Linking fish-based biological indicators with hydrological dynamics in a Mediterranean river: Relevance for environmental flow regimes

The relationship between flow dynamics and biological communities becomes especially relevant in Mediterranean rivers. Given their natural variability and growing anthropogenic pressures, their low sections are subjected to multiple impacts. The definition of ecohydrological relationships in Mediterranean rivers may constitute a useful management tool. Historically, fishes were the first group used to assess community-level ecological quality, and different indices and metrics have been proposed. However, up to date many of these indicators have showed to be insensitive to flow regime changes or hydrological alteration. There is therefore a need to deepen into the ecohydrological relationships between such indicators and flow regimes in Mediterranean (and other) rivers. This study presents an analysis of the relationship between interannual flow regimes in the lower section of the Ebro River, defined using a set of daily and hourly hydrological indices, and ecological quality based on fish community, assessed through indices designed to fulfill the Water Framework Directive (WFD) in Europe: the Indices of Biotic Integrity in Catalan rivers (IBICAT2010 and IBICAT2b) and the new European Fish Index (EFI+). In order to identify spatiotemporal patterns, hydrological indices were computed using time periods of different amplitude and ecological quality was obtained in different transects along the river section, even within the same water units or ‘water masses’ (subdivisions of surface waters to fulfill the WFD in Spain). Our results showed that IBICAT2010 was the most correlated with hydrological indices, followed by IBICAT2b and EFI+. The latter showed an almost null correlation with hydrological indices, which may be due to issues associated with the sampling technique, the definition of transects and because it does not uses stream typologies. Correlations among some hydrological and biological indices were observed, with temporal and spatial patterns. On one hand, daily hydrological indices showed relationship with ecological quality when they were computed using between 9 and 36 months of flow records (previous to the sampling date) whereas subdaily indices responded better to periods between 3 and 9 months of records. On the other hand, some sampling transects showed clearer relationships than others, even within the same water mass, which suggests an influence of hydromorphological variability on the obtained ecological quality scores.info:eu-repo/semantics/acceptedVersio

Basin-scale land use impacts on world deltas: Human vs natural forcings

A new global database of 86 deltas and river basins was analyzed to investigate the relative importance of deforestation and land use changes versus natural forcings in determining long-term total delta size. Results show that mean river flow and shelf slope were the most important variables, whereas population density and sediment load had a much lower importance. Deforestation and other variables related to land-use generally had a very small effect, but were more influential in a subset comprising Mediterranean and Black Sea deltas. As most deltas have developed over thousands of years, the much shorter-lived anthropogenic signals from deforestation and other landscape perturbations have had only secondary impact on the total area of deltas. Also, delta progradation is strongly influenced on sand deposition, whereas anthropogenic impacts on sediment load have more often impacted mostly the finer sediment being deposited offshore (prodelta deposits) or in the deltaic plain. These data disproves the hypothesis that delta size and growth is strongly influenced by human forcings, particularly for larger deltas, since Holocene delta building is mainly determined by natural forces. However, humans are influencing the geomorphology of deltas, particularly over the last century when the Anthropocene nature of deltas has become manifest. A more precise terminology is proposed to clarify concepts such as “human-made”, “human-engineered” or “human-influenced” deltas.info:eu-repo/semantics/acceptedVersio

A Single Nucleotide Polymorphism in the RASGRF2 Gene Is Associated with Alcoholic Liver Cirrhosis in Men

Background Genetic polymorphisms in the RAS gene family are associated with different diseases, which may include alcohol-related disorders. Previous studies showed an association of the allelic variant rs26907 in RASGRF2 gene with higher alcohol intake. Additionally, the rs61764370 polymorphism in the KRAS gene is located in a binding site for the let-7 micro-RNA family, which is potentially involved in alcohol-induced inflammation. Therefore, this study was designed to explore the association between these two polymorphisms and susceptibility to alcoholism or alcoholic liver disease (ALD). Methods We enrolled 301 male alcoholic patients and 156 healthy male volunteers in this study. Polymorphisms were genotyped by using TaqMan® PCR assays for allelic discrimination. Allelic and genotypic frequencies were compared between the two groups. Logistic regression analysis was performed to analyze the inheritance model. Results The A allele of the RASGRF2 polymorphism (rs26907) was significantly more prevalent among alcoholic patients with cirrhosis (23.2%) compared to alcoholic patients without ALD (14.2%). This difference remained significant in the group of patients with alcohol dependence (28.8% vs. 14.3%) but not in those with alcohol abuse (15.1% vs. 14.4%). Multivariable logistic regression analysis showed that the A allele of this polymorphism (AA or GA genotype) was associated with alcoholic cirrhosis both in the total group of alcoholics (odds ratio [OR]: 2.33, 95% confidence interval [CI]: 1.32–4.11; P = 0.002) and in the group of patients with alcohol dependence (OR: 3.1, 95% CI: 1.50–6.20; P = 0.001). Allelic distributions of the KRAS polymorphism (rs61764370) did not differ between the groups. Conclusions To our knowledge, this genetic association study represents the first to show an association of the RASGRF2 G>A (rs26907) polymorphism with ALD in men, particularly in the subgroup of patients with AD. The findings suggest the potential relevance of the RAS gene family in alcoholism and ALD

