Aegean Sea albacore (T. alalunga), fresh or processed, is marketed locally in Greece or exported, mainly to Japan, Italy, Spain, and France. To provide information for consumers and biomonitoring programs and assess the potential human health risks, concentrations of mercury (Hg), cadmium (Cd) and lead (Pb) were determined in albacore edible muscle samples from two fishing grounds of the Aegean Sea, Greece via graphite furnace atomic absorption spectrometry (GF-AAS). Of the 82 individuals, 28 contained Cd and three contained Pb above the permissible limits set by the European Union (0.1 mg kg⁻¹ wet wt and 0.3 mg kg⁻¹ wet wt, respectively). None of the samples contained mercury above the limit (1.0 mg kg⁻¹ wet wt). Potential health risks to human via dietary intake of albacore were estimated by the total target hazard quotients (TTHQs), which indicated that the consumers could acquire health problems due to consumption of Aegean Sea albacore. Thus consequently, concentrations of toxic heavy metals in albacore, especially mercury, must be monitored regularly and comprehensively with respect to consumer health.

Pollution with copper (Cu), lead (Pb), zinc (Zn), chromium (Cr), and nickel (Ni) heavy metals of the surface sediments collected from three semi-closed East Mediterranean Gulfs, namely Kavala, Strymonikos, and Ierissos Gulfs, North Aegean Sea, Greece, was investigated to evaluate potential benthic ecological risks. The mean concentrations of the studied metals decrease according to the order: Zn > Pb > Cr > Ni > Cu (176.50, 166.23, 127.41, 43.12, and 33.64 mg kg⁻¹ dry weight). Quality indicators and possible ecological risks for metals in surface sediments were evaluated at 60 sampling sites of these three gulfs using the contamination factor (CF), the contamination degree (CD), the pollution load index (PLI), the geoaccumulation index (I_geo), the potential risk factor (PRF_i), and the potential ecological risk index (PERI). Based on I_geo, the Ierissos Gulf sampling sites IER 2, 3, 7, and 9 exhibit moderate Pb pollution, whereas the sampling sites IER 6 and 8 show moderate to strong and strong Pb pollution, respectively. Based on the PRFi and PERI, the studied heavy metals did not pose any significant environmental risks for most of the investigated sites except IER 6 and 8 sampling sites, which may pose considerable environmental risk for Pb. To evaluate potential sources for each metal, multivariate techniques including hierarchical cluster analysis and ANOVA were used.

Despite significant progress, certain inflammation related to chronic disorders, including cardiovascular diseases (CVD) and cancer, still present high mortality rates. Thus, further study is needed to address such pathologies more appropriately. Apart from classic therapeutics, natural bioactives with less toxic side effects have gained attention, including those with potential pharmaceutical properties derived from several plants. Within this article, the potential utilization of freshwater aquatic plants as sources of bioactives with antithrombotic, anti-inflammatory and antioxidant properties is outlined. Emphasis is given to a well-established aquatic plant with known but not fully clarified and overviewed bio-functional and pharmaceutical properties, the Chinese lotus (Nelumbo nucifera), as well as to a so far neglected aquatic plant, Lemna minor, which has not yet been thoroughly reviewed for such applications. The latent usually grows naturally in large numbers at the surface of stored water basins of retrieved water from the last stages of wastewater treatment facilities. The continuous growth of this aquatic plant in such conditions further suggests that it can be a sustainable source of natural bioactives, if appropriately valorized, with an economic benefit and in a friendly environmental approach. The abundant content of both freshwater aquatic plants in bioactive components with potent antioxidant, anti-inflammatory and antithrombotic activities is thoroughly outlined, while their applications as functional ingredients in several functional products (functional foods, cosmetics and pharmaceuticals) are also discussed. The outlined outcomes urge further study of both aquatic plants and especially of Lemna spp. to fully elucidate their potential as alternative sustainable sources of bioactive ingredients for functional foods, supplements, nutraceuticals, nutricosmetics, cosmeceuticals, cosmetics and pharmaceutical products with health-promoting properties against inflammation and thrombosis related manifestations and their associated chronic disorders.

