Distinct patterns of sedimentary phosphorus fractionation and mobilization in the seafloor of the Black Sea, Marmara Sea and Mediterranean Sea.

Phosphorus (P) is a key element to all life that is used for structural and functional component of all organisms. The cycling of sedimentary P may differ depending on the redox-conditions of the overlying waters affecting the dynamics, and distribution of P-fractions and the elements that are highly coupled to P cycle. Though biogeochemistry of water column in the three interconnected marine basins of Black, Marmara and Mediterranean Seas have been studied extensively, few studies were carried out to understand sedimentary P dynamics in these regions. In this study, therefore, the biogeochemical cycling of sedimentary P and related variables such as porewater nutrients, sedimentary organic carbon, nitrogen and reactive iron were studied in selected sites at the three interconnected marine basins: Black Sea, Marmara and Northeastern (NE) Mediterranean Sea. The pool of "potentially mobile P" was also determined for the studied sites. The study results showed that porewater and sediment biogeochemistry displayed great variability in the studied sites with the maximum concentrations of porewater phosphate, ammonium, reactive silicate, surface sediment organic carbon, nitrogen, phosphorus and total phosphorus (TP) measured in the hypoxic Marmara Sea and suboxic/anoxic Black Sea. The decline in the TP concentrations of all sediment core samples indicated P-mobilization to the overlying water. The pool of "potentially mobile P" varied between 0.023 and 0.148 mol/m2 in the studied sites with the maximum values recorded in suboxic and anoxic/sulfidic parts of the Black Sea. This study predicts that the deoxygenation and eutrophication would further lead to the preferential release of P in these three interconnected marine basins, hence changing the remineralization, N/P molar ratios and eventually transform the deep-water nutrient stocks with implications for internal N/P control on marine ecosystems.

Increased deep vein thrombosis cases during the COVID-19 quarantine.

OBJECTIVE: The aim of this study was to compare the number of deep vein thrombosis (DVT) cases during the quarantine period for COVID-19 to that of the last year. METHODS: This study was conducted as a single-center and retrospective study. All hospital admissions during April 2020 and May 2020 were screened from the hospital records, and DVT cases were recorded. Likewise, all hospital admissions during April 2019 and May 2019 were screened, and DVT cases were noted. DVT cases of both years were compared. RESULTS: Among 480931 patients admitted to our hospital in April 2019 and May 2019, DVT was detected in 82 patients (0.017%) (47 males, 35 females) with a mean age of 56.99 ± 9.1 years (ranges 39 to 79 years). Besides, among 145101 patients admitted to our hospital in April 2020 and May 2020, DVT was detected in 123 patients (0.084%) (51 males, 72 females) with a mean age of 58.64 ± 8.9 years (ranges 40 to 83 years). Despite the decrease in the total number of patients admitted to the hospital, there was a significant increase in the number of DVT patients. Interestingly, there were only two symptomatic pulmonary-embolism cases in the 2019 period, whereas there were seven symptomatic pulmonary embolisms secondary to DVT in the 2020 period. Unfortunately, one patient died due to pulmonary embolism secondary to DVT in 2020. The previous history of DVT was remarkable in patients admitted during the COVID-19 confinement. CONCLUSION: In conclusion, COVID-19 confinement seems to be associated with increased rates of DVT. Strict preventive measures such as exercise training or prophylactic drug use should be considered to prevent immobility-related DVT during the COVID-19 quarantine.

Assessment of trophic status of the northeastern Mediterranean coastal waters: eutrophication classification tools revisited.

The Eastern Mediterranean and its Cilician Basin offshore waters have oligotrophic features with low nutrient concentrations, low primary production, and high water transparency. However, the wide shelf area of the Cilician Basin is subject to contaminated river inflows with enhanced nutrient loads and direct discharges of urban wastewaters of southern Turkey, leading to develop local eutrophic/mesotrophic conditions in the inner sites of Mersin and Iskenderun Bays on the Cilician Basin. For the assessment of changing trophic status of the coastal and the bay water bodies under anthropogenic pressures since the 1980s, five extensive field studies were performed in summer and winter periods of 2014, 2015, and 2016. Physical and eutrophication-related biochemical parameters (salinity, temperature, Secchi Disk Depth, nutrients, dissolved oxygen, chlorophyll-a) were measured at 65 stations in different water bodies occupying the Northeastern (NE) Mediterranean coastal, offshore areas and bays. The collected data sets were used in scaling the trophic status of the visited water bodies of NE Mediterranean coastal, offshore areas and semi-enclosed bays, using novel classification tools of Trophic Index (TRIX), Eutrophication Index (E.I.), chl-a, and HELCOM Eutrophication Assessment Tool (HEAT), developed by different experts for highly productive seas. These tools, which can successfully classify highly productive coastal water masses under human pressures, and their sensitivities have been tested for scaling of the current trophic status of the NE Mediterranean coastal water bodies being subject to human pressures. The scaling results of classical TRIX, E.I., and chl-a indices in the NE Mediterranean water masses are not sensitive enough to differentiate mesotrophic and eutrophic water bodies because these indices principally assume to have higher concentrations of eutrophication-related parameters in the least effected (reference) water bodies. The HEAT tool, which uses a site-specific "reference value" for each eutrophication-indicator, has allowed us to produce more reliable and sensitive scaling of the current trophic status of the NE Mediterranean shelf areas, even though we used only the "reference values" derived from the composite data sets. The results of the indices were compared with the HEAT tool and the actual status was assessed from observations, indicating revision requirements of the multi-metric classification tools. For this goal, scales of natural (oligotrophic) and anthropogenic (eutrophic) levels of eutrophication indicators should be determined at a sub-basin scale using long-term site-specific observations in the NE Mediterranean. The revised scale ranges of TRIX for oligotrophic, mesotrophic, and eutrophic water bodies of Mersin Bay are in line with ranges of TRIX classification tool proposed for Aegean Sea waters, which can be used to assess trophic status of the entire Eastern Mediterranean and Aegean coastal seas (surface salinity > 37.5) having oligotrophic properties in the offshore waters.