The role of rice fields and constructed wetlands as a source and a sink of pesticides and contaminants of emerging concern: Full-scale evaluation

Urban, industrial, and agricultural development in river basins has resulted in the pollution of estuarine and coastal ecosystems with a great amount of organic microcontaminants (OMCs) such as pesticides and contaminants of emerging concern (CECs). This study takes the Ebro Delta as a case study to assess the increase or reduction of 25 OMCs in rice fields and one 86 ha constructed wetland (CW). Bentazone and MCPA were the most abundant pesticides in the rice-field drainage water, with a peak concentration of 21,318 and 938 ng/L respectively, whereas the greatest CEC concentrations were found for caffeine, benzotriazoles, and bisphenol A (20–71 ng/L, on average) in the rice irrigation water. Pesticide concentration increased after the irrigation water passed through the rice fields (from 102 to 1973 ng/L, on average), but CECs present in the irrigation water decreased by 37% (from 14 to 10 ng/L, on average). A mass balance study showed that the CW was capable of reducing OMCs by 67%. Risk assessment analysis showed that the cumulative hazard quotient for Daphnia magna, green algae, and fish was greater than 1 during several sampling campaigns for the rice-field drainage water, but the CW was capable of reducing it by 60–63%, resulting in values below 1, which indicates that the risk was not significant. The results thus indicate that rice fields reduce CECs, but increase pesticides, whereas the use of CWs seems to be a feasible nature-based solution to reduce the discharge of OMCs into estuarine and coastal areas

Trophic interactions between native and introduced fish species in a littoral fish community

The trophic interactions between 15 native and two introduced fish species, silverside Odontesthes bonariensis and rainbow trout Oncorhynchus mykiss, collected in a major fishery area at Lake Titicaca were explored by integrating traditional ecological knowledge and stable-isotope analyses (SIA). SIA suggested the existence of six trophic groups in this fish community based on δ13C and δ15N signatures. This was supported by ecological evidence illustrating marked spatial segregation between groups, but a similar trophic level for most of the native groups. Based on Bayesian ellipse analyses, niche overlap appeared to occur between small O. bonariensis (<90 mm) and benthopelagic native species (31·6%), and between the native pelagic killifish Orestias ispi and large O. bonariensis (39%) or O. mykiss (19·7%). In addition, Bayesian mixing models suggested that O. ispi and epipelagic species are likely to be the main prey items for the two introduced fish species. This study reveals a trophic link between native and introduced fish species, and demonstrates the utility of combining both SIA and traditional ecological knowledge to understand trophic relationships between fish species with similar feeding habits

Biogas production from Sewage Sludge and Microalgae Co-digestion under mesophilic and thermophilic conditions

10.1016/j.renene.2014.10.019Isochrysis galbana and Selenastrum capricornutum, marine and freshwater microalgae species respectively,were co-digested with sewage sludge under mesophilic and thermophilic conditions. The substrates and the temperatures significantly influenced biogas production. Under mesophilic conditions, the sewage sludge digestion produced 451 ± 12 mLBiogas/gSV. Furthermore, all digesters were fed with I. galbana, or mixed with sludge, resulting in an average of 440 ± 25 mLBiogas/gSV. On the contrary, S. capricornutum produced 271 ± 6 mLBiogas/gSV and in the mixtures containing sludge produced intermediate values between sludge and microalgae production. Under thermophilic conditions, the sewage sludge digestion achieved yet the highest biogas yield, 566 ± 5 mLBiogas/gSV. During co-digestion, biogas production decreased when the microalgae content increased, and for I. galbana and for S. capricornutum it reached minimum values, 261 ± 11 and 185 ± 7 mLBiogas/gSV, respectively. However, no evidence of inhibition was found and the low yields were attributed to microalgae species characteristics. The methane content in biogas showed similar values, independently from the digested substrate, although this increased by approximately 5% under thermophilic condition

Life-history traits of the stone loach Barbatula barbatula

The life-history tactics of the stone loach Barbatula barbatula were studied in a Mediterranean-type climate stream (Matarranya River) located in the Ebro River basin (north-east Spain). Maximum observed ages were 2+ years in both sexes (1% of individuals), although only 0+ and 1+ year age groups were well represented. It is the lowest longevity reported for this species in its entire distribution. The seasonal growth period started in June and continued until November, but the pattern observed was different to northern populations. Barbatula barbatula in the Matarranya River was a multiple spawner, releasing small batches of oocytes between April and June. The fecundity of females was higher and the size of oocytes smaller in 1984 than in 1985. The relative fecundity (number of ripening and ripe oocytes g−1 of fish) was lower than in northern European populations. The role of the particular environmental conditions of a Mediterranean stream was discussed in relation to the life-history tactics of B. barbatula