In this paper, a series of field surveys were carried out along the Nestos River watershed (NE Greece) to assess the influence of two hydropower dams (Thissavros and Platanovrisi) upon the hydrology, hydrochemistry and nutrients stoichiometry of the river. Results showed that Nestos hydrology, downstream of the reservoirs, is entirely governed by the man-induced hydropower-driven dam retention/release policy. Dams’ operation increased the retention of dissolved inorganic nitrogen (DIN) and total suspended solids (TSS) significantly, affecting their downstream fluxes, even under water release regime. On the contrary, dams’ construction and operation did not seem to influence the downstream fluxes of dissolved inorganic phosphorus (DIP) and silica (DSi), although these elements also depended on the releasing policy. DIN retention, combined with the dependence of DIP to the water level of Thissavros, resulted in alteration of the N:P ratio at the downstream part. Almost all nutrients were stored at the bottom layer of Thissavros reservoir, especially under the summer stratification regime. Platanovrisi reservoir acts as a buffer zone between Thissavros and the Nestos downstream part. Anoxic conditions in the reservoirs favour the transformation of nitrates into ammonia and the remineralization of phosphorus from sediments, creating a degraded environment for freshwater fauna.

Mean temperature (MTC) and mean trophic level (MTL) spatiotemporal patterns of MEDITS survey catches were examined in 13 geographic statistical areas (GSAs) of the Mediterranean between 1994 and 2016. The study aimed to detect changes in the demersal community structure related to anthropogenic impacts. A generalized additive modelling approach was used to examine the effects of year and GSA on the MTC and MTL indexes and on bottom temperature by haul. For the MTC index, the year was significant only in 4 GSAs, while for MTL it was significant in 5. Higher MTC values were observed in central and eastern areas. Bottom temperature increased after 2010, and also from west to east and from north to south. Our results indicate that the recently observed increase in bottom sea temperature has not resulted in an immediate response by demersal marine communities, but areas with higher warming rates or shallow depths were found to be more susceptible to sea warming. For MTL, decreasing trends were observed in only 2 GSAs, while the temporal trends observed in 5 GSAs may have reflected changes in fishing activity patterns. However, higher MTL values were observed in GSAs with generally higher exploitation rates, indicating that factors other than fishing play an important structuring role in marine communities. The present results indicate differences among Mediterranean subareas in regard to changes in the community structure attributed to environmental conditions and exploitation patterns and have implications for the ecology and dynamics of the stocks.

Coastal aquaculture systems are complex environments with multiple microbial interactions that affect fish health and productivity. High-throughput amplicon sequencing is a valuable tool for identifying such bacterial communities and investigating the relationship between bacterial diversity and sustainability in these systems. In the present study, the seasonal dynamics of marine bacterial communities were assessed, in terms of diversity and composition, in three marine aquaculture farms in the northern Ionian Sea (western Greece) and a distant control site unaffected by aquaculture activities, using 16S rRNA amplicon metabarcoding. Results revealed that Proteobacteria, Bacteroidota, Cyanobacteria, and Verrucomicrobiota were the dominant phyla in the bacterial communities. Alpha diversity was significantly lower in the aquaculture farms compared to the control site. Season was the major factor driving bacterial community fluctuations. Comparative analysis between seasons revealed the presence of differentially abundant amplicon sequence variants (ASVs) in all pairwise comparisons, with the majority of them belonging to the phyla Bacteroidota (families Flavobacteriaceae, Cryomorphaceae) and Proteobacteria (family Rhodobacteraceae). Our study provides the first detailed description of bacterial communities present in Greek coastal aquaculture farms using amplicon metabarcoding analysis and expands our understanding of the impact of seasonality and environmental variables on marine bacterial community diversity and composition.