal of Fish Biology

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European anchovy, a small pelagic fish, plays a significant role in the blue economy, with remarkable commercial, ecological and culinary values. In this study, the variability in the shapes of the body and sagitta otoliths was examined to identify the different anchovy stocks in the Black Sea (26.5 E-39.9 E, 38.7 N-42.1 N) and adjacent regions, i.e., the Sea of Marmara and the Aegean Sea. The body shape was assessed with geometric morphometrics, while shape indices and elliptic Fourier analysis were used to evaluate the shape of the sagitta otoliths. The data were analysed using multivariate and univariate analysis of variance, discriminant function and principal component analysis. The anchovy population could be divided into five distinct stocks based on body shape, with an overall leave-one-out cross-validated correct classification of 85.6%. The geometric morphometrics revealed significant differences in body depth, snout, lower jaw and caudal fin. The differences in sagitta otolith shape also revealed the existence of four distinct stocks with an overall leave-one-out crossvalidated correct classification of 46.5%-69.3%. The elliptic Fourier analysis revealed two main stocks of anchovy from the Black Sea as the Eastern-Middle Black Sea stock and the Western Black Sea stock. Based on the elliptic Fourier analysis, the differences in the sagitta otoliths increase in magnitude with increasing geographic separation, first manifested at the otolith anterior notch, followed by changes in the otolith width. The findings affirmed the existence of distinct stocks that should have important implications for effective management of this pelagic fish in the Black Sea and adjacent regions.

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“…This index has been applied in many coastal marine areas in different regions of the world. There are many regions where this model has been applied, for example: the Adriatic Sea [22], the Black Sea [53], the Eastern Mediterranean Sea [54] and the Caspian Sea [55]. Dissolved inorganic nitrogen (DIN) and PO4/P are the primary forms of N and P that are readily bioavailable for phytoplankton growth.…”

Section: Eutrophication Statementioning

confidence: 99%

Application of eutrophication indices for assessment of the ecological quality of the Moroccan eastern Mediterranean coast: Ras Kabdana-Saïdia

et al. 2023

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Eutrophication of littoral seawater is estimated to be one of the main threats to marine biota. Therefore, continuous monitoring is necessary to define areas of potential risk. Our work is an essay to explore the possibility of applying the trophic state index (TRIX) to assess the state of eutrophication along the eastern coast of the Moroccan Mediterranean (Ras Kabdana-Saïdia) in concert with a number of hydro chemical parameters and nutrients descriptors aimed at selection of relevant indicators of marine coastal area ecological quality. Seawater samples were studied monthly during 2018. The following environmental parameters have been considered: temperature, salinity, pH, suspended matter, turbidity, dissolved oxygen, saturation levels, nitrite, nitrate, and orthophosphate. Principal Component Analysis was applied in order to figure out and score the most relevant combination of parameters to discriminate between sites and select representative descriptors (pressure/state) of eutrophication. The following variables are defined as relevant descriptors for classification of the sites: nutrients (N, P) and their molar ratios (N/P), the capacity of the system to produce and sustain organic matter (chlorophyll a), and the trophic state index (TRIX). The results show TRIX values below 4, the eutrophication range indicated that there is no ecological risk. The Ras Kabdana-Saïdia is located in an oligotrophic state.

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Spatial, temporal, and vertical variability of nutrients in the Southeastern Black Sea

Cited by 9 publications

References 43 publications

Unveiling the eutrophication crisis: 20 years of nutrient development in Zhanjiang Bay, China

Unveiling the eutrophication crisis: 20 years of nutrient development in Zhanjiang Bay, China

Using otolith and body shape to discriminate between stocks of European anchovy (Engraulidae: Engraulis encrasicolus) from the Aegean, Marmara and Black Seas

Application of eutrophication indices for assessment of the ecological quality of the Moroccan eastern Mediterranean coast: Ras Kabdana-Saïdia

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